xref: /linux/drivers/dma/qcom/bam_dma.c (revision 110e6f26af80dfd90b6e5c645b1aed7228aa580d)
1 /*
2  * Copyright (c) 2013-2014, The Linux Foundation. All rights reserved.
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License version 2 and
6  * only version 2 as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful,
9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
11  * GNU General Public License for more details.
12  *
13  */
14 /*
15  * QCOM BAM DMA engine driver
16  *
17  * QCOM BAM DMA blocks are distributed amongst a number of the on-chip
18  * peripherals on the MSM 8x74.  The configuration of the channels are dependent
19  * on the way they are hard wired to that specific peripheral.  The peripheral
20  * device tree entries specify the configuration of each channel.
21  *
22  * The DMA controller requires the use of external memory for storage of the
23  * hardware descriptors for each channel.  The descriptor FIFO is accessed as a
24  * circular buffer and operations are managed according to the offset within the
25  * FIFO.  After pipe/channel reset, all of the pipe registers and internal state
26  * are back to defaults.
27  *
28  * During DMA operations, we write descriptors to the FIFO, being careful to
29  * handle wrapping and then write the last FIFO offset to that channel's
30  * P_EVNT_REG register to kick off the transaction.  The P_SW_OFSTS register
31  * indicates the current FIFO offset that is being processed, so there is some
32  * indication of where the hardware is currently working.
33  */
34 
35 #include <linux/kernel.h>
36 #include <linux/io.h>
37 #include <linux/init.h>
38 #include <linux/slab.h>
39 #include <linux/module.h>
40 #include <linux/interrupt.h>
41 #include <linux/dma-mapping.h>
42 #include <linux/scatterlist.h>
43 #include <linux/device.h>
44 #include <linux/platform_device.h>
45 #include <linux/of.h>
46 #include <linux/of_address.h>
47 #include <linux/of_irq.h>
48 #include <linux/of_dma.h>
49 #include <linux/clk.h>
50 #include <linux/dmaengine.h>
51 
52 #include "../dmaengine.h"
53 #include "../virt-dma.h"
54 
55 struct bam_desc_hw {
56 	__le32 addr;		/* Buffer physical address */
57 	__le16 size;		/* Buffer size in bytes */
58 	__le16 flags;
59 };
60 
61 #define DESC_FLAG_INT BIT(15)
62 #define DESC_FLAG_EOT BIT(14)
63 #define DESC_FLAG_EOB BIT(13)
64 #define DESC_FLAG_NWD BIT(12)
65 
66 struct bam_async_desc {
67 	struct virt_dma_desc vd;
68 
69 	u32 num_desc;
70 	u32 xfer_len;
71 
72 	/* transaction flags, EOT|EOB|NWD */
73 	u16 flags;
74 
75 	struct bam_desc_hw *curr_desc;
76 
77 	enum dma_transfer_direction dir;
78 	size_t length;
79 	struct bam_desc_hw desc[0];
80 };
81 
82 enum bam_reg {
83 	BAM_CTRL,
84 	BAM_REVISION,
85 	BAM_NUM_PIPES,
86 	BAM_DESC_CNT_TRSHLD,
87 	BAM_IRQ_SRCS,
88 	BAM_IRQ_SRCS_MSK,
89 	BAM_IRQ_SRCS_UNMASKED,
90 	BAM_IRQ_STTS,
91 	BAM_IRQ_CLR,
92 	BAM_IRQ_EN,
93 	BAM_CNFG_BITS,
94 	BAM_IRQ_SRCS_EE,
95 	BAM_IRQ_SRCS_MSK_EE,
96 	BAM_P_CTRL,
97 	BAM_P_RST,
98 	BAM_P_HALT,
99 	BAM_P_IRQ_STTS,
100 	BAM_P_IRQ_CLR,
101 	BAM_P_IRQ_EN,
102 	BAM_P_EVNT_DEST_ADDR,
103 	BAM_P_EVNT_REG,
104 	BAM_P_SW_OFSTS,
105 	BAM_P_DATA_FIFO_ADDR,
106 	BAM_P_DESC_FIFO_ADDR,
107 	BAM_P_EVNT_GEN_TRSHLD,
108 	BAM_P_FIFO_SIZES,
109 };
110 
111 struct reg_offset_data {
112 	u32 base_offset;
113 	unsigned int pipe_mult, evnt_mult, ee_mult;
114 };
115 
116 static const struct reg_offset_data bam_v1_3_reg_info[] = {
117 	[BAM_CTRL]		= { 0x0F80, 0x00, 0x00, 0x00 },
118 	[BAM_REVISION]		= { 0x0F84, 0x00, 0x00, 0x00 },
119 	[BAM_NUM_PIPES]		= { 0x0FBC, 0x00, 0x00, 0x00 },
120 	[BAM_DESC_CNT_TRSHLD]	= { 0x0F88, 0x00, 0x00, 0x00 },
121 	[BAM_IRQ_SRCS]		= { 0x0F8C, 0x00, 0x00, 0x00 },
122 	[BAM_IRQ_SRCS_MSK]	= { 0x0F90, 0x00, 0x00, 0x00 },
123 	[BAM_IRQ_SRCS_UNMASKED]	= { 0x0FB0, 0x00, 0x00, 0x00 },
124 	[BAM_IRQ_STTS]		= { 0x0F94, 0x00, 0x00, 0x00 },
125 	[BAM_IRQ_CLR]		= { 0x0F98, 0x00, 0x00, 0x00 },
126 	[BAM_IRQ_EN]		= { 0x0F9C, 0x00, 0x00, 0x00 },
127 	[BAM_CNFG_BITS]		= { 0x0FFC, 0x00, 0x00, 0x00 },
128 	[BAM_IRQ_SRCS_EE]	= { 0x1800, 0x00, 0x00, 0x80 },
129 	[BAM_IRQ_SRCS_MSK_EE]	= { 0x1804, 0x00, 0x00, 0x80 },
130 	[BAM_P_CTRL]		= { 0x0000, 0x80, 0x00, 0x00 },
131 	[BAM_P_RST]		= { 0x0004, 0x80, 0x00, 0x00 },
132 	[BAM_P_HALT]		= { 0x0008, 0x80, 0x00, 0x00 },
133 	[BAM_P_IRQ_STTS]	= { 0x0010, 0x80, 0x00, 0x00 },
134 	[BAM_P_IRQ_CLR]		= { 0x0014, 0x80, 0x00, 0x00 },
135 	[BAM_P_IRQ_EN]		= { 0x0018, 0x80, 0x00, 0x00 },
136 	[BAM_P_EVNT_DEST_ADDR]	= { 0x102C, 0x00, 0x40, 0x00 },
137 	[BAM_P_EVNT_REG]	= { 0x1018, 0x00, 0x40, 0x00 },
138 	[BAM_P_SW_OFSTS]	= { 0x1000, 0x00, 0x40, 0x00 },
139 	[BAM_P_DATA_FIFO_ADDR]	= { 0x1024, 0x00, 0x40, 0x00 },
140 	[BAM_P_DESC_FIFO_ADDR]	= { 0x101C, 0x00, 0x40, 0x00 },
141 	[BAM_P_EVNT_GEN_TRSHLD]	= { 0x1028, 0x00, 0x40, 0x00 },
142 	[BAM_P_FIFO_SIZES]	= { 0x1020, 0x00, 0x40, 0x00 },
143 };
144 
145 static const struct reg_offset_data bam_v1_4_reg_info[] = {
146 	[BAM_CTRL]		= { 0x0000, 0x00, 0x00, 0x00 },
147 	[BAM_REVISION]		= { 0x0004, 0x00, 0x00, 0x00 },
148 	[BAM_NUM_PIPES]		= { 0x003C, 0x00, 0x00, 0x00 },
149 	[BAM_DESC_CNT_TRSHLD]	= { 0x0008, 0x00, 0x00, 0x00 },
150 	[BAM_IRQ_SRCS]		= { 0x000C, 0x00, 0x00, 0x00 },
151 	[BAM_IRQ_SRCS_MSK]	= { 0x0010, 0x00, 0x00, 0x00 },
152 	[BAM_IRQ_SRCS_UNMASKED]	= { 0x0030, 0x00, 0x00, 0x00 },
153 	[BAM_IRQ_STTS]		= { 0x0014, 0x00, 0x00, 0x00 },
154 	[BAM_IRQ_CLR]		= { 0x0018, 0x00, 0x00, 0x00 },
155 	[BAM_IRQ_EN]		= { 0x001C, 0x00, 0x00, 0x00 },
156 	[BAM_CNFG_BITS]		= { 0x007C, 0x00, 0x00, 0x00 },
157 	[BAM_IRQ_SRCS_EE]	= { 0x0800, 0x00, 0x00, 0x80 },
158 	[BAM_IRQ_SRCS_MSK_EE]	= { 0x0804, 0x00, 0x00, 0x80 },
159 	[BAM_P_CTRL]		= { 0x1000, 0x1000, 0x00, 0x00 },
160 	[BAM_P_RST]		= { 0x1004, 0x1000, 0x00, 0x00 },
161 	[BAM_P_HALT]		= { 0x1008, 0x1000, 0x00, 0x00 },
162 	[BAM_P_IRQ_STTS]	= { 0x1010, 0x1000, 0x00, 0x00 },
163 	[BAM_P_IRQ_CLR]		= { 0x1014, 0x1000, 0x00, 0x00 },
164 	[BAM_P_IRQ_EN]		= { 0x1018, 0x1000, 0x00, 0x00 },
165 	[BAM_P_EVNT_DEST_ADDR]	= { 0x182C, 0x00, 0x1000, 0x00 },
166 	[BAM_P_EVNT_REG]	= { 0x1818, 0x00, 0x1000, 0x00 },
167 	[BAM_P_SW_OFSTS]	= { 0x1800, 0x00, 0x1000, 0x00 },
168 	[BAM_P_DATA_FIFO_ADDR]	= { 0x1824, 0x00, 0x1000, 0x00 },
169 	[BAM_P_DESC_FIFO_ADDR]	= { 0x181C, 0x00, 0x1000, 0x00 },
170 	[BAM_P_EVNT_GEN_TRSHLD]	= { 0x1828, 0x00, 0x1000, 0x00 },
171 	[BAM_P_FIFO_SIZES]	= { 0x1820, 0x00, 0x1000, 0x00 },
172 };
173 
174 static const struct reg_offset_data bam_v1_7_reg_info[] = {
175 	[BAM_CTRL]		= { 0x00000, 0x00, 0x00, 0x00 },
176 	[BAM_REVISION]		= { 0x01000, 0x00, 0x00, 0x00 },
177 	[BAM_NUM_PIPES]		= { 0x01008, 0x00, 0x00, 0x00 },
178 	[BAM_DESC_CNT_TRSHLD]	= { 0x00008, 0x00, 0x00, 0x00 },
179 	[BAM_IRQ_SRCS]		= { 0x03010, 0x00, 0x00, 0x00 },
180 	[BAM_IRQ_SRCS_MSK]	= { 0x03014, 0x00, 0x00, 0x00 },
181 	[BAM_IRQ_SRCS_UNMASKED]	= { 0x03018, 0x00, 0x00, 0x00 },
182 	[BAM_IRQ_STTS]		= { 0x00014, 0x00, 0x00, 0x00 },
183 	[BAM_IRQ_CLR]		= { 0x00018, 0x00, 0x00, 0x00 },
184 	[BAM_IRQ_EN]		= { 0x0001C, 0x00, 0x00, 0x00 },
185 	[BAM_CNFG_BITS]		= { 0x0007C, 0x00, 0x00, 0x00 },
186 	[BAM_IRQ_SRCS_EE]	= { 0x03000, 0x00, 0x00, 0x1000 },
187 	[BAM_IRQ_SRCS_MSK_EE]	= { 0x03004, 0x00, 0x00, 0x1000 },
188 	[BAM_P_CTRL]		= { 0x13000, 0x1000, 0x00, 0x00 },
189 	[BAM_P_RST]		= { 0x13004, 0x1000, 0x00, 0x00 },
190 	[BAM_P_HALT]		= { 0x13008, 0x1000, 0x00, 0x00 },
191 	[BAM_P_IRQ_STTS]	= { 0x13010, 0x1000, 0x00, 0x00 },
192 	[BAM_P_IRQ_CLR]		= { 0x13014, 0x1000, 0x00, 0x00 },
193 	[BAM_P_IRQ_EN]		= { 0x13018, 0x1000, 0x00, 0x00 },
194 	[BAM_P_EVNT_DEST_ADDR]	= { 0x1382C, 0x00, 0x1000, 0x00 },
195 	[BAM_P_EVNT_REG]	= { 0x13818, 0x00, 0x1000, 0x00 },
196 	[BAM_P_SW_OFSTS]	= { 0x13800, 0x00, 0x1000, 0x00 },
197 	[BAM_P_DATA_FIFO_ADDR]	= { 0x13824, 0x00, 0x1000, 0x00 },
198 	[BAM_P_DESC_FIFO_ADDR]	= { 0x1381C, 0x00, 0x1000, 0x00 },
199 	[BAM_P_EVNT_GEN_TRSHLD]	= { 0x13828, 0x00, 0x1000, 0x00 },
200 	[BAM_P_FIFO_SIZES]	= { 0x13820, 0x00, 0x1000, 0x00 },
201 };
202 
203 /* BAM CTRL */
204 #define BAM_SW_RST			BIT(0)
205 #define BAM_EN				BIT(1)
206 #define BAM_EN_ACCUM			BIT(4)
207 #define BAM_TESTBUS_SEL_SHIFT		5
208 #define BAM_TESTBUS_SEL_MASK		0x3F
209 #define BAM_DESC_CACHE_SEL_SHIFT	13
210 #define BAM_DESC_CACHE_SEL_MASK		0x3
211 #define BAM_CACHED_DESC_STORE		BIT(15)
212 #define IBC_DISABLE			BIT(16)
213 
214 /* BAM REVISION */
215 #define REVISION_SHIFT		0
216 #define REVISION_MASK		0xFF
217 #define NUM_EES_SHIFT		8
218 #define NUM_EES_MASK		0xF
219 #define CE_BUFFER_SIZE		BIT(13)
220 #define AXI_ACTIVE		BIT(14)
221 #define USE_VMIDMT		BIT(15)
222 #define SECURED			BIT(16)
223 #define BAM_HAS_NO_BYPASS	BIT(17)
224 #define HIGH_FREQUENCY_BAM	BIT(18)
225 #define INACTIV_TMRS_EXST	BIT(19)
226 #define NUM_INACTIV_TMRS	BIT(20)
227 #define DESC_CACHE_DEPTH_SHIFT	21
228 #define DESC_CACHE_DEPTH_1	(0 << DESC_CACHE_DEPTH_SHIFT)
229 #define DESC_CACHE_DEPTH_2	(1 << DESC_CACHE_DEPTH_SHIFT)
230 #define DESC_CACHE_DEPTH_3	(2 << DESC_CACHE_DEPTH_SHIFT)
231 #define DESC_CACHE_DEPTH_4	(3 << DESC_CACHE_DEPTH_SHIFT)
232 #define CMD_DESC_EN		BIT(23)
233 #define INACTIV_TMR_BASE_SHIFT	24
234 #define INACTIV_TMR_BASE_MASK	0xFF
235 
236 /* BAM NUM PIPES */
237 #define BAM_NUM_PIPES_SHIFT		0
238 #define BAM_NUM_PIPES_MASK		0xFF
239 #define PERIPH_NON_PIPE_GRP_SHIFT	16
240 #define PERIPH_NON_PIP_GRP_MASK		0xFF
241 #define BAM_NON_PIPE_GRP_SHIFT		24
242 #define BAM_NON_PIPE_GRP_MASK		0xFF
243 
244 /* BAM CNFG BITS */
245 #define BAM_PIPE_CNFG		BIT(2)
246 #define BAM_FULL_PIPE		BIT(11)
247 #define BAM_NO_EXT_P_RST	BIT(12)
248 #define BAM_IBC_DISABLE		BIT(13)
249 #define BAM_SB_CLK_REQ		BIT(14)
250 #define BAM_PSM_CSW_REQ		BIT(15)
251 #define BAM_PSM_P_RES		BIT(16)
252 #define BAM_AU_P_RES		BIT(17)
253 #define BAM_SI_P_RES		BIT(18)
254 #define BAM_WB_P_RES		BIT(19)
255 #define BAM_WB_BLK_CSW		BIT(20)
256 #define BAM_WB_CSW_ACK_IDL	BIT(21)
257 #define BAM_WB_RETR_SVPNT	BIT(22)
258 #define BAM_WB_DSC_AVL_P_RST	BIT(23)
259 #define BAM_REG_P_EN		BIT(24)
260 #define BAM_PSM_P_HD_DATA	BIT(25)
261 #define BAM_AU_ACCUMED		BIT(26)
262 #define BAM_CMD_ENABLE		BIT(27)
263 
264 #define BAM_CNFG_BITS_DEFAULT	(BAM_PIPE_CNFG |	\
265 				 BAM_NO_EXT_P_RST |	\
266 				 BAM_IBC_DISABLE |	\
267 				 BAM_SB_CLK_REQ |	\
268 				 BAM_PSM_CSW_REQ |	\
269 				 BAM_PSM_P_RES |	\
270 				 BAM_AU_P_RES |		\
271 				 BAM_SI_P_RES |		\
272 				 BAM_WB_P_RES |		\
273 				 BAM_WB_BLK_CSW |	\
274 				 BAM_WB_CSW_ACK_IDL |	\
275 				 BAM_WB_RETR_SVPNT |	\
276 				 BAM_WB_DSC_AVL_P_RST |	\
277 				 BAM_REG_P_EN |		\
278 				 BAM_PSM_P_HD_DATA |	\
279 				 BAM_AU_ACCUMED |	\
280 				 BAM_CMD_ENABLE)
281 
282 /* PIPE CTRL */
283 #define P_EN			BIT(1)
284 #define P_DIRECTION		BIT(3)
285 #define P_SYS_STRM		BIT(4)
286 #define P_SYS_MODE		BIT(5)
287 #define P_AUTO_EOB		BIT(6)
288 #define P_AUTO_EOB_SEL_SHIFT	7
289 #define P_AUTO_EOB_SEL_512	(0 << P_AUTO_EOB_SEL_SHIFT)
290 #define P_AUTO_EOB_SEL_256	(1 << P_AUTO_EOB_SEL_SHIFT)
291 #define P_AUTO_EOB_SEL_128	(2 << P_AUTO_EOB_SEL_SHIFT)
292 #define P_AUTO_EOB_SEL_64	(3 << P_AUTO_EOB_SEL_SHIFT)
293 #define P_PREFETCH_LIMIT_SHIFT	9
294 #define P_PREFETCH_LIMIT_32	(0 << P_PREFETCH_LIMIT_SHIFT)
295 #define P_PREFETCH_LIMIT_16	(1 << P_PREFETCH_LIMIT_SHIFT)
296 #define P_PREFETCH_LIMIT_4	(2 << P_PREFETCH_LIMIT_SHIFT)
297 #define P_WRITE_NWD		BIT(11)
298 #define P_LOCK_GROUP_SHIFT	16
299 #define P_LOCK_GROUP_MASK	0x1F
300 
301 /* BAM_DESC_CNT_TRSHLD */
302 #define CNT_TRSHLD		0xffff
303 #define DEFAULT_CNT_THRSHLD	0x4
304 
305 /* BAM_IRQ_SRCS */
306 #define BAM_IRQ			BIT(31)
307 #define P_IRQ			0x7fffffff
308 
309 /* BAM_IRQ_SRCS_MSK */
310 #define BAM_IRQ_MSK		BAM_IRQ
311 #define P_IRQ_MSK		P_IRQ
312 
313 /* BAM_IRQ_STTS */
314 #define BAM_TIMER_IRQ		BIT(4)
315 #define BAM_EMPTY_IRQ		BIT(3)
316 #define BAM_ERROR_IRQ		BIT(2)
317 #define BAM_HRESP_ERR_IRQ	BIT(1)
318 
319 /* BAM_IRQ_CLR */
320 #define BAM_TIMER_CLR		BIT(4)
321 #define BAM_EMPTY_CLR		BIT(3)
322 #define BAM_ERROR_CLR		BIT(2)
323 #define BAM_HRESP_ERR_CLR	BIT(1)
324 
325 /* BAM_IRQ_EN */
326 #define BAM_TIMER_EN		BIT(4)
327 #define BAM_EMPTY_EN		BIT(3)
328 #define BAM_ERROR_EN		BIT(2)
329 #define BAM_HRESP_ERR_EN	BIT(1)
330 
331 /* BAM_P_IRQ_EN */
332 #define P_PRCSD_DESC_EN		BIT(0)
333 #define P_TIMER_EN		BIT(1)
334 #define P_WAKE_EN		BIT(2)
335 #define P_OUT_OF_DESC_EN	BIT(3)
336 #define P_ERR_EN		BIT(4)
337 #define P_TRNSFR_END_EN		BIT(5)
338 #define P_DEFAULT_IRQS_EN	(P_PRCSD_DESC_EN | P_ERR_EN | P_TRNSFR_END_EN)
339 
340 /* BAM_P_SW_OFSTS */
341 #define P_SW_OFSTS_MASK		0xffff
342 
343 #define BAM_DESC_FIFO_SIZE	SZ_32K
344 #define MAX_DESCRIPTORS (BAM_DESC_FIFO_SIZE / sizeof(struct bam_desc_hw) - 1)
345 #define BAM_MAX_DATA_SIZE	(SZ_32K - 8)
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 	struct bam_async_desc *curr_txd;	/* current running dma */
356 
357 	/* runtime configuration */
358 	struct dma_slave_config slave;
359 
360 	/* fifo storage */
361 	struct bam_desc_hw *fifo_virt;
362 	dma_addr_t fifo_phys;
363 
364 	/* fifo markers */
365 	unsigned short head;		/* start of active descriptor entries */
366 	unsigned short tail;		/* end of active descriptor entries */
367 
368 	unsigned int initialized;	/* is the channel hw initialized? */
369 	unsigned int paused;		/* is the channel paused? */
370 	unsigned int reconfigure;	/* new slave config? */
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 
388 	/* execution environment ID, from DT */
389 	u32 ee;
390 
391 	const struct reg_offset_data *layout;
392 
393 	struct clk *bamclk;
394 	int irq;
395 
396 	/* dma start transaction tasklet */
397 	struct tasklet_struct task;
398 };
399 
400 /**
401  * bam_addr - returns BAM register address
402  * @bdev: bam device
403  * @pipe: pipe instance (ignored when register doesn't have multiple instances)
404  * @reg:  register enum
405  */
406 static inline void __iomem *bam_addr(struct bam_device *bdev, u32 pipe,
407 		enum bam_reg reg)
408 {
409 	const struct reg_offset_data r = bdev->layout[reg];
410 
411 	return bdev->regs + r.base_offset +
412 		r.pipe_mult * pipe +
413 		r.evnt_mult * pipe +
414 		r.ee_mult * bdev->ee;
415 }
416 
417 /**
418  * bam_reset_channel - Reset individual BAM DMA channel
419  * @bchan: bam channel
420  *
421  * This function resets a specific BAM channel
422  */
423 static void bam_reset_channel(struct bam_chan *bchan)
424 {
425 	struct bam_device *bdev = bchan->bdev;
426 
427 	lockdep_assert_held(&bchan->vc.lock);
428 
429 	/* reset channel */
430 	writel_relaxed(1, bam_addr(bdev, bchan->id, BAM_P_RST));
431 	writel_relaxed(0, bam_addr(bdev, bchan->id, BAM_P_RST));
432 
433 	/* don't allow cpu to reorder BAM register accesses done after this */
434 	wmb();
435 
436 	/* make sure hw is initialized when channel is used the first time  */
437 	bchan->initialized = 0;
438 }
439 
440 /**
441  * bam_chan_init_hw - Initialize channel hardware
442  * @bchan: bam channel
443  *
444  * This function resets and initializes the BAM channel
445  */
446 static void bam_chan_init_hw(struct bam_chan *bchan,
447 	enum dma_transfer_direction dir)
448 {
449 	struct bam_device *bdev = bchan->bdev;
450 	u32 val;
451 
452 	/* Reset the channel to clear internal state of the FIFO */
453 	bam_reset_channel(bchan);
454 
455 	/*
456 	 * write out 8 byte aligned address.  We have enough space for this
457 	 * because we allocated 1 more descriptor (8 bytes) than we can use
458 	 */
459 	writel_relaxed(ALIGN(bchan->fifo_phys, sizeof(struct bam_desc_hw)),
460 			bam_addr(bdev, bchan->id, BAM_P_DESC_FIFO_ADDR));
461 	writel_relaxed(BAM_DESC_FIFO_SIZE,
462 			bam_addr(bdev, bchan->id, BAM_P_FIFO_SIZES));
463 
464 	/* enable the per pipe interrupts, enable EOT, ERR, and INT irqs */
465 	writel_relaxed(P_DEFAULT_IRQS_EN,
466 			bam_addr(bdev, bchan->id, BAM_P_IRQ_EN));
467 
468 	/* unmask the specific pipe and EE combo */
469 	val = readl_relaxed(bam_addr(bdev, 0, BAM_IRQ_SRCS_MSK_EE));
470 	val |= BIT(bchan->id);
471 	writel_relaxed(val, bam_addr(bdev, 0, BAM_IRQ_SRCS_MSK_EE));
472 
473 	/* don't allow cpu to reorder the channel enable done below */
474 	wmb();
475 
476 	/* set fixed direction and mode, then enable channel */
477 	val = P_EN | P_SYS_MODE;
478 	if (dir == DMA_DEV_TO_MEM)
479 		val |= P_DIRECTION;
480 
481 	writel_relaxed(val, bam_addr(bdev, bchan->id, BAM_P_CTRL));
482 
483 	bchan->initialized = 1;
484 
485 	/* init FIFO pointers */
486 	bchan->head = 0;
487 	bchan->tail = 0;
488 }
489 
490 /**
491  * bam_alloc_chan - Allocate channel resources for DMA channel.
492  * @chan: specified channel
493  *
494  * This function allocates the FIFO descriptor memory
495  */
496 static int bam_alloc_chan(struct dma_chan *chan)
497 {
498 	struct bam_chan *bchan = to_bam_chan(chan);
499 	struct bam_device *bdev = bchan->bdev;
500 
501 	if (bchan->fifo_virt)
502 		return 0;
503 
504 	/* allocate FIFO descriptor space, but only if necessary */
505 	bchan->fifo_virt = dma_alloc_wc(bdev->dev, BAM_DESC_FIFO_SIZE,
506 					&bchan->fifo_phys, GFP_KERNEL);
507 
508 	if (!bchan->fifo_virt) {
509 		dev_err(bdev->dev, "Failed to allocate desc fifo\n");
510 		return -ENOMEM;
511 	}
512 
513 	return 0;
514 }
515 
516 /**
517  * bam_free_chan - Frees dma resources associated with specific channel
518  * @chan: specified channel
519  *
520  * Free the allocated fifo descriptor memory and channel resources
521  *
522  */
523 static void bam_free_chan(struct dma_chan *chan)
524 {
525 	struct bam_chan *bchan = to_bam_chan(chan);
526 	struct bam_device *bdev = bchan->bdev;
527 	u32 val;
528 	unsigned long flags;
529 
530 	vchan_free_chan_resources(to_virt_chan(chan));
531 
532 	if (bchan->curr_txd) {
533 		dev_err(bchan->bdev->dev, "Cannot free busy channel\n");
534 		return;
535 	}
536 
537 	spin_lock_irqsave(&bchan->vc.lock, flags);
538 	bam_reset_channel(bchan);
539 	spin_unlock_irqrestore(&bchan->vc.lock, flags);
540 
541 	dma_free_wc(bdev->dev, BAM_DESC_FIFO_SIZE, bchan->fifo_virt,
542 		    bchan->fifo_phys);
543 	bchan->fifo_virt = NULL;
544 
545 	/* mask irq for pipe/channel */
546 	val = readl_relaxed(bam_addr(bdev, 0, BAM_IRQ_SRCS_MSK_EE));
547 	val &= ~BIT(bchan->id);
548 	writel_relaxed(val, bam_addr(bdev, 0, BAM_IRQ_SRCS_MSK_EE));
549 
550 	/* disable irq */
551 	writel_relaxed(0, bam_addr(bdev, bchan->id, BAM_P_IRQ_EN));
552 }
553 
554 /**
555  * bam_slave_config - set slave configuration for channel
556  * @chan: dma channel
557  * @cfg: slave configuration
558  *
559  * Sets slave configuration for channel
560  *
561  */
562 static int bam_slave_config(struct dma_chan *chan,
563 			    struct dma_slave_config *cfg)
564 {
565 	struct bam_chan *bchan = to_bam_chan(chan);
566 	unsigned long flag;
567 
568 	spin_lock_irqsave(&bchan->vc.lock, flag);
569 	memcpy(&bchan->slave, cfg, sizeof(*cfg));
570 	bchan->reconfigure = 1;
571 	spin_unlock_irqrestore(&bchan->vc.lock, flag);
572 
573 	return 0;
574 }
575 
576 /**
577  * bam_prep_slave_sg - Prep slave sg transaction
578  *
579  * @chan: dma channel
580  * @sgl: scatter gather list
581  * @sg_len: length of sg
582  * @direction: DMA transfer direction
583  * @flags: DMA flags
584  * @context: transfer context (unused)
585  */
586 static struct dma_async_tx_descriptor *bam_prep_slave_sg(struct dma_chan *chan,
587 	struct scatterlist *sgl, unsigned int sg_len,
588 	enum dma_transfer_direction direction, unsigned long flags,
589 	void *context)
590 {
591 	struct bam_chan *bchan = to_bam_chan(chan);
592 	struct bam_device *bdev = bchan->bdev;
593 	struct bam_async_desc *async_desc;
594 	struct scatterlist *sg;
595 	u32 i;
596 	struct bam_desc_hw *desc;
597 	unsigned int num_alloc = 0;
598 
599 
600 	if (!is_slave_direction(direction)) {
601 		dev_err(bdev->dev, "invalid dma direction\n");
602 		return NULL;
603 	}
604 
605 	/* calculate number of required entries */
606 	for_each_sg(sgl, sg, sg_len, i)
607 		num_alloc += DIV_ROUND_UP(sg_dma_len(sg), BAM_MAX_DATA_SIZE);
608 
609 	/* allocate enough room to accomodate the number of entries */
610 	async_desc = kzalloc(sizeof(*async_desc) +
611 			(num_alloc * sizeof(struct bam_desc_hw)), GFP_NOWAIT);
612 
613 	if (!async_desc)
614 		goto err_out;
615 
616 	if (flags & DMA_PREP_FENCE)
617 		async_desc->flags |= DESC_FLAG_NWD;
618 
619 	if (flags & DMA_PREP_INTERRUPT)
620 		async_desc->flags |= DESC_FLAG_EOT;
621 	else
622 		async_desc->flags |= DESC_FLAG_INT;
623 
624 	async_desc->num_desc = num_alloc;
625 	async_desc->curr_desc = async_desc->desc;
626 	async_desc->dir = direction;
627 
628 	/* fill in temporary descriptors */
629 	desc = async_desc->desc;
630 	for_each_sg(sgl, sg, sg_len, i) {
631 		unsigned int remainder = sg_dma_len(sg);
632 		unsigned int curr_offset = 0;
633 
634 		do {
635 			desc->addr = cpu_to_le32(sg_dma_address(sg) +
636 						 curr_offset);
637 
638 			if (remainder > BAM_MAX_DATA_SIZE) {
639 				desc->size = cpu_to_le16(BAM_MAX_DATA_SIZE);
640 				remainder -= BAM_MAX_DATA_SIZE;
641 				curr_offset += BAM_MAX_DATA_SIZE;
642 			} else {
643 				desc->size = cpu_to_le16(remainder);
644 				remainder = 0;
645 			}
646 
647 			async_desc->length += desc->size;
648 			desc++;
649 		} while (remainder > 0);
650 	}
651 
652 	return vchan_tx_prep(&bchan->vc, &async_desc->vd, flags);
653 
654 err_out:
655 	kfree(async_desc);
656 	return NULL;
657 }
658 
659 /**
660  * bam_dma_terminate_all - terminate all transactions on a channel
661  * @bchan: bam dma channel
662  *
663  * Dequeues and frees all transactions
664  * No callbacks are done
665  *
666  */
667 static int bam_dma_terminate_all(struct dma_chan *chan)
668 {
669 	struct bam_chan *bchan = to_bam_chan(chan);
670 	unsigned long flag;
671 	LIST_HEAD(head);
672 
673 	/* remove all transactions, including active transaction */
674 	spin_lock_irqsave(&bchan->vc.lock, flag);
675 	if (bchan->curr_txd) {
676 		list_add(&bchan->curr_txd->vd.node, &bchan->vc.desc_issued);
677 		bchan->curr_txd = NULL;
678 	}
679 
680 	vchan_get_all_descriptors(&bchan->vc, &head);
681 	spin_unlock_irqrestore(&bchan->vc.lock, flag);
682 
683 	vchan_dma_desc_free_list(&bchan->vc, &head);
684 
685 	return 0;
686 }
687 
688 /**
689  * bam_pause - Pause DMA channel
690  * @chan: dma channel
691  *
692  */
693 static int bam_pause(struct dma_chan *chan)
694 {
695 	struct bam_chan *bchan = to_bam_chan(chan);
696 	struct bam_device *bdev = bchan->bdev;
697 	unsigned long flag;
698 
699 	spin_lock_irqsave(&bchan->vc.lock, flag);
700 	writel_relaxed(1, bam_addr(bdev, bchan->id, BAM_P_HALT));
701 	bchan->paused = 1;
702 	spin_unlock_irqrestore(&bchan->vc.lock, flag);
703 
704 	return 0;
705 }
706 
707 /**
708  * bam_resume - Resume DMA channel operations
709  * @chan: dma channel
710  *
711  */
712 static int bam_resume(struct dma_chan *chan)
713 {
714 	struct bam_chan *bchan = to_bam_chan(chan);
715 	struct bam_device *bdev = bchan->bdev;
716 	unsigned long flag;
717 
718 	spin_lock_irqsave(&bchan->vc.lock, flag);
719 	writel_relaxed(0, bam_addr(bdev, bchan->id, BAM_P_HALT));
720 	bchan->paused = 0;
721 	spin_unlock_irqrestore(&bchan->vc.lock, flag);
722 
723 	return 0;
724 }
725 
726 /**
727  * process_channel_irqs - processes the channel interrupts
728  * @bdev: bam controller
729  *
730  * This function processes the channel interrupts
731  *
732  */
733 static u32 process_channel_irqs(struct bam_device *bdev)
734 {
735 	u32 i, srcs, pipe_stts;
736 	unsigned long flags;
737 	struct bam_async_desc *async_desc;
738 
739 	srcs = readl_relaxed(bam_addr(bdev, 0, BAM_IRQ_SRCS_EE));
740 
741 	/* return early if no pipe/channel interrupts are present */
742 	if (!(srcs & P_IRQ))
743 		return srcs;
744 
745 	for (i = 0; i < bdev->num_channels; i++) {
746 		struct bam_chan *bchan = &bdev->channels[i];
747 
748 		if (!(srcs & BIT(i)))
749 			continue;
750 
751 		/* clear pipe irq */
752 		pipe_stts = readl_relaxed(bam_addr(bdev, i, BAM_P_IRQ_STTS));
753 
754 		writel_relaxed(pipe_stts, bam_addr(bdev, i, BAM_P_IRQ_CLR));
755 
756 		spin_lock_irqsave(&bchan->vc.lock, flags);
757 		async_desc = bchan->curr_txd;
758 
759 		if (async_desc) {
760 			async_desc->num_desc -= async_desc->xfer_len;
761 			async_desc->curr_desc += async_desc->xfer_len;
762 			bchan->curr_txd = NULL;
763 
764 			/* manage FIFO */
765 			bchan->head += async_desc->xfer_len;
766 			bchan->head %= MAX_DESCRIPTORS;
767 
768 			/*
769 			 * if complete, process cookie.  Otherwise
770 			 * push back to front of desc_issued so that
771 			 * it gets restarted by the tasklet
772 			 */
773 			if (!async_desc->num_desc)
774 				vchan_cookie_complete(&async_desc->vd);
775 			else
776 				list_add(&async_desc->vd.node,
777 					&bchan->vc.desc_issued);
778 		}
779 
780 		spin_unlock_irqrestore(&bchan->vc.lock, flags);
781 	}
782 
783 	return srcs;
784 }
785 
786 /**
787  * bam_dma_irq - irq handler for bam controller
788  * @irq: IRQ of interrupt
789  * @data: callback data
790  *
791  * IRQ handler for the bam controller
792  */
793 static irqreturn_t bam_dma_irq(int irq, void *data)
794 {
795 	struct bam_device *bdev = data;
796 	u32 clr_mask = 0, srcs = 0;
797 
798 	srcs |= process_channel_irqs(bdev);
799 
800 	/* kick off tasklet to start next dma transfer */
801 	if (srcs & P_IRQ)
802 		tasklet_schedule(&bdev->task);
803 
804 	if (srcs & BAM_IRQ)
805 		clr_mask = readl_relaxed(bam_addr(bdev, 0, BAM_IRQ_STTS));
806 
807 	/* don't allow reorder of the various accesses to the BAM registers */
808 	mb();
809 
810 	writel_relaxed(clr_mask, bam_addr(bdev, 0, BAM_IRQ_CLR));
811 
812 	return IRQ_HANDLED;
813 }
814 
815 /**
816  * bam_tx_status - returns status of transaction
817  * @chan: dma channel
818  * @cookie: transaction cookie
819  * @txstate: DMA transaction state
820  *
821  * Return status of dma transaction
822  */
823 static enum dma_status bam_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
824 		struct dma_tx_state *txstate)
825 {
826 	struct bam_chan *bchan = to_bam_chan(chan);
827 	struct virt_dma_desc *vd;
828 	int ret;
829 	size_t residue = 0;
830 	unsigned int i;
831 	unsigned long flags;
832 
833 	ret = dma_cookie_status(chan, cookie, txstate);
834 	if (ret == DMA_COMPLETE)
835 		return ret;
836 
837 	if (!txstate)
838 		return bchan->paused ? DMA_PAUSED : ret;
839 
840 	spin_lock_irqsave(&bchan->vc.lock, flags);
841 	vd = vchan_find_desc(&bchan->vc, cookie);
842 	if (vd)
843 		residue = container_of(vd, struct bam_async_desc, vd)->length;
844 	else if (bchan->curr_txd && bchan->curr_txd->vd.tx.cookie == cookie)
845 		for (i = 0; i < bchan->curr_txd->num_desc; i++)
846 			residue += bchan->curr_txd->curr_desc[i].size;
847 
848 	spin_unlock_irqrestore(&bchan->vc.lock, flags);
849 
850 	dma_set_residue(txstate, residue);
851 
852 	if (ret == DMA_IN_PROGRESS && bchan->paused)
853 		ret = DMA_PAUSED;
854 
855 	return ret;
856 }
857 
858 /**
859  * bam_apply_new_config
860  * @bchan: bam dma channel
861  * @dir: DMA direction
862  */
863 static void bam_apply_new_config(struct bam_chan *bchan,
864 	enum dma_transfer_direction dir)
865 {
866 	struct bam_device *bdev = bchan->bdev;
867 	u32 maxburst;
868 
869 	if (dir == DMA_DEV_TO_MEM)
870 		maxburst = bchan->slave.src_maxburst;
871 	else
872 		maxburst = bchan->slave.dst_maxburst;
873 
874 	writel_relaxed(maxburst, bam_addr(bdev, 0, BAM_DESC_CNT_TRSHLD));
875 
876 	bchan->reconfigure = 0;
877 }
878 
879 /**
880  * bam_start_dma - start next transaction
881  * @bchan - bam dma channel
882  */
883 static void bam_start_dma(struct bam_chan *bchan)
884 {
885 	struct virt_dma_desc *vd = vchan_next_desc(&bchan->vc);
886 	struct bam_device *bdev = bchan->bdev;
887 	struct bam_async_desc *async_desc;
888 	struct bam_desc_hw *desc;
889 	struct bam_desc_hw *fifo = PTR_ALIGN(bchan->fifo_virt,
890 					sizeof(struct bam_desc_hw));
891 
892 	lockdep_assert_held(&bchan->vc.lock);
893 
894 	if (!vd)
895 		return;
896 
897 	list_del(&vd->node);
898 
899 	async_desc = container_of(vd, struct bam_async_desc, vd);
900 	bchan->curr_txd = async_desc;
901 
902 	/* on first use, initialize the channel hardware */
903 	if (!bchan->initialized)
904 		bam_chan_init_hw(bchan, async_desc->dir);
905 
906 	/* apply new slave config changes, if necessary */
907 	if (bchan->reconfigure)
908 		bam_apply_new_config(bchan, async_desc->dir);
909 
910 	desc = bchan->curr_txd->curr_desc;
911 
912 	if (async_desc->num_desc > MAX_DESCRIPTORS)
913 		async_desc->xfer_len = MAX_DESCRIPTORS;
914 	else
915 		async_desc->xfer_len = async_desc->num_desc;
916 
917 	/* set any special flags on the last descriptor */
918 	if (async_desc->num_desc == async_desc->xfer_len)
919 		desc[async_desc->xfer_len - 1].flags =
920 					cpu_to_le16(async_desc->flags);
921 	else
922 		desc[async_desc->xfer_len - 1].flags |=
923 					cpu_to_le16(DESC_FLAG_INT);
924 
925 	if (bchan->tail + async_desc->xfer_len > MAX_DESCRIPTORS) {
926 		u32 partial = MAX_DESCRIPTORS - bchan->tail;
927 
928 		memcpy(&fifo[bchan->tail], desc,
929 				partial * sizeof(struct bam_desc_hw));
930 		memcpy(fifo, &desc[partial], (async_desc->xfer_len - partial) *
931 				sizeof(struct bam_desc_hw));
932 	} else {
933 		memcpy(&fifo[bchan->tail], desc,
934 			async_desc->xfer_len * sizeof(struct bam_desc_hw));
935 	}
936 
937 	bchan->tail += async_desc->xfer_len;
938 	bchan->tail %= MAX_DESCRIPTORS;
939 
940 	/* ensure descriptor writes and dma start not reordered */
941 	wmb();
942 	writel_relaxed(bchan->tail * sizeof(struct bam_desc_hw),
943 			bam_addr(bdev, bchan->id, BAM_P_EVNT_REG));
944 }
945 
946 /**
947  * dma_tasklet - DMA IRQ tasklet
948  * @data: tasklet argument (bam controller structure)
949  *
950  * Sets up next DMA operation and then processes all completed transactions
951  */
952 static void dma_tasklet(unsigned long data)
953 {
954 	struct bam_device *bdev = (struct bam_device *)data;
955 	struct bam_chan *bchan;
956 	unsigned long flags;
957 	unsigned int i;
958 
959 	/* go through the channels and kick off transactions */
960 	for (i = 0; i < bdev->num_channels; i++) {
961 		bchan = &bdev->channels[i];
962 		spin_lock_irqsave(&bchan->vc.lock, flags);
963 
964 		if (!list_empty(&bchan->vc.desc_issued) && !bchan->curr_txd)
965 			bam_start_dma(bchan);
966 		spin_unlock_irqrestore(&bchan->vc.lock, flags);
967 	}
968 }
969 
970 /**
971  * bam_issue_pending - starts pending transactions
972  * @chan: dma channel
973  *
974  * Calls tasklet directly which in turn starts any pending transactions
975  */
976 static void bam_issue_pending(struct dma_chan *chan)
977 {
978 	struct bam_chan *bchan = to_bam_chan(chan);
979 	unsigned long flags;
980 
981 	spin_lock_irqsave(&bchan->vc.lock, flags);
982 
983 	/* if work pending and idle, start a transaction */
984 	if (vchan_issue_pending(&bchan->vc) && !bchan->curr_txd)
985 		bam_start_dma(bchan);
986 
987 	spin_unlock_irqrestore(&bchan->vc.lock, flags);
988 }
989 
990 /**
991  * bam_dma_free_desc - free descriptor memory
992  * @vd: virtual descriptor
993  *
994  */
995 static void bam_dma_free_desc(struct virt_dma_desc *vd)
996 {
997 	struct bam_async_desc *async_desc = container_of(vd,
998 			struct bam_async_desc, vd);
999 
1000 	kfree(async_desc);
1001 }
1002 
1003 static struct dma_chan *bam_dma_xlate(struct of_phandle_args *dma_spec,
1004 		struct of_dma *of)
1005 {
1006 	struct bam_device *bdev = container_of(of->of_dma_data,
1007 					struct bam_device, common);
1008 	unsigned int request;
1009 
1010 	if (dma_spec->args_count != 1)
1011 		return NULL;
1012 
1013 	request = dma_spec->args[0];
1014 	if (request >= bdev->num_channels)
1015 		return NULL;
1016 
1017 	return dma_get_slave_channel(&(bdev->channels[request].vc.chan));
1018 }
1019 
1020 /**
1021  * bam_init
1022  * @bdev: bam device
1023  *
1024  * Initialization helper for global bam registers
1025  */
1026 static int bam_init(struct bam_device *bdev)
1027 {
1028 	u32 val;
1029 
1030 	/* read revision and configuration information */
1031 	val = readl_relaxed(bam_addr(bdev, 0, BAM_REVISION)) >> NUM_EES_SHIFT;
1032 	val &= NUM_EES_MASK;
1033 
1034 	/* check that configured EE is within range */
1035 	if (bdev->ee >= val)
1036 		return -EINVAL;
1037 
1038 	val = readl_relaxed(bam_addr(bdev, 0, BAM_NUM_PIPES));
1039 	bdev->num_channels = val & BAM_NUM_PIPES_MASK;
1040 
1041 	/* s/w reset bam */
1042 	/* after reset all pipes are disabled and idle */
1043 	val = readl_relaxed(bam_addr(bdev, 0, BAM_CTRL));
1044 	val |= BAM_SW_RST;
1045 	writel_relaxed(val, bam_addr(bdev, 0, BAM_CTRL));
1046 	val &= ~BAM_SW_RST;
1047 	writel_relaxed(val, bam_addr(bdev, 0, BAM_CTRL));
1048 
1049 	/* make sure previous stores are visible before enabling BAM */
1050 	wmb();
1051 
1052 	/* enable bam */
1053 	val |= BAM_EN;
1054 	writel_relaxed(val, bam_addr(bdev, 0, BAM_CTRL));
1055 
1056 	/* set descriptor threshhold, start with 4 bytes */
1057 	writel_relaxed(DEFAULT_CNT_THRSHLD,
1058 			bam_addr(bdev, 0, BAM_DESC_CNT_TRSHLD));
1059 
1060 	/* Enable default set of h/w workarounds, ie all except BAM_FULL_PIPE */
1061 	writel_relaxed(BAM_CNFG_BITS_DEFAULT, bam_addr(bdev, 0, BAM_CNFG_BITS));
1062 
1063 	/* enable irqs for errors */
1064 	writel_relaxed(BAM_ERROR_EN | BAM_HRESP_ERR_EN,
1065 			bam_addr(bdev, 0, BAM_IRQ_EN));
1066 
1067 	/* unmask global bam interrupt */
1068 	writel_relaxed(BAM_IRQ_MSK, bam_addr(bdev, 0, BAM_IRQ_SRCS_MSK_EE));
1069 
1070 	return 0;
1071 }
1072 
1073 static void bam_channel_init(struct bam_device *bdev, struct bam_chan *bchan,
1074 	u32 index)
1075 {
1076 	bchan->id = index;
1077 	bchan->bdev = bdev;
1078 
1079 	vchan_init(&bchan->vc, &bdev->common);
1080 	bchan->vc.desc_free = bam_dma_free_desc;
1081 }
1082 
1083 static const struct of_device_id bam_of_match[] = {
1084 	{ .compatible = "qcom,bam-v1.3.0", .data = &bam_v1_3_reg_info },
1085 	{ .compatible = "qcom,bam-v1.4.0", .data = &bam_v1_4_reg_info },
1086 	{ .compatible = "qcom,bam-v1.7.0", .data = &bam_v1_7_reg_info },
1087 	{}
1088 };
1089 
1090 MODULE_DEVICE_TABLE(of, bam_of_match);
1091 
1092 static int bam_dma_probe(struct platform_device *pdev)
1093 {
1094 	struct bam_device *bdev;
1095 	const struct of_device_id *match;
1096 	struct resource *iores;
1097 	int ret, i;
1098 
1099 	bdev = devm_kzalloc(&pdev->dev, sizeof(*bdev), GFP_KERNEL);
1100 	if (!bdev)
1101 		return -ENOMEM;
1102 
1103 	bdev->dev = &pdev->dev;
1104 
1105 	match = of_match_node(bam_of_match, pdev->dev.of_node);
1106 	if (!match) {
1107 		dev_err(&pdev->dev, "Unsupported BAM module\n");
1108 		return -ENODEV;
1109 	}
1110 
1111 	bdev->layout = match->data;
1112 
1113 	iores = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1114 	bdev->regs = devm_ioremap_resource(&pdev->dev, iores);
1115 	if (IS_ERR(bdev->regs))
1116 		return PTR_ERR(bdev->regs);
1117 
1118 	bdev->irq = platform_get_irq(pdev, 0);
1119 	if (bdev->irq < 0)
1120 		return bdev->irq;
1121 
1122 	ret = of_property_read_u32(pdev->dev.of_node, "qcom,ee", &bdev->ee);
1123 	if (ret) {
1124 		dev_err(bdev->dev, "Execution environment unspecified\n");
1125 		return ret;
1126 	}
1127 
1128 	bdev->bamclk = devm_clk_get(bdev->dev, "bam_clk");
1129 	if (IS_ERR(bdev->bamclk))
1130 		return PTR_ERR(bdev->bamclk);
1131 
1132 	ret = clk_prepare_enable(bdev->bamclk);
1133 	if (ret) {
1134 		dev_err(bdev->dev, "failed to prepare/enable clock\n");
1135 		return ret;
1136 	}
1137 
1138 	ret = bam_init(bdev);
1139 	if (ret)
1140 		goto err_disable_clk;
1141 
1142 	tasklet_init(&bdev->task, dma_tasklet, (unsigned long)bdev);
1143 
1144 	bdev->channels = devm_kcalloc(bdev->dev, bdev->num_channels,
1145 				sizeof(*bdev->channels), GFP_KERNEL);
1146 
1147 	if (!bdev->channels) {
1148 		ret = -ENOMEM;
1149 		goto err_tasklet_kill;
1150 	}
1151 
1152 	/* allocate and initialize channels */
1153 	INIT_LIST_HEAD(&bdev->common.channels);
1154 
1155 	for (i = 0; i < bdev->num_channels; i++)
1156 		bam_channel_init(bdev, &bdev->channels[i], i);
1157 
1158 	ret = devm_request_irq(bdev->dev, bdev->irq, bam_dma_irq,
1159 			IRQF_TRIGGER_HIGH, "bam_dma", bdev);
1160 	if (ret)
1161 		goto err_bam_channel_exit;
1162 
1163 	/* set max dma segment size */
1164 	bdev->common.dev = bdev->dev;
1165 	bdev->common.dev->dma_parms = &bdev->dma_parms;
1166 	ret = dma_set_max_seg_size(bdev->common.dev, BAM_MAX_DATA_SIZE);
1167 	if (ret) {
1168 		dev_err(bdev->dev, "cannot set maximum segment size\n");
1169 		goto err_bam_channel_exit;
1170 	}
1171 
1172 	platform_set_drvdata(pdev, bdev);
1173 
1174 	/* set capabilities */
1175 	dma_cap_zero(bdev->common.cap_mask);
1176 	dma_cap_set(DMA_SLAVE, bdev->common.cap_mask);
1177 
1178 	/* initialize dmaengine apis */
1179 	bdev->common.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
1180 	bdev->common.residue_granularity = DMA_RESIDUE_GRANULARITY_SEGMENT;
1181 	bdev->common.src_addr_widths = DMA_SLAVE_BUSWIDTH_4_BYTES;
1182 	bdev->common.dst_addr_widths = DMA_SLAVE_BUSWIDTH_4_BYTES;
1183 	bdev->common.device_alloc_chan_resources = bam_alloc_chan;
1184 	bdev->common.device_free_chan_resources = bam_free_chan;
1185 	bdev->common.device_prep_slave_sg = bam_prep_slave_sg;
1186 	bdev->common.device_config = bam_slave_config;
1187 	bdev->common.device_pause = bam_pause;
1188 	bdev->common.device_resume = bam_resume;
1189 	bdev->common.device_terminate_all = bam_dma_terminate_all;
1190 	bdev->common.device_issue_pending = bam_issue_pending;
1191 	bdev->common.device_tx_status = bam_tx_status;
1192 	bdev->common.dev = bdev->dev;
1193 
1194 	ret = dma_async_device_register(&bdev->common);
1195 	if (ret) {
1196 		dev_err(bdev->dev, "failed to register dma async device\n");
1197 		goto err_bam_channel_exit;
1198 	}
1199 
1200 	ret = of_dma_controller_register(pdev->dev.of_node, bam_dma_xlate,
1201 					&bdev->common);
1202 	if (ret)
1203 		goto err_unregister_dma;
1204 
1205 	return 0;
1206 
1207 err_unregister_dma:
1208 	dma_async_device_unregister(&bdev->common);
1209 err_bam_channel_exit:
1210 	for (i = 0; i < bdev->num_channels; i++)
1211 		tasklet_kill(&bdev->channels[i].vc.task);
1212 err_tasklet_kill:
1213 	tasklet_kill(&bdev->task);
1214 err_disable_clk:
1215 	clk_disable_unprepare(bdev->bamclk);
1216 
1217 	return ret;
1218 }
1219 
1220 static int bam_dma_remove(struct platform_device *pdev)
1221 {
1222 	struct bam_device *bdev = platform_get_drvdata(pdev);
1223 	u32 i;
1224 
1225 	of_dma_controller_free(pdev->dev.of_node);
1226 	dma_async_device_unregister(&bdev->common);
1227 
1228 	/* mask all interrupts for this execution environment */
1229 	writel_relaxed(0, bam_addr(bdev, 0,  BAM_IRQ_SRCS_MSK_EE));
1230 
1231 	devm_free_irq(bdev->dev, bdev->irq, bdev);
1232 
1233 	for (i = 0; i < bdev->num_channels; i++) {
1234 		bam_dma_terminate_all(&bdev->channels[i].vc.chan);
1235 		tasklet_kill(&bdev->channels[i].vc.task);
1236 
1237 		dma_free_wc(bdev->dev, BAM_DESC_FIFO_SIZE,
1238 			    bdev->channels[i].fifo_virt,
1239 			    bdev->channels[i].fifo_phys);
1240 	}
1241 
1242 	tasklet_kill(&bdev->task);
1243 
1244 	clk_disable_unprepare(bdev->bamclk);
1245 
1246 	return 0;
1247 }
1248 
1249 static struct platform_driver bam_dma_driver = {
1250 	.probe = bam_dma_probe,
1251 	.remove = bam_dma_remove,
1252 	.driver = {
1253 		.name = "bam-dma-engine",
1254 		.of_match_table = bam_of_match,
1255 	},
1256 };
1257 
1258 module_platform_driver(bam_dma_driver);
1259 
1260 MODULE_AUTHOR("Andy Gross <agross@codeaurora.org>");
1261 MODULE_DESCRIPTION("QCOM BAM DMA engine driver");
1262 MODULE_LICENSE("GPL v2");
1263