1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright (C) 2007, 2011 Wolfgang Grandegger <wg@grandegger.com>
3  * Copyright (C) 2012 Stephane Grosjean <s.grosjean@peak-system.com>
4  *
5  * Derived from the PCAN project file driver/src/pcan_pci.c:
6  *
7  * Copyright (C) 2001-2006  PEAK System-Technik GmbH
8  */
9 
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/interrupt.h>
13 #include <linux/netdevice.h>
14 #include <linux/delay.h>
15 #include <linux/pci.h>
16 #include <linux/io.h>
17 #include <linux/can.h>
18 #include <linux/can/dev.h>
19 
20 #include "peak_canfd_user.h"
21 
22 MODULE_AUTHOR("Stephane Grosjean <s.grosjean@peak-system.com>");
23 MODULE_DESCRIPTION("Socket-CAN driver for PEAK PCAN PCIe/M.2 FD family cards");
24 MODULE_SUPPORTED_DEVICE("PEAK PCAN PCIe/M.2 FD CAN cards");
25 MODULE_LICENSE("GPL v2");
26 
27 #define PCIEFD_DRV_NAME		"peak_pciefd"
28 
29 #define PEAK_PCI_VENDOR_ID	0x001c	/* The PCI device and vendor IDs */
30 #define PEAK_PCIEFD_ID		0x0013	/* for PCIe slot cards */
31 #define PCAN_CPCIEFD_ID		0x0014	/* for Compact-PCI Serial slot cards */
32 #define PCAN_PCIE104FD_ID	0x0017	/* for PCIe-104 Express slot cards */
33 #define PCAN_MINIPCIEFD_ID      0x0018	/* for mini-PCIe slot cards */
34 #define PCAN_PCIEFD_OEM_ID      0x0019	/* for PCIe slot OEM cards */
35 #define PCAN_M2_ID		0x001a	/* for M2 slot cards */
36 
37 /* PEAK PCIe board access description */
38 #define PCIEFD_BAR0_SIZE		(64 * 1024)
39 #define PCIEFD_RX_DMA_SIZE		(4 * 1024)
40 #define PCIEFD_TX_DMA_SIZE		(4 * 1024)
41 
42 #define PCIEFD_TX_PAGE_SIZE		(2 * 1024)
43 
44 /* System Control Registers */
45 #define PCIEFD_REG_SYS_CTL_SET		0x0000	/* set bits */
46 #define PCIEFD_REG_SYS_CTL_CLR		0x0004	/* clear bits */
47 
48 /* Version info registers */
49 #define PCIEFD_REG_SYS_VER1		0x0040	/* version reg #1 */
50 #define PCIEFD_REG_SYS_VER2		0x0044	/* version reg #2 */
51 
52 #define PCIEFD_FW_VERSION(x, y, z)	(((u32)(x) << 24) | \
53 					 ((u32)(y) << 16) | \
54 					 ((u32)(z) << 8))
55 
56 /* System Control Registers Bits */
57 #define PCIEFD_SYS_CTL_TS_RST		0x00000001	/* timestamp clock */
58 #define PCIEFD_SYS_CTL_CLK_EN		0x00000002	/* system clock */
59 
60 /* CAN-FD channel addresses */
61 #define PCIEFD_CANX_OFF(c)		(((c) + 1) * 0x1000)
62 
63 #define PCIEFD_ECHO_SKB_MAX		PCANFD_ECHO_SKB_DEF
64 
65 /* CAN-FD channel registers */
66 #define PCIEFD_REG_CAN_MISC		0x0000	/* Misc. control */
67 #define PCIEFD_REG_CAN_CLK_SEL		0x0008	/* Clock selector */
68 #define PCIEFD_REG_CAN_CMD_PORT_L	0x0010	/* 64-bits command port */
69 #define PCIEFD_REG_CAN_CMD_PORT_H	0x0014
70 #define PCIEFD_REG_CAN_TX_REQ_ACC	0x0020	/* Tx request accumulator */
71 #define PCIEFD_REG_CAN_TX_CTL_SET	0x0030	/* Tx control set register */
72 #define PCIEFD_REG_CAN_TX_CTL_CLR	0x0038	/* Tx control clear register */
73 #define PCIEFD_REG_CAN_TX_DMA_ADDR_L	0x0040	/* 64-bits addr for Tx DMA */
74 #define PCIEFD_REG_CAN_TX_DMA_ADDR_H	0x0044
75 #define PCIEFD_REG_CAN_RX_CTL_SET	0x0050	/* Rx control set register */
76 #define PCIEFD_REG_CAN_RX_CTL_CLR	0x0058	/* Rx control clear register */
77 #define PCIEFD_REG_CAN_RX_CTL_WRT	0x0060	/* Rx control write register */
78 #define PCIEFD_REG_CAN_RX_CTL_ACK	0x0068	/* Rx control ACK register */
79 #define PCIEFD_REG_CAN_RX_DMA_ADDR_L	0x0070	/* 64-bits addr for Rx DMA */
80 #define PCIEFD_REG_CAN_RX_DMA_ADDR_H	0x0074
81 
82 /* CAN-FD channel misc register bits */
83 #define CANFD_MISC_TS_RST		0x00000001	/* timestamp cnt rst */
84 
85 /* CAN-FD channel Clock SELector Source & DIVider */
86 #define CANFD_CLK_SEL_DIV_MASK		0x00000007
87 #define CANFD_CLK_SEL_DIV_60MHZ		0x00000000	/* SRC=240MHz only */
88 #define CANFD_CLK_SEL_DIV_40MHZ		0x00000001	/* SRC=240MHz only */
89 #define CANFD_CLK_SEL_DIV_30MHZ		0x00000002	/* SRC=240MHz only */
90 #define CANFD_CLK_SEL_DIV_24MHZ		0x00000003	/* SRC=240MHz only */
91 #define CANFD_CLK_SEL_DIV_20MHZ		0x00000004	/* SRC=240MHz only */
92 
93 #define CANFD_CLK_SEL_SRC_MASK		0x00000008	/* 0=80MHz, 1=240MHz */
94 #define CANFD_CLK_SEL_SRC_240MHZ	0x00000008
95 #define CANFD_CLK_SEL_SRC_80MHZ		(~CANFD_CLK_SEL_SRC_240MHZ & \
96 							CANFD_CLK_SEL_SRC_MASK)
97 
98 #define CANFD_CLK_SEL_20MHZ		(CANFD_CLK_SEL_SRC_240MHZ |\
99 						CANFD_CLK_SEL_DIV_20MHZ)
100 #define CANFD_CLK_SEL_24MHZ		(CANFD_CLK_SEL_SRC_240MHZ |\
101 						CANFD_CLK_SEL_DIV_24MHZ)
102 #define CANFD_CLK_SEL_30MHZ		(CANFD_CLK_SEL_SRC_240MHZ |\
103 						CANFD_CLK_SEL_DIV_30MHZ)
104 #define CANFD_CLK_SEL_40MHZ		(CANFD_CLK_SEL_SRC_240MHZ |\
105 						CANFD_CLK_SEL_DIV_40MHZ)
106 #define CANFD_CLK_SEL_60MHZ		(CANFD_CLK_SEL_SRC_240MHZ |\
107 						CANFD_CLK_SEL_DIV_60MHZ)
108 #define CANFD_CLK_SEL_80MHZ		(CANFD_CLK_SEL_SRC_80MHZ)
109 
110 /* CAN-FD channel Rx/Tx control register bits */
111 #define CANFD_CTL_UNC_BIT		0x00010000	/* Uncached DMA mem */
112 #define CANFD_CTL_RST_BIT		0x00020000	/* reset DMA action */
113 #define CANFD_CTL_IEN_BIT		0x00040000	/* IRQ enable */
114 
115 /* Rx IRQ Count and Time Limits */
116 #define CANFD_CTL_IRQ_CL_DEF	16	/* Rx msg max nb per IRQ in Rx DMA */
117 #define CANFD_CTL_IRQ_TL_DEF	10	/* Time before IRQ if < CL (x100 µs) */
118 
119 #define CANFD_OPTIONS_SET	(CANFD_OPTION_ERROR | CANFD_OPTION_BUSLOAD)
120 
121 /* Tx anticipation window (link logical address should be aligned on 2K
122  * boundary)
123  */
124 #define PCIEFD_TX_PAGE_COUNT	(PCIEFD_TX_DMA_SIZE / PCIEFD_TX_PAGE_SIZE)
125 
126 #define CANFD_MSG_LNK_TX	0x1001	/* Tx msgs link */
127 
128 /* 32-bits IRQ status fields, heading Rx DMA area */
129 static inline int pciefd_irq_tag(u32 irq_status)
130 {
131 	return irq_status & 0x0000000f;
132 }
133 
134 static inline int pciefd_irq_rx_cnt(u32 irq_status)
135 {
136 	return (irq_status & 0x000007f0) >> 4;
137 }
138 
139 static inline int pciefd_irq_is_lnk(u32 irq_status)
140 {
141 	return irq_status & 0x00010000;
142 }
143 
144 /* Rx record */
145 struct pciefd_rx_dma {
146 	__le32 irq_status;
147 	__le32 sys_time_low;
148 	__le32 sys_time_high;
149 	struct pucan_rx_msg msg[];
150 } __packed __aligned(4);
151 
152 /* Tx Link record */
153 struct pciefd_tx_link {
154 	__le16 size;
155 	__le16 type;
156 	__le32 laddr_lo;
157 	__le32 laddr_hi;
158 } __packed __aligned(4);
159 
160 /* Tx page descriptor */
161 struct pciefd_page {
162 	void *vbase;			/* page virtual address */
163 	dma_addr_t lbase;		/* page logical address */
164 	u32 offset;
165 	u32 size;
166 };
167 
168 /* CAN-FD channel object */
169 struct pciefd_board;
170 struct pciefd_can {
171 	struct peak_canfd_priv ucan;	/* must be the first member */
172 	void __iomem *reg_base;		/* channel config base addr */
173 	struct pciefd_board *board;	/* reverse link */
174 
175 	struct pucan_command pucan_cmd;	/* command buffer */
176 
177 	dma_addr_t rx_dma_laddr;	/* DMA virtual and logical addr */
178 	void *rx_dma_vaddr;		/* for Rx and Tx areas */
179 	dma_addr_t tx_dma_laddr;
180 	void *tx_dma_vaddr;
181 
182 	struct pciefd_page tx_pages[PCIEFD_TX_PAGE_COUNT];
183 	u16 tx_pages_free;		/* free Tx pages counter */
184 	u16 tx_page_index;		/* current page used for Tx */
185 	spinlock_t tx_lock;
186 
187 	u32 irq_status;
188 	u32 irq_tag;				/* next irq tag */
189 };
190 
191 /* PEAK-PCIe FD board object */
192 struct pciefd_board {
193 	void __iomem *reg_base;
194 	struct pci_dev *pci_dev;
195 	int can_count;
196 	spinlock_t cmd_lock;		/* 64-bits cmds must be atomic */
197 	struct pciefd_can *can[];	/* array of network devices */
198 };
199 
200 /* supported device ids. */
201 static const struct pci_device_id peak_pciefd_tbl[] = {
202 	{PEAK_PCI_VENDOR_ID, PEAK_PCIEFD_ID, PCI_ANY_ID, PCI_ANY_ID,},
203 	{PEAK_PCI_VENDOR_ID, PCAN_CPCIEFD_ID, PCI_ANY_ID, PCI_ANY_ID,},
204 	{PEAK_PCI_VENDOR_ID, PCAN_PCIE104FD_ID, PCI_ANY_ID, PCI_ANY_ID,},
205 	{PEAK_PCI_VENDOR_ID, PCAN_MINIPCIEFD_ID, PCI_ANY_ID, PCI_ANY_ID,},
206 	{PEAK_PCI_VENDOR_ID, PCAN_PCIEFD_OEM_ID, PCI_ANY_ID, PCI_ANY_ID,},
207 	{PEAK_PCI_VENDOR_ID, PCAN_M2_ID, PCI_ANY_ID, PCI_ANY_ID,},
208 	{0,}
209 };
210 
211 MODULE_DEVICE_TABLE(pci, peak_pciefd_tbl);
212 
213 /* read a 32 bits value from a SYS block register */
214 static inline u32 pciefd_sys_readreg(const struct pciefd_board *priv, u16 reg)
215 {
216 	return readl(priv->reg_base + reg);
217 }
218 
219 /* write a 32 bits value into a SYS block register */
220 static inline void pciefd_sys_writereg(const struct pciefd_board *priv,
221 				       u32 val, u16 reg)
222 {
223 	writel(val, priv->reg_base + reg);
224 }
225 
226 /* read a 32 bits value from CAN-FD block register */
227 static inline u32 pciefd_can_readreg(const struct pciefd_can *priv, u16 reg)
228 {
229 	return readl(priv->reg_base + reg);
230 }
231 
232 /* write a 32 bits value into a CAN-FD block register */
233 static inline void pciefd_can_writereg(const struct pciefd_can *priv,
234 				       u32 val, u16 reg)
235 {
236 	writel(val, priv->reg_base + reg);
237 }
238 
239 /* give a channel logical Rx DMA address to the board */
240 static void pciefd_can_setup_rx_dma(struct pciefd_can *priv)
241 {
242 #ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
243 	const u32 dma_addr_h = (u32)(priv->rx_dma_laddr >> 32);
244 #else
245 	const u32 dma_addr_h = 0;
246 #endif
247 
248 	/* (DMA must be reset for Rx) */
249 	pciefd_can_writereg(priv, CANFD_CTL_RST_BIT, PCIEFD_REG_CAN_RX_CTL_SET);
250 
251 	/* write the logical address of the Rx DMA area for this channel */
252 	pciefd_can_writereg(priv, (u32)priv->rx_dma_laddr,
253 			    PCIEFD_REG_CAN_RX_DMA_ADDR_L);
254 	pciefd_can_writereg(priv, dma_addr_h, PCIEFD_REG_CAN_RX_DMA_ADDR_H);
255 
256 	/* also indicates that Rx DMA is cacheable */
257 	pciefd_can_writereg(priv, CANFD_CTL_UNC_BIT, PCIEFD_REG_CAN_RX_CTL_CLR);
258 }
259 
260 /* clear channel logical Rx DMA address from the board */
261 static void pciefd_can_clear_rx_dma(struct pciefd_can *priv)
262 {
263 	/* DMA must be reset for Rx */
264 	pciefd_can_writereg(priv, CANFD_CTL_RST_BIT, PCIEFD_REG_CAN_RX_CTL_SET);
265 
266 	/* clear the logical address of the Rx DMA area for this channel */
267 	pciefd_can_writereg(priv, 0, PCIEFD_REG_CAN_RX_DMA_ADDR_L);
268 	pciefd_can_writereg(priv, 0, PCIEFD_REG_CAN_RX_DMA_ADDR_H);
269 }
270 
271 /* give a channel logical Tx DMA address to the board */
272 static void pciefd_can_setup_tx_dma(struct pciefd_can *priv)
273 {
274 #ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
275 	const u32 dma_addr_h = (u32)(priv->tx_dma_laddr >> 32);
276 #else
277 	const u32 dma_addr_h = 0;
278 #endif
279 
280 	/* (DMA must be reset for Tx) */
281 	pciefd_can_writereg(priv, CANFD_CTL_RST_BIT, PCIEFD_REG_CAN_TX_CTL_SET);
282 
283 	/* write the logical address of the Tx DMA area for this channel */
284 	pciefd_can_writereg(priv, (u32)priv->tx_dma_laddr,
285 			    PCIEFD_REG_CAN_TX_DMA_ADDR_L);
286 	pciefd_can_writereg(priv, dma_addr_h, PCIEFD_REG_CAN_TX_DMA_ADDR_H);
287 
288 	/* also indicates that Tx DMA is cacheable */
289 	pciefd_can_writereg(priv, CANFD_CTL_UNC_BIT, PCIEFD_REG_CAN_TX_CTL_CLR);
290 }
291 
292 /* clear channel logical Tx DMA address from the board */
293 static void pciefd_can_clear_tx_dma(struct pciefd_can *priv)
294 {
295 	/* DMA must be reset for Tx */
296 	pciefd_can_writereg(priv, CANFD_CTL_RST_BIT, PCIEFD_REG_CAN_TX_CTL_SET);
297 
298 	/* clear the logical address of the Tx DMA area for this channel */
299 	pciefd_can_writereg(priv, 0, PCIEFD_REG_CAN_TX_DMA_ADDR_L);
300 	pciefd_can_writereg(priv, 0, PCIEFD_REG_CAN_TX_DMA_ADDR_H);
301 }
302 
303 static void pciefd_can_ack_rx_dma(struct pciefd_can *priv)
304 {
305 	/* read value of current IRQ tag and inc it for next one */
306 	priv->irq_tag = le32_to_cpu(*(__le32 *)priv->rx_dma_vaddr);
307 	priv->irq_tag++;
308 	priv->irq_tag &= 0xf;
309 
310 	/* write the next IRQ tag for this CAN */
311 	pciefd_can_writereg(priv, priv->irq_tag, PCIEFD_REG_CAN_RX_CTL_ACK);
312 }
313 
314 /* IRQ handler */
315 static irqreturn_t pciefd_irq_handler(int irq, void *arg)
316 {
317 	struct pciefd_can *priv = arg;
318 	struct pciefd_rx_dma *rx_dma = priv->rx_dma_vaddr;
319 
320 	/* INTA mode only to sync with PCIe transaction */
321 	if (!pci_dev_msi_enabled(priv->board->pci_dev))
322 		(void)pciefd_sys_readreg(priv->board, PCIEFD_REG_SYS_VER1);
323 
324 	/* read IRQ status from the first 32-bits of the Rx DMA area */
325 	priv->irq_status = le32_to_cpu(rx_dma->irq_status);
326 
327 	/* check if this (shared) IRQ is for this CAN */
328 	if (pciefd_irq_tag(priv->irq_status) != priv->irq_tag)
329 		return IRQ_NONE;
330 
331 	/* handle rx messages (if any) */
332 	peak_canfd_handle_msgs_list(&priv->ucan,
333 				    rx_dma->msg,
334 				    pciefd_irq_rx_cnt(priv->irq_status));
335 
336 	/* handle tx link interrupt (if any) */
337 	if (pciefd_irq_is_lnk(priv->irq_status)) {
338 		unsigned long flags;
339 
340 		spin_lock_irqsave(&priv->tx_lock, flags);
341 		priv->tx_pages_free++;
342 		spin_unlock_irqrestore(&priv->tx_lock, flags);
343 
344 		/* wake producer up (only if enough room in echo_skb array) */
345 		spin_lock_irqsave(&priv->ucan.echo_lock, flags);
346 		if (!priv->ucan.can.echo_skb[priv->ucan.echo_idx])
347 			netif_wake_queue(priv->ucan.ndev);
348 
349 		spin_unlock_irqrestore(&priv->ucan.echo_lock, flags);
350 	}
351 
352 	/* re-enable Rx DMA transfer for this CAN */
353 	pciefd_can_ack_rx_dma(priv);
354 
355 	return IRQ_HANDLED;
356 }
357 
358 static int pciefd_enable_tx_path(struct peak_canfd_priv *ucan)
359 {
360 	struct pciefd_can *priv = (struct pciefd_can *)ucan;
361 	int i;
362 
363 	/* initialize the Tx pages descriptors */
364 	priv->tx_pages_free = PCIEFD_TX_PAGE_COUNT - 1;
365 	priv->tx_page_index = 0;
366 
367 	priv->tx_pages[0].vbase = priv->tx_dma_vaddr;
368 	priv->tx_pages[0].lbase = priv->tx_dma_laddr;
369 
370 	for (i = 0; i < PCIEFD_TX_PAGE_COUNT; i++) {
371 		priv->tx_pages[i].offset = 0;
372 		priv->tx_pages[i].size = PCIEFD_TX_PAGE_SIZE -
373 					 sizeof(struct pciefd_tx_link);
374 		if (i) {
375 			priv->tx_pages[i].vbase =
376 					  priv->tx_pages[i - 1].vbase +
377 					  PCIEFD_TX_PAGE_SIZE;
378 			priv->tx_pages[i].lbase =
379 					  priv->tx_pages[i - 1].lbase +
380 					  PCIEFD_TX_PAGE_SIZE;
381 		}
382 	}
383 
384 	/* setup Tx DMA addresses into IP core */
385 	pciefd_can_setup_tx_dma(priv);
386 
387 	/* start (TX_RST=0) Tx Path */
388 	pciefd_can_writereg(priv, CANFD_CTL_RST_BIT, PCIEFD_REG_CAN_TX_CTL_CLR);
389 
390 	return 0;
391 }
392 
393 /* board specific CANFD command pre-processing */
394 static int pciefd_pre_cmd(struct peak_canfd_priv *ucan)
395 {
396 	struct pciefd_can *priv = (struct pciefd_can *)ucan;
397 	u16 cmd = pucan_cmd_get_opcode(&priv->pucan_cmd);
398 	int err;
399 
400 	/* pre-process command */
401 	switch (cmd) {
402 	case PUCAN_CMD_NORMAL_MODE:
403 	case PUCAN_CMD_LISTEN_ONLY_MODE:
404 
405 		if (ucan->can.state == CAN_STATE_BUS_OFF)
406 			break;
407 
408 		/* going into operational mode: setup IRQ handler */
409 		err = request_irq(priv->ucan.ndev->irq,
410 				  pciefd_irq_handler,
411 				  IRQF_SHARED,
412 				  PCIEFD_DRV_NAME,
413 				  priv);
414 		if (err)
415 			return err;
416 
417 		/* setup Rx DMA address */
418 		pciefd_can_setup_rx_dma(priv);
419 
420 		/* setup max count of msgs per IRQ */
421 		pciefd_can_writereg(priv, (CANFD_CTL_IRQ_TL_DEF) << 8 |
422 				    CANFD_CTL_IRQ_CL_DEF,
423 				    PCIEFD_REG_CAN_RX_CTL_WRT);
424 
425 		/* clear DMA RST for Rx (Rx start) */
426 		pciefd_can_writereg(priv, CANFD_CTL_RST_BIT,
427 				    PCIEFD_REG_CAN_RX_CTL_CLR);
428 
429 		/* reset timestamps */
430 		pciefd_can_writereg(priv, !CANFD_MISC_TS_RST,
431 				    PCIEFD_REG_CAN_MISC);
432 
433 		/* do an initial ACK */
434 		pciefd_can_ack_rx_dma(priv);
435 
436 		/* enable IRQ for this CAN after having set next irq_tag */
437 		pciefd_can_writereg(priv, CANFD_CTL_IEN_BIT,
438 				    PCIEFD_REG_CAN_RX_CTL_SET);
439 
440 		/* Tx path will be setup as soon as RX_BARRIER is received */
441 		break;
442 	default:
443 		break;
444 	}
445 
446 	return 0;
447 }
448 
449 /* write a command */
450 static int pciefd_write_cmd(struct peak_canfd_priv *ucan)
451 {
452 	struct pciefd_can *priv = (struct pciefd_can *)ucan;
453 	unsigned long flags;
454 
455 	/* 64-bits command is atomic */
456 	spin_lock_irqsave(&priv->board->cmd_lock, flags);
457 
458 	pciefd_can_writereg(priv, *(u32 *)ucan->cmd_buffer,
459 			    PCIEFD_REG_CAN_CMD_PORT_L);
460 	pciefd_can_writereg(priv, *(u32 *)(ucan->cmd_buffer + 4),
461 			    PCIEFD_REG_CAN_CMD_PORT_H);
462 
463 	spin_unlock_irqrestore(&priv->board->cmd_lock, flags);
464 
465 	return 0;
466 }
467 
468 /* board specific CANFD command post-processing */
469 static int pciefd_post_cmd(struct peak_canfd_priv *ucan)
470 {
471 	struct pciefd_can *priv = (struct pciefd_can *)ucan;
472 	u16 cmd = pucan_cmd_get_opcode(&priv->pucan_cmd);
473 
474 	switch (cmd) {
475 	case PUCAN_CMD_RESET_MODE:
476 
477 		if (ucan->can.state == CAN_STATE_STOPPED)
478 			break;
479 
480 		/* controller now in reset mode: */
481 
482 		/* disable IRQ for this CAN */
483 		pciefd_can_writereg(priv, CANFD_CTL_IEN_BIT,
484 				    PCIEFD_REG_CAN_RX_CTL_CLR);
485 
486 		/* stop and reset DMA addresses in Tx/Rx engines */
487 		pciefd_can_clear_tx_dma(priv);
488 		pciefd_can_clear_rx_dma(priv);
489 
490 		/* wait for above commands to complete (read cycle) */
491 		(void)pciefd_sys_readreg(priv->board, PCIEFD_REG_SYS_VER1);
492 
493 		free_irq(priv->ucan.ndev->irq, priv);
494 
495 		ucan->can.state = CAN_STATE_STOPPED;
496 
497 		break;
498 	}
499 
500 	return 0;
501 }
502 
503 static void *pciefd_alloc_tx_msg(struct peak_canfd_priv *ucan, u16 msg_size,
504 				 int *room_left)
505 {
506 	struct pciefd_can *priv = (struct pciefd_can *)ucan;
507 	struct pciefd_page *page = priv->tx_pages + priv->tx_page_index;
508 	unsigned long flags;
509 	void *msg;
510 
511 	spin_lock_irqsave(&priv->tx_lock, flags);
512 
513 	if (page->offset + msg_size > page->size) {
514 		struct pciefd_tx_link *lk;
515 
516 		/* not enough space in this page: try another one */
517 		if (!priv->tx_pages_free) {
518 			spin_unlock_irqrestore(&priv->tx_lock, flags);
519 
520 			/* Tx overflow */
521 			return NULL;
522 		}
523 
524 		priv->tx_pages_free--;
525 
526 		/* keep address of the very last free slot of current page */
527 		lk = page->vbase + page->offset;
528 
529 		/* next, move on a new free page */
530 		priv->tx_page_index = (priv->tx_page_index + 1) %
531 				      PCIEFD_TX_PAGE_COUNT;
532 		page = priv->tx_pages + priv->tx_page_index;
533 
534 		/* put link record to this new page at the end of prev one */
535 		lk->size = cpu_to_le16(sizeof(*lk));
536 		lk->type = cpu_to_le16(CANFD_MSG_LNK_TX);
537 		lk->laddr_lo = cpu_to_le32(page->lbase);
538 
539 #ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
540 		lk->laddr_hi = cpu_to_le32(page->lbase >> 32);
541 #else
542 		lk->laddr_hi = 0;
543 #endif
544 		/* next msgs will be put from the begininng of this new page */
545 		page->offset = 0;
546 	}
547 
548 	*room_left = priv->tx_pages_free * page->size;
549 
550 	spin_unlock_irqrestore(&priv->tx_lock, flags);
551 
552 	msg = page->vbase + page->offset;
553 
554 	/* give back room left in the tx ring */
555 	*room_left += page->size - (page->offset + msg_size);
556 
557 	return msg;
558 }
559 
560 static int pciefd_write_tx_msg(struct peak_canfd_priv *ucan,
561 			       struct pucan_tx_msg *msg)
562 {
563 	struct pciefd_can *priv = (struct pciefd_can *)ucan;
564 	struct pciefd_page *page = priv->tx_pages + priv->tx_page_index;
565 
566 	/* this slot is now reserved for writing the frame */
567 	page->offset += le16_to_cpu(msg->size);
568 
569 	/* tell the board a frame has been written in Tx DMA area */
570 	pciefd_can_writereg(priv, 1, PCIEFD_REG_CAN_TX_REQ_ACC);
571 
572 	return 0;
573 }
574 
575 /* probe for CAN-FD channel #pciefd_board->can_count */
576 static int pciefd_can_probe(struct pciefd_board *pciefd)
577 {
578 	struct net_device *ndev;
579 	struct pciefd_can *priv;
580 	u32 clk;
581 	int err;
582 
583 	/* allocate the candev object with default isize of echo skbs ring */
584 	ndev = alloc_peak_canfd_dev(sizeof(*priv), pciefd->can_count,
585 				    PCIEFD_ECHO_SKB_MAX);
586 	if (!ndev) {
587 		dev_err(&pciefd->pci_dev->dev,
588 			"failed to alloc candev object\n");
589 		goto failure;
590 	}
591 
592 	priv = netdev_priv(ndev);
593 
594 	/* fill-in candev private object: */
595 
596 	/* setup PCIe-FD own callbacks */
597 	priv->ucan.pre_cmd = pciefd_pre_cmd;
598 	priv->ucan.write_cmd = pciefd_write_cmd;
599 	priv->ucan.post_cmd = pciefd_post_cmd;
600 	priv->ucan.enable_tx_path = pciefd_enable_tx_path;
601 	priv->ucan.alloc_tx_msg = pciefd_alloc_tx_msg;
602 	priv->ucan.write_tx_msg = pciefd_write_tx_msg;
603 
604 	/* setup PCIe-FD own command buffer */
605 	priv->ucan.cmd_buffer = &priv->pucan_cmd;
606 	priv->ucan.cmd_maxlen = sizeof(priv->pucan_cmd);
607 
608 	priv->board = pciefd;
609 
610 	/* CAN config regs block address */
611 	priv->reg_base = pciefd->reg_base + PCIEFD_CANX_OFF(priv->ucan.index);
612 
613 	/* allocate non-cacheable DMA'able 4KB memory area for Rx */
614 	priv->rx_dma_vaddr = dmam_alloc_coherent(&pciefd->pci_dev->dev,
615 						 PCIEFD_RX_DMA_SIZE,
616 						 &priv->rx_dma_laddr,
617 						 GFP_KERNEL);
618 	if (!priv->rx_dma_vaddr) {
619 		dev_err(&pciefd->pci_dev->dev,
620 			"Rx dmam_alloc_coherent(%u) failure\n",
621 			PCIEFD_RX_DMA_SIZE);
622 		goto err_free_candev;
623 	}
624 
625 	/* allocate non-cacheable DMA'able 4KB memory area for Tx */
626 	priv->tx_dma_vaddr = dmam_alloc_coherent(&pciefd->pci_dev->dev,
627 						 PCIEFD_TX_DMA_SIZE,
628 						 &priv->tx_dma_laddr,
629 						 GFP_KERNEL);
630 	if (!priv->tx_dma_vaddr) {
631 		dev_err(&pciefd->pci_dev->dev,
632 			"Tx dmam_alloc_coherent(%u) failure\n",
633 			PCIEFD_TX_DMA_SIZE);
634 		goto err_free_candev;
635 	}
636 
637 	/* CAN clock in RST mode */
638 	pciefd_can_writereg(priv, CANFD_MISC_TS_RST, PCIEFD_REG_CAN_MISC);
639 
640 	/* read current clock value */
641 	clk = pciefd_can_readreg(priv, PCIEFD_REG_CAN_CLK_SEL);
642 	switch (clk) {
643 	case CANFD_CLK_SEL_20MHZ:
644 		priv->ucan.can.clock.freq = 20 * 1000 * 1000;
645 		break;
646 	case CANFD_CLK_SEL_24MHZ:
647 		priv->ucan.can.clock.freq = 24 * 1000 * 1000;
648 		break;
649 	case CANFD_CLK_SEL_30MHZ:
650 		priv->ucan.can.clock.freq = 30 * 1000 * 1000;
651 		break;
652 	case CANFD_CLK_SEL_40MHZ:
653 		priv->ucan.can.clock.freq = 40 * 1000 * 1000;
654 		break;
655 	case CANFD_CLK_SEL_60MHZ:
656 		priv->ucan.can.clock.freq = 60 * 1000 * 1000;
657 		break;
658 	default:
659 		pciefd_can_writereg(priv, CANFD_CLK_SEL_80MHZ,
660 				    PCIEFD_REG_CAN_CLK_SEL);
661 
662 		/* fall through */
663 	case CANFD_CLK_SEL_80MHZ:
664 		priv->ucan.can.clock.freq = 80 * 1000 * 1000;
665 		break;
666 	}
667 
668 	ndev->irq = pciefd->pci_dev->irq;
669 
670 	SET_NETDEV_DEV(ndev, &pciefd->pci_dev->dev);
671 
672 	err = register_candev(ndev);
673 	if (err) {
674 		dev_err(&pciefd->pci_dev->dev,
675 			"couldn't register CAN device: %d\n", err);
676 		goto err_free_candev;
677 	}
678 
679 	spin_lock_init(&priv->tx_lock);
680 
681 	/* save the object address in the board structure */
682 	pciefd->can[pciefd->can_count] = priv;
683 
684 	dev_info(&pciefd->pci_dev->dev, "%s at reg_base=0x%p irq=%d\n",
685 		 ndev->name, priv->reg_base, ndev->irq);
686 
687 	return 0;
688 
689 err_free_candev:
690 	free_candev(ndev);
691 
692 failure:
693 	return -ENOMEM;
694 }
695 
696 /* remove a CAN-FD channel by releasing all of its resources */
697 static void pciefd_can_remove(struct pciefd_can *priv)
698 {
699 	/* unregister (close) the can device to go back to RST mode first */
700 	unregister_candev(priv->ucan.ndev);
701 
702 	/* finally, free the candev object */
703 	free_candev(priv->ucan.ndev);
704 }
705 
706 /* remove all CAN-FD channels by releasing their own resources */
707 static void pciefd_can_remove_all(struct pciefd_board *pciefd)
708 {
709 	while (pciefd->can_count > 0)
710 		pciefd_can_remove(pciefd->can[--pciefd->can_count]);
711 }
712 
713 /* probe for the entire device */
714 static int peak_pciefd_probe(struct pci_dev *pdev,
715 			     const struct pci_device_id *ent)
716 {
717 	struct pciefd_board *pciefd;
718 	int err, can_count;
719 	u16 sub_sys_id;
720 	u8 hw_ver_major;
721 	u8 hw_ver_minor;
722 	u8 hw_ver_sub;
723 	u32 v2;
724 
725 	err = pci_enable_device(pdev);
726 	if (err)
727 		return err;
728 	err = pci_request_regions(pdev, PCIEFD_DRV_NAME);
729 	if (err)
730 		goto err_disable_pci;
731 
732 	/* the number of channels depends on sub-system id */
733 	err = pci_read_config_word(pdev, PCI_SUBSYSTEM_ID, &sub_sys_id);
734 	if (err)
735 		goto err_release_regions;
736 
737 	dev_dbg(&pdev->dev, "probing device %04x:%04x:%04x\n",
738 		pdev->vendor, pdev->device, sub_sys_id);
739 
740 	if (sub_sys_id >= 0x0012)
741 		can_count = 4;
742 	else if (sub_sys_id >= 0x0010)
743 		can_count = 3;
744 	else if (sub_sys_id >= 0x0004)
745 		can_count = 2;
746 	else
747 		can_count = 1;
748 
749 	/* allocate board structure object */
750 	pciefd = devm_kzalloc(&pdev->dev, struct_size(pciefd, can, can_count),
751 			      GFP_KERNEL);
752 	if (!pciefd) {
753 		err = -ENOMEM;
754 		goto err_release_regions;
755 	}
756 
757 	/* initialize the board structure */
758 	pciefd->pci_dev = pdev;
759 	spin_lock_init(&pciefd->cmd_lock);
760 
761 	/* save the PCI BAR0 virtual address for further system regs access */
762 	pciefd->reg_base = pci_iomap(pdev, 0, PCIEFD_BAR0_SIZE);
763 	if (!pciefd->reg_base) {
764 		dev_err(&pdev->dev, "failed to map PCI resource #0\n");
765 		err = -ENOMEM;
766 		goto err_release_regions;
767 	}
768 
769 	/* read the firmware version number */
770 	v2 = pciefd_sys_readreg(pciefd, PCIEFD_REG_SYS_VER2);
771 
772 	hw_ver_major = (v2 & 0x0000f000) >> 12;
773 	hw_ver_minor = (v2 & 0x00000f00) >> 8;
774 	hw_ver_sub = (v2 & 0x000000f0) >> 4;
775 
776 	dev_info(&pdev->dev,
777 		 "%ux CAN-FD PCAN-PCIe FPGA v%u.%u.%u:\n", can_count,
778 		 hw_ver_major, hw_ver_minor, hw_ver_sub);
779 
780 #ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
781 	/* FW < v3.3.0 DMA logic doesn't handle correctly the mix of 32-bit and
782 	 * 64-bit logical addresses: this workaround forces usage of 32-bit
783 	 * DMA addresses only when such a fw is detected.
784 	 */
785 	if (PCIEFD_FW_VERSION(hw_ver_major, hw_ver_minor, hw_ver_sub) <
786 	    PCIEFD_FW_VERSION(3, 3, 0)) {
787 		err = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
788 		if (err)
789 			dev_warn(&pdev->dev,
790 				 "warning: can't set DMA mask %llxh (err %d)\n",
791 				 DMA_BIT_MASK(32), err);
792 	}
793 #endif
794 
795 	/* stop system clock */
796 	pciefd_sys_writereg(pciefd, PCIEFD_SYS_CTL_CLK_EN,
797 			    PCIEFD_REG_SYS_CTL_CLR);
798 
799 	pci_set_master(pdev);
800 
801 	/* create now the corresponding channels objects */
802 	while (pciefd->can_count < can_count) {
803 		err = pciefd_can_probe(pciefd);
804 		if (err)
805 			goto err_free_canfd;
806 
807 		pciefd->can_count++;
808 	}
809 
810 	/* set system timestamps counter in RST mode */
811 	pciefd_sys_writereg(pciefd, PCIEFD_SYS_CTL_TS_RST,
812 			    PCIEFD_REG_SYS_CTL_SET);
813 
814 	/* wait a bit (read cycle) */
815 	(void)pciefd_sys_readreg(pciefd, PCIEFD_REG_SYS_VER1);
816 
817 	/* free all clocks */
818 	pciefd_sys_writereg(pciefd, PCIEFD_SYS_CTL_TS_RST,
819 			    PCIEFD_REG_SYS_CTL_CLR);
820 
821 	/* start system clock */
822 	pciefd_sys_writereg(pciefd, PCIEFD_SYS_CTL_CLK_EN,
823 			    PCIEFD_REG_SYS_CTL_SET);
824 
825 	/* remember the board structure address in the device user data */
826 	pci_set_drvdata(pdev, pciefd);
827 
828 	return 0;
829 
830 err_free_canfd:
831 	pciefd_can_remove_all(pciefd);
832 
833 	pci_iounmap(pdev, pciefd->reg_base);
834 
835 err_release_regions:
836 	pci_release_regions(pdev);
837 
838 err_disable_pci:
839 	pci_disable_device(pdev);
840 
841 	/* pci_xxx_config_word() return positive PCIBIOS_xxx error codes while
842 	 * the probe() function must return a negative errno in case of failure
843 	 * (err is unchanged if negative)
844 	 */
845 	return pcibios_err_to_errno(err);
846 }
847 
848 /* free the board structure object, as well as its resources: */
849 static void peak_pciefd_remove(struct pci_dev *pdev)
850 {
851 	struct pciefd_board *pciefd = pci_get_drvdata(pdev);
852 
853 	/* release CAN-FD channels resources */
854 	pciefd_can_remove_all(pciefd);
855 
856 	pci_iounmap(pdev, pciefd->reg_base);
857 
858 	pci_release_regions(pdev);
859 	pci_disable_device(pdev);
860 }
861 
862 static struct pci_driver peak_pciefd_driver = {
863 	.name = PCIEFD_DRV_NAME,
864 	.id_table = peak_pciefd_tbl,
865 	.probe = peak_pciefd_probe,
866 	.remove = peak_pciefd_remove,
867 };
868 
869 module_pci_driver(peak_pciefd_driver);
870