xref: /openbmc/linux/drivers/dma/qcom/bam_dma.c (revision a44e4f3a)
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[0];
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 device_dma_parameters dma_parms;
385 	struct bam_chan *channels;
386 	u32 num_channels;
387 	u32 num_ees;
388 
389 	/* execution environment ID, from DT */
390 	u32 ee;
391 	bool controlled_remotely;
392 
393 	const struct reg_offset_data *layout;
394 
395 	struct clk *bamclk;
396 	int irq;
397 
398 	/* dma start transaction tasklet */
399 	struct tasklet_struct task;
400 };
401 
402 /**
403  * bam_addr - returns BAM register address
404  * @bdev: bam device
405  * @pipe: pipe instance (ignored when register doesn't have multiple instances)
406  * @reg:  register enum
407  */
408 static inline void __iomem *bam_addr(struct bam_device *bdev, u32 pipe,
409 		enum bam_reg reg)
410 {
411 	const struct reg_offset_data r = bdev->layout[reg];
412 
413 	return bdev->regs + r.base_offset +
414 		r.pipe_mult * pipe +
415 		r.evnt_mult * pipe +
416 		r.ee_mult * bdev->ee;
417 }
418 
419 /**
420  * bam_reset_channel - Reset individual BAM DMA channel
421  * @bchan: bam channel
422  *
423  * This function resets a specific BAM channel
424  */
425 static void bam_reset_channel(struct bam_chan *bchan)
426 {
427 	struct bam_device *bdev = bchan->bdev;
428 
429 	lockdep_assert_held(&bchan->vc.lock);
430 
431 	/* reset channel */
432 	writel_relaxed(1, bam_addr(bdev, bchan->id, BAM_P_RST));
433 	writel_relaxed(0, bam_addr(bdev, bchan->id, BAM_P_RST));
434 
435 	/* don't allow cpu to reorder BAM register accesses done after this */
436 	wmb();
437 
438 	/* make sure hw is initialized when channel is used the first time  */
439 	bchan->initialized = 0;
440 }
441 
442 /**
443  * bam_chan_init_hw - Initialize channel hardware
444  * @bchan: bam channel
445  * @dir: DMA transfer direction
446  *
447  * This function resets and initializes the BAM channel
448  */
449 static void bam_chan_init_hw(struct bam_chan *bchan,
450 	enum dma_transfer_direction dir)
451 {
452 	struct bam_device *bdev = bchan->bdev;
453 	u32 val;
454 
455 	/* Reset the channel to clear internal state of the FIFO */
456 	bam_reset_channel(bchan);
457 
458 	/*
459 	 * write out 8 byte aligned address.  We have enough space for this
460 	 * because we allocated 1 more descriptor (8 bytes) than we can use
461 	 */
462 	writel_relaxed(ALIGN(bchan->fifo_phys, sizeof(struct bam_desc_hw)),
463 			bam_addr(bdev, bchan->id, BAM_P_DESC_FIFO_ADDR));
464 	writel_relaxed(BAM_FIFO_SIZE,
465 			bam_addr(bdev, bchan->id, BAM_P_FIFO_SIZES));
466 
467 	/* enable the per pipe interrupts, enable EOT, ERR, and INT irqs */
468 	writel_relaxed(P_DEFAULT_IRQS_EN,
469 			bam_addr(bdev, bchan->id, BAM_P_IRQ_EN));
470 
471 	/* unmask the specific pipe and EE combo */
472 	val = readl_relaxed(bam_addr(bdev, 0, BAM_IRQ_SRCS_MSK_EE));
473 	val |= BIT(bchan->id);
474 	writel_relaxed(val, bam_addr(bdev, 0, BAM_IRQ_SRCS_MSK_EE));
475 
476 	/* don't allow cpu to reorder the channel enable done below */
477 	wmb();
478 
479 	/* set fixed direction and mode, then enable channel */
480 	val = P_EN | P_SYS_MODE;
481 	if (dir == DMA_DEV_TO_MEM)
482 		val |= P_DIRECTION;
483 
484 	writel_relaxed(val, bam_addr(bdev, bchan->id, BAM_P_CTRL));
485 
486 	bchan->initialized = 1;
487 
488 	/* init FIFO pointers */
489 	bchan->head = 0;
490 	bchan->tail = 0;
491 }
492 
493 /**
494  * bam_alloc_chan - Allocate channel resources for DMA channel.
495  * @chan: specified channel
496  *
497  * This function allocates the FIFO descriptor memory
498  */
499 static int bam_alloc_chan(struct dma_chan *chan)
500 {
501 	struct bam_chan *bchan = to_bam_chan(chan);
502 	struct bam_device *bdev = bchan->bdev;
503 
504 	if (bchan->fifo_virt)
505 		return 0;
506 
507 	/* allocate FIFO descriptor space, but only if necessary */
508 	bchan->fifo_virt = dma_alloc_wc(bdev->dev, BAM_DESC_FIFO_SIZE,
509 					&bchan->fifo_phys, GFP_KERNEL);
510 
511 	if (!bchan->fifo_virt) {
512 		dev_err(bdev->dev, "Failed to allocate desc fifo\n");
513 		return -ENOMEM;
514 	}
515 
516 	return 0;
517 }
518 
519 static int bam_pm_runtime_get_sync(struct device *dev)
520 {
521 	if (pm_runtime_enabled(dev))
522 		return pm_runtime_get_sync(dev);
523 
524 	return 0;
525 }
526 
527 /**
528  * bam_free_chan - Frees dma resources associated with specific channel
529  * @chan: specified channel
530  *
531  * Free the allocated fifo descriptor memory and channel resources
532  *
533  */
534 static void bam_free_chan(struct dma_chan *chan)
535 {
536 	struct bam_chan *bchan = to_bam_chan(chan);
537 	struct bam_device *bdev = bchan->bdev;
538 	u32 val;
539 	unsigned long flags;
540 	int ret;
541 
542 	ret = bam_pm_runtime_get_sync(bdev->dev);
543 	if (ret < 0)
544 		return;
545 
546 	vchan_free_chan_resources(to_virt_chan(chan));
547 
548 	if (!list_empty(&bchan->desc_list)) {
549 		dev_err(bchan->bdev->dev, "Cannot free busy channel\n");
550 		goto err;
551 	}
552 
553 	spin_lock_irqsave(&bchan->vc.lock, flags);
554 	bam_reset_channel(bchan);
555 	spin_unlock_irqrestore(&bchan->vc.lock, flags);
556 
557 	dma_free_wc(bdev->dev, BAM_DESC_FIFO_SIZE, bchan->fifo_virt,
558 		    bchan->fifo_phys);
559 	bchan->fifo_virt = NULL;
560 
561 	/* mask irq for pipe/channel */
562 	val = readl_relaxed(bam_addr(bdev, 0, BAM_IRQ_SRCS_MSK_EE));
563 	val &= ~BIT(bchan->id);
564 	writel_relaxed(val, bam_addr(bdev, 0, BAM_IRQ_SRCS_MSK_EE));
565 
566 	/* disable irq */
567 	writel_relaxed(0, bam_addr(bdev, bchan->id, BAM_P_IRQ_EN));
568 
569 err:
570 	pm_runtime_mark_last_busy(bdev->dev);
571 	pm_runtime_put_autosuspend(bdev->dev);
572 }
573 
574 /**
575  * bam_slave_config - set slave configuration for channel
576  * @chan: dma channel
577  * @cfg: slave configuration
578  *
579  * Sets slave configuration for channel
580  *
581  */
582 static int bam_slave_config(struct dma_chan *chan,
583 			    struct dma_slave_config *cfg)
584 {
585 	struct bam_chan *bchan = to_bam_chan(chan);
586 	unsigned long flag;
587 
588 	spin_lock_irqsave(&bchan->vc.lock, flag);
589 	memcpy(&bchan->slave, cfg, sizeof(*cfg));
590 	bchan->reconfigure = 1;
591 	spin_unlock_irqrestore(&bchan->vc.lock, flag);
592 
593 	return 0;
594 }
595 
596 /**
597  * bam_prep_slave_sg - Prep slave sg transaction
598  *
599  * @chan: dma channel
600  * @sgl: scatter gather list
601  * @sg_len: length of sg
602  * @direction: DMA transfer direction
603  * @flags: DMA flags
604  * @context: transfer context (unused)
605  */
606 static struct dma_async_tx_descriptor *bam_prep_slave_sg(struct dma_chan *chan,
607 	struct scatterlist *sgl, unsigned int sg_len,
608 	enum dma_transfer_direction direction, unsigned long flags,
609 	void *context)
610 {
611 	struct bam_chan *bchan = to_bam_chan(chan);
612 	struct bam_device *bdev = bchan->bdev;
613 	struct bam_async_desc *async_desc;
614 	struct scatterlist *sg;
615 	u32 i;
616 	struct bam_desc_hw *desc;
617 	unsigned int num_alloc = 0;
618 
619 
620 	if (!is_slave_direction(direction)) {
621 		dev_err(bdev->dev, "invalid dma direction\n");
622 		return NULL;
623 	}
624 
625 	/* calculate number of required entries */
626 	for_each_sg(sgl, sg, sg_len, i)
627 		num_alloc += DIV_ROUND_UP(sg_dma_len(sg), BAM_FIFO_SIZE);
628 
629 	/* allocate enough room to accomodate the number of entries */
630 	async_desc = kzalloc(struct_size(async_desc, desc, num_alloc),
631 			     GFP_NOWAIT);
632 
633 	if (!async_desc)
634 		goto err_out;
635 
636 	if (flags & DMA_PREP_FENCE)
637 		async_desc->flags |= DESC_FLAG_NWD;
638 
639 	if (flags & DMA_PREP_INTERRUPT)
640 		async_desc->flags |= DESC_FLAG_EOT;
641 
642 	async_desc->num_desc = num_alloc;
643 	async_desc->curr_desc = async_desc->desc;
644 	async_desc->dir = direction;
645 
646 	/* fill in temporary descriptors */
647 	desc = async_desc->desc;
648 	for_each_sg(sgl, sg, sg_len, i) {
649 		unsigned int remainder = sg_dma_len(sg);
650 		unsigned int curr_offset = 0;
651 
652 		do {
653 			if (flags & DMA_PREP_CMD)
654 				desc->flags |= cpu_to_le16(DESC_FLAG_CMD);
655 
656 			desc->addr = cpu_to_le32(sg_dma_address(sg) +
657 						 curr_offset);
658 
659 			if (remainder > BAM_FIFO_SIZE) {
660 				desc->size = cpu_to_le16(BAM_FIFO_SIZE);
661 				remainder -= BAM_FIFO_SIZE;
662 				curr_offset += BAM_FIFO_SIZE;
663 			} else {
664 				desc->size = cpu_to_le16(remainder);
665 				remainder = 0;
666 			}
667 
668 			async_desc->length += le16_to_cpu(desc->size);
669 			desc++;
670 		} while (remainder > 0);
671 	}
672 
673 	return vchan_tx_prep(&bchan->vc, &async_desc->vd, flags);
674 
675 err_out:
676 	kfree(async_desc);
677 	return NULL;
678 }
679 
680 /**
681  * bam_dma_terminate_all - terminate all transactions on a channel
682  * @chan: bam dma channel
683  *
684  * Dequeues and frees all transactions
685  * No callbacks are done
686  *
687  */
688 static int bam_dma_terminate_all(struct dma_chan *chan)
689 {
690 	struct bam_chan *bchan = to_bam_chan(chan);
691 	struct bam_async_desc *async_desc, *tmp;
692 	unsigned long flag;
693 	LIST_HEAD(head);
694 
695 	/* remove all transactions, including active transaction */
696 	spin_lock_irqsave(&bchan->vc.lock, flag);
697 	/*
698 	 * If we have transactions queued, then some might be committed to the
699 	 * hardware in the desc fifo.  The only way to reset the desc fifo is
700 	 * to do a hardware reset (either by pipe or the entire block).
701 	 * bam_chan_init_hw() will trigger a pipe reset, and also reinit the
702 	 * pipe.  If the pipe is left disabled (default state after pipe reset)
703 	 * and is accessed by a connected hardware engine, a fatal error in
704 	 * the BAM will occur.  There is a small window where this could happen
705 	 * with bam_chan_init_hw(), but it is assumed that the caller has
706 	 * stopped activity on any attached hardware engine.  Make sure to do
707 	 * this first so that the BAM hardware doesn't cause memory corruption
708 	 * by accessing freed resources.
709 	 */
710 	if (!list_empty(&bchan->desc_list)) {
711 		async_desc = list_first_entry(&bchan->desc_list,
712 					      struct bam_async_desc, desc_node);
713 		bam_chan_init_hw(bchan, async_desc->dir);
714 	}
715 
716 	list_for_each_entry_safe(async_desc, tmp,
717 				 &bchan->desc_list, desc_node) {
718 		list_add(&async_desc->vd.node, &bchan->vc.desc_issued);
719 		list_del(&async_desc->desc_node);
720 	}
721 
722 	vchan_get_all_descriptors(&bchan->vc, &head);
723 	spin_unlock_irqrestore(&bchan->vc.lock, flag);
724 
725 	vchan_dma_desc_free_list(&bchan->vc, &head);
726 
727 	return 0;
728 }
729 
730 /**
731  * bam_pause - Pause DMA channel
732  * @chan: dma channel
733  *
734  */
735 static int bam_pause(struct dma_chan *chan)
736 {
737 	struct bam_chan *bchan = to_bam_chan(chan);
738 	struct bam_device *bdev = bchan->bdev;
739 	unsigned long flag;
740 	int ret;
741 
742 	ret = bam_pm_runtime_get_sync(bdev->dev);
743 	if (ret < 0)
744 		return ret;
745 
746 	spin_lock_irqsave(&bchan->vc.lock, flag);
747 	writel_relaxed(1, bam_addr(bdev, bchan->id, BAM_P_HALT));
748 	bchan->paused = 1;
749 	spin_unlock_irqrestore(&bchan->vc.lock, flag);
750 	pm_runtime_mark_last_busy(bdev->dev);
751 	pm_runtime_put_autosuspend(bdev->dev);
752 
753 	return 0;
754 }
755 
756 /**
757  * bam_resume - Resume DMA channel operations
758  * @chan: dma channel
759  *
760  */
761 static int bam_resume(struct dma_chan *chan)
762 {
763 	struct bam_chan *bchan = to_bam_chan(chan);
764 	struct bam_device *bdev = bchan->bdev;
765 	unsigned long flag;
766 	int ret;
767 
768 	ret = bam_pm_runtime_get_sync(bdev->dev);
769 	if (ret < 0)
770 		return ret;
771 
772 	spin_lock_irqsave(&bchan->vc.lock, flag);
773 	writel_relaxed(0, bam_addr(bdev, bchan->id, BAM_P_HALT));
774 	bchan->paused = 0;
775 	spin_unlock_irqrestore(&bchan->vc.lock, flag);
776 	pm_runtime_mark_last_busy(bdev->dev);
777 	pm_runtime_put_autosuspend(bdev->dev);
778 
779 	return 0;
780 }
781 
782 /**
783  * process_channel_irqs - processes the channel interrupts
784  * @bdev: bam controller
785  *
786  * This function processes the channel interrupts
787  *
788  */
789 static u32 process_channel_irqs(struct bam_device *bdev)
790 {
791 	u32 i, srcs, pipe_stts, offset, avail;
792 	unsigned long flags;
793 	struct bam_async_desc *async_desc, *tmp;
794 
795 	srcs = readl_relaxed(bam_addr(bdev, 0, BAM_IRQ_SRCS_EE));
796 
797 	/* return early if no pipe/channel interrupts are present */
798 	if (!(srcs & P_IRQ))
799 		return srcs;
800 
801 	for (i = 0; i < bdev->num_channels; i++) {
802 		struct bam_chan *bchan = &bdev->channels[i];
803 
804 		if (!(srcs & BIT(i)))
805 			continue;
806 
807 		/* clear pipe irq */
808 		pipe_stts = readl_relaxed(bam_addr(bdev, i, BAM_P_IRQ_STTS));
809 
810 		writel_relaxed(pipe_stts, bam_addr(bdev, i, BAM_P_IRQ_CLR));
811 
812 		spin_lock_irqsave(&bchan->vc.lock, flags);
813 
814 		offset = readl_relaxed(bam_addr(bdev, i, BAM_P_SW_OFSTS)) &
815 				       P_SW_OFSTS_MASK;
816 		offset /= sizeof(struct bam_desc_hw);
817 
818 		/* Number of bytes available to read */
819 		avail = CIRC_CNT(offset, bchan->head, MAX_DESCRIPTORS + 1);
820 
821 		if (offset < bchan->head)
822 			avail--;
823 
824 		list_for_each_entry_safe(async_desc, tmp,
825 					 &bchan->desc_list, desc_node) {
826 			/* Not enough data to read */
827 			if (avail < async_desc->xfer_len)
828 				break;
829 
830 			/* manage FIFO */
831 			bchan->head += async_desc->xfer_len;
832 			bchan->head %= MAX_DESCRIPTORS;
833 
834 			async_desc->num_desc -= async_desc->xfer_len;
835 			async_desc->curr_desc += async_desc->xfer_len;
836 			avail -= async_desc->xfer_len;
837 
838 			/*
839 			 * if complete, process cookie. Otherwise
840 			 * push back to front of desc_issued so that
841 			 * it gets restarted by the tasklet
842 			 */
843 			if (!async_desc->num_desc) {
844 				vchan_cookie_complete(&async_desc->vd);
845 			} else {
846 				list_add(&async_desc->vd.node,
847 					 &bchan->vc.desc_issued);
848 			}
849 			list_del(&async_desc->desc_node);
850 		}
851 
852 		spin_unlock_irqrestore(&bchan->vc.lock, flags);
853 	}
854 
855 	return srcs;
856 }
857 
858 /**
859  * bam_dma_irq - irq handler for bam controller
860  * @irq: IRQ of interrupt
861  * @data: callback data
862  *
863  * IRQ handler for the bam controller
864  */
865 static irqreturn_t bam_dma_irq(int irq, void *data)
866 {
867 	struct bam_device *bdev = data;
868 	u32 clr_mask = 0, srcs = 0;
869 	int ret;
870 
871 	srcs |= process_channel_irqs(bdev);
872 
873 	/* kick off tasklet to start next dma transfer */
874 	if (srcs & P_IRQ)
875 		tasklet_schedule(&bdev->task);
876 
877 	ret = bam_pm_runtime_get_sync(bdev->dev);
878 	if (ret < 0)
879 		return ret;
880 
881 	if (srcs & BAM_IRQ) {
882 		clr_mask = readl_relaxed(bam_addr(bdev, 0, BAM_IRQ_STTS));
883 
884 		/*
885 		 * don't allow reorder of the various accesses to the BAM
886 		 * registers
887 		 */
888 		mb();
889 
890 		writel_relaxed(clr_mask, bam_addr(bdev, 0, BAM_IRQ_CLR));
891 	}
892 
893 	pm_runtime_mark_last_busy(bdev->dev);
894 	pm_runtime_put_autosuspend(bdev->dev);
895 
896 	return IRQ_HANDLED;
897 }
898 
899 /**
900  * bam_tx_status - returns status of transaction
901  * @chan: dma channel
902  * @cookie: transaction cookie
903  * @txstate: DMA transaction state
904  *
905  * Return status of dma transaction
906  */
907 static enum dma_status bam_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
908 		struct dma_tx_state *txstate)
909 {
910 	struct bam_chan *bchan = to_bam_chan(chan);
911 	struct bam_async_desc *async_desc;
912 	struct virt_dma_desc *vd;
913 	int ret;
914 	size_t residue = 0;
915 	unsigned int i;
916 	unsigned long flags;
917 
918 	ret = dma_cookie_status(chan, cookie, txstate);
919 	if (ret == DMA_COMPLETE)
920 		return ret;
921 
922 	if (!txstate)
923 		return bchan->paused ? DMA_PAUSED : ret;
924 
925 	spin_lock_irqsave(&bchan->vc.lock, flags);
926 	vd = vchan_find_desc(&bchan->vc, cookie);
927 	if (vd) {
928 		residue = container_of(vd, struct bam_async_desc, vd)->length;
929 	} else {
930 		list_for_each_entry(async_desc, &bchan->desc_list, desc_node) {
931 			if (async_desc->vd.tx.cookie != cookie)
932 				continue;
933 
934 			for (i = 0; i < async_desc->num_desc; i++)
935 				residue += le16_to_cpu(
936 						async_desc->curr_desc[i].size);
937 		}
938 	}
939 
940 	spin_unlock_irqrestore(&bchan->vc.lock, flags);
941 
942 	dma_set_residue(txstate, residue);
943 
944 	if (ret == DMA_IN_PROGRESS && bchan->paused)
945 		ret = DMA_PAUSED;
946 
947 	return ret;
948 }
949 
950 /**
951  * bam_apply_new_config
952  * @bchan: bam dma channel
953  * @dir: DMA direction
954  */
955 static void bam_apply_new_config(struct bam_chan *bchan,
956 	enum dma_transfer_direction dir)
957 {
958 	struct bam_device *bdev = bchan->bdev;
959 	u32 maxburst;
960 
961 	if (!bdev->controlled_remotely) {
962 		if (dir == DMA_DEV_TO_MEM)
963 			maxburst = bchan->slave.src_maxburst;
964 		else
965 			maxburst = bchan->slave.dst_maxburst;
966 
967 		writel_relaxed(maxburst,
968 			       bam_addr(bdev, 0, BAM_DESC_CNT_TRSHLD));
969 	}
970 
971 	bchan->reconfigure = 0;
972 }
973 
974 /**
975  * bam_start_dma - start next transaction
976  * @bchan: bam dma channel
977  */
978 static void bam_start_dma(struct bam_chan *bchan)
979 {
980 	struct virt_dma_desc *vd = vchan_next_desc(&bchan->vc);
981 	struct bam_device *bdev = bchan->bdev;
982 	struct bam_async_desc *async_desc = NULL;
983 	struct bam_desc_hw *desc;
984 	struct bam_desc_hw *fifo = PTR_ALIGN(bchan->fifo_virt,
985 					sizeof(struct bam_desc_hw));
986 	int ret;
987 	unsigned int avail;
988 	struct dmaengine_desc_callback cb;
989 
990 	lockdep_assert_held(&bchan->vc.lock);
991 
992 	if (!vd)
993 		return;
994 
995 	ret = bam_pm_runtime_get_sync(bdev->dev);
996 	if (ret < 0)
997 		return;
998 
999 	while (vd && !IS_BUSY(bchan)) {
1000 		list_del(&vd->node);
1001 
1002 		async_desc = container_of(vd, struct bam_async_desc, vd);
1003 
1004 		/* on first use, initialize the channel hardware */
1005 		if (!bchan->initialized)
1006 			bam_chan_init_hw(bchan, async_desc->dir);
1007 
1008 		/* apply new slave config changes, if necessary */
1009 		if (bchan->reconfigure)
1010 			bam_apply_new_config(bchan, async_desc->dir);
1011 
1012 		desc = async_desc->curr_desc;
1013 		avail = CIRC_SPACE(bchan->tail, bchan->head,
1014 				   MAX_DESCRIPTORS + 1);
1015 
1016 		if (async_desc->num_desc > avail)
1017 			async_desc->xfer_len = avail;
1018 		else
1019 			async_desc->xfer_len = async_desc->num_desc;
1020 
1021 		/* set any special flags on the last descriptor */
1022 		if (async_desc->num_desc == async_desc->xfer_len)
1023 			desc[async_desc->xfer_len - 1].flags |=
1024 						cpu_to_le16(async_desc->flags);
1025 
1026 		vd = vchan_next_desc(&bchan->vc);
1027 
1028 		dmaengine_desc_get_callback(&async_desc->vd.tx, &cb);
1029 
1030 		/*
1031 		 * An interrupt is generated at this desc, if
1032 		 *  - FIFO is FULL.
1033 		 *  - No more descriptors to add.
1034 		 *  - If a callback completion was requested for this DESC,
1035 		 *     In this case, BAM will deliver the completion callback
1036 		 *     for this desc and continue processing the next desc.
1037 		 */
1038 		if (((avail <= async_desc->xfer_len) || !vd ||
1039 		     dmaengine_desc_callback_valid(&cb)) &&
1040 		    !(async_desc->flags & DESC_FLAG_EOT))
1041 			desc[async_desc->xfer_len - 1].flags |=
1042 				cpu_to_le16(DESC_FLAG_INT);
1043 
1044 		if (bchan->tail + async_desc->xfer_len > MAX_DESCRIPTORS) {
1045 			u32 partial = MAX_DESCRIPTORS - bchan->tail;
1046 
1047 			memcpy(&fifo[bchan->tail], desc,
1048 			       partial * sizeof(struct bam_desc_hw));
1049 			memcpy(fifo, &desc[partial],
1050 			       (async_desc->xfer_len - partial) *
1051 				sizeof(struct bam_desc_hw));
1052 		} else {
1053 			memcpy(&fifo[bchan->tail], desc,
1054 			       async_desc->xfer_len *
1055 			       sizeof(struct bam_desc_hw));
1056 		}
1057 
1058 		bchan->tail += async_desc->xfer_len;
1059 		bchan->tail %= MAX_DESCRIPTORS;
1060 		list_add_tail(&async_desc->desc_node, &bchan->desc_list);
1061 	}
1062 
1063 	/* ensure descriptor writes and dma start not reordered */
1064 	wmb();
1065 	writel_relaxed(bchan->tail * sizeof(struct bam_desc_hw),
1066 			bam_addr(bdev, bchan->id, BAM_P_EVNT_REG));
1067 
1068 	pm_runtime_mark_last_busy(bdev->dev);
1069 	pm_runtime_put_autosuspend(bdev->dev);
1070 }
1071 
1072 /**
1073  * dma_tasklet - DMA IRQ tasklet
1074  * @data: tasklet argument (bam controller structure)
1075  *
1076  * Sets up next DMA operation and then processes all completed transactions
1077  */
1078 static void dma_tasklet(unsigned long data)
1079 {
1080 	struct bam_device *bdev = (struct bam_device *)data;
1081 	struct bam_chan *bchan;
1082 	unsigned long flags;
1083 	unsigned int i;
1084 
1085 	/* go through the channels and kick off transactions */
1086 	for (i = 0; i < bdev->num_channels; i++) {
1087 		bchan = &bdev->channels[i];
1088 		spin_lock_irqsave(&bchan->vc.lock, flags);
1089 
1090 		if (!list_empty(&bchan->vc.desc_issued) && !IS_BUSY(bchan))
1091 			bam_start_dma(bchan);
1092 		spin_unlock_irqrestore(&bchan->vc.lock, flags);
1093 	}
1094 
1095 }
1096 
1097 /**
1098  * bam_issue_pending - starts pending transactions
1099  * @chan: dma channel
1100  *
1101  * Calls tasklet directly which in turn starts any pending transactions
1102  */
1103 static void bam_issue_pending(struct dma_chan *chan)
1104 {
1105 	struct bam_chan *bchan = to_bam_chan(chan);
1106 	unsigned long flags;
1107 
1108 	spin_lock_irqsave(&bchan->vc.lock, flags);
1109 
1110 	/* if work pending and idle, start a transaction */
1111 	if (vchan_issue_pending(&bchan->vc) && !IS_BUSY(bchan))
1112 		bam_start_dma(bchan);
1113 
1114 	spin_unlock_irqrestore(&bchan->vc.lock, flags);
1115 }
1116 
1117 /**
1118  * bam_dma_free_desc - free descriptor memory
1119  * @vd: virtual descriptor
1120  *
1121  */
1122 static void bam_dma_free_desc(struct virt_dma_desc *vd)
1123 {
1124 	struct bam_async_desc *async_desc = container_of(vd,
1125 			struct bam_async_desc, vd);
1126 
1127 	kfree(async_desc);
1128 }
1129 
1130 static struct dma_chan *bam_dma_xlate(struct of_phandle_args *dma_spec,
1131 		struct of_dma *of)
1132 {
1133 	struct bam_device *bdev = container_of(of->of_dma_data,
1134 					struct bam_device, common);
1135 	unsigned int request;
1136 
1137 	if (dma_spec->args_count != 1)
1138 		return NULL;
1139 
1140 	request = dma_spec->args[0];
1141 	if (request >= bdev->num_channels)
1142 		return NULL;
1143 
1144 	return dma_get_slave_channel(&(bdev->channels[request].vc.chan));
1145 }
1146 
1147 /**
1148  * bam_init
1149  * @bdev: bam device
1150  *
1151  * Initialization helper for global bam registers
1152  */
1153 static int bam_init(struct bam_device *bdev)
1154 {
1155 	u32 val;
1156 
1157 	/* read revision and configuration information */
1158 	if (!bdev->num_ees) {
1159 		val = readl_relaxed(bam_addr(bdev, 0, BAM_REVISION));
1160 		bdev->num_ees = (val >> NUM_EES_SHIFT) & NUM_EES_MASK;
1161 	}
1162 
1163 	/* check that configured EE is within range */
1164 	if (bdev->ee >= bdev->num_ees)
1165 		return -EINVAL;
1166 
1167 	if (!bdev->num_channels) {
1168 		val = readl_relaxed(bam_addr(bdev, 0, BAM_NUM_PIPES));
1169 		bdev->num_channels = val & BAM_NUM_PIPES_MASK;
1170 	}
1171 
1172 	if (bdev->controlled_remotely)
1173 		return 0;
1174 
1175 	/* s/w reset bam */
1176 	/* after reset all pipes are disabled and idle */
1177 	val = readl_relaxed(bam_addr(bdev, 0, BAM_CTRL));
1178 	val |= BAM_SW_RST;
1179 	writel_relaxed(val, bam_addr(bdev, 0, BAM_CTRL));
1180 	val &= ~BAM_SW_RST;
1181 	writel_relaxed(val, bam_addr(bdev, 0, BAM_CTRL));
1182 
1183 	/* make sure previous stores are visible before enabling BAM */
1184 	wmb();
1185 
1186 	/* enable bam */
1187 	val |= BAM_EN;
1188 	writel_relaxed(val, bam_addr(bdev, 0, BAM_CTRL));
1189 
1190 	/* set descriptor threshhold, start with 4 bytes */
1191 	writel_relaxed(DEFAULT_CNT_THRSHLD,
1192 			bam_addr(bdev, 0, BAM_DESC_CNT_TRSHLD));
1193 
1194 	/* Enable default set of h/w workarounds, ie all except BAM_FULL_PIPE */
1195 	writel_relaxed(BAM_CNFG_BITS_DEFAULT, bam_addr(bdev, 0, BAM_CNFG_BITS));
1196 
1197 	/* enable irqs for errors */
1198 	writel_relaxed(BAM_ERROR_EN | BAM_HRESP_ERR_EN,
1199 			bam_addr(bdev, 0, BAM_IRQ_EN));
1200 
1201 	/* unmask global bam interrupt */
1202 	writel_relaxed(BAM_IRQ_MSK, bam_addr(bdev, 0, BAM_IRQ_SRCS_MSK_EE));
1203 
1204 	return 0;
1205 }
1206 
1207 static void bam_channel_init(struct bam_device *bdev, struct bam_chan *bchan,
1208 	u32 index)
1209 {
1210 	bchan->id = index;
1211 	bchan->bdev = bdev;
1212 
1213 	vchan_init(&bchan->vc, &bdev->common);
1214 	bchan->vc.desc_free = bam_dma_free_desc;
1215 	INIT_LIST_HEAD(&bchan->desc_list);
1216 }
1217 
1218 static const struct of_device_id bam_of_match[] = {
1219 	{ .compatible = "qcom,bam-v1.3.0", .data = &bam_v1_3_reg_info },
1220 	{ .compatible = "qcom,bam-v1.4.0", .data = &bam_v1_4_reg_info },
1221 	{ .compatible = "qcom,bam-v1.7.0", .data = &bam_v1_7_reg_info },
1222 	{}
1223 };
1224 
1225 MODULE_DEVICE_TABLE(of, bam_of_match);
1226 
1227 static int bam_dma_probe(struct platform_device *pdev)
1228 {
1229 	struct bam_device *bdev;
1230 	const struct of_device_id *match;
1231 	struct resource *iores;
1232 	int ret, i;
1233 
1234 	bdev = devm_kzalloc(&pdev->dev, sizeof(*bdev), GFP_KERNEL);
1235 	if (!bdev)
1236 		return -ENOMEM;
1237 
1238 	bdev->dev = &pdev->dev;
1239 
1240 	match = of_match_node(bam_of_match, pdev->dev.of_node);
1241 	if (!match) {
1242 		dev_err(&pdev->dev, "Unsupported BAM module\n");
1243 		return -ENODEV;
1244 	}
1245 
1246 	bdev->layout = match->data;
1247 
1248 	iores = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1249 	bdev->regs = devm_ioremap_resource(&pdev->dev, iores);
1250 	if (IS_ERR(bdev->regs))
1251 		return PTR_ERR(bdev->regs);
1252 
1253 	bdev->irq = platform_get_irq(pdev, 0);
1254 	if (bdev->irq < 0)
1255 		return bdev->irq;
1256 
1257 	ret = of_property_read_u32(pdev->dev.of_node, "qcom,ee", &bdev->ee);
1258 	if (ret) {
1259 		dev_err(bdev->dev, "Execution environment unspecified\n");
1260 		return ret;
1261 	}
1262 
1263 	bdev->controlled_remotely = of_property_read_bool(pdev->dev.of_node,
1264 						"qcom,controlled-remotely");
1265 
1266 	if (bdev->controlled_remotely) {
1267 		ret = of_property_read_u32(pdev->dev.of_node, "num-channels",
1268 					   &bdev->num_channels);
1269 		if (ret)
1270 			dev_err(bdev->dev, "num-channels unspecified in dt\n");
1271 
1272 		ret = of_property_read_u32(pdev->dev.of_node, "qcom,num-ees",
1273 					   &bdev->num_ees);
1274 		if (ret)
1275 			dev_err(bdev->dev, "num-ees unspecified in dt\n");
1276 	}
1277 
1278 	bdev->bamclk = devm_clk_get(bdev->dev, "bam_clk");
1279 	if (IS_ERR(bdev->bamclk)) {
1280 		if (!bdev->controlled_remotely)
1281 			return PTR_ERR(bdev->bamclk);
1282 
1283 		bdev->bamclk = NULL;
1284 	}
1285 
1286 	ret = clk_prepare_enable(bdev->bamclk);
1287 	if (ret) {
1288 		dev_err(bdev->dev, "failed to prepare/enable clock\n");
1289 		return ret;
1290 	}
1291 
1292 	ret = bam_init(bdev);
1293 	if (ret)
1294 		goto err_disable_clk;
1295 
1296 	tasklet_init(&bdev->task, dma_tasklet, (unsigned long)bdev);
1297 
1298 	bdev->channels = devm_kcalloc(bdev->dev, bdev->num_channels,
1299 				sizeof(*bdev->channels), GFP_KERNEL);
1300 
1301 	if (!bdev->channels) {
1302 		ret = -ENOMEM;
1303 		goto err_tasklet_kill;
1304 	}
1305 
1306 	/* allocate and initialize channels */
1307 	INIT_LIST_HEAD(&bdev->common.channels);
1308 
1309 	for (i = 0; i < bdev->num_channels; i++)
1310 		bam_channel_init(bdev, &bdev->channels[i], i);
1311 
1312 	ret = devm_request_irq(bdev->dev, bdev->irq, bam_dma_irq,
1313 			IRQF_TRIGGER_HIGH, "bam_dma", bdev);
1314 	if (ret)
1315 		goto err_bam_channel_exit;
1316 
1317 	/* set max dma segment size */
1318 	bdev->common.dev = bdev->dev;
1319 	bdev->common.dev->dma_parms = &bdev->dma_parms;
1320 	ret = dma_set_max_seg_size(bdev->common.dev, BAM_FIFO_SIZE);
1321 	if (ret) {
1322 		dev_err(bdev->dev, "cannot set maximum segment size\n");
1323 		goto err_bam_channel_exit;
1324 	}
1325 
1326 	platform_set_drvdata(pdev, bdev);
1327 
1328 	/* set capabilities */
1329 	dma_cap_zero(bdev->common.cap_mask);
1330 	dma_cap_set(DMA_SLAVE, bdev->common.cap_mask);
1331 
1332 	/* initialize dmaengine apis */
1333 	bdev->common.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
1334 	bdev->common.residue_granularity = DMA_RESIDUE_GRANULARITY_SEGMENT;
1335 	bdev->common.src_addr_widths = DMA_SLAVE_BUSWIDTH_4_BYTES;
1336 	bdev->common.dst_addr_widths = DMA_SLAVE_BUSWIDTH_4_BYTES;
1337 	bdev->common.device_alloc_chan_resources = bam_alloc_chan;
1338 	bdev->common.device_free_chan_resources = bam_free_chan;
1339 	bdev->common.device_prep_slave_sg = bam_prep_slave_sg;
1340 	bdev->common.device_config = bam_slave_config;
1341 	bdev->common.device_pause = bam_pause;
1342 	bdev->common.device_resume = bam_resume;
1343 	bdev->common.device_terminate_all = bam_dma_terminate_all;
1344 	bdev->common.device_issue_pending = bam_issue_pending;
1345 	bdev->common.device_tx_status = bam_tx_status;
1346 	bdev->common.dev = bdev->dev;
1347 
1348 	ret = dma_async_device_register(&bdev->common);
1349 	if (ret) {
1350 		dev_err(bdev->dev, "failed to register dma async device\n");
1351 		goto err_bam_channel_exit;
1352 	}
1353 
1354 	ret = of_dma_controller_register(pdev->dev.of_node, bam_dma_xlate,
1355 					&bdev->common);
1356 	if (ret)
1357 		goto err_unregister_dma;
1358 
1359 	if (bdev->controlled_remotely) {
1360 		pm_runtime_disable(&pdev->dev);
1361 		return 0;
1362 	}
1363 
1364 	pm_runtime_irq_safe(&pdev->dev);
1365 	pm_runtime_set_autosuspend_delay(&pdev->dev, BAM_DMA_AUTOSUSPEND_DELAY);
1366 	pm_runtime_use_autosuspend(&pdev->dev);
1367 	pm_runtime_mark_last_busy(&pdev->dev);
1368 	pm_runtime_set_active(&pdev->dev);
1369 	pm_runtime_enable(&pdev->dev);
1370 
1371 	return 0;
1372 
1373 err_unregister_dma:
1374 	dma_async_device_unregister(&bdev->common);
1375 err_bam_channel_exit:
1376 	for (i = 0; i < bdev->num_channels; i++)
1377 		tasklet_kill(&bdev->channels[i].vc.task);
1378 err_tasklet_kill:
1379 	tasklet_kill(&bdev->task);
1380 err_disable_clk:
1381 	clk_disable_unprepare(bdev->bamclk);
1382 
1383 	return ret;
1384 }
1385 
1386 static int bam_dma_remove(struct platform_device *pdev)
1387 {
1388 	struct bam_device *bdev = platform_get_drvdata(pdev);
1389 	u32 i;
1390 
1391 	pm_runtime_force_suspend(&pdev->dev);
1392 
1393 	of_dma_controller_free(pdev->dev.of_node);
1394 	dma_async_device_unregister(&bdev->common);
1395 
1396 	/* mask all interrupts for this execution environment */
1397 	writel_relaxed(0, bam_addr(bdev, 0,  BAM_IRQ_SRCS_MSK_EE));
1398 
1399 	devm_free_irq(bdev->dev, bdev->irq, bdev);
1400 
1401 	for (i = 0; i < bdev->num_channels; i++) {
1402 		bam_dma_terminate_all(&bdev->channels[i].vc.chan);
1403 		tasklet_kill(&bdev->channels[i].vc.task);
1404 
1405 		if (!bdev->channels[i].fifo_virt)
1406 			continue;
1407 
1408 		dma_free_wc(bdev->dev, BAM_DESC_FIFO_SIZE,
1409 			    bdev->channels[i].fifo_virt,
1410 			    bdev->channels[i].fifo_phys);
1411 	}
1412 
1413 	tasklet_kill(&bdev->task);
1414 
1415 	clk_disable_unprepare(bdev->bamclk);
1416 
1417 	return 0;
1418 }
1419 
1420 static int __maybe_unused bam_dma_runtime_suspend(struct device *dev)
1421 {
1422 	struct bam_device *bdev = dev_get_drvdata(dev);
1423 
1424 	clk_disable(bdev->bamclk);
1425 
1426 	return 0;
1427 }
1428 
1429 static int __maybe_unused bam_dma_runtime_resume(struct device *dev)
1430 {
1431 	struct bam_device *bdev = dev_get_drvdata(dev);
1432 	int ret;
1433 
1434 	ret = clk_enable(bdev->bamclk);
1435 	if (ret < 0) {
1436 		dev_err(dev, "clk_enable failed: %d\n", ret);
1437 		return ret;
1438 	}
1439 
1440 	return 0;
1441 }
1442 
1443 static int __maybe_unused bam_dma_suspend(struct device *dev)
1444 {
1445 	struct bam_device *bdev = dev_get_drvdata(dev);
1446 
1447 	if (!bdev->controlled_remotely)
1448 		pm_runtime_force_suspend(dev);
1449 
1450 	clk_unprepare(bdev->bamclk);
1451 
1452 	return 0;
1453 }
1454 
1455 static int __maybe_unused bam_dma_resume(struct device *dev)
1456 {
1457 	struct bam_device *bdev = dev_get_drvdata(dev);
1458 	int ret;
1459 
1460 	ret = clk_prepare(bdev->bamclk);
1461 	if (ret)
1462 		return ret;
1463 
1464 	if (!bdev->controlled_remotely)
1465 		pm_runtime_force_resume(dev);
1466 
1467 	return 0;
1468 }
1469 
1470 static const struct dev_pm_ops bam_dma_pm_ops = {
1471 	SET_LATE_SYSTEM_SLEEP_PM_OPS(bam_dma_suspend, bam_dma_resume)
1472 	SET_RUNTIME_PM_OPS(bam_dma_runtime_suspend, bam_dma_runtime_resume,
1473 				NULL)
1474 };
1475 
1476 static struct platform_driver bam_dma_driver = {
1477 	.probe = bam_dma_probe,
1478 	.remove = bam_dma_remove,
1479 	.driver = {
1480 		.name = "bam-dma-engine",
1481 		.pm = &bam_dma_pm_ops,
1482 		.of_match_table = bam_of_match,
1483 	},
1484 };
1485 
1486 module_platform_driver(bam_dma_driver);
1487 
1488 MODULE_AUTHOR("Andy Gross <agross@codeaurora.org>");
1489 MODULE_DESCRIPTION("QCOM BAM DMA engine driver");
1490 MODULE_LICENSE("GPL v2");
1491