1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright 2016 Broadcom
4  */
5 
6 /*
7  * Broadcom PDC Mailbox Driver
8  * The PDC provides a ring based programming interface to one or more hardware
9  * offload engines. For example, the PDC driver works with both SPU-M and SPU2
10  * cryptographic offload hardware. In some chips the PDC is referred to as MDE,
11  * and in others the FA2/FA+ hardware is used with this PDC driver.
12  *
13  * The PDC driver registers with the Linux mailbox framework as a mailbox
14  * controller, once for each PDC instance. Ring 0 for each PDC is registered as
15  * a mailbox channel. The PDC driver uses interrupts to determine when data
16  * transfers to and from an offload engine are complete. The PDC driver uses
17  * threaded IRQs so that response messages are handled outside of interrupt
18  * context.
19  *
20  * The PDC driver allows multiple messages to be pending in the descriptor
21  * rings. The tx_msg_start descriptor index indicates where the last message
22  * starts. The txin_numd value at this index indicates how many descriptor
23  * indexes make up the message. Similar state is kept on the receive side. When
24  * an rx interrupt indicates a response is ready, the PDC driver processes numd
25  * descriptors from the tx and rx ring, thus processing one response at a time.
26  */
27 
28 #include <linux/errno.h>
29 #include <linux/module.h>
30 #include <linux/init.h>
31 #include <linux/slab.h>
32 #include <linux/debugfs.h>
33 #include <linux/interrupt.h>
34 #include <linux/wait.h>
35 #include <linux/platform_device.h>
36 #include <linux/io.h>
37 #include <linux/of.h>
38 #include <linux/of_device.h>
39 #include <linux/of_address.h>
40 #include <linux/of_irq.h>
41 #include <linux/mailbox_controller.h>
42 #include <linux/mailbox/brcm-message.h>
43 #include <linux/scatterlist.h>
44 #include <linux/dma-direction.h>
45 #include <linux/dma-mapping.h>
46 #include <linux/dmapool.h>
47 
48 #define PDC_SUCCESS  0
49 
50 #define RING_ENTRY_SIZE   sizeof(struct dma64dd)
51 
52 /* # entries in PDC dma ring */
53 #define PDC_RING_ENTRIES  512
54 /*
55  * Minimum number of ring descriptor entries that must be free to tell mailbox
56  * framework that it can submit another request
57  */
58 #define PDC_RING_SPACE_MIN  15
59 
60 #define PDC_RING_SIZE    (PDC_RING_ENTRIES * RING_ENTRY_SIZE)
61 /* Rings are 8k aligned */
62 #define RING_ALIGN_ORDER  13
63 #define RING_ALIGN        BIT(RING_ALIGN_ORDER)
64 
65 #define RX_BUF_ALIGN_ORDER  5
66 #define RX_BUF_ALIGN	    BIT(RX_BUF_ALIGN_ORDER)
67 
68 /* descriptor bumping macros */
69 #define XXD(x, max_mask)              ((x) & (max_mask))
70 #define TXD(x, max_mask)              XXD((x), (max_mask))
71 #define RXD(x, max_mask)              XXD((x), (max_mask))
72 #define NEXTTXD(i, max_mask)          TXD((i) + 1, (max_mask))
73 #define PREVTXD(i, max_mask)          TXD((i) - 1, (max_mask))
74 #define NEXTRXD(i, max_mask)          RXD((i) + 1, (max_mask))
75 #define PREVRXD(i, max_mask)          RXD((i) - 1, (max_mask))
76 #define NTXDACTIVE(h, t, max_mask)    TXD((t) - (h), (max_mask))
77 #define NRXDACTIVE(h, t, max_mask)    RXD((t) - (h), (max_mask))
78 
79 /* Length of BCM header at start of SPU msg, in bytes */
80 #define BCM_HDR_LEN  8
81 
82 /*
83  * PDC driver reserves ringset 0 on each SPU for its own use. The driver does
84  * not currently support use of multiple ringsets on a single PDC engine.
85  */
86 #define PDC_RINGSET  0
87 
88 /*
89  * Interrupt mask and status definitions. Enable interrupts for tx and rx on
90  * ring 0
91  */
92 #define PDC_RCVINT_0         (16 + PDC_RINGSET)
93 #define PDC_RCVINTEN_0       BIT(PDC_RCVINT_0)
94 #define PDC_INTMASK	     (PDC_RCVINTEN_0)
95 #define PDC_LAZY_FRAMECOUNT  1
96 #define PDC_LAZY_TIMEOUT     10000
97 #define PDC_LAZY_INT  (PDC_LAZY_TIMEOUT | (PDC_LAZY_FRAMECOUNT << 24))
98 #define PDC_INTMASK_OFFSET   0x24
99 #define PDC_INTSTATUS_OFFSET 0x20
100 #define PDC_RCVLAZY0_OFFSET  (0x30 + 4 * PDC_RINGSET)
101 #define FA_RCVLAZY0_OFFSET   0x100
102 
103 /*
104  * For SPU2, configure MDE_CKSUM_CONTROL to write 17 bytes of metadata
105  * before frame
106  */
107 #define PDC_SPU2_RESP_HDR_LEN  17
108 #define PDC_CKSUM_CTRL         BIT(27)
109 #define PDC_CKSUM_CTRL_OFFSET  0x400
110 
111 #define PDC_SPUM_RESP_HDR_LEN  32
112 
113 /*
114  * Sets the following bits for write to transmit control reg:
115  * 11    - PtyChkDisable - parity check is disabled
116  * 20:18 - BurstLen = 3 -> 2^7 = 128 byte data reads from memory
117  */
118 #define PDC_TX_CTL		0x000C0800
119 
120 /* Bit in tx control reg to enable tx channel */
121 #define PDC_TX_ENABLE		0x1
122 
123 /*
124  * Sets the following bits for write to receive control reg:
125  * 7:1   - RcvOffset - size in bytes of status region at start of rx frame buf
126  * 9     - SepRxHdrDescEn - place start of new frames only in descriptors
127  *                          that have StartOfFrame set
128  * 10    - OflowContinue - on rx FIFO overflow, clear rx fifo, discard all
129  *                         remaining bytes in current frame, report error
130  *                         in rx frame status for current frame
131  * 11    - PtyChkDisable - parity check is disabled
132  * 20:18 - BurstLen = 3 -> 2^7 = 128 byte data reads from memory
133  */
134 #define PDC_RX_CTL		0x000C0E00
135 
136 /* Bit in rx control reg to enable rx channel */
137 #define PDC_RX_ENABLE		0x1
138 
139 #define CRYPTO_D64_RS0_CD_MASK   ((PDC_RING_ENTRIES * RING_ENTRY_SIZE) - 1)
140 
141 /* descriptor flags */
142 #define D64_CTRL1_EOT   BIT(28)	/* end of descriptor table */
143 #define D64_CTRL1_IOC   BIT(29)	/* interrupt on complete */
144 #define D64_CTRL1_EOF   BIT(30)	/* end of frame */
145 #define D64_CTRL1_SOF   BIT(31)	/* start of frame */
146 
147 #define RX_STATUS_OVERFLOW       0x00800000
148 #define RX_STATUS_LEN            0x0000FFFF
149 
150 #define PDC_TXREGS_OFFSET  0x200
151 #define PDC_RXREGS_OFFSET  0x220
152 
153 /* Maximum size buffer the DMA engine can handle */
154 #define PDC_DMA_BUF_MAX 16384
155 
156 enum pdc_hw {
157 	FA_HW,		/* FA2/FA+ hardware (i.e. Northstar Plus) */
158 	PDC_HW		/* PDC/MDE hardware (i.e. Northstar 2, Pegasus) */
159 };
160 
161 struct pdc_dma_map {
162 	void *ctx;          /* opaque context associated with frame */
163 };
164 
165 /* dma descriptor */
166 struct dma64dd {
167 	u32 ctrl1;      /* misc control bits */
168 	u32 ctrl2;      /* buffer count and address extension */
169 	u32 addrlow;    /* memory address of the date buffer, bits 31:0 */
170 	u32 addrhigh;   /* memory address of the date buffer, bits 63:32 */
171 };
172 
173 /* dma registers per channel(xmt or rcv) */
174 struct dma64_regs {
175 	u32  control;   /* enable, et al */
176 	u32  ptr;       /* last descriptor posted to chip */
177 	u32  addrlow;   /* descriptor ring base address low 32-bits */
178 	u32  addrhigh;  /* descriptor ring base address bits 63:32 */
179 	u32  status0;   /* last rx descriptor written by hw */
180 	u32  status1;   /* driver does not use */
181 };
182 
183 /* cpp contortions to concatenate w/arg prescan */
184 #ifndef PAD
185 #define _PADLINE(line)  pad ## line
186 #define _XSTR(line)     _PADLINE(line)
187 #define PAD             _XSTR(__LINE__)
188 #endif  /* PAD */
189 
190 /* dma registers. matches hw layout. */
191 struct dma64 {
192 	struct dma64_regs dmaxmt;  /* dma tx */
193 	u32          PAD[2];
194 	struct dma64_regs dmarcv;  /* dma rx */
195 	u32          PAD[2];
196 };
197 
198 /* PDC registers */
199 struct pdc_regs {
200 	u32  devcontrol;             /* 0x000 */
201 	u32  devstatus;              /* 0x004 */
202 	u32  PAD;
203 	u32  biststatus;             /* 0x00c */
204 	u32  PAD[4];
205 	u32  intstatus;              /* 0x020 */
206 	u32  intmask;                /* 0x024 */
207 	u32  gptimer;                /* 0x028 */
208 
209 	u32  PAD;
210 	u32  intrcvlazy_0;           /* 0x030 (Only in PDC, not FA2) */
211 	u32  intrcvlazy_1;           /* 0x034 (Only in PDC, not FA2) */
212 	u32  intrcvlazy_2;           /* 0x038 (Only in PDC, not FA2) */
213 	u32  intrcvlazy_3;           /* 0x03c (Only in PDC, not FA2) */
214 
215 	u32  PAD[48];
216 	u32  fa_intrecvlazy;         /* 0x100 (Only in FA2, not PDC) */
217 	u32  flowctlthresh;          /* 0x104 */
218 	u32  wrrthresh;              /* 0x108 */
219 	u32  gmac_idle_cnt_thresh;   /* 0x10c */
220 
221 	u32  PAD[4];
222 	u32  ifioaccessaddr;         /* 0x120 */
223 	u32  ifioaccessbyte;         /* 0x124 */
224 	u32  ifioaccessdata;         /* 0x128 */
225 
226 	u32  PAD[21];
227 	u32  phyaccess;              /* 0x180 */
228 	u32  PAD;
229 	u32  phycontrol;             /* 0x188 */
230 	u32  txqctl;                 /* 0x18c */
231 	u32  rxqctl;                 /* 0x190 */
232 	u32  gpioselect;             /* 0x194 */
233 	u32  gpio_output_en;         /* 0x198 */
234 	u32  PAD;                    /* 0x19c */
235 	u32  txq_rxq_mem_ctl;        /* 0x1a0 */
236 	u32  memory_ecc_status;      /* 0x1a4 */
237 	u32  serdes_ctl;             /* 0x1a8 */
238 	u32  serdes_status0;         /* 0x1ac */
239 	u32  serdes_status1;         /* 0x1b0 */
240 	u32  PAD[11];                /* 0x1b4-1dc */
241 	u32  clk_ctl_st;             /* 0x1e0 */
242 	u32  hw_war;                 /* 0x1e4 (Only in PDC, not FA2) */
243 	u32  pwrctl;                 /* 0x1e8 */
244 	u32  PAD[5];
245 
246 #define PDC_NUM_DMA_RINGS   4
247 	struct dma64 dmaregs[PDC_NUM_DMA_RINGS];  /* 0x0200 - 0x2fc */
248 
249 	/* more registers follow, but we don't use them */
250 };
251 
252 /* structure for allocating/freeing DMA rings */
253 struct pdc_ring_alloc {
254 	dma_addr_t  dmabase; /* DMA address of start of ring */
255 	void	   *vbase;   /* base kernel virtual address of ring */
256 	u32	    size;    /* ring allocation size in bytes */
257 };
258 
259 /*
260  * context associated with a receive descriptor.
261  * @rxp_ctx: opaque context associated with frame that starts at each
262  *           rx ring index.
263  * @dst_sg:  Scatterlist used to form reply frames beginning at a given ring
264  *           index. Retained in order to unmap each sg after reply is processed.
265  * @rxin_numd: Number of rx descriptors associated with the message that starts
266  *             at a descriptor index. Not set for every index. For example,
267  *             if descriptor index i points to a scatterlist with 4 entries,
268  *             then the next three descriptor indexes don't have a value set.
269  * @resp_hdr: Virtual address of buffer used to catch DMA rx status
270  * @resp_hdr_daddr: physical address of DMA rx status buffer
271  */
272 struct pdc_rx_ctx {
273 	void *rxp_ctx;
274 	struct scatterlist *dst_sg;
275 	u32  rxin_numd;
276 	void *resp_hdr;
277 	dma_addr_t resp_hdr_daddr;
278 };
279 
280 /* PDC state structure */
281 struct pdc_state {
282 	/* Index of the PDC whose state is in this structure instance */
283 	u8 pdc_idx;
284 
285 	/* Platform device for this PDC instance */
286 	struct platform_device *pdev;
287 
288 	/*
289 	 * Each PDC instance has a mailbox controller. PDC receives request
290 	 * messages through mailboxes, and sends response messages through the
291 	 * mailbox framework.
292 	 */
293 	struct mbox_controller mbc;
294 
295 	unsigned int pdc_irq;
296 
297 	/* tasklet for deferred processing after DMA rx interrupt */
298 	struct tasklet_struct rx_tasklet;
299 
300 	/* Number of bytes of receive status prior to each rx frame */
301 	u32 rx_status_len;
302 	/* Whether a BCM header is prepended to each frame */
303 	bool use_bcm_hdr;
304 	/* Sum of length of BCM header and rx status header */
305 	u32 pdc_resp_hdr_len;
306 
307 	/* The base virtual address of DMA hw registers */
308 	void __iomem *pdc_reg_vbase;
309 
310 	/* Pool for allocation of DMA rings */
311 	struct dma_pool *ring_pool;
312 
313 	/* Pool for allocation of metadata buffers for response messages */
314 	struct dma_pool *rx_buf_pool;
315 
316 	/*
317 	 * The base virtual address of DMA tx/rx descriptor rings. Corresponding
318 	 * DMA address and size of ring allocation.
319 	 */
320 	struct pdc_ring_alloc tx_ring_alloc;
321 	struct pdc_ring_alloc rx_ring_alloc;
322 
323 	struct pdc_regs *regs;    /* start of PDC registers */
324 
325 	struct dma64_regs *txregs_64; /* dma tx engine registers */
326 	struct dma64_regs *rxregs_64; /* dma rx engine registers */
327 
328 	/*
329 	 * Arrays of PDC_RING_ENTRIES descriptors
330 	 * To use multiple ringsets, this needs to be extended
331 	 */
332 	struct dma64dd   *txd_64;  /* tx descriptor ring */
333 	struct dma64dd   *rxd_64;  /* rx descriptor ring */
334 
335 	/* descriptor ring sizes */
336 	u32      ntxd;       /* # tx descriptors */
337 	u32      nrxd;       /* # rx descriptors */
338 	u32      nrxpost;    /* # rx buffers to keep posted */
339 	u32      ntxpost;    /* max number of tx buffers that can be posted */
340 
341 	/*
342 	 * Index of next tx descriptor to reclaim. That is, the descriptor
343 	 * index of the oldest tx buffer for which the host has yet to process
344 	 * the corresponding response.
345 	 */
346 	u32  txin;
347 
348 	/*
349 	 * Index of the first receive descriptor for the sequence of
350 	 * message fragments currently under construction. Used to build up
351 	 * the rxin_numd count for a message. Updated to rxout when the host
352 	 * starts a new sequence of rx buffers for a new message.
353 	 */
354 	u32  tx_msg_start;
355 
356 	/* Index of next tx descriptor to post. */
357 	u32  txout;
358 
359 	/*
360 	 * Number of tx descriptors associated with the message that starts
361 	 * at this tx descriptor index.
362 	 */
363 	u32      txin_numd[PDC_RING_ENTRIES];
364 
365 	/*
366 	 * Index of next rx descriptor to reclaim. This is the index of
367 	 * the next descriptor whose data has yet to be processed by the host.
368 	 */
369 	u32  rxin;
370 
371 	/*
372 	 * Index of the first receive descriptor for the sequence of
373 	 * message fragments currently under construction. Used to build up
374 	 * the rxin_numd count for a message. Updated to rxout when the host
375 	 * starts a new sequence of rx buffers for a new message.
376 	 */
377 	u32  rx_msg_start;
378 
379 	/*
380 	 * Saved value of current hardware rx descriptor index.
381 	 * The last rx buffer written by the hw is the index previous to
382 	 * this one.
383 	 */
384 	u32  last_rx_curr;
385 
386 	/* Index of next rx descriptor to post. */
387 	u32  rxout;
388 
389 	struct pdc_rx_ctx rx_ctx[PDC_RING_ENTRIES];
390 
391 	/*
392 	 * Scatterlists used to form request and reply frames beginning at a
393 	 * given ring index. Retained in order to unmap each sg after reply
394 	 * is processed
395 	 */
396 	struct scatterlist *src_sg[PDC_RING_ENTRIES];
397 
398 	/* counters */
399 	u32  pdc_requests;     /* number of request messages submitted */
400 	u32  pdc_replies;      /* number of reply messages received */
401 	u32  last_tx_not_done; /* too few tx descriptors to indicate done */
402 	u32  tx_ring_full;     /* unable to accept msg because tx ring full */
403 	u32  rx_ring_full;     /* unable to accept msg because rx ring full */
404 	u32  txnobuf;          /* unable to create tx descriptor */
405 	u32  rxnobuf;          /* unable to create rx descriptor */
406 	u32  rx_oflow;         /* count of rx overflows */
407 
408 	/* hardware type - FA2 or PDC/MDE */
409 	enum pdc_hw hw_type;
410 };
411 
412 /* Global variables */
413 
414 struct pdc_globals {
415 	/* Actual number of SPUs in hardware, as reported by device tree */
416 	u32 num_spu;
417 };
418 
419 static struct pdc_globals pdcg;
420 
421 /* top level debug FS directory for PDC driver */
422 static struct dentry *debugfs_dir;
423 
424 static ssize_t pdc_debugfs_read(struct file *filp, char __user *ubuf,
425 				size_t count, loff_t *offp)
426 {
427 	struct pdc_state *pdcs;
428 	char *buf;
429 	ssize_t ret, out_offset, out_count;
430 
431 	out_count = 512;
432 
433 	buf = kmalloc(out_count, GFP_KERNEL);
434 	if (!buf)
435 		return -ENOMEM;
436 
437 	pdcs = filp->private_data;
438 	out_offset = 0;
439 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
440 			       "SPU %u stats:\n", pdcs->pdc_idx);
441 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
442 			       "PDC requests....................%u\n",
443 			       pdcs->pdc_requests);
444 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
445 			       "PDC responses...................%u\n",
446 			       pdcs->pdc_replies);
447 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
448 			       "Tx not done.....................%u\n",
449 			       pdcs->last_tx_not_done);
450 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
451 			       "Tx ring full....................%u\n",
452 			       pdcs->tx_ring_full);
453 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
454 			       "Rx ring full....................%u\n",
455 			       pdcs->rx_ring_full);
456 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
457 			       "Tx desc write fail. Ring full...%u\n",
458 			       pdcs->txnobuf);
459 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
460 			       "Rx desc write fail. Ring full...%u\n",
461 			       pdcs->rxnobuf);
462 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
463 			       "Receive overflow................%u\n",
464 			       pdcs->rx_oflow);
465 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
466 			       "Num frags in rx ring............%u\n",
467 			       NRXDACTIVE(pdcs->rxin, pdcs->last_rx_curr,
468 					  pdcs->nrxpost));
469 
470 	if (out_offset > out_count)
471 		out_offset = out_count;
472 
473 	ret = simple_read_from_buffer(ubuf, count, offp, buf, out_offset);
474 	kfree(buf);
475 	return ret;
476 }
477 
478 static const struct file_operations pdc_debugfs_stats = {
479 	.owner = THIS_MODULE,
480 	.open = simple_open,
481 	.read = pdc_debugfs_read,
482 };
483 
484 /**
485  * pdc_setup_debugfs() - Create the debug FS directories. If the top-level
486  * directory has not yet been created, create it now. Create a stats file in
487  * this directory for a SPU.
488  * @pdcs: PDC state structure
489  */
490 static void pdc_setup_debugfs(struct pdc_state *pdcs)
491 {
492 	char spu_stats_name[16];
493 
494 	if (!debugfs_initialized())
495 		return;
496 
497 	snprintf(spu_stats_name, 16, "pdc%d_stats", pdcs->pdc_idx);
498 	if (!debugfs_dir)
499 		debugfs_dir = debugfs_create_dir(KBUILD_MODNAME, NULL);
500 
501 	/* S_IRUSR == 0400 */
502 	debugfs_create_file(spu_stats_name, 0400, debugfs_dir, pdcs,
503 			    &pdc_debugfs_stats);
504 }
505 
506 static void pdc_free_debugfs(void)
507 {
508 	debugfs_remove_recursive(debugfs_dir);
509 	debugfs_dir = NULL;
510 }
511 
512 /**
513  * pdc_build_rxd() - Build DMA descriptor to receive SPU result.
514  * @pdcs:      PDC state for SPU that will generate result
515  * @dma_addr:  DMA address of buffer that descriptor is being built for
516  * @buf_len:   Length of the receive buffer, in bytes
517  * @flags:     Flags to be stored in descriptor
518  */
519 static inline void
520 pdc_build_rxd(struct pdc_state *pdcs, dma_addr_t dma_addr,
521 	      u32 buf_len, u32 flags)
522 {
523 	struct device *dev = &pdcs->pdev->dev;
524 	struct dma64dd *rxd = &pdcs->rxd_64[pdcs->rxout];
525 
526 	dev_dbg(dev,
527 		"Writing rx descriptor for PDC %u at index %u with length %u. flags %#x\n",
528 		pdcs->pdc_idx, pdcs->rxout, buf_len, flags);
529 
530 	rxd->addrlow = cpu_to_le32(lower_32_bits(dma_addr));
531 	rxd->addrhigh = cpu_to_le32(upper_32_bits(dma_addr));
532 	rxd->ctrl1 = cpu_to_le32(flags);
533 	rxd->ctrl2 = cpu_to_le32(buf_len);
534 
535 	/* bump ring index and return */
536 	pdcs->rxout = NEXTRXD(pdcs->rxout, pdcs->nrxpost);
537 }
538 
539 /**
540  * pdc_build_txd() - Build a DMA descriptor to transmit a SPU request to
541  * hardware.
542  * @pdcs:        PDC state for the SPU that will process this request
543  * @dma_addr:    DMA address of packet to be transmitted
544  * @buf_len:     Length of tx buffer, in bytes
545  * @flags:       Flags to be stored in descriptor
546  */
547 static inline void
548 pdc_build_txd(struct pdc_state *pdcs, dma_addr_t dma_addr, u32 buf_len,
549 	      u32 flags)
550 {
551 	struct device *dev = &pdcs->pdev->dev;
552 	struct dma64dd *txd = &pdcs->txd_64[pdcs->txout];
553 
554 	dev_dbg(dev,
555 		"Writing tx descriptor for PDC %u at index %u with length %u, flags %#x\n",
556 		pdcs->pdc_idx, pdcs->txout, buf_len, flags);
557 
558 	txd->addrlow = cpu_to_le32(lower_32_bits(dma_addr));
559 	txd->addrhigh = cpu_to_le32(upper_32_bits(dma_addr));
560 	txd->ctrl1 = cpu_to_le32(flags);
561 	txd->ctrl2 = cpu_to_le32(buf_len);
562 
563 	/* bump ring index and return */
564 	pdcs->txout = NEXTTXD(pdcs->txout, pdcs->ntxpost);
565 }
566 
567 /**
568  * pdc_receive_one() - Receive a response message from a given SPU.
569  * @pdcs:    PDC state for the SPU to receive from
570  *
571  * When the return code indicates success, the response message is available in
572  * the receive buffers provided prior to submission of the request.
573  *
574  * Return:  PDC_SUCCESS if one or more receive descriptors was processed
575  *          -EAGAIN indicates that no response message is available
576  *          -EIO an error occurred
577  */
578 static int
579 pdc_receive_one(struct pdc_state *pdcs)
580 {
581 	struct device *dev = &pdcs->pdev->dev;
582 	struct mbox_controller *mbc;
583 	struct mbox_chan *chan;
584 	struct brcm_message mssg;
585 	u32 len, rx_status;
586 	u32 num_frags;
587 	u8 *resp_hdr;    /* virtual addr of start of resp message DMA header */
588 	u32 frags_rdy;   /* number of fragments ready to read */
589 	u32 rx_idx;      /* ring index of start of receive frame */
590 	dma_addr_t resp_hdr_daddr;
591 	struct pdc_rx_ctx *rx_ctx;
592 
593 	mbc = &pdcs->mbc;
594 	chan = &mbc->chans[0];
595 	mssg.type = BRCM_MESSAGE_SPU;
596 
597 	/*
598 	 * return if a complete response message is not yet ready.
599 	 * rxin_numd[rxin] is the number of fragments in the next msg
600 	 * to read.
601 	 */
602 	frags_rdy = NRXDACTIVE(pdcs->rxin, pdcs->last_rx_curr, pdcs->nrxpost);
603 	if ((frags_rdy == 0) ||
604 	    (frags_rdy < pdcs->rx_ctx[pdcs->rxin].rxin_numd))
605 		/* No response ready */
606 		return -EAGAIN;
607 
608 	num_frags = pdcs->txin_numd[pdcs->txin];
609 	WARN_ON(num_frags == 0);
610 
611 	dma_unmap_sg(dev, pdcs->src_sg[pdcs->txin],
612 		     sg_nents(pdcs->src_sg[pdcs->txin]), DMA_TO_DEVICE);
613 
614 	pdcs->txin = (pdcs->txin + num_frags) & pdcs->ntxpost;
615 
616 	dev_dbg(dev, "PDC %u reclaimed %d tx descriptors",
617 		pdcs->pdc_idx, num_frags);
618 
619 	rx_idx = pdcs->rxin;
620 	rx_ctx = &pdcs->rx_ctx[rx_idx];
621 	num_frags = rx_ctx->rxin_numd;
622 	/* Return opaque context with result */
623 	mssg.ctx = rx_ctx->rxp_ctx;
624 	rx_ctx->rxp_ctx = NULL;
625 	resp_hdr = rx_ctx->resp_hdr;
626 	resp_hdr_daddr = rx_ctx->resp_hdr_daddr;
627 	dma_unmap_sg(dev, rx_ctx->dst_sg, sg_nents(rx_ctx->dst_sg),
628 		     DMA_FROM_DEVICE);
629 
630 	pdcs->rxin = (pdcs->rxin + num_frags) & pdcs->nrxpost;
631 
632 	dev_dbg(dev, "PDC %u reclaimed %d rx descriptors",
633 		pdcs->pdc_idx, num_frags);
634 
635 	dev_dbg(dev,
636 		"PDC %u txin %u, txout %u, rxin %u, rxout %u, last_rx_curr %u\n",
637 		pdcs->pdc_idx, pdcs->txin, pdcs->txout, pdcs->rxin,
638 		pdcs->rxout, pdcs->last_rx_curr);
639 
640 	if (pdcs->pdc_resp_hdr_len == PDC_SPUM_RESP_HDR_LEN) {
641 		/*
642 		 * For SPU-M, get length of response msg and rx overflow status.
643 		 */
644 		rx_status = *((u32 *)resp_hdr);
645 		len = rx_status & RX_STATUS_LEN;
646 		dev_dbg(dev,
647 			"SPU response length %u bytes", len);
648 		if (unlikely(((rx_status & RX_STATUS_OVERFLOW) || (!len)))) {
649 			if (rx_status & RX_STATUS_OVERFLOW) {
650 				dev_err_ratelimited(dev,
651 						    "crypto receive overflow");
652 				pdcs->rx_oflow++;
653 			} else {
654 				dev_info_ratelimited(dev, "crypto rx len = 0");
655 			}
656 			return -EIO;
657 		}
658 	}
659 
660 	dma_pool_free(pdcs->rx_buf_pool, resp_hdr, resp_hdr_daddr);
661 
662 	mbox_chan_received_data(chan, &mssg);
663 
664 	pdcs->pdc_replies++;
665 	return PDC_SUCCESS;
666 }
667 
668 /**
669  * pdc_receive() - Process as many responses as are available in the rx ring.
670  * @pdcs:  PDC state
671  *
672  * Called within the hard IRQ.
673  * Return:
674  */
675 static int
676 pdc_receive(struct pdc_state *pdcs)
677 {
678 	int rx_status;
679 
680 	/* read last_rx_curr from register once */
681 	pdcs->last_rx_curr =
682 	    (ioread32((const void __iomem *)&pdcs->rxregs_64->status0) &
683 	     CRYPTO_D64_RS0_CD_MASK) / RING_ENTRY_SIZE;
684 
685 	do {
686 		/* Could be many frames ready */
687 		rx_status = pdc_receive_one(pdcs);
688 	} while (rx_status == PDC_SUCCESS);
689 
690 	return 0;
691 }
692 
693 /**
694  * pdc_tx_list_sg_add() - Add the buffers in a scatterlist to the transmit
695  * descriptors for a given SPU. The scatterlist buffers contain the data for a
696  * SPU request message.
697  * @spu_idx:   The index of the SPU to submit the request to, [0, max_spu)
698  * @sg:        Scatterlist whose buffers contain part of the SPU request
699  *
700  * If a scatterlist buffer is larger than PDC_DMA_BUF_MAX, multiple descriptors
701  * are written for that buffer, each <= PDC_DMA_BUF_MAX byte in length.
702  *
703  * Return: PDC_SUCCESS if successful
704  *         < 0 otherwise
705  */
706 static int pdc_tx_list_sg_add(struct pdc_state *pdcs, struct scatterlist *sg)
707 {
708 	u32 flags = 0;
709 	u32 eot;
710 	u32 tx_avail;
711 
712 	/*
713 	 * Num descriptors needed. Conservatively assume we need a descriptor
714 	 * for every entry in sg.
715 	 */
716 	u32 num_desc;
717 	u32 desc_w = 0;	/* Number of tx descriptors written */
718 	u32 bufcnt;	/* Number of bytes of buffer pointed to by descriptor */
719 	dma_addr_t databufptr;	/* DMA address to put in descriptor */
720 
721 	num_desc = (u32)sg_nents(sg);
722 
723 	/* check whether enough tx descriptors are available */
724 	tx_avail = pdcs->ntxpost - NTXDACTIVE(pdcs->txin, pdcs->txout,
725 					      pdcs->ntxpost);
726 	if (unlikely(num_desc > tx_avail)) {
727 		pdcs->txnobuf++;
728 		return -ENOSPC;
729 	}
730 
731 	/* build tx descriptors */
732 	if (pdcs->tx_msg_start == pdcs->txout) {
733 		/* Start of frame */
734 		pdcs->txin_numd[pdcs->tx_msg_start] = 0;
735 		pdcs->src_sg[pdcs->txout] = sg;
736 		flags = D64_CTRL1_SOF;
737 	}
738 
739 	while (sg) {
740 		if (unlikely(pdcs->txout == (pdcs->ntxd - 1)))
741 			eot = D64_CTRL1_EOT;
742 		else
743 			eot = 0;
744 
745 		/*
746 		 * If sg buffer larger than PDC limit, split across
747 		 * multiple descriptors
748 		 */
749 		bufcnt = sg_dma_len(sg);
750 		databufptr = sg_dma_address(sg);
751 		while (bufcnt > PDC_DMA_BUF_MAX) {
752 			pdc_build_txd(pdcs, databufptr, PDC_DMA_BUF_MAX,
753 				      flags | eot);
754 			desc_w++;
755 			bufcnt -= PDC_DMA_BUF_MAX;
756 			databufptr += PDC_DMA_BUF_MAX;
757 			if (unlikely(pdcs->txout == (pdcs->ntxd - 1)))
758 				eot = D64_CTRL1_EOT;
759 			else
760 				eot = 0;
761 		}
762 		sg = sg_next(sg);
763 		if (!sg)
764 			/* Writing last descriptor for frame */
765 			flags |= (D64_CTRL1_EOF | D64_CTRL1_IOC);
766 		pdc_build_txd(pdcs, databufptr, bufcnt, flags | eot);
767 		desc_w++;
768 		/* Clear start of frame after first descriptor */
769 		flags &= ~D64_CTRL1_SOF;
770 	}
771 	pdcs->txin_numd[pdcs->tx_msg_start] += desc_w;
772 
773 	return PDC_SUCCESS;
774 }
775 
776 /**
777  * pdc_tx_list_final() - Initiate DMA transfer of last frame written to tx
778  * ring.
779  * @pdcs:  PDC state for SPU to process the request
780  *
781  * Sets the index of the last descriptor written in both the rx and tx ring.
782  *
783  * Return: PDC_SUCCESS
784  */
785 static int pdc_tx_list_final(struct pdc_state *pdcs)
786 {
787 	/*
788 	 * write barrier to ensure all register writes are complete
789 	 * before chip starts to process new request
790 	 */
791 	wmb();
792 	iowrite32(pdcs->rxout << 4, &pdcs->rxregs_64->ptr);
793 	iowrite32(pdcs->txout << 4, &pdcs->txregs_64->ptr);
794 	pdcs->pdc_requests++;
795 
796 	return PDC_SUCCESS;
797 }
798 
799 /**
800  * pdc_rx_list_init() - Start a new receive descriptor list for a given PDC.
801  * @pdcs:   PDC state for SPU handling request
802  * @dst_sg: scatterlist providing rx buffers for response to be returned to
803  *	    mailbox client
804  * @ctx:    Opaque context for this request
805  *
806  * Posts a single receive descriptor to hold the metadata that precedes a
807  * response. For example, with SPU-M, the metadata is a 32-byte DMA header and
808  * an 8-byte BCM header. Moves the msg_start descriptor indexes for both tx and
809  * rx to indicate the start of a new message.
810  *
811  * Return:  PDC_SUCCESS if successful
812  *          < 0 if an error (e.g., rx ring is full)
813  */
814 static int pdc_rx_list_init(struct pdc_state *pdcs, struct scatterlist *dst_sg,
815 			    void *ctx)
816 {
817 	u32 flags = 0;
818 	u32 rx_avail;
819 	u32 rx_pkt_cnt = 1;	/* Adding a single rx buffer */
820 	dma_addr_t daddr;
821 	void *vaddr;
822 	struct pdc_rx_ctx *rx_ctx;
823 
824 	rx_avail = pdcs->nrxpost - NRXDACTIVE(pdcs->rxin, pdcs->rxout,
825 					      pdcs->nrxpost);
826 	if (unlikely(rx_pkt_cnt > rx_avail)) {
827 		pdcs->rxnobuf++;
828 		return -ENOSPC;
829 	}
830 
831 	/* allocate a buffer for the dma rx status */
832 	vaddr = dma_pool_zalloc(pdcs->rx_buf_pool, GFP_ATOMIC, &daddr);
833 	if (unlikely(!vaddr))
834 		return -ENOMEM;
835 
836 	/*
837 	 * Update msg_start indexes for both tx and rx to indicate the start
838 	 * of a new sequence of descriptor indexes that contain the fragments
839 	 * of the same message.
840 	 */
841 	pdcs->rx_msg_start = pdcs->rxout;
842 	pdcs->tx_msg_start = pdcs->txout;
843 
844 	/* This is always the first descriptor in the receive sequence */
845 	flags = D64_CTRL1_SOF;
846 	pdcs->rx_ctx[pdcs->rx_msg_start].rxin_numd = 1;
847 
848 	if (unlikely(pdcs->rxout == (pdcs->nrxd - 1)))
849 		flags |= D64_CTRL1_EOT;
850 
851 	rx_ctx = &pdcs->rx_ctx[pdcs->rxout];
852 	rx_ctx->rxp_ctx = ctx;
853 	rx_ctx->dst_sg = dst_sg;
854 	rx_ctx->resp_hdr = vaddr;
855 	rx_ctx->resp_hdr_daddr = daddr;
856 	pdc_build_rxd(pdcs, daddr, pdcs->pdc_resp_hdr_len, flags);
857 	return PDC_SUCCESS;
858 }
859 
860 /**
861  * pdc_rx_list_sg_add() - Add the buffers in a scatterlist to the receive
862  * descriptors for a given SPU. The caller must have already DMA mapped the
863  * scatterlist.
864  * @spu_idx:    Indicates which SPU the buffers are for
865  * @sg:         Scatterlist whose buffers are added to the receive ring
866  *
867  * If a receive buffer in the scatterlist is larger than PDC_DMA_BUF_MAX,
868  * multiple receive descriptors are written, each with a buffer <=
869  * PDC_DMA_BUF_MAX.
870  *
871  * Return: PDC_SUCCESS if successful
872  *         < 0 otherwise (e.g., receive ring is full)
873  */
874 static int pdc_rx_list_sg_add(struct pdc_state *pdcs, struct scatterlist *sg)
875 {
876 	u32 flags = 0;
877 	u32 rx_avail;
878 
879 	/*
880 	 * Num descriptors needed. Conservatively assume we need a descriptor
881 	 * for every entry from our starting point in the scatterlist.
882 	 */
883 	u32 num_desc;
884 	u32 desc_w = 0;	/* Number of tx descriptors written */
885 	u32 bufcnt;	/* Number of bytes of buffer pointed to by descriptor */
886 	dma_addr_t databufptr;	/* DMA address to put in descriptor */
887 
888 	num_desc = (u32)sg_nents(sg);
889 
890 	rx_avail = pdcs->nrxpost - NRXDACTIVE(pdcs->rxin, pdcs->rxout,
891 					      pdcs->nrxpost);
892 	if (unlikely(num_desc > rx_avail)) {
893 		pdcs->rxnobuf++;
894 		return -ENOSPC;
895 	}
896 
897 	while (sg) {
898 		if (unlikely(pdcs->rxout == (pdcs->nrxd - 1)))
899 			flags = D64_CTRL1_EOT;
900 		else
901 			flags = 0;
902 
903 		/*
904 		 * If sg buffer larger than PDC limit, split across
905 		 * multiple descriptors
906 		 */
907 		bufcnt = sg_dma_len(sg);
908 		databufptr = sg_dma_address(sg);
909 		while (bufcnt > PDC_DMA_BUF_MAX) {
910 			pdc_build_rxd(pdcs, databufptr, PDC_DMA_BUF_MAX, flags);
911 			desc_w++;
912 			bufcnt -= PDC_DMA_BUF_MAX;
913 			databufptr += PDC_DMA_BUF_MAX;
914 			if (unlikely(pdcs->rxout == (pdcs->nrxd - 1)))
915 				flags = D64_CTRL1_EOT;
916 			else
917 				flags = 0;
918 		}
919 		pdc_build_rxd(pdcs, databufptr, bufcnt, flags);
920 		desc_w++;
921 		sg = sg_next(sg);
922 	}
923 	pdcs->rx_ctx[pdcs->rx_msg_start].rxin_numd += desc_w;
924 
925 	return PDC_SUCCESS;
926 }
927 
928 /**
929  * pdc_irq_handler() - Interrupt handler called in interrupt context.
930  * @irq:      Interrupt number that has fired
931  * @data:     device struct for DMA engine that generated the interrupt
932  *
933  * We have to clear the device interrupt status flags here. So cache the
934  * status for later use in the thread function. Other than that, just return
935  * WAKE_THREAD to invoke the thread function.
936  *
937  * Return: IRQ_WAKE_THREAD if interrupt is ours
938  *         IRQ_NONE otherwise
939  */
940 static irqreturn_t pdc_irq_handler(int irq, void *data)
941 {
942 	struct device *dev = (struct device *)data;
943 	struct pdc_state *pdcs = dev_get_drvdata(dev);
944 	u32 intstatus = ioread32(pdcs->pdc_reg_vbase + PDC_INTSTATUS_OFFSET);
945 
946 	if (unlikely(intstatus == 0))
947 		return IRQ_NONE;
948 
949 	/* Disable interrupts until soft handler runs */
950 	iowrite32(0, pdcs->pdc_reg_vbase + PDC_INTMASK_OFFSET);
951 
952 	/* Clear interrupt flags in device */
953 	iowrite32(intstatus, pdcs->pdc_reg_vbase + PDC_INTSTATUS_OFFSET);
954 
955 	/* Wakeup IRQ thread */
956 	tasklet_schedule(&pdcs->rx_tasklet);
957 	return IRQ_HANDLED;
958 }
959 
960 /**
961  * pdc_tasklet_cb() - Tasklet callback that runs the deferred processing after
962  * a DMA receive interrupt. Reenables the receive interrupt.
963  * @data: PDC state structure
964  */
965 static void pdc_tasklet_cb(struct tasklet_struct *t)
966 {
967 	struct pdc_state *pdcs = from_tasklet(pdcs, t, rx_tasklet);
968 
969 	pdc_receive(pdcs);
970 
971 	/* reenable interrupts */
972 	iowrite32(PDC_INTMASK, pdcs->pdc_reg_vbase + PDC_INTMASK_OFFSET);
973 }
974 
975 /**
976  * pdc_ring_init() - Allocate DMA rings and initialize constant fields of
977  * descriptors in one ringset.
978  * @pdcs:    PDC instance state
979  * @ringset: index of ringset being used
980  *
981  * Return: PDC_SUCCESS if ring initialized
982  *         < 0 otherwise
983  */
984 static int pdc_ring_init(struct pdc_state *pdcs, int ringset)
985 {
986 	int i;
987 	int err = PDC_SUCCESS;
988 	struct dma64 *dma_reg;
989 	struct device *dev = &pdcs->pdev->dev;
990 	struct pdc_ring_alloc tx;
991 	struct pdc_ring_alloc rx;
992 
993 	/* Allocate tx ring */
994 	tx.vbase = dma_pool_zalloc(pdcs->ring_pool, GFP_KERNEL, &tx.dmabase);
995 	if (unlikely(!tx.vbase)) {
996 		err = -ENOMEM;
997 		goto done;
998 	}
999 
1000 	/* Allocate rx ring */
1001 	rx.vbase = dma_pool_zalloc(pdcs->ring_pool, GFP_KERNEL, &rx.dmabase);
1002 	if (unlikely(!rx.vbase)) {
1003 		err = -ENOMEM;
1004 		goto fail_dealloc;
1005 	}
1006 
1007 	dev_dbg(dev, " - base DMA addr of tx ring      %pad", &tx.dmabase);
1008 	dev_dbg(dev, " - base virtual addr of tx ring  %p", tx.vbase);
1009 	dev_dbg(dev, " - base DMA addr of rx ring      %pad", &rx.dmabase);
1010 	dev_dbg(dev, " - base virtual addr of rx ring  %p", rx.vbase);
1011 
1012 	memcpy(&pdcs->tx_ring_alloc, &tx, sizeof(tx));
1013 	memcpy(&pdcs->rx_ring_alloc, &rx, sizeof(rx));
1014 
1015 	pdcs->rxin = 0;
1016 	pdcs->rx_msg_start = 0;
1017 	pdcs->last_rx_curr = 0;
1018 	pdcs->rxout = 0;
1019 	pdcs->txin = 0;
1020 	pdcs->tx_msg_start = 0;
1021 	pdcs->txout = 0;
1022 
1023 	/* Set descriptor array base addresses */
1024 	pdcs->txd_64 = (struct dma64dd *)pdcs->tx_ring_alloc.vbase;
1025 	pdcs->rxd_64 = (struct dma64dd *)pdcs->rx_ring_alloc.vbase;
1026 
1027 	/* Tell device the base DMA address of each ring */
1028 	dma_reg = &pdcs->regs->dmaregs[ringset];
1029 
1030 	/* But first disable DMA and set curptr to 0 for both TX & RX */
1031 	iowrite32(PDC_TX_CTL, &dma_reg->dmaxmt.control);
1032 	iowrite32((PDC_RX_CTL + (pdcs->rx_status_len << 1)),
1033 		  &dma_reg->dmarcv.control);
1034 	iowrite32(0, &dma_reg->dmaxmt.ptr);
1035 	iowrite32(0, &dma_reg->dmarcv.ptr);
1036 
1037 	/* Set base DMA addresses */
1038 	iowrite32(lower_32_bits(pdcs->tx_ring_alloc.dmabase),
1039 		  &dma_reg->dmaxmt.addrlow);
1040 	iowrite32(upper_32_bits(pdcs->tx_ring_alloc.dmabase),
1041 		  &dma_reg->dmaxmt.addrhigh);
1042 
1043 	iowrite32(lower_32_bits(pdcs->rx_ring_alloc.dmabase),
1044 		  &dma_reg->dmarcv.addrlow);
1045 	iowrite32(upper_32_bits(pdcs->rx_ring_alloc.dmabase),
1046 		  &dma_reg->dmarcv.addrhigh);
1047 
1048 	/* Re-enable DMA */
1049 	iowrite32(PDC_TX_CTL | PDC_TX_ENABLE, &dma_reg->dmaxmt.control);
1050 	iowrite32((PDC_RX_CTL | PDC_RX_ENABLE | (pdcs->rx_status_len << 1)),
1051 		  &dma_reg->dmarcv.control);
1052 
1053 	/* Initialize descriptors */
1054 	for (i = 0; i < PDC_RING_ENTRIES; i++) {
1055 		/* Every tx descriptor can be used for start of frame. */
1056 		if (i != pdcs->ntxpost) {
1057 			iowrite32(D64_CTRL1_SOF | D64_CTRL1_EOF,
1058 				  &pdcs->txd_64[i].ctrl1);
1059 		} else {
1060 			/* Last descriptor in ringset. Set End of Table. */
1061 			iowrite32(D64_CTRL1_SOF | D64_CTRL1_EOF |
1062 				  D64_CTRL1_EOT, &pdcs->txd_64[i].ctrl1);
1063 		}
1064 
1065 		/* Every rx descriptor can be used for start of frame */
1066 		if (i != pdcs->nrxpost) {
1067 			iowrite32(D64_CTRL1_SOF,
1068 				  &pdcs->rxd_64[i].ctrl1);
1069 		} else {
1070 			/* Last descriptor in ringset. Set End of Table. */
1071 			iowrite32(D64_CTRL1_SOF | D64_CTRL1_EOT,
1072 				  &pdcs->rxd_64[i].ctrl1);
1073 		}
1074 	}
1075 	return PDC_SUCCESS;
1076 
1077 fail_dealloc:
1078 	dma_pool_free(pdcs->ring_pool, tx.vbase, tx.dmabase);
1079 done:
1080 	return err;
1081 }
1082 
1083 static void pdc_ring_free(struct pdc_state *pdcs)
1084 {
1085 	if (pdcs->tx_ring_alloc.vbase) {
1086 		dma_pool_free(pdcs->ring_pool, pdcs->tx_ring_alloc.vbase,
1087 			      pdcs->tx_ring_alloc.dmabase);
1088 		pdcs->tx_ring_alloc.vbase = NULL;
1089 	}
1090 
1091 	if (pdcs->rx_ring_alloc.vbase) {
1092 		dma_pool_free(pdcs->ring_pool, pdcs->rx_ring_alloc.vbase,
1093 			      pdcs->rx_ring_alloc.dmabase);
1094 		pdcs->rx_ring_alloc.vbase = NULL;
1095 	}
1096 }
1097 
1098 /**
1099  * pdc_desc_count() - Count the number of DMA descriptors that will be required
1100  * for a given scatterlist. Account for the max length of a DMA buffer.
1101  * @sg:    Scatterlist to be DMA'd
1102  * Return: Number of descriptors required
1103  */
1104 static u32 pdc_desc_count(struct scatterlist *sg)
1105 {
1106 	u32 cnt = 0;
1107 
1108 	while (sg) {
1109 		cnt += ((sg->length / PDC_DMA_BUF_MAX) + 1);
1110 		sg = sg_next(sg);
1111 	}
1112 	return cnt;
1113 }
1114 
1115 /**
1116  * pdc_rings_full() - Check whether the tx ring has room for tx_cnt descriptors
1117  * and the rx ring has room for rx_cnt descriptors.
1118  * @pdcs:  PDC state
1119  * @tx_cnt: The number of descriptors required in the tx ring
1120  * @rx_cnt: The number of descriptors required i the rx ring
1121  *
1122  * Return: true if one of the rings does not have enough space
1123  *         false if sufficient space is available in both rings
1124  */
1125 static bool pdc_rings_full(struct pdc_state *pdcs, int tx_cnt, int rx_cnt)
1126 {
1127 	u32 rx_avail;
1128 	u32 tx_avail;
1129 	bool full = false;
1130 
1131 	/* Check if the tx and rx rings are likely to have enough space */
1132 	rx_avail = pdcs->nrxpost - NRXDACTIVE(pdcs->rxin, pdcs->rxout,
1133 					      pdcs->nrxpost);
1134 	if (unlikely(rx_cnt > rx_avail)) {
1135 		pdcs->rx_ring_full++;
1136 		full = true;
1137 	}
1138 
1139 	if (likely(!full)) {
1140 		tx_avail = pdcs->ntxpost - NTXDACTIVE(pdcs->txin, pdcs->txout,
1141 						      pdcs->ntxpost);
1142 		if (unlikely(tx_cnt > tx_avail)) {
1143 			pdcs->tx_ring_full++;
1144 			full = true;
1145 		}
1146 	}
1147 	return full;
1148 }
1149 
1150 /**
1151  * pdc_last_tx_done() - If both the tx and rx rings have at least
1152  * PDC_RING_SPACE_MIN descriptors available, then indicate that the mailbox
1153  * framework can submit another message.
1154  * @chan:  mailbox channel to check
1155  * Return: true if PDC can accept another message on this channel
1156  */
1157 static bool pdc_last_tx_done(struct mbox_chan *chan)
1158 {
1159 	struct pdc_state *pdcs = chan->con_priv;
1160 	bool ret;
1161 
1162 	if (unlikely(pdc_rings_full(pdcs, PDC_RING_SPACE_MIN,
1163 				    PDC_RING_SPACE_MIN))) {
1164 		pdcs->last_tx_not_done++;
1165 		ret = false;
1166 	} else {
1167 		ret = true;
1168 	}
1169 	return ret;
1170 }
1171 
1172 /**
1173  * pdc_send_data() - mailbox send_data function
1174  * @chan:	The mailbox channel on which the data is sent. The channel
1175  *              corresponds to a DMA ringset.
1176  * @data:	The mailbox message to be sent. The message must be a
1177  *              brcm_message structure.
1178  *
1179  * This function is registered as the send_data function for the mailbox
1180  * controller. From the destination scatterlist in the mailbox message, it
1181  * creates a sequence of receive descriptors in the rx ring. From the source
1182  * scatterlist, it creates a sequence of transmit descriptors in the tx ring.
1183  * After creating the descriptors, it writes the rx ptr and tx ptr registers to
1184  * initiate the DMA transfer.
1185  *
1186  * This function does the DMA map and unmap of the src and dst scatterlists in
1187  * the mailbox message.
1188  *
1189  * Return: 0 if successful
1190  *	   -ENOTSUPP if the mailbox message is a type this driver does not
1191  *			support
1192  *         < 0 if an error
1193  */
1194 static int pdc_send_data(struct mbox_chan *chan, void *data)
1195 {
1196 	struct pdc_state *pdcs = chan->con_priv;
1197 	struct device *dev = &pdcs->pdev->dev;
1198 	struct brcm_message *mssg = data;
1199 	int err = PDC_SUCCESS;
1200 	int src_nent;
1201 	int dst_nent;
1202 	int nent;
1203 	u32 tx_desc_req;
1204 	u32 rx_desc_req;
1205 
1206 	if (unlikely(mssg->type != BRCM_MESSAGE_SPU))
1207 		return -ENOTSUPP;
1208 
1209 	src_nent = sg_nents(mssg->spu.src);
1210 	if (likely(src_nent)) {
1211 		nent = dma_map_sg(dev, mssg->spu.src, src_nent, DMA_TO_DEVICE);
1212 		if (unlikely(nent == 0))
1213 			return -EIO;
1214 	}
1215 
1216 	dst_nent = sg_nents(mssg->spu.dst);
1217 	if (likely(dst_nent)) {
1218 		nent = dma_map_sg(dev, mssg->spu.dst, dst_nent,
1219 				  DMA_FROM_DEVICE);
1220 		if (unlikely(nent == 0)) {
1221 			dma_unmap_sg(dev, mssg->spu.src, src_nent,
1222 				     DMA_TO_DEVICE);
1223 			return -EIO;
1224 		}
1225 	}
1226 
1227 	/*
1228 	 * Check if the tx and rx rings have enough space. Do this prior to
1229 	 * writing any tx or rx descriptors. Need to ensure that we do not write
1230 	 * a partial set of descriptors, or write just rx descriptors but
1231 	 * corresponding tx descriptors don't fit. Note that we want this check
1232 	 * and the entire sequence of descriptor to happen without another
1233 	 * thread getting in. The channel spin lock in the mailbox framework
1234 	 * ensures this.
1235 	 */
1236 	tx_desc_req = pdc_desc_count(mssg->spu.src);
1237 	rx_desc_req = pdc_desc_count(mssg->spu.dst);
1238 	if (unlikely(pdc_rings_full(pdcs, tx_desc_req, rx_desc_req + 1)))
1239 		return -ENOSPC;
1240 
1241 	/* Create rx descriptors to SPU catch response */
1242 	err = pdc_rx_list_init(pdcs, mssg->spu.dst, mssg->ctx);
1243 	err |= pdc_rx_list_sg_add(pdcs, mssg->spu.dst);
1244 
1245 	/* Create tx descriptors to submit SPU request */
1246 	err |= pdc_tx_list_sg_add(pdcs, mssg->spu.src);
1247 	err |= pdc_tx_list_final(pdcs);	/* initiate transfer */
1248 
1249 	if (unlikely(err))
1250 		dev_err(&pdcs->pdev->dev,
1251 			"%s failed with error %d", __func__, err);
1252 
1253 	return err;
1254 }
1255 
1256 static int pdc_startup(struct mbox_chan *chan)
1257 {
1258 	return pdc_ring_init(chan->con_priv, PDC_RINGSET);
1259 }
1260 
1261 static void pdc_shutdown(struct mbox_chan *chan)
1262 {
1263 	struct pdc_state *pdcs = chan->con_priv;
1264 
1265 	if (!pdcs)
1266 		return;
1267 
1268 	dev_dbg(&pdcs->pdev->dev,
1269 		"Shutdown mailbox channel for PDC %u", pdcs->pdc_idx);
1270 	pdc_ring_free(pdcs);
1271 }
1272 
1273 /**
1274  * pdc_hw_init() - Use the given initialization parameters to initialize the
1275  * state for one of the PDCs.
1276  * @pdcs:  state of the PDC
1277  */
1278 static
1279 void pdc_hw_init(struct pdc_state *pdcs)
1280 {
1281 	struct platform_device *pdev;
1282 	struct device *dev;
1283 	struct dma64 *dma_reg;
1284 	int ringset = PDC_RINGSET;
1285 
1286 	pdev = pdcs->pdev;
1287 	dev = &pdev->dev;
1288 
1289 	dev_dbg(dev, "PDC %u initial values:", pdcs->pdc_idx);
1290 	dev_dbg(dev, "state structure:                   %p",
1291 		pdcs);
1292 	dev_dbg(dev, " - base virtual addr of hw regs    %p",
1293 		pdcs->pdc_reg_vbase);
1294 
1295 	/* initialize data structures */
1296 	pdcs->regs = (struct pdc_regs *)pdcs->pdc_reg_vbase;
1297 	pdcs->txregs_64 = (struct dma64_regs *)
1298 	    (((u8 *)pdcs->pdc_reg_vbase) +
1299 		     PDC_TXREGS_OFFSET + (sizeof(struct dma64) * ringset));
1300 	pdcs->rxregs_64 = (struct dma64_regs *)
1301 	    (((u8 *)pdcs->pdc_reg_vbase) +
1302 		     PDC_RXREGS_OFFSET + (sizeof(struct dma64) * ringset));
1303 
1304 	pdcs->ntxd = PDC_RING_ENTRIES;
1305 	pdcs->nrxd = PDC_RING_ENTRIES;
1306 	pdcs->ntxpost = PDC_RING_ENTRIES - 1;
1307 	pdcs->nrxpost = PDC_RING_ENTRIES - 1;
1308 	iowrite32(0, &pdcs->regs->intmask);
1309 
1310 	dma_reg = &pdcs->regs->dmaregs[ringset];
1311 
1312 	/* Configure DMA but will enable later in pdc_ring_init() */
1313 	iowrite32(PDC_TX_CTL, &dma_reg->dmaxmt.control);
1314 
1315 	iowrite32(PDC_RX_CTL + (pdcs->rx_status_len << 1),
1316 		  &dma_reg->dmarcv.control);
1317 
1318 	/* Reset current index pointers after making sure DMA is disabled */
1319 	iowrite32(0, &dma_reg->dmaxmt.ptr);
1320 	iowrite32(0, &dma_reg->dmarcv.ptr);
1321 
1322 	if (pdcs->pdc_resp_hdr_len == PDC_SPU2_RESP_HDR_LEN)
1323 		iowrite32(PDC_CKSUM_CTRL,
1324 			  pdcs->pdc_reg_vbase + PDC_CKSUM_CTRL_OFFSET);
1325 }
1326 
1327 /**
1328  * pdc_hw_disable() - Disable the tx and rx control in the hw.
1329  * @pdcs: PDC state structure
1330  *
1331  */
1332 static void pdc_hw_disable(struct pdc_state *pdcs)
1333 {
1334 	struct dma64 *dma_reg;
1335 
1336 	dma_reg = &pdcs->regs->dmaregs[PDC_RINGSET];
1337 	iowrite32(PDC_TX_CTL, &dma_reg->dmaxmt.control);
1338 	iowrite32(PDC_RX_CTL + (pdcs->rx_status_len << 1),
1339 		  &dma_reg->dmarcv.control);
1340 }
1341 
1342 /**
1343  * pdc_rx_buf_pool_create() - Pool of receive buffers used to catch the metadata
1344  * header returned with each response message.
1345  * @pdcs: PDC state structure
1346  *
1347  * The metadata is not returned to the mailbox client. So the PDC driver
1348  * manages these buffers.
1349  *
1350  * Return: PDC_SUCCESS
1351  *         -ENOMEM if pool creation fails
1352  */
1353 static int pdc_rx_buf_pool_create(struct pdc_state *pdcs)
1354 {
1355 	struct platform_device *pdev;
1356 	struct device *dev;
1357 
1358 	pdev = pdcs->pdev;
1359 	dev = &pdev->dev;
1360 
1361 	pdcs->pdc_resp_hdr_len = pdcs->rx_status_len;
1362 	if (pdcs->use_bcm_hdr)
1363 		pdcs->pdc_resp_hdr_len += BCM_HDR_LEN;
1364 
1365 	pdcs->rx_buf_pool = dma_pool_create("pdc rx bufs", dev,
1366 					    pdcs->pdc_resp_hdr_len,
1367 					    RX_BUF_ALIGN, 0);
1368 	if (!pdcs->rx_buf_pool)
1369 		return -ENOMEM;
1370 
1371 	return PDC_SUCCESS;
1372 }
1373 
1374 /**
1375  * pdc_interrupts_init() - Initialize the interrupt configuration for a PDC and
1376  * specify a threaded IRQ handler for deferred handling of interrupts outside of
1377  * interrupt context.
1378  * @pdcs:   PDC state
1379  *
1380  * Set the interrupt mask for transmit and receive done.
1381  * Set the lazy interrupt frame count to generate an interrupt for just one pkt.
1382  *
1383  * Return:  PDC_SUCCESS
1384  *          <0 if threaded irq request fails
1385  */
1386 static int pdc_interrupts_init(struct pdc_state *pdcs)
1387 {
1388 	struct platform_device *pdev = pdcs->pdev;
1389 	struct device *dev = &pdev->dev;
1390 	struct device_node *dn = pdev->dev.of_node;
1391 	int err;
1392 
1393 	/* interrupt configuration */
1394 	iowrite32(PDC_INTMASK, pdcs->pdc_reg_vbase + PDC_INTMASK_OFFSET);
1395 
1396 	if (pdcs->hw_type == FA_HW)
1397 		iowrite32(PDC_LAZY_INT, pdcs->pdc_reg_vbase +
1398 			  FA_RCVLAZY0_OFFSET);
1399 	else
1400 		iowrite32(PDC_LAZY_INT, pdcs->pdc_reg_vbase +
1401 			  PDC_RCVLAZY0_OFFSET);
1402 
1403 	/* read irq from device tree */
1404 	pdcs->pdc_irq = irq_of_parse_and_map(dn, 0);
1405 	dev_dbg(dev, "pdc device %s irq %u for pdcs %p",
1406 		dev_name(dev), pdcs->pdc_irq, pdcs);
1407 
1408 	err = devm_request_irq(dev, pdcs->pdc_irq, pdc_irq_handler, 0,
1409 			       dev_name(dev), dev);
1410 	if (err) {
1411 		dev_err(dev, "IRQ %u request failed with err %d\n",
1412 			pdcs->pdc_irq, err);
1413 		return err;
1414 	}
1415 	return PDC_SUCCESS;
1416 }
1417 
1418 static const struct mbox_chan_ops pdc_mbox_chan_ops = {
1419 	.send_data = pdc_send_data,
1420 	.last_tx_done = pdc_last_tx_done,
1421 	.startup = pdc_startup,
1422 	.shutdown = pdc_shutdown
1423 };
1424 
1425 /**
1426  * pdc_mb_init() - Initialize the mailbox controller.
1427  * @pdcs:  PDC state
1428  *
1429  * Each PDC is a mailbox controller. Each ringset is a mailbox channel. Kernel
1430  * driver only uses one ringset and thus one mb channel. PDC uses the transmit
1431  * complete interrupt to determine when a mailbox message has successfully been
1432  * transmitted.
1433  *
1434  * Return: 0 on success
1435  *         < 0 if there is an allocation or registration failure
1436  */
1437 static int pdc_mb_init(struct pdc_state *pdcs)
1438 {
1439 	struct device *dev = &pdcs->pdev->dev;
1440 	struct mbox_controller *mbc;
1441 	int chan_index;
1442 	int err;
1443 
1444 	mbc = &pdcs->mbc;
1445 	mbc->dev = dev;
1446 	mbc->ops = &pdc_mbox_chan_ops;
1447 	mbc->num_chans = 1;
1448 	mbc->chans = devm_kcalloc(dev, mbc->num_chans, sizeof(*mbc->chans),
1449 				  GFP_KERNEL);
1450 	if (!mbc->chans)
1451 		return -ENOMEM;
1452 
1453 	mbc->txdone_irq = false;
1454 	mbc->txdone_poll = true;
1455 	mbc->txpoll_period = 1;
1456 	for (chan_index = 0; chan_index < mbc->num_chans; chan_index++)
1457 		mbc->chans[chan_index].con_priv = pdcs;
1458 
1459 	/* Register mailbox controller */
1460 	err = devm_mbox_controller_register(dev, mbc);
1461 	if (err) {
1462 		dev_crit(dev,
1463 			 "Failed to register PDC mailbox controller. Error %d.",
1464 			 err);
1465 		return err;
1466 	}
1467 	return 0;
1468 }
1469 
1470 /* Device tree API */
1471 static const int pdc_hw = PDC_HW;
1472 static const int fa_hw = FA_HW;
1473 
1474 static const struct of_device_id pdc_mbox_of_match[] = {
1475 	{.compatible = "brcm,iproc-pdc-mbox", .data = &pdc_hw},
1476 	{.compatible = "brcm,iproc-fa2-mbox", .data = &fa_hw},
1477 	{ /* sentinel */ }
1478 };
1479 MODULE_DEVICE_TABLE(of, pdc_mbox_of_match);
1480 
1481 /**
1482  * pdc_dt_read() - Read application-specific data from device tree.
1483  * @pdev:  Platform device
1484  * @pdcs:  PDC state
1485  *
1486  * Reads the number of bytes of receive status that precede each received frame.
1487  * Reads whether transmit and received frames should be preceded by an 8-byte
1488  * BCM header.
1489  *
1490  * Return: 0 if successful
1491  *         -ENODEV if device not available
1492  */
1493 static int pdc_dt_read(struct platform_device *pdev, struct pdc_state *pdcs)
1494 {
1495 	struct device *dev = &pdev->dev;
1496 	struct device_node *dn = pdev->dev.of_node;
1497 	const struct of_device_id *match;
1498 	const int *hw_type;
1499 	int err;
1500 
1501 	err = of_property_read_u32(dn, "brcm,rx-status-len",
1502 				   &pdcs->rx_status_len);
1503 	if (err < 0)
1504 		dev_err(dev,
1505 			"%s failed to get DMA receive status length from device tree",
1506 			__func__);
1507 
1508 	pdcs->use_bcm_hdr = of_property_read_bool(dn, "brcm,use-bcm-hdr");
1509 
1510 	pdcs->hw_type = PDC_HW;
1511 
1512 	match = of_match_device(of_match_ptr(pdc_mbox_of_match), dev);
1513 	if (match != NULL) {
1514 		hw_type = match->data;
1515 		pdcs->hw_type = *hw_type;
1516 	}
1517 
1518 	return 0;
1519 }
1520 
1521 /**
1522  * pdc_probe() - Probe function for PDC driver.
1523  * @pdev:   PDC platform device
1524  *
1525  * Reserve and map register regions defined in device tree.
1526  * Allocate and initialize tx and rx DMA rings.
1527  * Initialize a mailbox controller for each PDC.
1528  *
1529  * Return: 0 if successful
1530  *         < 0 if an error
1531  */
1532 static int pdc_probe(struct platform_device *pdev)
1533 {
1534 	int err = 0;
1535 	struct device *dev = &pdev->dev;
1536 	struct resource *pdc_regs;
1537 	struct pdc_state *pdcs;
1538 
1539 	/* PDC state for one SPU */
1540 	pdcs = devm_kzalloc(dev, sizeof(*pdcs), GFP_KERNEL);
1541 	if (!pdcs) {
1542 		err = -ENOMEM;
1543 		goto cleanup;
1544 	}
1545 
1546 	pdcs->pdev = pdev;
1547 	platform_set_drvdata(pdev, pdcs);
1548 	pdcs->pdc_idx = pdcg.num_spu;
1549 	pdcg.num_spu++;
1550 
1551 	err = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(39));
1552 	if (err) {
1553 		dev_warn(dev, "PDC device cannot perform DMA. Error %d.", err);
1554 		goto cleanup;
1555 	}
1556 
1557 	/* Create DMA pool for tx ring */
1558 	pdcs->ring_pool = dma_pool_create("pdc rings", dev, PDC_RING_SIZE,
1559 					  RING_ALIGN, 0);
1560 	if (!pdcs->ring_pool) {
1561 		err = -ENOMEM;
1562 		goto cleanup;
1563 	}
1564 
1565 	err = pdc_dt_read(pdev, pdcs);
1566 	if (err)
1567 		goto cleanup_ring_pool;
1568 
1569 	pdc_regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1570 	if (!pdc_regs) {
1571 		err = -ENODEV;
1572 		goto cleanup_ring_pool;
1573 	}
1574 	dev_dbg(dev, "PDC register region res.start = %pa, res.end = %pa",
1575 		&pdc_regs->start, &pdc_regs->end);
1576 
1577 	pdcs->pdc_reg_vbase = devm_ioremap_resource(&pdev->dev, pdc_regs);
1578 	if (IS_ERR(pdcs->pdc_reg_vbase)) {
1579 		err = PTR_ERR(pdcs->pdc_reg_vbase);
1580 		goto cleanup_ring_pool;
1581 	}
1582 
1583 	/* create rx buffer pool after dt read to know how big buffers are */
1584 	err = pdc_rx_buf_pool_create(pdcs);
1585 	if (err)
1586 		goto cleanup_ring_pool;
1587 
1588 	pdc_hw_init(pdcs);
1589 
1590 	/* Init tasklet for deferred DMA rx processing */
1591 	tasklet_setup(&pdcs->rx_tasklet, pdc_tasklet_cb);
1592 
1593 	err = pdc_interrupts_init(pdcs);
1594 	if (err)
1595 		goto cleanup_buf_pool;
1596 
1597 	/* Initialize mailbox controller */
1598 	err = pdc_mb_init(pdcs);
1599 	if (err)
1600 		goto cleanup_buf_pool;
1601 
1602 	pdc_setup_debugfs(pdcs);
1603 
1604 	dev_dbg(dev, "pdc_probe() successful");
1605 	return PDC_SUCCESS;
1606 
1607 cleanup_buf_pool:
1608 	tasklet_kill(&pdcs->rx_tasklet);
1609 	dma_pool_destroy(pdcs->rx_buf_pool);
1610 
1611 cleanup_ring_pool:
1612 	dma_pool_destroy(pdcs->ring_pool);
1613 
1614 cleanup:
1615 	return err;
1616 }
1617 
1618 static int pdc_remove(struct platform_device *pdev)
1619 {
1620 	struct pdc_state *pdcs = platform_get_drvdata(pdev);
1621 
1622 	pdc_free_debugfs();
1623 
1624 	tasklet_kill(&pdcs->rx_tasklet);
1625 
1626 	pdc_hw_disable(pdcs);
1627 
1628 	dma_pool_destroy(pdcs->rx_buf_pool);
1629 	dma_pool_destroy(pdcs->ring_pool);
1630 	return 0;
1631 }
1632 
1633 static struct platform_driver pdc_mbox_driver = {
1634 	.probe = pdc_probe,
1635 	.remove = pdc_remove,
1636 	.driver = {
1637 		   .name = "brcm-iproc-pdc-mbox",
1638 		   .of_match_table = of_match_ptr(pdc_mbox_of_match),
1639 		   },
1640 };
1641 module_platform_driver(pdc_mbox_driver);
1642 
1643 MODULE_AUTHOR("Rob Rice <rob.rice@broadcom.com>");
1644 MODULE_DESCRIPTION("Broadcom PDC mailbox driver");
1645 MODULE_LICENSE("GPL v2");
1646