xref: /openbmc/linux/drivers/dma/qcom/bam_dma.c (revision f5cc14e4)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (c) 2013-2014, The Linux Foundation. All rights reserved.
4  */
5 /*
6  * QCOM BAM DMA engine driver
7  *
8  * QCOM BAM DMA blocks are distributed amongst a number of the on-chip
9  * peripherals on the MSM 8x74.  The configuration of the channels are dependent
10  * on the way they are hard wired to that specific peripheral.  The peripheral
11  * device tree entries specify the configuration of each channel.
12  *
13  * The DMA controller requires the use of external memory for storage of the
14  * hardware descriptors for each channel.  The descriptor FIFO is accessed as a
15  * circular buffer and operations are managed according to the offset within the
16  * FIFO.  After pipe/channel reset, all of the pipe registers and internal state
17  * are back to defaults.
18  *
19  * During DMA operations, we write descriptors to the FIFO, being careful to
20  * handle wrapping and then write the last FIFO offset to that channel's
21  * P_EVNT_REG register to kick off the transaction.  The P_SW_OFSTS register
22  * indicates the current FIFO offset that is being processed, so there is some
23  * indication of where the hardware is currently working.
24  */
25 
26 #include <linux/kernel.h>
27 #include <linux/io.h>
28 #include <linux/init.h>
29 #include <linux/slab.h>
30 #include <linux/module.h>
31 #include <linux/interrupt.h>
32 #include <linux/dma-mapping.h>
33 #include <linux/scatterlist.h>
34 #include <linux/device.h>
35 #include <linux/platform_device.h>
36 #include <linux/of.h>
37 #include <linux/of_address.h>
38 #include <linux/of_irq.h>
39 #include <linux/of_dma.h>
40 #include <linux/circ_buf.h>
41 #include <linux/clk.h>
42 #include <linux/dmaengine.h>
43 #include <linux/pm_runtime.h>
44 
45 #include "../dmaengine.h"
46 #include "../virt-dma.h"
47 
48 struct bam_desc_hw {
49 	__le32 addr;		/* Buffer physical address */
50 	__le16 size;		/* Buffer size in bytes */
51 	__le16 flags;
52 };
53 
54 #define BAM_DMA_AUTOSUSPEND_DELAY 100
55 
56 #define DESC_FLAG_INT BIT(15)
57 #define DESC_FLAG_EOT BIT(14)
58 #define DESC_FLAG_EOB BIT(13)
59 #define DESC_FLAG_NWD BIT(12)
60 #define DESC_FLAG_CMD BIT(11)
61 
62 struct bam_async_desc {
63 	struct virt_dma_desc vd;
64 
65 	u32 num_desc;
66 	u32 xfer_len;
67 
68 	/* transaction flags, EOT|EOB|NWD */
69 	u16 flags;
70 
71 	struct bam_desc_hw *curr_desc;
72 
73 	/* list node for the desc in the bam_chan list of descriptors */
74 	struct list_head desc_node;
75 	enum dma_transfer_direction dir;
76 	size_t length;
77 	struct bam_desc_hw desc[];
78 };
79 
80 enum bam_reg {
81 	BAM_CTRL,
82 	BAM_REVISION,
83 	BAM_NUM_PIPES,
84 	BAM_DESC_CNT_TRSHLD,
85 	BAM_IRQ_SRCS,
86 	BAM_IRQ_SRCS_MSK,
87 	BAM_IRQ_SRCS_UNMASKED,
88 	BAM_IRQ_STTS,
89 	BAM_IRQ_CLR,
90 	BAM_IRQ_EN,
91 	BAM_CNFG_BITS,
92 	BAM_IRQ_SRCS_EE,
93 	BAM_IRQ_SRCS_MSK_EE,
94 	BAM_P_CTRL,
95 	BAM_P_RST,
96 	BAM_P_HALT,
97 	BAM_P_IRQ_STTS,
98 	BAM_P_IRQ_CLR,
99 	BAM_P_IRQ_EN,
100 	BAM_P_EVNT_DEST_ADDR,
101 	BAM_P_EVNT_REG,
102 	BAM_P_SW_OFSTS,
103 	BAM_P_DATA_FIFO_ADDR,
104 	BAM_P_DESC_FIFO_ADDR,
105 	BAM_P_EVNT_GEN_TRSHLD,
106 	BAM_P_FIFO_SIZES,
107 };
108 
109 struct reg_offset_data {
110 	u32 base_offset;
111 	unsigned int pipe_mult, evnt_mult, ee_mult;
112 };
113 
114 static const struct reg_offset_data bam_v1_3_reg_info[] = {
115 	[BAM_CTRL]		= { 0x0F80, 0x00, 0x00, 0x00 },
116 	[BAM_REVISION]		= { 0x0F84, 0x00, 0x00, 0x00 },
117 	[BAM_NUM_PIPES]		= { 0x0FBC, 0x00, 0x00, 0x00 },
118 	[BAM_DESC_CNT_TRSHLD]	= { 0x0F88, 0x00, 0x00, 0x00 },
119 	[BAM_IRQ_SRCS]		= { 0x0F8C, 0x00, 0x00, 0x00 },
120 	[BAM_IRQ_SRCS_MSK]	= { 0x0F90, 0x00, 0x00, 0x00 },
121 	[BAM_IRQ_SRCS_UNMASKED]	= { 0x0FB0, 0x00, 0x00, 0x00 },
122 	[BAM_IRQ_STTS]		= { 0x0F94, 0x00, 0x00, 0x00 },
123 	[BAM_IRQ_CLR]		= { 0x0F98, 0x00, 0x00, 0x00 },
124 	[BAM_IRQ_EN]		= { 0x0F9C, 0x00, 0x00, 0x00 },
125 	[BAM_CNFG_BITS]		= { 0x0FFC, 0x00, 0x00, 0x00 },
126 	[BAM_IRQ_SRCS_EE]	= { 0x1800, 0x00, 0x00, 0x80 },
127 	[BAM_IRQ_SRCS_MSK_EE]	= { 0x1804, 0x00, 0x00, 0x80 },
128 	[BAM_P_CTRL]		= { 0x0000, 0x80, 0x00, 0x00 },
129 	[BAM_P_RST]		= { 0x0004, 0x80, 0x00, 0x00 },
130 	[BAM_P_HALT]		= { 0x0008, 0x80, 0x00, 0x00 },
131 	[BAM_P_IRQ_STTS]	= { 0x0010, 0x80, 0x00, 0x00 },
132 	[BAM_P_IRQ_CLR]		= { 0x0014, 0x80, 0x00, 0x00 },
133 	[BAM_P_IRQ_EN]		= { 0x0018, 0x80, 0x00, 0x00 },
134 	[BAM_P_EVNT_DEST_ADDR]	= { 0x102C, 0x00, 0x40, 0x00 },
135 	[BAM_P_EVNT_REG]	= { 0x1018, 0x00, 0x40, 0x00 },
136 	[BAM_P_SW_OFSTS]	= { 0x1000, 0x00, 0x40, 0x00 },
137 	[BAM_P_DATA_FIFO_ADDR]	= { 0x1024, 0x00, 0x40, 0x00 },
138 	[BAM_P_DESC_FIFO_ADDR]	= { 0x101C, 0x00, 0x40, 0x00 },
139 	[BAM_P_EVNT_GEN_TRSHLD]	= { 0x1028, 0x00, 0x40, 0x00 },
140 	[BAM_P_FIFO_SIZES]	= { 0x1020, 0x00, 0x40, 0x00 },
141 };
142 
143 static const struct reg_offset_data bam_v1_4_reg_info[] = {
144 	[BAM_CTRL]		= { 0x0000, 0x00, 0x00, 0x00 },
145 	[BAM_REVISION]		= { 0x0004, 0x00, 0x00, 0x00 },
146 	[BAM_NUM_PIPES]		= { 0x003C, 0x00, 0x00, 0x00 },
147 	[BAM_DESC_CNT_TRSHLD]	= { 0x0008, 0x00, 0x00, 0x00 },
148 	[BAM_IRQ_SRCS]		= { 0x000C, 0x00, 0x00, 0x00 },
149 	[BAM_IRQ_SRCS_MSK]	= { 0x0010, 0x00, 0x00, 0x00 },
150 	[BAM_IRQ_SRCS_UNMASKED]	= { 0x0030, 0x00, 0x00, 0x00 },
151 	[BAM_IRQ_STTS]		= { 0x0014, 0x00, 0x00, 0x00 },
152 	[BAM_IRQ_CLR]		= { 0x0018, 0x00, 0x00, 0x00 },
153 	[BAM_IRQ_EN]		= { 0x001C, 0x00, 0x00, 0x00 },
154 	[BAM_CNFG_BITS]		= { 0x007C, 0x00, 0x00, 0x00 },
155 	[BAM_IRQ_SRCS_EE]	= { 0x0800, 0x00, 0x00, 0x80 },
156 	[BAM_IRQ_SRCS_MSK_EE]	= { 0x0804, 0x00, 0x00, 0x80 },
157 	[BAM_P_CTRL]		= { 0x1000, 0x1000, 0x00, 0x00 },
158 	[BAM_P_RST]		= { 0x1004, 0x1000, 0x00, 0x00 },
159 	[BAM_P_HALT]		= { 0x1008, 0x1000, 0x00, 0x00 },
160 	[BAM_P_IRQ_STTS]	= { 0x1010, 0x1000, 0x00, 0x00 },
161 	[BAM_P_IRQ_CLR]		= { 0x1014, 0x1000, 0x00, 0x00 },
162 	[BAM_P_IRQ_EN]		= { 0x1018, 0x1000, 0x00, 0x00 },
163 	[BAM_P_EVNT_DEST_ADDR]	= { 0x182C, 0x00, 0x1000, 0x00 },
164 	[BAM_P_EVNT_REG]	= { 0x1818, 0x00, 0x1000, 0x00 },
165 	[BAM_P_SW_OFSTS]	= { 0x1800, 0x00, 0x1000, 0x00 },
166 	[BAM_P_DATA_FIFO_ADDR]	= { 0x1824, 0x00, 0x1000, 0x00 },
167 	[BAM_P_DESC_FIFO_ADDR]	= { 0x181C, 0x00, 0x1000, 0x00 },
168 	[BAM_P_EVNT_GEN_TRSHLD]	= { 0x1828, 0x00, 0x1000, 0x00 },
169 	[BAM_P_FIFO_SIZES]	= { 0x1820, 0x00, 0x1000, 0x00 },
170 };
171 
172 static const struct reg_offset_data bam_v1_7_reg_info[] = {
173 	[BAM_CTRL]		= { 0x00000, 0x00, 0x00, 0x00 },
174 	[BAM_REVISION]		= { 0x01000, 0x00, 0x00, 0x00 },
175 	[BAM_NUM_PIPES]		= { 0x01008, 0x00, 0x00, 0x00 },
176 	[BAM_DESC_CNT_TRSHLD]	= { 0x00008, 0x00, 0x00, 0x00 },
177 	[BAM_IRQ_SRCS]		= { 0x03010, 0x00, 0x00, 0x00 },
178 	[BAM_IRQ_SRCS_MSK]	= { 0x03014, 0x00, 0x00, 0x00 },
179 	[BAM_IRQ_SRCS_UNMASKED]	= { 0x03018, 0x00, 0x00, 0x00 },
180 	[BAM_IRQ_STTS]		= { 0x00014, 0x00, 0x00, 0x00 },
181 	[BAM_IRQ_CLR]		= { 0x00018, 0x00, 0x00, 0x00 },
182 	[BAM_IRQ_EN]		= { 0x0001C, 0x00, 0x00, 0x00 },
183 	[BAM_CNFG_BITS]		= { 0x0007C, 0x00, 0x00, 0x00 },
184 	[BAM_IRQ_SRCS_EE]	= { 0x03000, 0x00, 0x00, 0x1000 },
185 	[BAM_IRQ_SRCS_MSK_EE]	= { 0x03004, 0x00, 0x00, 0x1000 },
186 	[BAM_P_CTRL]		= { 0x13000, 0x1000, 0x00, 0x00 },
187 	[BAM_P_RST]		= { 0x13004, 0x1000, 0x00, 0x00 },
188 	[BAM_P_HALT]		= { 0x13008, 0x1000, 0x00, 0x00 },
189 	[BAM_P_IRQ_STTS]	= { 0x13010, 0x1000, 0x00, 0x00 },
190 	[BAM_P_IRQ_CLR]		= { 0x13014, 0x1000, 0x00, 0x00 },
191 	[BAM_P_IRQ_EN]		= { 0x13018, 0x1000, 0x00, 0x00 },
192 	[BAM_P_EVNT_DEST_ADDR]	= { 0x1382C, 0x00, 0x1000, 0x00 },
193 	[BAM_P_EVNT_REG]	= { 0x13818, 0x00, 0x1000, 0x00 },
194 	[BAM_P_SW_OFSTS]	= { 0x13800, 0x00, 0x1000, 0x00 },
195 	[BAM_P_DATA_FIFO_ADDR]	= { 0x13824, 0x00, 0x1000, 0x00 },
196 	[BAM_P_DESC_FIFO_ADDR]	= { 0x1381C, 0x00, 0x1000, 0x00 },
197 	[BAM_P_EVNT_GEN_TRSHLD]	= { 0x13828, 0x00, 0x1000, 0x00 },
198 	[BAM_P_FIFO_SIZES]	= { 0x13820, 0x00, 0x1000, 0x00 },
199 };
200 
201 /* BAM CTRL */
202 #define BAM_SW_RST			BIT(0)
203 #define BAM_EN				BIT(1)
204 #define BAM_EN_ACCUM			BIT(4)
205 #define BAM_TESTBUS_SEL_SHIFT		5
206 #define BAM_TESTBUS_SEL_MASK		0x3F
207 #define BAM_DESC_CACHE_SEL_SHIFT	13
208 #define BAM_DESC_CACHE_SEL_MASK		0x3
209 #define BAM_CACHED_DESC_STORE		BIT(15)
210 #define IBC_DISABLE			BIT(16)
211 
212 /* BAM REVISION */
213 #define REVISION_SHIFT		0
214 #define REVISION_MASK		0xFF
215 #define NUM_EES_SHIFT		8
216 #define NUM_EES_MASK		0xF
217 #define CE_BUFFER_SIZE		BIT(13)
218 #define AXI_ACTIVE		BIT(14)
219 #define USE_VMIDMT		BIT(15)
220 #define SECURED			BIT(16)
221 #define BAM_HAS_NO_BYPASS	BIT(17)
222 #define HIGH_FREQUENCY_BAM	BIT(18)
223 #define INACTIV_TMRS_EXST	BIT(19)
224 #define NUM_INACTIV_TMRS	BIT(20)
225 #define DESC_CACHE_DEPTH_SHIFT	21
226 #define DESC_CACHE_DEPTH_1	(0 << DESC_CACHE_DEPTH_SHIFT)
227 #define DESC_CACHE_DEPTH_2	(1 << DESC_CACHE_DEPTH_SHIFT)
228 #define DESC_CACHE_DEPTH_3	(2 << DESC_CACHE_DEPTH_SHIFT)
229 #define DESC_CACHE_DEPTH_4	(3 << DESC_CACHE_DEPTH_SHIFT)
230 #define CMD_DESC_EN		BIT(23)
231 #define INACTIV_TMR_BASE_SHIFT	24
232 #define INACTIV_TMR_BASE_MASK	0xFF
233 
234 /* BAM NUM PIPES */
235 #define BAM_NUM_PIPES_SHIFT		0
236 #define BAM_NUM_PIPES_MASK		0xFF
237 #define PERIPH_NON_PIPE_GRP_SHIFT	16
238 #define PERIPH_NON_PIP_GRP_MASK		0xFF
239 #define BAM_NON_PIPE_GRP_SHIFT		24
240 #define BAM_NON_PIPE_GRP_MASK		0xFF
241 
242 /* BAM CNFG BITS */
243 #define BAM_PIPE_CNFG		BIT(2)
244 #define BAM_FULL_PIPE		BIT(11)
245 #define BAM_NO_EXT_P_RST	BIT(12)
246 #define BAM_IBC_DISABLE		BIT(13)
247 #define BAM_SB_CLK_REQ		BIT(14)
248 #define BAM_PSM_CSW_REQ		BIT(15)
249 #define BAM_PSM_P_RES		BIT(16)
250 #define BAM_AU_P_RES		BIT(17)
251 #define BAM_SI_P_RES		BIT(18)
252 #define BAM_WB_P_RES		BIT(19)
253 #define BAM_WB_BLK_CSW		BIT(20)
254 #define BAM_WB_CSW_ACK_IDL	BIT(21)
255 #define BAM_WB_RETR_SVPNT	BIT(22)
256 #define BAM_WB_DSC_AVL_P_RST	BIT(23)
257 #define BAM_REG_P_EN		BIT(24)
258 #define BAM_PSM_P_HD_DATA	BIT(25)
259 #define BAM_AU_ACCUMED		BIT(26)
260 #define BAM_CMD_ENABLE		BIT(27)
261 
262 #define BAM_CNFG_BITS_DEFAULT	(BAM_PIPE_CNFG |	\
263 				 BAM_NO_EXT_P_RST |	\
264 				 BAM_IBC_DISABLE |	\
265 				 BAM_SB_CLK_REQ |	\
266 				 BAM_PSM_CSW_REQ |	\
267 				 BAM_PSM_P_RES |	\
268 				 BAM_AU_P_RES |		\
269 				 BAM_SI_P_RES |		\
270 				 BAM_WB_P_RES |		\
271 				 BAM_WB_BLK_CSW |	\
272 				 BAM_WB_CSW_ACK_IDL |	\
273 				 BAM_WB_RETR_SVPNT |	\
274 				 BAM_WB_DSC_AVL_P_RST |	\
275 				 BAM_REG_P_EN |		\
276 				 BAM_PSM_P_HD_DATA |	\
277 				 BAM_AU_ACCUMED |	\
278 				 BAM_CMD_ENABLE)
279 
280 /* PIPE CTRL */
281 #define P_EN			BIT(1)
282 #define P_DIRECTION		BIT(3)
283 #define P_SYS_STRM		BIT(4)
284 #define P_SYS_MODE		BIT(5)
285 #define P_AUTO_EOB		BIT(6)
286 #define P_AUTO_EOB_SEL_SHIFT	7
287 #define P_AUTO_EOB_SEL_512	(0 << P_AUTO_EOB_SEL_SHIFT)
288 #define P_AUTO_EOB_SEL_256	(1 << P_AUTO_EOB_SEL_SHIFT)
289 #define P_AUTO_EOB_SEL_128	(2 << P_AUTO_EOB_SEL_SHIFT)
290 #define P_AUTO_EOB_SEL_64	(3 << P_AUTO_EOB_SEL_SHIFT)
291 #define P_PREFETCH_LIMIT_SHIFT	9
292 #define P_PREFETCH_LIMIT_32	(0 << P_PREFETCH_LIMIT_SHIFT)
293 #define P_PREFETCH_LIMIT_16	(1 << P_PREFETCH_LIMIT_SHIFT)
294 #define P_PREFETCH_LIMIT_4	(2 << P_PREFETCH_LIMIT_SHIFT)
295 #define P_WRITE_NWD		BIT(11)
296 #define P_LOCK_GROUP_SHIFT	16
297 #define P_LOCK_GROUP_MASK	0x1F
298 
299 /* BAM_DESC_CNT_TRSHLD */
300 #define CNT_TRSHLD		0xffff
301 #define DEFAULT_CNT_THRSHLD	0x4
302 
303 /* BAM_IRQ_SRCS */
304 #define BAM_IRQ			BIT(31)
305 #define P_IRQ			0x7fffffff
306 
307 /* BAM_IRQ_SRCS_MSK */
308 #define BAM_IRQ_MSK		BAM_IRQ
309 #define P_IRQ_MSK		P_IRQ
310 
311 /* BAM_IRQ_STTS */
312 #define BAM_TIMER_IRQ		BIT(4)
313 #define BAM_EMPTY_IRQ		BIT(3)
314 #define BAM_ERROR_IRQ		BIT(2)
315 #define BAM_HRESP_ERR_IRQ	BIT(1)
316 
317 /* BAM_IRQ_CLR */
318 #define BAM_TIMER_CLR		BIT(4)
319 #define BAM_EMPTY_CLR		BIT(3)
320 #define BAM_ERROR_CLR		BIT(2)
321 #define BAM_HRESP_ERR_CLR	BIT(1)
322 
323 /* BAM_IRQ_EN */
324 #define BAM_TIMER_EN		BIT(4)
325 #define BAM_EMPTY_EN		BIT(3)
326 #define BAM_ERROR_EN		BIT(2)
327 #define BAM_HRESP_ERR_EN	BIT(1)
328 
329 /* BAM_P_IRQ_EN */
330 #define P_PRCSD_DESC_EN		BIT(0)
331 #define P_TIMER_EN		BIT(1)
332 #define P_WAKE_EN		BIT(2)
333 #define P_OUT_OF_DESC_EN	BIT(3)
334 #define P_ERR_EN		BIT(4)
335 #define P_TRNSFR_END_EN		BIT(5)
336 #define P_DEFAULT_IRQS_EN	(P_PRCSD_DESC_EN | P_ERR_EN | P_TRNSFR_END_EN)
337 
338 /* BAM_P_SW_OFSTS */
339 #define P_SW_OFSTS_MASK		0xffff
340 
341 #define BAM_DESC_FIFO_SIZE	SZ_32K
342 #define MAX_DESCRIPTORS (BAM_DESC_FIFO_SIZE / sizeof(struct bam_desc_hw) - 1)
343 #define BAM_FIFO_SIZE	(SZ_32K - 8)
344 #define IS_BUSY(chan)	(CIRC_SPACE(bchan->tail, bchan->head,\
345 			 MAX_DESCRIPTORS + 1) == 0)
346 
347 struct bam_chan {
348 	struct virt_dma_chan vc;
349 
350 	struct bam_device *bdev;
351 
352 	/* configuration from device tree */
353 	u32 id;
354 
355 	/* runtime configuration */
356 	struct dma_slave_config slave;
357 
358 	/* fifo storage */
359 	struct bam_desc_hw *fifo_virt;
360 	dma_addr_t fifo_phys;
361 
362 	/* fifo markers */
363 	unsigned short head;		/* start of active descriptor entries */
364 	unsigned short tail;		/* end of active descriptor entries */
365 
366 	unsigned int initialized;	/* is the channel hw initialized? */
367 	unsigned int paused;		/* is the channel paused? */
368 	unsigned int reconfigure;	/* new slave config? */
369 	/* list of descriptors currently processed */
370 	struct list_head desc_list;
371 
372 	struct list_head node;
373 };
374 
375 static inline struct bam_chan *to_bam_chan(struct dma_chan *common)
376 {
377 	return container_of(common, struct bam_chan, vc.chan);
378 }
379 
380 struct bam_device {
381 	void __iomem *regs;
382 	struct device *dev;
383 	struct dma_device common;
384 	struct bam_chan *channels;
385 	u32 num_channels;
386 	u32 num_ees;
387 
388 	/* execution environment ID, from DT */
389 	u32 ee;
390 	bool controlled_remotely;
391 
392 	const struct reg_offset_data *layout;
393 
394 	struct clk *bamclk;
395 	int irq;
396 
397 	/* dma start transaction tasklet */
398 	struct tasklet_struct task;
399 };
400 
401 /**
402  * bam_addr - returns BAM register address
403  * @bdev: bam device
404  * @pipe: pipe instance (ignored when register doesn't have multiple instances)
405  * @reg:  register enum
406  */
407 static inline void __iomem *bam_addr(struct bam_device *bdev, u32 pipe,
408 		enum bam_reg reg)
409 {
410 	const struct reg_offset_data r = bdev->layout[reg];
411 
412 	return bdev->regs + r.base_offset +
413 		r.pipe_mult * pipe +
414 		r.evnt_mult * pipe +
415 		r.ee_mult * bdev->ee;
416 }
417 
418 /**
419  * bam_reset_channel - Reset individual BAM DMA channel
420  * @bchan: bam channel
421  *
422  * This function resets a specific BAM channel
423  */
424 static void bam_reset_channel(struct bam_chan *bchan)
425 {
426 	struct bam_device *bdev = bchan->bdev;
427 
428 	lockdep_assert_held(&bchan->vc.lock);
429 
430 	/* reset channel */
431 	writel_relaxed(1, bam_addr(bdev, bchan->id, BAM_P_RST));
432 	writel_relaxed(0, bam_addr(bdev, bchan->id, BAM_P_RST));
433 
434 	/* don't allow cpu to reorder BAM register accesses done after this */
435 	wmb();
436 
437 	/* make sure hw is initialized when channel is used the first time  */
438 	bchan->initialized = 0;
439 }
440 
441 /**
442  * bam_chan_init_hw - Initialize channel hardware
443  * @bchan: bam channel
444  * @dir: DMA transfer direction
445  *
446  * This function resets and initializes the BAM channel
447  */
448 static void bam_chan_init_hw(struct bam_chan *bchan,
449 	enum dma_transfer_direction dir)
450 {
451 	struct bam_device *bdev = bchan->bdev;
452 	u32 val;
453 
454 	/* Reset the channel to clear internal state of the FIFO */
455 	bam_reset_channel(bchan);
456 
457 	/*
458 	 * write out 8 byte aligned address.  We have enough space for this
459 	 * because we allocated 1 more descriptor (8 bytes) than we can use
460 	 */
461 	writel_relaxed(ALIGN(bchan->fifo_phys, sizeof(struct bam_desc_hw)),
462 			bam_addr(bdev, bchan->id, BAM_P_DESC_FIFO_ADDR));
463 	writel_relaxed(BAM_FIFO_SIZE,
464 			bam_addr(bdev, bchan->id, BAM_P_FIFO_SIZES));
465 
466 	/* enable the per pipe interrupts, enable EOT, ERR, and INT irqs */
467 	writel_relaxed(P_DEFAULT_IRQS_EN,
468 			bam_addr(bdev, bchan->id, BAM_P_IRQ_EN));
469 
470 	/* unmask the specific pipe and EE combo */
471 	val = readl_relaxed(bam_addr(bdev, 0, BAM_IRQ_SRCS_MSK_EE));
472 	val |= BIT(bchan->id);
473 	writel_relaxed(val, bam_addr(bdev, 0, BAM_IRQ_SRCS_MSK_EE));
474 
475 	/* don't allow cpu to reorder the channel enable done below */
476 	wmb();
477 
478 	/* set fixed direction and mode, then enable channel */
479 	val = P_EN | P_SYS_MODE;
480 	if (dir == DMA_DEV_TO_MEM)
481 		val |= P_DIRECTION;
482 
483 	writel_relaxed(val, bam_addr(bdev, bchan->id, BAM_P_CTRL));
484 
485 	bchan->initialized = 1;
486 
487 	/* init FIFO pointers */
488 	bchan->head = 0;
489 	bchan->tail = 0;
490 }
491 
492 /**
493  * bam_alloc_chan - Allocate channel resources for DMA channel.
494  * @chan: specified channel
495  *
496  * This function allocates the FIFO descriptor memory
497  */
498 static int bam_alloc_chan(struct dma_chan *chan)
499 {
500 	struct bam_chan *bchan = to_bam_chan(chan);
501 	struct bam_device *bdev = bchan->bdev;
502 
503 	if (bchan->fifo_virt)
504 		return 0;
505 
506 	/* allocate FIFO descriptor space, but only if necessary */
507 	bchan->fifo_virt = dma_alloc_wc(bdev->dev, BAM_DESC_FIFO_SIZE,
508 					&bchan->fifo_phys, GFP_KERNEL);
509 
510 	if (!bchan->fifo_virt) {
511 		dev_err(bdev->dev, "Failed to allocate desc fifo\n");
512 		return -ENOMEM;
513 	}
514 
515 	return 0;
516 }
517 
518 static int bam_pm_runtime_get_sync(struct device *dev)
519 {
520 	if (pm_runtime_enabled(dev))
521 		return pm_runtime_get_sync(dev);
522 
523 	return 0;
524 }
525 
526 /**
527  * bam_free_chan - Frees dma resources associated with specific channel
528  * @chan: specified channel
529  *
530  * Free the allocated fifo descriptor memory and channel resources
531  *
532  */
533 static void bam_free_chan(struct dma_chan *chan)
534 {
535 	struct bam_chan *bchan = to_bam_chan(chan);
536 	struct bam_device *bdev = bchan->bdev;
537 	u32 val;
538 	unsigned long flags;
539 	int ret;
540 
541 	ret = bam_pm_runtime_get_sync(bdev->dev);
542 	if (ret < 0)
543 		return;
544 
545 	vchan_free_chan_resources(to_virt_chan(chan));
546 
547 	if (!list_empty(&bchan->desc_list)) {
548 		dev_err(bchan->bdev->dev, "Cannot free busy channel\n");
549 		goto err;
550 	}
551 
552 	spin_lock_irqsave(&bchan->vc.lock, flags);
553 	bam_reset_channel(bchan);
554 	spin_unlock_irqrestore(&bchan->vc.lock, flags);
555 
556 	dma_free_wc(bdev->dev, BAM_DESC_FIFO_SIZE, bchan->fifo_virt,
557 		    bchan->fifo_phys);
558 	bchan->fifo_virt = NULL;
559 
560 	/* mask irq for pipe/channel */
561 	val = readl_relaxed(bam_addr(bdev, 0, BAM_IRQ_SRCS_MSK_EE));
562 	val &= ~BIT(bchan->id);
563 	writel_relaxed(val, bam_addr(bdev, 0, BAM_IRQ_SRCS_MSK_EE));
564 
565 	/* disable irq */
566 	writel_relaxed(0, bam_addr(bdev, bchan->id, BAM_P_IRQ_EN));
567 
568 err:
569 	pm_runtime_mark_last_busy(bdev->dev);
570 	pm_runtime_put_autosuspend(bdev->dev);
571 }
572 
573 /**
574  * bam_slave_config - set slave configuration for channel
575  * @chan: dma channel
576  * @cfg: slave configuration
577  *
578  * Sets slave configuration for channel
579  *
580  */
581 static int bam_slave_config(struct dma_chan *chan,
582 			    struct dma_slave_config *cfg)
583 {
584 	struct bam_chan *bchan = to_bam_chan(chan);
585 	unsigned long flag;
586 
587 	spin_lock_irqsave(&bchan->vc.lock, flag);
588 	memcpy(&bchan->slave, cfg, sizeof(*cfg));
589 	bchan->reconfigure = 1;
590 	spin_unlock_irqrestore(&bchan->vc.lock, flag);
591 
592 	return 0;
593 }
594 
595 /**
596  * bam_prep_slave_sg - Prep slave sg transaction
597  *
598  * @chan: dma channel
599  * @sgl: scatter gather list
600  * @sg_len: length of sg
601  * @direction: DMA transfer direction
602  * @flags: DMA flags
603  * @context: transfer context (unused)
604  */
605 static struct dma_async_tx_descriptor *bam_prep_slave_sg(struct dma_chan *chan,
606 	struct scatterlist *sgl, unsigned int sg_len,
607 	enum dma_transfer_direction direction, unsigned long flags,
608 	void *context)
609 {
610 	struct bam_chan *bchan = to_bam_chan(chan);
611 	struct bam_device *bdev = bchan->bdev;
612 	struct bam_async_desc *async_desc;
613 	struct scatterlist *sg;
614 	u32 i;
615 	struct bam_desc_hw *desc;
616 	unsigned int num_alloc = 0;
617 
618 
619 	if (!is_slave_direction(direction)) {
620 		dev_err(bdev->dev, "invalid dma direction\n");
621 		return NULL;
622 	}
623 
624 	/* calculate number of required entries */
625 	for_each_sg(sgl, sg, sg_len, i)
626 		num_alloc += DIV_ROUND_UP(sg_dma_len(sg), BAM_FIFO_SIZE);
627 
628 	/* allocate enough room to accomodate the number of entries */
629 	async_desc = kzalloc(struct_size(async_desc, desc, num_alloc),
630 			     GFP_NOWAIT);
631 
632 	if (!async_desc)
633 		goto err_out;
634 
635 	if (flags & DMA_PREP_FENCE)
636 		async_desc->flags |= DESC_FLAG_NWD;
637 
638 	if (flags & DMA_PREP_INTERRUPT)
639 		async_desc->flags |= DESC_FLAG_EOT;
640 
641 	async_desc->num_desc = num_alloc;
642 	async_desc->curr_desc = async_desc->desc;
643 	async_desc->dir = direction;
644 
645 	/* fill in temporary descriptors */
646 	desc = async_desc->desc;
647 	for_each_sg(sgl, sg, sg_len, i) {
648 		unsigned int remainder = sg_dma_len(sg);
649 		unsigned int curr_offset = 0;
650 
651 		do {
652 			if (flags & DMA_PREP_CMD)
653 				desc->flags |= cpu_to_le16(DESC_FLAG_CMD);
654 
655 			desc->addr = cpu_to_le32(sg_dma_address(sg) +
656 						 curr_offset);
657 
658 			if (remainder > BAM_FIFO_SIZE) {
659 				desc->size = cpu_to_le16(BAM_FIFO_SIZE);
660 				remainder -= BAM_FIFO_SIZE;
661 				curr_offset += BAM_FIFO_SIZE;
662 			} else {
663 				desc->size = cpu_to_le16(remainder);
664 				remainder = 0;
665 			}
666 
667 			async_desc->length += le16_to_cpu(desc->size);
668 			desc++;
669 		} while (remainder > 0);
670 	}
671 
672 	return vchan_tx_prep(&bchan->vc, &async_desc->vd, flags);
673 
674 err_out:
675 	kfree(async_desc);
676 	return NULL;
677 }
678 
679 /**
680  * bam_dma_terminate_all - terminate all transactions on a channel
681  * @chan: bam dma channel
682  *
683  * Dequeues and frees all transactions
684  * No callbacks are done
685  *
686  */
687 static int bam_dma_terminate_all(struct dma_chan *chan)
688 {
689 	struct bam_chan *bchan = to_bam_chan(chan);
690 	struct bam_async_desc *async_desc, *tmp;
691 	unsigned long flag;
692 	LIST_HEAD(head);
693 
694 	/* remove all transactions, including active transaction */
695 	spin_lock_irqsave(&bchan->vc.lock, flag);
696 	/*
697 	 * If we have transactions queued, then some might be committed to the
698 	 * hardware in the desc fifo.  The only way to reset the desc fifo is
699 	 * to do a hardware reset (either by pipe or the entire block).
700 	 * bam_chan_init_hw() will trigger a pipe reset, and also reinit the
701 	 * pipe.  If the pipe is left disabled (default state after pipe reset)
702 	 * and is accessed by a connected hardware engine, a fatal error in
703 	 * the BAM will occur.  There is a small window where this could happen
704 	 * with bam_chan_init_hw(), but it is assumed that the caller has
705 	 * stopped activity on any attached hardware engine.  Make sure to do
706 	 * this first so that the BAM hardware doesn't cause memory corruption
707 	 * by accessing freed resources.
708 	 */
709 	if (!list_empty(&bchan->desc_list)) {
710 		async_desc = list_first_entry(&bchan->desc_list,
711 					      struct bam_async_desc, desc_node);
712 		bam_chan_init_hw(bchan, async_desc->dir);
713 	}
714 
715 	list_for_each_entry_safe(async_desc, tmp,
716 				 &bchan->desc_list, desc_node) {
717 		list_add(&async_desc->vd.node, &bchan->vc.desc_issued);
718 		list_del(&async_desc->desc_node);
719 	}
720 
721 	vchan_get_all_descriptors(&bchan->vc, &head);
722 	spin_unlock_irqrestore(&bchan->vc.lock, flag);
723 
724 	vchan_dma_desc_free_list(&bchan->vc, &head);
725 
726 	return 0;
727 }
728 
729 /**
730  * bam_pause - Pause DMA channel
731  * @chan: dma channel
732  *
733  */
734 static int bam_pause(struct dma_chan *chan)
735 {
736 	struct bam_chan *bchan = to_bam_chan(chan);
737 	struct bam_device *bdev = bchan->bdev;
738 	unsigned long flag;
739 	int ret;
740 
741 	ret = bam_pm_runtime_get_sync(bdev->dev);
742 	if (ret < 0)
743 		return ret;
744 
745 	spin_lock_irqsave(&bchan->vc.lock, flag);
746 	writel_relaxed(1, bam_addr(bdev, bchan->id, BAM_P_HALT));
747 	bchan->paused = 1;
748 	spin_unlock_irqrestore(&bchan->vc.lock, flag);
749 	pm_runtime_mark_last_busy(bdev->dev);
750 	pm_runtime_put_autosuspend(bdev->dev);
751 
752 	return 0;
753 }
754 
755 /**
756  * bam_resume - Resume DMA channel operations
757  * @chan: dma channel
758  *
759  */
760 static int bam_resume(struct dma_chan *chan)
761 {
762 	struct bam_chan *bchan = to_bam_chan(chan);
763 	struct bam_device *bdev = bchan->bdev;
764 	unsigned long flag;
765 	int ret;
766 
767 	ret = bam_pm_runtime_get_sync(bdev->dev);
768 	if (ret < 0)
769 		return ret;
770 
771 	spin_lock_irqsave(&bchan->vc.lock, flag);
772 	writel_relaxed(0, bam_addr(bdev, bchan->id, BAM_P_HALT));
773 	bchan->paused = 0;
774 	spin_unlock_irqrestore(&bchan->vc.lock, flag);
775 	pm_runtime_mark_last_busy(bdev->dev);
776 	pm_runtime_put_autosuspend(bdev->dev);
777 
778 	return 0;
779 }
780 
781 /**
782  * process_channel_irqs - processes the channel interrupts
783  * @bdev: bam controller
784  *
785  * This function processes the channel interrupts
786  *
787  */
788 static u32 process_channel_irqs(struct bam_device *bdev)
789 {
790 	u32 i, srcs, pipe_stts, offset, avail;
791 	unsigned long flags;
792 	struct bam_async_desc *async_desc, *tmp;
793 
794 	srcs = readl_relaxed(bam_addr(bdev, 0, BAM_IRQ_SRCS_EE));
795 
796 	/* return early if no pipe/channel interrupts are present */
797 	if (!(srcs & P_IRQ))
798 		return srcs;
799 
800 	for (i = 0; i < bdev->num_channels; i++) {
801 		struct bam_chan *bchan = &bdev->channels[i];
802 
803 		if (!(srcs & BIT(i)))
804 			continue;
805 
806 		/* clear pipe irq */
807 		pipe_stts = readl_relaxed(bam_addr(bdev, i, BAM_P_IRQ_STTS));
808 
809 		writel_relaxed(pipe_stts, bam_addr(bdev, i, BAM_P_IRQ_CLR));
810 
811 		spin_lock_irqsave(&bchan->vc.lock, flags);
812 
813 		offset = readl_relaxed(bam_addr(bdev, i, BAM_P_SW_OFSTS)) &
814 				       P_SW_OFSTS_MASK;
815 		offset /= sizeof(struct bam_desc_hw);
816 
817 		/* Number of bytes available to read */
818 		avail = CIRC_CNT(offset, bchan->head, MAX_DESCRIPTORS + 1);
819 
820 		if (offset < bchan->head)
821 			avail--;
822 
823 		list_for_each_entry_safe(async_desc, tmp,
824 					 &bchan->desc_list, desc_node) {
825 			/* Not enough data to read */
826 			if (avail < async_desc->xfer_len)
827 				break;
828 
829 			/* manage FIFO */
830 			bchan->head += async_desc->xfer_len;
831 			bchan->head %= MAX_DESCRIPTORS;
832 
833 			async_desc->num_desc -= async_desc->xfer_len;
834 			async_desc->curr_desc += async_desc->xfer_len;
835 			avail -= async_desc->xfer_len;
836 
837 			/*
838 			 * if complete, process cookie. Otherwise
839 			 * push back to front of desc_issued so that
840 			 * it gets restarted by the tasklet
841 			 */
842 			if (!async_desc->num_desc) {
843 				vchan_cookie_complete(&async_desc->vd);
844 			} else {
845 				list_add(&async_desc->vd.node,
846 					 &bchan->vc.desc_issued);
847 			}
848 			list_del(&async_desc->desc_node);
849 		}
850 
851 		spin_unlock_irqrestore(&bchan->vc.lock, flags);
852 	}
853 
854 	return srcs;
855 }
856 
857 /**
858  * bam_dma_irq - irq handler for bam controller
859  * @irq: IRQ of interrupt
860  * @data: callback data
861  *
862  * IRQ handler for the bam controller
863  */
864 static irqreturn_t bam_dma_irq(int irq, void *data)
865 {
866 	struct bam_device *bdev = data;
867 	u32 clr_mask = 0, srcs = 0;
868 	int ret;
869 
870 	srcs |= process_channel_irqs(bdev);
871 
872 	/* kick off tasklet to start next dma transfer */
873 	if (srcs & P_IRQ)
874 		tasklet_schedule(&bdev->task);
875 
876 	ret = bam_pm_runtime_get_sync(bdev->dev);
877 	if (ret < 0)
878 		return IRQ_NONE;
879 
880 	if (srcs & BAM_IRQ) {
881 		clr_mask = readl_relaxed(bam_addr(bdev, 0, BAM_IRQ_STTS));
882 
883 		/*
884 		 * don't allow reorder of the various accesses to the BAM
885 		 * registers
886 		 */
887 		mb();
888 
889 		writel_relaxed(clr_mask, bam_addr(bdev, 0, BAM_IRQ_CLR));
890 	}
891 
892 	pm_runtime_mark_last_busy(bdev->dev);
893 	pm_runtime_put_autosuspend(bdev->dev);
894 
895 	return IRQ_HANDLED;
896 }
897 
898 /**
899  * bam_tx_status - returns status of transaction
900  * @chan: dma channel
901  * @cookie: transaction cookie
902  * @txstate: DMA transaction state
903  *
904  * Return status of dma transaction
905  */
906 static enum dma_status bam_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
907 		struct dma_tx_state *txstate)
908 {
909 	struct bam_chan *bchan = to_bam_chan(chan);
910 	struct bam_async_desc *async_desc;
911 	struct virt_dma_desc *vd;
912 	int ret;
913 	size_t residue = 0;
914 	unsigned int i;
915 	unsigned long flags;
916 
917 	ret = dma_cookie_status(chan, cookie, txstate);
918 	if (ret == DMA_COMPLETE)
919 		return ret;
920 
921 	if (!txstate)
922 		return bchan->paused ? DMA_PAUSED : ret;
923 
924 	spin_lock_irqsave(&bchan->vc.lock, flags);
925 	vd = vchan_find_desc(&bchan->vc, cookie);
926 	if (vd) {
927 		residue = container_of(vd, struct bam_async_desc, vd)->length;
928 	} else {
929 		list_for_each_entry(async_desc, &bchan->desc_list, desc_node) {
930 			if (async_desc->vd.tx.cookie != cookie)
931 				continue;
932 
933 			for (i = 0; i < async_desc->num_desc; i++)
934 				residue += le16_to_cpu(
935 						async_desc->curr_desc[i].size);
936 		}
937 	}
938 
939 	spin_unlock_irqrestore(&bchan->vc.lock, flags);
940 
941 	dma_set_residue(txstate, residue);
942 
943 	if (ret == DMA_IN_PROGRESS && bchan->paused)
944 		ret = DMA_PAUSED;
945 
946 	return ret;
947 }
948 
949 /**
950  * bam_apply_new_config
951  * @bchan: bam dma channel
952  * @dir: DMA direction
953  */
954 static void bam_apply_new_config(struct bam_chan *bchan,
955 	enum dma_transfer_direction dir)
956 {
957 	struct bam_device *bdev = bchan->bdev;
958 	u32 maxburst;
959 
960 	if (!bdev->controlled_remotely) {
961 		if (dir == DMA_DEV_TO_MEM)
962 			maxburst = bchan->slave.src_maxburst;
963 		else
964 			maxburst = bchan->slave.dst_maxburst;
965 
966 		writel_relaxed(maxburst,
967 			       bam_addr(bdev, 0, BAM_DESC_CNT_TRSHLD));
968 	}
969 
970 	bchan->reconfigure = 0;
971 }
972 
973 /**
974  * bam_start_dma - start next transaction
975  * @bchan: bam dma channel
976  */
977 static void bam_start_dma(struct bam_chan *bchan)
978 {
979 	struct virt_dma_desc *vd = vchan_next_desc(&bchan->vc);
980 	struct bam_device *bdev = bchan->bdev;
981 	struct bam_async_desc *async_desc = NULL;
982 	struct bam_desc_hw *desc;
983 	struct bam_desc_hw *fifo = PTR_ALIGN(bchan->fifo_virt,
984 					sizeof(struct bam_desc_hw));
985 	int ret;
986 	unsigned int avail;
987 	struct dmaengine_desc_callback cb;
988 
989 	lockdep_assert_held(&bchan->vc.lock);
990 
991 	if (!vd)
992 		return;
993 
994 	ret = bam_pm_runtime_get_sync(bdev->dev);
995 	if (ret < 0)
996 		return;
997 
998 	while (vd && !IS_BUSY(bchan)) {
999 		list_del(&vd->node);
1000 
1001 		async_desc = container_of(vd, struct bam_async_desc, vd);
1002 
1003 		/* on first use, initialize the channel hardware */
1004 		if (!bchan->initialized)
1005 			bam_chan_init_hw(bchan, async_desc->dir);
1006 
1007 		/* apply new slave config changes, if necessary */
1008 		if (bchan->reconfigure)
1009 			bam_apply_new_config(bchan, async_desc->dir);
1010 
1011 		desc = async_desc->curr_desc;
1012 		avail = CIRC_SPACE(bchan->tail, bchan->head,
1013 				   MAX_DESCRIPTORS + 1);
1014 
1015 		if (async_desc->num_desc > avail)
1016 			async_desc->xfer_len = avail;
1017 		else
1018 			async_desc->xfer_len = async_desc->num_desc;
1019 
1020 		/* set any special flags on the last descriptor */
1021 		if (async_desc->num_desc == async_desc->xfer_len)
1022 			desc[async_desc->xfer_len - 1].flags |=
1023 						cpu_to_le16(async_desc->flags);
1024 
1025 		vd = vchan_next_desc(&bchan->vc);
1026 
1027 		dmaengine_desc_get_callback(&async_desc->vd.tx, &cb);
1028 
1029 		/*
1030 		 * An interrupt is generated at this desc, if
1031 		 *  - FIFO is FULL.
1032 		 *  - No more descriptors to add.
1033 		 *  - If a callback completion was requested for this DESC,
1034 		 *     In this case, BAM will deliver the completion callback
1035 		 *     for this desc and continue processing the next desc.
1036 		 */
1037 		if (((avail <= async_desc->xfer_len) || !vd ||
1038 		     dmaengine_desc_callback_valid(&cb)) &&
1039 		    !(async_desc->flags & DESC_FLAG_EOT))
1040 			desc[async_desc->xfer_len - 1].flags |=
1041 				cpu_to_le16(DESC_FLAG_INT);
1042 
1043 		if (bchan->tail + async_desc->xfer_len > MAX_DESCRIPTORS) {
1044 			u32 partial = MAX_DESCRIPTORS - bchan->tail;
1045 
1046 			memcpy(&fifo[bchan->tail], desc,
1047 			       partial * sizeof(struct bam_desc_hw));
1048 			memcpy(fifo, &desc[partial],
1049 			       (async_desc->xfer_len - partial) *
1050 				sizeof(struct bam_desc_hw));
1051 		} else {
1052 			memcpy(&fifo[bchan->tail], desc,
1053 			       async_desc->xfer_len *
1054 			       sizeof(struct bam_desc_hw));
1055 		}
1056 
1057 		bchan->tail += async_desc->xfer_len;
1058 		bchan->tail %= MAX_DESCRIPTORS;
1059 		list_add_tail(&async_desc->desc_node, &bchan->desc_list);
1060 	}
1061 
1062 	/* ensure descriptor writes and dma start not reordered */
1063 	wmb();
1064 	writel_relaxed(bchan->tail * sizeof(struct bam_desc_hw),
1065 			bam_addr(bdev, bchan->id, BAM_P_EVNT_REG));
1066 
1067 	pm_runtime_mark_last_busy(bdev->dev);
1068 	pm_runtime_put_autosuspend(bdev->dev);
1069 }
1070 
1071 /**
1072  * dma_tasklet - DMA IRQ tasklet
1073  * @t: tasklet argument (bam controller structure)
1074  *
1075  * Sets up next DMA operation and then processes all completed transactions
1076  */
1077 static void dma_tasklet(struct tasklet_struct *t)
1078 {
1079 	struct bam_device *bdev = from_tasklet(bdev, t, task);
1080 	struct bam_chan *bchan;
1081 	unsigned long flags;
1082 	unsigned int i;
1083 
1084 	/* go through the channels and kick off transactions */
1085 	for (i = 0; i < bdev->num_channels; i++) {
1086 		bchan = &bdev->channels[i];
1087 		spin_lock_irqsave(&bchan->vc.lock, flags);
1088 
1089 		if (!list_empty(&bchan->vc.desc_issued) && !IS_BUSY(bchan))
1090 			bam_start_dma(bchan);
1091 		spin_unlock_irqrestore(&bchan->vc.lock, flags);
1092 	}
1093 
1094 }
1095 
1096 /**
1097  * bam_issue_pending - starts pending transactions
1098  * @chan: dma channel
1099  *
1100  * Calls tasklet directly which in turn starts any pending transactions
1101  */
1102 static void bam_issue_pending(struct dma_chan *chan)
1103 {
1104 	struct bam_chan *bchan = to_bam_chan(chan);
1105 	unsigned long flags;
1106 
1107 	spin_lock_irqsave(&bchan->vc.lock, flags);
1108 
1109 	/* if work pending and idle, start a transaction */
1110 	if (vchan_issue_pending(&bchan->vc) && !IS_BUSY(bchan))
1111 		bam_start_dma(bchan);
1112 
1113 	spin_unlock_irqrestore(&bchan->vc.lock, flags);
1114 }
1115 
1116 /**
1117  * bam_dma_free_desc - free descriptor memory
1118  * @vd: virtual descriptor
1119  *
1120  */
1121 static void bam_dma_free_desc(struct virt_dma_desc *vd)
1122 {
1123 	struct bam_async_desc *async_desc = container_of(vd,
1124 			struct bam_async_desc, vd);
1125 
1126 	kfree(async_desc);
1127 }
1128 
1129 static struct dma_chan *bam_dma_xlate(struct of_phandle_args *dma_spec,
1130 		struct of_dma *of)
1131 {
1132 	struct bam_device *bdev = container_of(of->of_dma_data,
1133 					struct bam_device, common);
1134 	unsigned int request;
1135 
1136 	if (dma_spec->args_count != 1)
1137 		return NULL;
1138 
1139 	request = dma_spec->args[0];
1140 	if (request >= bdev->num_channels)
1141 		return NULL;
1142 
1143 	return dma_get_slave_channel(&(bdev->channels[request].vc.chan));
1144 }
1145 
1146 /**
1147  * bam_init
1148  * @bdev: bam device
1149  *
1150  * Initialization helper for global bam registers
1151  */
1152 static int bam_init(struct bam_device *bdev)
1153 {
1154 	u32 val;
1155 
1156 	/* read revision and configuration information */
1157 	if (!bdev->num_ees) {
1158 		val = readl_relaxed(bam_addr(bdev, 0, BAM_REVISION));
1159 		bdev->num_ees = (val >> NUM_EES_SHIFT) & NUM_EES_MASK;
1160 	}
1161 
1162 	/* check that configured EE is within range */
1163 	if (bdev->ee >= bdev->num_ees)
1164 		return -EINVAL;
1165 
1166 	if (!bdev->num_channels) {
1167 		val = readl_relaxed(bam_addr(bdev, 0, BAM_NUM_PIPES));
1168 		bdev->num_channels = val & BAM_NUM_PIPES_MASK;
1169 	}
1170 
1171 	if (bdev->controlled_remotely)
1172 		return 0;
1173 
1174 	/* s/w reset bam */
1175 	/* after reset all pipes are disabled and idle */
1176 	val = readl_relaxed(bam_addr(bdev, 0, BAM_CTRL));
1177 	val |= BAM_SW_RST;
1178 	writel_relaxed(val, bam_addr(bdev, 0, BAM_CTRL));
1179 	val &= ~BAM_SW_RST;
1180 	writel_relaxed(val, bam_addr(bdev, 0, BAM_CTRL));
1181 
1182 	/* make sure previous stores are visible before enabling BAM */
1183 	wmb();
1184 
1185 	/* enable bam */
1186 	val |= BAM_EN;
1187 	writel_relaxed(val, bam_addr(bdev, 0, BAM_CTRL));
1188 
1189 	/* set descriptor threshhold, start with 4 bytes */
1190 	writel_relaxed(DEFAULT_CNT_THRSHLD,
1191 			bam_addr(bdev, 0, BAM_DESC_CNT_TRSHLD));
1192 
1193 	/* Enable default set of h/w workarounds, ie all except BAM_FULL_PIPE */
1194 	writel_relaxed(BAM_CNFG_BITS_DEFAULT, bam_addr(bdev, 0, BAM_CNFG_BITS));
1195 
1196 	/* enable irqs for errors */
1197 	writel_relaxed(BAM_ERROR_EN | BAM_HRESP_ERR_EN,
1198 			bam_addr(bdev, 0, BAM_IRQ_EN));
1199 
1200 	/* unmask global bam interrupt */
1201 	writel_relaxed(BAM_IRQ_MSK, bam_addr(bdev, 0, BAM_IRQ_SRCS_MSK_EE));
1202 
1203 	return 0;
1204 }
1205 
1206 static void bam_channel_init(struct bam_device *bdev, struct bam_chan *bchan,
1207 	u32 index)
1208 {
1209 	bchan->id = index;
1210 	bchan->bdev = bdev;
1211 
1212 	vchan_init(&bchan->vc, &bdev->common);
1213 	bchan->vc.desc_free = bam_dma_free_desc;
1214 	INIT_LIST_HEAD(&bchan->desc_list);
1215 }
1216 
1217 static const struct of_device_id bam_of_match[] = {
1218 	{ .compatible = "qcom,bam-v1.3.0", .data = &bam_v1_3_reg_info },
1219 	{ .compatible = "qcom,bam-v1.4.0", .data = &bam_v1_4_reg_info },
1220 	{ .compatible = "qcom,bam-v1.7.0", .data = &bam_v1_7_reg_info },
1221 	{}
1222 };
1223 
1224 MODULE_DEVICE_TABLE(of, bam_of_match);
1225 
1226 static int bam_dma_probe(struct platform_device *pdev)
1227 {
1228 	struct bam_device *bdev;
1229 	const struct of_device_id *match;
1230 	struct resource *iores;
1231 	int ret, i;
1232 
1233 	bdev = devm_kzalloc(&pdev->dev, sizeof(*bdev), GFP_KERNEL);
1234 	if (!bdev)
1235 		return -ENOMEM;
1236 
1237 	bdev->dev = &pdev->dev;
1238 
1239 	match = of_match_node(bam_of_match, pdev->dev.of_node);
1240 	if (!match) {
1241 		dev_err(&pdev->dev, "Unsupported BAM module\n");
1242 		return -ENODEV;
1243 	}
1244 
1245 	bdev->layout = match->data;
1246 
1247 	iores = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1248 	bdev->regs = devm_ioremap_resource(&pdev->dev, iores);
1249 	if (IS_ERR(bdev->regs))
1250 		return PTR_ERR(bdev->regs);
1251 
1252 	bdev->irq = platform_get_irq(pdev, 0);
1253 	if (bdev->irq < 0)
1254 		return bdev->irq;
1255 
1256 	ret = of_property_read_u32(pdev->dev.of_node, "qcom,ee", &bdev->ee);
1257 	if (ret) {
1258 		dev_err(bdev->dev, "Execution environment unspecified\n");
1259 		return ret;
1260 	}
1261 
1262 	bdev->controlled_remotely = of_property_read_bool(pdev->dev.of_node,
1263 						"qcom,controlled-remotely");
1264 
1265 	if (bdev->controlled_remotely) {
1266 		ret = of_property_read_u32(pdev->dev.of_node, "num-channels",
1267 					   &bdev->num_channels);
1268 		if (ret)
1269 			dev_err(bdev->dev, "num-channels unspecified in dt\n");
1270 
1271 		ret = of_property_read_u32(pdev->dev.of_node, "qcom,num-ees",
1272 					   &bdev->num_ees);
1273 		if (ret)
1274 			dev_err(bdev->dev, "num-ees unspecified in dt\n");
1275 	}
1276 
1277 	bdev->bamclk = devm_clk_get(bdev->dev, "bam_clk");
1278 	if (IS_ERR(bdev->bamclk)) {
1279 		if (!bdev->controlled_remotely)
1280 			return PTR_ERR(bdev->bamclk);
1281 
1282 		bdev->bamclk = NULL;
1283 	}
1284 
1285 	ret = clk_prepare_enable(bdev->bamclk);
1286 	if (ret) {
1287 		dev_err(bdev->dev, "failed to prepare/enable clock\n");
1288 		return ret;
1289 	}
1290 
1291 	ret = bam_init(bdev);
1292 	if (ret)
1293 		goto err_disable_clk;
1294 
1295 	tasklet_setup(&bdev->task, dma_tasklet);
1296 
1297 	bdev->channels = devm_kcalloc(bdev->dev, bdev->num_channels,
1298 				sizeof(*bdev->channels), GFP_KERNEL);
1299 
1300 	if (!bdev->channels) {
1301 		ret = -ENOMEM;
1302 		goto err_tasklet_kill;
1303 	}
1304 
1305 	/* allocate and initialize channels */
1306 	INIT_LIST_HEAD(&bdev->common.channels);
1307 
1308 	for (i = 0; i < bdev->num_channels; i++)
1309 		bam_channel_init(bdev, &bdev->channels[i], i);
1310 
1311 	ret = devm_request_irq(bdev->dev, bdev->irq, bam_dma_irq,
1312 			IRQF_TRIGGER_HIGH, "bam_dma", bdev);
1313 	if (ret)
1314 		goto err_bam_channel_exit;
1315 
1316 	/* set max dma segment size */
1317 	bdev->common.dev = bdev->dev;
1318 	ret = dma_set_max_seg_size(bdev->common.dev, BAM_FIFO_SIZE);
1319 	if (ret) {
1320 		dev_err(bdev->dev, "cannot set maximum segment size\n");
1321 		goto err_bam_channel_exit;
1322 	}
1323 
1324 	platform_set_drvdata(pdev, bdev);
1325 
1326 	/* set capabilities */
1327 	dma_cap_zero(bdev->common.cap_mask);
1328 	dma_cap_set(DMA_SLAVE, bdev->common.cap_mask);
1329 
1330 	/* initialize dmaengine apis */
1331 	bdev->common.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
1332 	bdev->common.residue_granularity = DMA_RESIDUE_GRANULARITY_SEGMENT;
1333 	bdev->common.src_addr_widths = DMA_SLAVE_BUSWIDTH_4_BYTES;
1334 	bdev->common.dst_addr_widths = DMA_SLAVE_BUSWIDTH_4_BYTES;
1335 	bdev->common.device_alloc_chan_resources = bam_alloc_chan;
1336 	bdev->common.device_free_chan_resources = bam_free_chan;
1337 	bdev->common.device_prep_slave_sg = bam_prep_slave_sg;
1338 	bdev->common.device_config = bam_slave_config;
1339 	bdev->common.device_pause = bam_pause;
1340 	bdev->common.device_resume = bam_resume;
1341 	bdev->common.device_terminate_all = bam_dma_terminate_all;
1342 	bdev->common.device_issue_pending = bam_issue_pending;
1343 	bdev->common.device_tx_status = bam_tx_status;
1344 	bdev->common.dev = bdev->dev;
1345 
1346 	ret = dma_async_device_register(&bdev->common);
1347 	if (ret) {
1348 		dev_err(bdev->dev, "failed to register dma async device\n");
1349 		goto err_bam_channel_exit;
1350 	}
1351 
1352 	ret = of_dma_controller_register(pdev->dev.of_node, bam_dma_xlate,
1353 					&bdev->common);
1354 	if (ret)
1355 		goto err_unregister_dma;
1356 
1357 	if (bdev->controlled_remotely) {
1358 		pm_runtime_disable(&pdev->dev);
1359 		return 0;
1360 	}
1361 
1362 	pm_runtime_irq_safe(&pdev->dev);
1363 	pm_runtime_set_autosuspend_delay(&pdev->dev, BAM_DMA_AUTOSUSPEND_DELAY);
1364 	pm_runtime_use_autosuspend(&pdev->dev);
1365 	pm_runtime_mark_last_busy(&pdev->dev);
1366 	pm_runtime_set_active(&pdev->dev);
1367 	pm_runtime_enable(&pdev->dev);
1368 
1369 	return 0;
1370 
1371 err_unregister_dma:
1372 	dma_async_device_unregister(&bdev->common);
1373 err_bam_channel_exit:
1374 	for (i = 0; i < bdev->num_channels; i++)
1375 		tasklet_kill(&bdev->channels[i].vc.task);
1376 err_tasklet_kill:
1377 	tasklet_kill(&bdev->task);
1378 err_disable_clk:
1379 	clk_disable_unprepare(bdev->bamclk);
1380 
1381 	return ret;
1382 }
1383 
1384 static int bam_dma_remove(struct platform_device *pdev)
1385 {
1386 	struct bam_device *bdev = platform_get_drvdata(pdev);
1387 	u32 i;
1388 
1389 	pm_runtime_force_suspend(&pdev->dev);
1390 
1391 	of_dma_controller_free(pdev->dev.of_node);
1392 	dma_async_device_unregister(&bdev->common);
1393 
1394 	/* mask all interrupts for this execution environment */
1395 	writel_relaxed(0, bam_addr(bdev, 0,  BAM_IRQ_SRCS_MSK_EE));
1396 
1397 	devm_free_irq(bdev->dev, bdev->irq, bdev);
1398 
1399 	for (i = 0; i < bdev->num_channels; i++) {
1400 		bam_dma_terminate_all(&bdev->channels[i].vc.chan);
1401 		tasklet_kill(&bdev->channels[i].vc.task);
1402 
1403 		if (!bdev->channels[i].fifo_virt)
1404 			continue;
1405 
1406 		dma_free_wc(bdev->dev, BAM_DESC_FIFO_SIZE,
1407 			    bdev->channels[i].fifo_virt,
1408 			    bdev->channels[i].fifo_phys);
1409 	}
1410 
1411 	tasklet_kill(&bdev->task);
1412 
1413 	clk_disable_unprepare(bdev->bamclk);
1414 
1415 	return 0;
1416 }
1417 
1418 static int __maybe_unused bam_dma_runtime_suspend(struct device *dev)
1419 {
1420 	struct bam_device *bdev = dev_get_drvdata(dev);
1421 
1422 	clk_disable(bdev->bamclk);
1423 
1424 	return 0;
1425 }
1426 
1427 static int __maybe_unused bam_dma_runtime_resume(struct device *dev)
1428 {
1429 	struct bam_device *bdev = dev_get_drvdata(dev);
1430 	int ret;
1431 
1432 	ret = clk_enable(bdev->bamclk);
1433 	if (ret < 0) {
1434 		dev_err(dev, "clk_enable failed: %d\n", ret);
1435 		return ret;
1436 	}
1437 
1438 	return 0;
1439 }
1440 
1441 static int __maybe_unused bam_dma_suspend(struct device *dev)
1442 {
1443 	struct bam_device *bdev = dev_get_drvdata(dev);
1444 
1445 	if (!bdev->controlled_remotely)
1446 		pm_runtime_force_suspend(dev);
1447 
1448 	clk_unprepare(bdev->bamclk);
1449 
1450 	return 0;
1451 }
1452 
1453 static int __maybe_unused bam_dma_resume(struct device *dev)
1454 {
1455 	struct bam_device *bdev = dev_get_drvdata(dev);
1456 	int ret;
1457 
1458 	ret = clk_prepare(bdev->bamclk);
1459 	if (ret)
1460 		return ret;
1461 
1462 	if (!bdev->controlled_remotely)
1463 		pm_runtime_force_resume(dev);
1464 
1465 	return 0;
1466 }
1467 
1468 static const struct dev_pm_ops bam_dma_pm_ops = {
1469 	SET_LATE_SYSTEM_SLEEP_PM_OPS(bam_dma_suspend, bam_dma_resume)
1470 	SET_RUNTIME_PM_OPS(bam_dma_runtime_suspend, bam_dma_runtime_resume,
1471 				NULL)
1472 };
1473 
1474 static struct platform_driver bam_dma_driver = {
1475 	.probe = bam_dma_probe,
1476 	.remove = bam_dma_remove,
1477 	.driver = {
1478 		.name = "bam-dma-engine",
1479 		.pm = &bam_dma_pm_ops,
1480 		.of_match_table = bam_of_match,
1481 	},
1482 };
1483 
1484 module_platform_driver(bam_dma_driver);
1485 
1486 MODULE_AUTHOR("Andy Gross <agross@codeaurora.org>");
1487 MODULE_DESCRIPTION("QCOM BAM DMA engine driver");
1488 MODULE_LICENSE("GPL v2");
1489