* [PATCH 3/3 v2] sh: implement DMA_SLAVE capability in SH dmaengine
@ 2010-01-19 7:27 Guennadi Liakhovetski
2010-02-01 19:05 ` Guennadi Liakhovetski
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Guennadi Liakhovetski @ 2010-01-19 7:27 UTC (permalink / raw)
To: linux-sh
Tested to work with a SIU ASoC driver on sh7722 (migor).
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
---
v1 -> v2: v1 didn't work in the input direction, because capture wasn't
implemented for SIU audio at that time yet. This version fixes the receive
direction too.
arch/sh/include/asm/dma-sh.h | 41 +++++++-
arch/sh/include/cpu-sh4/cpu/dma-sh4a.h | 15 ++-
drivers/dma/shdma.c | 190 ++++++++++++++++++++++++--------
drivers/dma/shdma.h | 7 +-
4 files changed, 192 insertions(+), 61 deletions(-)
diff --git a/arch/sh/include/asm/dma-sh.h b/arch/sh/include/asm/dma-sh.h
index 01d2fc7..c8d8ce7 100644
--- a/arch/sh/include/asm/dma-sh.h
+++ b/arch/sh/include/asm/dma-sh.h
@@ -64,8 +64,10 @@ static int dmte_irq_map[] __maybe_unused = {
#define ACK_L 0x00010000
#define DM_INC 0x00004000
#define DM_DEC 0x00008000
+#define DM_FIX 0x0000c000
#define SM_INC 0x00001000
#define SM_DEC 0x00002000
+#define SM_FIX 0x00003000
#define RS_IN 0x00000200
#define RS_OUT 0x00000300
#define TS_BLK 0x00000040
@@ -123,10 +125,47 @@ static u32 dma_base_addr[] __maybe_unused = {
*/
#define SHDMA_MIX_IRQ (1 << 1)
#define SHDMA_DMAOR1 (1 << 2)
-#define SHDMA_DMAE1 (1 << 3)
+#define SHDMA_DMAE1 (1 << 3)
+
+enum sh_dmae_slave_chan_id {
+ SHDMA_SLAVE_SCIF0_TX,
+ SHDMA_SLAVE_SCIF0_RX,
+ SHDMA_SLAVE_SCIF1_TX,
+ SHDMA_SLAVE_SCIF1_RX,
+ SHDMA_SLAVE_SCIF2_TX,
+ SHDMA_SLAVE_SCIF2_RX,
+ SHDMA_SLAVE_SCIF3_TX,
+ SHDMA_SLAVE_SCIF3_RX,
+ SHDMA_SLAVE_SCIF4_TX,
+ SHDMA_SLAVE_SCIF4_RX,
+ SHDMA_SLAVE_SCIF5_TX,
+ SHDMA_SLAVE_SCIF5_RX,
+ SHDMA_SLAVE_SIUA_TX,
+ SHDMA_SLAVE_SIUA_RX,
+ SHDMA_SLAVE_SIUB_TX,
+ SHDMA_SLAVE_SIUB_RX,
+ SHDMA_SLAVE_NUMBER, /* Must stay last */
+};
+
+struct sh_dmae_slave_config {
+ enum sh_dmae_slave_chan_id slave_id;
+ dma_addr_t addr;
+ u32 chcr;
+ char mid_rid;
+};
struct sh_dmae_pdata {
unsigned int mode;
+ struct sh_dmae_slave_config *config;
+ int config_num;
+};
+
+struct device;
+
+struct sh_dmae_slave {
+ enum sh_dmae_slave_chan_id slave_id; /* Set by the platform */
+ struct device *dma_dev; /* Set by the platform */
+ struct sh_dmae_slave_config *config; /* Set by the driver */
};
#endif /* __DMA_SH_H */
diff --git a/arch/sh/include/cpu-sh4/cpu/dma-sh4a.h b/arch/sh/include/cpu-sh4/cpu/dma-sh4a.h
index 561538c..3d8bb27 100644
--- a/arch/sh/include/cpu-sh4/cpu/dma-sh4a.h
+++ b/arch/sh/include/cpu-sh4/cpu/dma-sh4a.h
@@ -7,7 +7,7 @@
#define DMTE4_IRQ 76
#define DMAE0_IRQ 78 /* DMA Error IRQ*/
#define SH_DMAC_BASE0 0xFE008020
-#define SH_DMARS_BASE 0xFE009000
+#define SH_DMARS_BASE0 0xFE009000
#define CHCR_TS01_MASK 0x00000018
#define CHCR_TS01_SHIFT 3
#define CHCR_TS23_MASK 0
@@ -17,7 +17,7 @@
#define DMTE4_IRQ 76
#define DMAE0_IRQ 78 /* DMA Error IRQ*/
#define SH_DMAC_BASE0 0xFE008020
-#define SH_DMARS_BASE 0xFE009000
+#define SH_DMARS_BASE0 0xFE009000
#define CHCR_TS01_MASK 0x00000018
#define CHCR_TS01_SHIFT 3
#define CHCR_TS23_MASK 0x00300000
@@ -28,7 +28,7 @@
#define DMTE4_IRQ 44
#define DMAE0_IRQ 38
#define SH_DMAC_BASE0 0xFF608020
-#define SH_DMARS_BASE 0xFF609000
+#define SH_DMARS_BASE0 0xFF609000
#define CHCR_TS01_MASK 0x00000018
#define CHCR_TS01_SHIFT 3
#define CHCR_TS23_MASK 0
@@ -45,7 +45,7 @@
#define DMAE1_IRQ 74 /* DMA Error IRQ*/
#define SH_DMAC_BASE0 0xFE008020
#define SH_DMAC_BASE1 0xFDC08020
-#define SH_DMARS_BASE 0xFDC09000
+#define SH_DMARS_BASE0 0xFDC09000
#define CHCR_TS01_MASK 0x00000018
#define CHCR_TS01_SHIFT 3
#define CHCR_TS23_MASK 0
@@ -62,7 +62,8 @@
#define DMAE1_IRQ 74 /* DMA Error IRQ*/
#define SH_DMAC_BASE0 0xFE008020
#define SH_DMAC_BASE1 0xFDC08020
-#define SH_DMARS_BASE 0xFDC09000
+#define SH_DMARS_BASE0 0xFE009000
+#define SH_DMARS_BASE1 0xFDC09000
#define CHCR_TS01_MASK 0x00000018
#define CHCR_TS01_SHIFT 3
#define CHCR_TS23_MASK 0x00600000
@@ -78,7 +79,7 @@
#define DMAE0_IRQ 38 /* DMA Error IRQ */
#define SH_DMAC_BASE0 0xFC808020
#define SH_DMAC_BASE1 0xFC818020
-#define SH_DMARS_BASE 0xFC809000
+#define SH_DMARS_BASE0 0xFC809000
#define CHCR_TS01_MASK 0x00000018
#define CHCR_TS01_SHIFT 3
#define CHCR_TS23_MASK 0
@@ -95,7 +96,7 @@
#define DMAE1_IRQ 58 /* DMA Error IRQ1 */
#define SH_DMAC_BASE0 0xFC808020
#define SH_DMAC_BASE1 0xFCC08020
-#define SH_DMARS_BASE 0xFC809000
+#define SH_DMARS_BASE0 0xFC809000
#define CHCR_TS01_MASK 0x00000018
#define CHCR_TS01_SHIFT 3
#define CHCR_TS23_MASK 0
diff --git a/drivers/dma/shdma.c b/drivers/dma/shdma.c
index a7c1f54..22e3a5d 100644
--- a/drivers/dma/shdma.c
+++ b/drivers/dma/shdma.c
@@ -48,6 +48,9 @@ enum sh_dmae_desc_status {
*/
#define RS_DEFAULT (RS_DUAL)
+/* A bitmask with bits enough for enum sh_dmae_slave_chan_id */
+static unsigned long sh_dmae_slave_used[BITS_TO_LONGS(SHDMA_SLAVE_NUMBER)];
+
static void sh_dmae_chan_ld_cleanup(struct sh_dmae_chan *sh_chan, bool all);
#define SH_DMAC_CHAN_BASE(id) (dma_base_addr[id])
@@ -61,12 +64,6 @@ static u32 sh_dmae_readl(struct sh_dmae_chan *sh_dc, u32 reg)
return ctrl_inl(SH_DMAC_CHAN_BASE(sh_dc->id) + reg);
}
-static void dmae_init(struct sh_dmae_chan *sh_chan)
-{
- u32 chcr = RS_DEFAULT; /* default is DUAL mode */
- sh_dmae_writel(sh_chan, chcr, CHCR);
-}
-
/*
* Reset DMA controller
*
@@ -106,9 +103,8 @@ static bool dmae_is_busy(struct sh_dmae_chan *sh_chan)
}
static unsigned int ts_shift[] = TS_SHIFT;
-static inline unsigned int calc_xmit_shift(struct sh_dmae_chan *sh_chan)
+static inline unsigned int calc_xmit_shift(u32 chcr)
{
- u32 chcr = sh_dmae_readl(sh_chan, CHCR);
int cnt = ((chcr & CHCR_TS01_MASK) >> CHCR_TS01_SHIFT) |
((chcr & CHCR_TS23_MASK) >> CHCR_TS23_SHIFT);
@@ -119,7 +115,7 @@ static void dmae_set_reg(struct sh_dmae_chan *sh_chan, struct sh_dmae_regs *hw)
{
sh_dmae_writel(sh_chan, hw->sar, SAR);
sh_dmae_writel(sh_chan, hw->dar, DAR);
- sh_dmae_writel(sh_chan, hw->tcr >> calc_xmit_shift(sh_chan), TCR);
+ sh_dmae_writel(sh_chan, hw->tcr >> sh_chan->xmit_shift, TCR);
}
static void dmae_start(struct sh_dmae_chan *sh_chan)
@@ -127,7 +123,7 @@ static void dmae_start(struct sh_dmae_chan *sh_chan)
u32 chcr = sh_dmae_readl(sh_chan, CHCR);
chcr |= CHCR_DE | CHCR_IE;
- sh_dmae_writel(sh_chan, chcr, CHCR);
+ sh_dmae_writel(sh_chan, chcr & ~CHCR_TE, CHCR);
}
static void dmae_halt(struct sh_dmae_chan *sh_chan)
@@ -138,20 +134,27 @@ static void dmae_halt(struct sh_dmae_chan *sh_chan)
sh_dmae_writel(sh_chan, chcr, CHCR);
}
+static void dmae_init(struct sh_dmae_chan *sh_chan)
+{
+ u32 chcr = RS_DEFAULT; /* default is DUAL mode */
+ sh_chan->xmit_shift = calc_xmit_shift(chcr);
+ sh_dmae_writel(sh_chan, chcr, CHCR);
+}
+
static int dmae_set_chcr(struct sh_dmae_chan *sh_chan, u32 val)
{
/* When DMA was working, can not set data to CHCR */
if (dmae_is_busy(sh_chan))
return -EBUSY;
+ sh_chan->xmit_shift = calc_xmit_shift(val);
sh_dmae_writel(sh_chan, val, CHCR);
+
return 0;
}
-#define DMARS1_ADDR 0x04
-#define DMARS2_ADDR 0x08
-#define DMARS_SHIFT 8
-#define DMARS_CHAN_MSK 0x01
+#define DMARS_SHIFT 8
+#define DMARS_CHAN_MSK 0x01
static int dmae_set_dmars(struct sh_dmae_chan *sh_chan, u16 val)
{
u32 addr;
@@ -163,29 +166,18 @@ static int dmae_set_dmars(struct sh_dmae_chan *sh_chan, u16 val)
if (sh_chan->id & DMARS_CHAN_MSK)
shift = DMARS_SHIFT;
- switch (sh_chan->id) {
- /* DMARS0 */
- case 0:
- case 1:
- addr = SH_DMARS_BASE;
- break;
- /* DMARS1 */
- case 2:
- case 3:
- addr = (SH_DMARS_BASE + DMARS1_ADDR);
- break;
- /* DMARS2 */
- case 4:
- case 5:
- addr = (SH_DMARS_BASE + DMARS2_ADDR);
- break;
- default:
+ if (sh_chan->id < 6)
+ /* DMA0RS0 - DMA0RS2 */
+ addr = SH_DMARS_BASE0 + (sh_chan->id / 2) * 4;
+#ifdef SH_DMARS_BASE1
+ else if (sh_chan->id < 12)
+ /* DMA1RS0 - DMA1RS2 */
+ addr = SH_DMARS_BASE1 + ((sh_chan->id - 6) / 2) * 4;
+#endif
+ else
return -EINVAL;
- }
- ctrl_outw((val << shift) |
- (ctrl_inw(addr) & (shift ? 0xFF00 : 0x00FF)),
- addr);
+ ctrl_outw((val << shift) | (ctrl_inw(addr) & (0xFF00 >> shift)), addr);
return 0;
}
@@ -253,10 +245,53 @@ static struct sh_desc *sh_dmae_get_desc(struct sh_dmae_chan *sh_chan)
return NULL;
}
+static struct sh_dmae_slave_config *sh_dmae_find_slave(
+ struct sh_dmae_chan *sh_chan, enum sh_dmae_slave_chan_id slave_id)
+{
+ struct dma_device *dma_dev = sh_chan->common.device;
+ struct sh_dmae_device *shdev = container_of(dma_dev,
+ struct sh_dmae_device, common);
+ struct sh_dmae_pdata *pdata = &shdev->pdata;
+ int i;
+
+ if ((unsigned)slave_id >= SHDMA_SLAVE_NUMBER)
+ return NULL;
+
+ for (i = 0; i < pdata->config_num; i++)
+ if (pdata->config[i].slave_id = slave_id)
+ return pdata->config + i;
+
+ return NULL;
+}
+
static int sh_dmae_alloc_chan_resources(struct dma_chan *chan)
{
struct sh_dmae_chan *sh_chan = to_sh_chan(chan);
struct sh_desc *desc;
+ struct sh_dmae_slave *param = chan->private;
+
+ /*
+ * Called under dma_list_mutex, take care to perform all slave channel
+ * ID manipulations under that lock.
+ */
+ if (param) {
+ struct sh_dmae_slave_config *cfg;
+
+ cfg = sh_dmae_find_slave(sh_chan, param->slave_id);
+ if (!cfg)
+ return -EINVAL;
+
+ if (test_and_set_bit(param->slave_id, sh_dmae_slave_used))
+ return -EBUSY;
+
+ param->config = cfg;
+
+ dmae_set_dmars(sh_chan, cfg->mid_rid);
+ dmae_set_chcr(sh_chan, cfg->chcr);
+ } else {
+ if ((sh_dmae_readl(sh_chan, CHCR) & 0x700) != 0x400)
+ dmae_set_chcr(sh_chan, RS_DEFAULT);
+ }
spin_lock_bh(&sh_chan->desc_lock);
while (sh_chan->descs_allocated < NR_DESCS_PER_CHANNEL) {
@@ -289,10 +324,18 @@ static void sh_dmae_free_chan_resources(struct dma_chan *chan)
struct sh_desc *desc, *_desc;
LIST_HEAD(list);
+ dmae_halt(sh_chan);
+
/* Prepared and not submitted descriptors can still be on the queue */
if (!list_empty(&sh_chan->ld_queue))
sh_dmae_chan_ld_cleanup(sh_chan, true);
+ if (chan->private) {
+ /* The caller is holding dma_list_mutex */
+ struct sh_dmae_slave *param = chan->private;
+ clear_bit(param->slave_id, sh_dmae_slave_used);
+ }
+
spin_lock_bh(&sh_chan->desc_lock);
list_splice_init(&sh_chan->ld_free, &list);
@@ -304,7 +347,7 @@ static void sh_dmae_free_chan_resources(struct dma_chan *chan)
kfree(desc);
}
-/*
+/**
* sh_dmae_add_desc - get, set up and return one transfer descriptor
* @sh_chan: DMA channel
* @flags: DMA transfer flags
@@ -351,12 +394,14 @@ static struct sh_desc *sh_dmae_add_desc(struct sh_dmae_chan *sh_chan,
new->async_tx.cookie = -EINVAL;
}
- dev_dbg(sh_chan->dev, "chaining (%u/%u)@%x -> %x with %p, cookie %d\n",
+ dev_dbg(sh_chan->dev,
+ "chaining (%u/%u)@%x -> %x with %p, cookie %d, shift %d\n",
copy_size, *len, *src, *dest, &new->async_tx,
- new->async_tx.cookie);
+ new->async_tx.cookie, sh_chan->xmit_shift);
new->mark = DESC_PREPARED;
new->async_tx.flags = flags;
+ new->direction = direction;
*len -= copy_size;
if (direction = DMA_BIDIRECTIONAL || direction = DMA_TO_DEVICE)
@@ -465,6 +510,8 @@ static struct dma_async_tx_descriptor *sh_dmae_prep_memcpy(
if (!chan || !len)
return NULL;
+ chan->private = NULL;
+
sh_chan = to_sh_chan(chan);
sg_init_table(&sg, 1);
@@ -477,6 +524,44 @@ static struct dma_async_tx_descriptor *sh_dmae_prep_memcpy(
flags);
}
+static struct dma_async_tx_descriptor *sh_dmae_prep_slave_sg(
+ struct dma_chan *chan, struct scatterlist *sgl, unsigned int sg_len,
+ enum dma_data_direction direction, unsigned long flags)
+{
+ struct sh_dmae_slave *param;
+ struct sh_dmae_chan *sh_chan;
+
+ if (!chan)
+ return NULL;
+
+ sh_chan = to_sh_chan(chan);
+ param = chan->private;
+
+ /* Someone calling slave DMA on a public channel? */
+ if (!param || !sg_len) {
+ dev_warn(sh_chan->dev, "%s: bad parameter: %p, %d, %d\n",
+ __func__, param, sg_len, param ? param->slave_id : -1);
+ return NULL;
+ }
+
+ /*
+ * if (param != NULL), this is a successfully requested slave channel,
+ * therefore param->config != NULL too.
+ */
+ return sh_dmae_prep_sg(sh_chan, sgl, sg_len, ¶m->config->addr,
+ direction, flags);
+}
+
+static void sh_dmae_terminate_all(struct dma_chan *chan)
+{
+ struct sh_dmae_chan *sh_chan = to_sh_chan(chan);
+
+ if (!chan)
+ return;
+
+ sh_dmae_chan_ld_cleanup(sh_chan, true);
+}
+
static dma_async_tx_callback __ld_cleanup(struct sh_dmae_chan *sh_chan, bool all)
{
struct sh_desc *desc, *_desc;
@@ -508,7 +593,11 @@ static dma_async_tx_callback __ld_cleanup(struct sh_dmae_chan *sh_chan, bool all
cookie = tx->cookie;
if (desc->mark = DESC_COMPLETED && desc->chunks = 1) {
- BUG_ON(sh_chan->completed_cookie != desc->cookie - 1);
+ if (sh_chan->completed_cookie != desc->cookie - 1)
+ dev_dbg(sh_chan->dev,
+ "Completing cookie %d, expected %d\n",
+ desc->cookie,
+ sh_chan->completed_cookie + 1);
sh_chan->completed_cookie = desc->cookie;
}
@@ -581,7 +670,7 @@ static void sh_chan_xfer_ld_queue(struct sh_dmae_chan *sh_chan)
return;
}
- /* Find the first un-transfer desciptor */
+ /* Find the first not transferred desciptor */
list_for_each_entry(sd, &sh_chan->ld_queue, node)
if (sd->mark = DESC_SUBMITTED) {
/* Get the ld start address from ld_queue */
@@ -685,11 +774,14 @@ static void dmae_do_tasklet(unsigned long data)
struct sh_dmae_chan *sh_chan = (struct sh_dmae_chan *)data;
struct sh_desc *desc;
u32 sar_buf = sh_dmae_readl(sh_chan, SAR);
+ u32 dar_buf = sh_dmae_readl(sh_chan, DAR);
spin_lock(&sh_chan->desc_lock);
list_for_each_entry(desc, &sh_chan->ld_queue, node) {
- if ((desc->hw.sar + desc->hw.tcr) = sar_buf &&
- desc->mark = DESC_SUBMITTED) {
+ if (desc->mark = DESC_SUBMITTED &&
+ ((desc->direction = DMA_FROM_DEVICE &&
+ (desc->hw.dar + desc->hw.tcr) = dar_buf) ||
+ (desc->hw.sar + desc->hw.tcr) = sar_buf)) {
dev_dbg(sh_chan->dev, "done #%d@%p dst %u\n",
desc->async_tx.cookie, &desc->async_tx,
desc->hw.dar);
@@ -762,7 +854,7 @@ static int __devinit sh_dmae_chan_probe(struct sh_dmae_device *shdev, int id)
}
snprintf(new_sh_chan->dev_id, sizeof(new_sh_chan->dev_id),
- "sh-dmae%d", new_sh_chan->id);
+ "sh-dmae%d", new_sh_chan->id);
/* set up channel irq */
err = request_irq(irq, &sh_dmae_interrupt, irqflags,
@@ -773,11 +865,6 @@ static int __devinit sh_dmae_chan_probe(struct sh_dmae_device *shdev, int id)
goto err_no_irq;
}
- /* CHCR register control function */
- new_sh_chan->set_chcr = dmae_set_chcr;
- /* DMARS register control function */
- new_sh_chan->set_dmars = dmae_set_dmars;
-
shdev->chan[id] = new_sh_chan;
return 0;
@@ -848,12 +935,19 @@ static int __init sh_dmae_probe(struct platform_device *pdev)
INIT_LIST_HEAD(&shdev->common.channels);
dma_cap_set(DMA_MEMCPY, shdev->common.cap_mask);
+ dma_cap_set(DMA_SLAVE, shdev->common.cap_mask);
+
shdev->common.device_alloc_chan_resources
= sh_dmae_alloc_chan_resources;
shdev->common.device_free_chan_resources = sh_dmae_free_chan_resources;
shdev->common.device_prep_dma_memcpy = sh_dmae_prep_memcpy;
shdev->common.device_is_tx_complete = sh_dmae_is_complete;
shdev->common.device_issue_pending = sh_dmae_memcpy_issue_pending;
+
+ /* Compulsory for DMA_SLAVE fields */
+ shdev->common.device_prep_slave_sg = sh_dmae_prep_slave_sg;
+ shdev->common.device_terminate_all = sh_dmae_terminate_all;
+
shdev->common.dev = &pdev->dev;
/* Default transfer size of 32 bytes requires 32-byte alignment */
shdev->common.copy_align = 5;
diff --git a/drivers/dma/shdma.h b/drivers/dma/shdma.h
index 108f1cf..7e227f3 100644
--- a/drivers/dma/shdma.h
+++ b/drivers/dma/shdma.h
@@ -29,6 +29,7 @@ struct sh_desc {
struct sh_dmae_regs hw;
struct list_head node;
struct dma_async_tx_descriptor async_tx;
+ enum dma_data_direction direction;
dma_cookie_t cookie;
int chunks;
int mark;
@@ -45,13 +46,9 @@ struct sh_dmae_chan {
struct device *dev; /* Channel device */
struct tasklet_struct tasklet; /* Tasklet */
int descs_allocated; /* desc count */
+ int xmit_shift; /* log_2(bytes_per_xfer) */
int id; /* Raw id of this channel */
char dev_id[16]; /* unique name per DMAC of channel */
-
- /* Set chcr */
- int (*set_chcr)(struct sh_dmae_chan *sh_chan, u32 regs);
- /* Set DMA resource */
- int (*set_dmars)(struct sh_dmae_chan *sh_chan, u16 res);
};
struct sh_dmae_device {
--
1.6.2.4
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH 3/3 v2] sh: implement DMA_SLAVE capability in SH dmaengine
2010-01-19 7:27 [PATCH 3/3 v2] sh: implement DMA_SLAVE capability in SH dmaengine Guennadi Liakhovetski
@ 2010-02-01 19:05 ` Guennadi Liakhovetski
2010-02-03 0:34 ` Dan Williams
2010-02-03 0:36 ` Dan Williams
2 siblings, 0 replies; 4+ messages in thread
From: Guennadi Liakhovetski @ 2010-02-01 19:05 UTC (permalink / raw)
To: linux-sh
Tested to work with a SIU ASoC driver on sh7722 (migor).
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
---
v1 -> v2:
1. no real changes, just rebased to new CHCR_TS_{LOW,HIGH}_{MASK,SHIFT}
names
arch/sh/include/asm/dma-sh.h | 41 +++++++-
arch/sh/include/cpu-sh4/cpu/dma-sh4a.h | 15 ++-
drivers/dma/shdma.c | 190 ++++++++++++++++++++++++--------
drivers/dma/shdma.h | 7 +-
4 files changed, 192 insertions(+), 61 deletions(-)
diff --git a/arch/sh/include/asm/dma-sh.h b/arch/sh/include/asm/dma-sh.h
index 01d2fc7..c8d8ce7 100644
--- a/arch/sh/include/asm/dma-sh.h
+++ b/arch/sh/include/asm/dma-sh.h
@@ -64,8 +64,10 @@ static int dmte_irq_map[] __maybe_unused = {
#define ACK_L 0x00010000
#define DM_INC 0x00004000
#define DM_DEC 0x00008000
+#define DM_FIX 0x0000c000
#define SM_INC 0x00001000
#define SM_DEC 0x00002000
+#define SM_FIX 0x00003000
#define RS_IN 0x00000200
#define RS_OUT 0x00000300
#define TS_BLK 0x00000040
@@ -123,10 +125,47 @@ static u32 dma_base_addr[] __maybe_unused = {
*/
#define SHDMA_MIX_IRQ (1 << 1)
#define SHDMA_DMAOR1 (1 << 2)
-#define SHDMA_DMAE1 (1 << 3)
+#define SHDMA_DMAE1 (1 << 3)
+
+enum sh_dmae_slave_chan_id {
+ SHDMA_SLAVE_SCIF0_TX,
+ SHDMA_SLAVE_SCIF0_RX,
+ SHDMA_SLAVE_SCIF1_TX,
+ SHDMA_SLAVE_SCIF1_RX,
+ SHDMA_SLAVE_SCIF2_TX,
+ SHDMA_SLAVE_SCIF2_RX,
+ SHDMA_SLAVE_SCIF3_TX,
+ SHDMA_SLAVE_SCIF3_RX,
+ SHDMA_SLAVE_SCIF4_TX,
+ SHDMA_SLAVE_SCIF4_RX,
+ SHDMA_SLAVE_SCIF5_TX,
+ SHDMA_SLAVE_SCIF5_RX,
+ SHDMA_SLAVE_SIUA_TX,
+ SHDMA_SLAVE_SIUA_RX,
+ SHDMA_SLAVE_SIUB_TX,
+ SHDMA_SLAVE_SIUB_RX,
+ SHDMA_SLAVE_NUMBER, /* Must stay last */
+};
+
+struct sh_dmae_slave_config {
+ enum sh_dmae_slave_chan_id slave_id;
+ dma_addr_t addr;
+ u32 chcr;
+ char mid_rid;
+};
struct sh_dmae_pdata {
unsigned int mode;
+ struct sh_dmae_slave_config *config;
+ int config_num;
+};
+
+struct device;
+
+struct sh_dmae_slave {
+ enum sh_dmae_slave_chan_id slave_id; /* Set by the platform */
+ struct device *dma_dev; /* Set by the platform */
+ struct sh_dmae_slave_config *config; /* Set by the driver */
};
#endif /* __DMA_SH_H */
diff --git a/arch/sh/include/cpu-sh4/cpu/dma-sh4a.h b/arch/sh/include/cpu-sh4/cpu/dma-sh4a.h
index cc1cf3e..e734ea4 100644
--- a/arch/sh/include/cpu-sh4/cpu/dma-sh4a.h
+++ b/arch/sh/include/cpu-sh4/cpu/dma-sh4a.h
@@ -7,7 +7,7 @@
#define DMTE4_IRQ 76
#define DMAE0_IRQ 78 /* DMA Error IRQ*/
#define SH_DMAC_BASE0 0xFE008020
-#define SH_DMARS_BASE 0xFE009000
+#define SH_DMARS_BASE0 0xFE009000
#define CHCR_TS_LOW_MASK 0x00000018
#define CHCR_TS_LOW_SHIFT 3
#define CHCR_TS_HIGH_MASK 0
@@ -17,7 +17,7 @@
#define DMTE4_IRQ 76
#define DMAE0_IRQ 78 /* DMA Error IRQ*/
#define SH_DMAC_BASE0 0xFE008020
-#define SH_DMARS_BASE 0xFE009000
+#define SH_DMARS_BASE0 0xFE009000
#define CHCR_TS_LOW_MASK 0x00000018
#define CHCR_TS_LOW_SHIFT 3
#define CHCR_TS_HIGH_MASK 0x00300000
@@ -28,7 +28,7 @@
#define DMTE4_IRQ 44
#define DMAE0_IRQ 38
#define SH_DMAC_BASE0 0xFF608020
-#define SH_DMARS_BASE 0xFF609000
+#define SH_DMARS_BASE0 0xFF609000
#define CHCR_TS_LOW_MASK 0x00000018
#define CHCR_TS_LOW_SHIFT 3
#define CHCR_TS_HIGH_MASK 0
@@ -45,7 +45,7 @@
#define DMAE1_IRQ 74 /* DMA Error IRQ*/
#define SH_DMAC_BASE0 0xFE008020
#define SH_DMAC_BASE1 0xFDC08020
-#define SH_DMARS_BASE 0xFDC09000
+#define SH_DMARS_BASE0 0xFDC09000
#define CHCR_TS_LOW_MASK 0x00000018
#define CHCR_TS_LOW_SHIFT 3
#define CHCR_TS_HIGH_MASK 0
@@ -62,7 +62,8 @@
#define DMAE1_IRQ 74 /* DMA Error IRQ*/
#define SH_DMAC_BASE0 0xFE008020
#define SH_DMAC_BASE1 0xFDC08020
-#define SH_DMARS_BASE 0xFDC09000
+#define SH_DMARS_BASE0 0xFE009000
+#define SH_DMARS_BASE1 0xFDC09000
#define CHCR_TS_LOW_MASK 0x00000018
#define CHCR_TS_LOW_SHIFT 3
#define CHCR_TS_HIGH_MASK 0x00600000
@@ -78,7 +79,7 @@
#define DMAE0_IRQ 38 /* DMA Error IRQ */
#define SH_DMAC_BASE0 0xFC808020
#define SH_DMAC_BASE1 0xFC818020
-#define SH_DMARS_BASE 0xFC809000
+#define SH_DMARS_BASE0 0xFC809000
#define CHCR_TS_LOW_MASK 0x00000018
#define CHCR_TS_LOW_SHIFT 3
#define CHCR_TS_HIGH_MASK 0
@@ -95,7 +96,7 @@
#define DMAE1_IRQ 58 /* DMA Error IRQ1 */
#define SH_DMAC_BASE0 0xFC808020
#define SH_DMAC_BASE1 0xFCC08020
-#define SH_DMARS_BASE 0xFC809000
+#define SH_DMARS_BASE0 0xFC809000
#define CHCR_TS_LOW_MASK 0x00000018
#define CHCR_TS_LOW_SHIFT 3
#define CHCR_TS_HIGH_MASK 0
diff --git a/drivers/dma/shdma.c b/drivers/dma/shdma.c
index 3e1037c..9837a50 100644
--- a/drivers/dma/shdma.c
+++ b/drivers/dma/shdma.c
@@ -48,6 +48,9 @@ enum sh_dmae_desc_status {
*/
#define RS_DEFAULT (RS_DUAL)
+/* A bitmask with bits enough for enum sh_dmae_slave_chan_id */
+static unsigned long sh_dmae_slave_used[BITS_TO_LONGS(SHDMA_SLAVE_NUMBER)];
+
static void sh_dmae_chan_ld_cleanup(struct sh_dmae_chan *sh_chan, bool all);
#define SH_DMAC_CHAN_BASE(id) (dma_base_addr[id])
@@ -61,12 +64,6 @@ static u32 sh_dmae_readl(struct sh_dmae_chan *sh_dc, u32 reg)
return ctrl_inl(SH_DMAC_CHAN_BASE(sh_dc->id) + reg);
}
-static void dmae_init(struct sh_dmae_chan *sh_chan)
-{
- u32 chcr = RS_DEFAULT; /* default is DUAL mode */
- sh_dmae_writel(sh_chan, chcr, CHCR);
-}
-
/*
* Reset DMA controller
*
@@ -106,9 +103,8 @@ static bool dmae_is_busy(struct sh_dmae_chan *sh_chan)
}
static unsigned int ts_shift[] = TS_SHIFT;
-static inline unsigned int calc_xmit_shift(struct sh_dmae_chan *sh_chan)
+static inline unsigned int calc_xmit_shift(u32 chcr)
{
- u32 chcr = sh_dmae_readl(sh_chan, CHCR);
int cnt = ((chcr & CHCR_TS_LOW_MASK) >> CHCR_TS_LOW_SHIFT) |
((chcr & CHCR_TS_HIGH_MASK) >> CHCR_TS_HIGH_SHIFT);
@@ -119,7 +115,7 @@ static void dmae_set_reg(struct sh_dmae_chan *sh_chan, struct sh_dmae_regs *hw)
{
sh_dmae_writel(sh_chan, hw->sar, SAR);
sh_dmae_writel(sh_chan, hw->dar, DAR);
- sh_dmae_writel(sh_chan, hw->tcr >> calc_xmit_shift(sh_chan), TCR);
+ sh_dmae_writel(sh_chan, hw->tcr >> sh_chan->xmit_shift, TCR);
}
static void dmae_start(struct sh_dmae_chan *sh_chan)
@@ -127,7 +123,7 @@ static void dmae_start(struct sh_dmae_chan *sh_chan)
u32 chcr = sh_dmae_readl(sh_chan, CHCR);
chcr |= CHCR_DE | CHCR_IE;
- sh_dmae_writel(sh_chan, chcr, CHCR);
+ sh_dmae_writel(sh_chan, chcr & ~CHCR_TE, CHCR);
}
static void dmae_halt(struct sh_dmae_chan *sh_chan)
@@ -138,20 +134,27 @@ static void dmae_halt(struct sh_dmae_chan *sh_chan)
sh_dmae_writel(sh_chan, chcr, CHCR);
}
+static void dmae_init(struct sh_dmae_chan *sh_chan)
+{
+ u32 chcr = RS_DEFAULT; /* default is DUAL mode */
+ sh_chan->xmit_shift = calc_xmit_shift(chcr);
+ sh_dmae_writel(sh_chan, chcr, CHCR);
+}
+
static int dmae_set_chcr(struct sh_dmae_chan *sh_chan, u32 val)
{
/* When DMA was working, can not set data to CHCR */
if (dmae_is_busy(sh_chan))
return -EBUSY;
+ sh_chan->xmit_shift = calc_xmit_shift(val);
sh_dmae_writel(sh_chan, val, CHCR);
+
return 0;
}
-#define DMARS1_ADDR 0x04
-#define DMARS2_ADDR 0x08
-#define DMARS_SHIFT 8
-#define DMARS_CHAN_MSK 0x01
+#define DMARS_SHIFT 8
+#define DMARS_CHAN_MSK 0x01
static int dmae_set_dmars(struct sh_dmae_chan *sh_chan, u16 val)
{
u32 addr;
@@ -163,29 +166,18 @@ static int dmae_set_dmars(struct sh_dmae_chan *sh_chan, u16 val)
if (sh_chan->id & DMARS_CHAN_MSK)
shift = DMARS_SHIFT;
- switch (sh_chan->id) {
- /* DMARS0 */
- case 0:
- case 1:
- addr = SH_DMARS_BASE;
- break;
- /* DMARS1 */
- case 2:
- case 3:
- addr = (SH_DMARS_BASE + DMARS1_ADDR);
- break;
- /* DMARS2 */
- case 4:
- case 5:
- addr = (SH_DMARS_BASE + DMARS2_ADDR);
- break;
- default:
+ if (sh_chan->id < 6)
+ /* DMA0RS0 - DMA0RS2 */
+ addr = SH_DMARS_BASE0 + (sh_chan->id / 2) * 4;
+#ifdef SH_DMARS_BASE1
+ else if (sh_chan->id < 12)
+ /* DMA1RS0 - DMA1RS2 */
+ addr = SH_DMARS_BASE1 + ((sh_chan->id - 6) / 2) * 4;
+#endif
+ else
return -EINVAL;
- }
- ctrl_outw((val << shift) |
- (ctrl_inw(addr) & (shift ? 0xFF00 : 0x00FF)),
- addr);
+ ctrl_outw((val << shift) | (ctrl_inw(addr) & (0xFF00 >> shift)), addr);
return 0;
}
@@ -253,10 +245,53 @@ static struct sh_desc *sh_dmae_get_desc(struct sh_dmae_chan *sh_chan)
return NULL;
}
+static struct sh_dmae_slave_config *sh_dmae_find_slave(
+ struct sh_dmae_chan *sh_chan, enum sh_dmae_slave_chan_id slave_id)
+{
+ struct dma_device *dma_dev = sh_chan->common.device;
+ struct sh_dmae_device *shdev = container_of(dma_dev,
+ struct sh_dmae_device, common);
+ struct sh_dmae_pdata *pdata = &shdev->pdata;
+ int i;
+
+ if ((unsigned)slave_id >= SHDMA_SLAVE_NUMBER)
+ return NULL;
+
+ for (i = 0; i < pdata->config_num; i++)
+ if (pdata->config[i].slave_id = slave_id)
+ return pdata->config + i;
+
+ return NULL;
+}
+
static int sh_dmae_alloc_chan_resources(struct dma_chan *chan)
{
struct sh_dmae_chan *sh_chan = to_sh_chan(chan);
struct sh_desc *desc;
+ struct sh_dmae_slave *param = chan->private;
+
+ /*
+ * Called under dma_list_mutex, take care to perform all slave channel
+ * ID manipulations under that lock.
+ */
+ if (param) {
+ struct sh_dmae_slave_config *cfg;
+
+ cfg = sh_dmae_find_slave(sh_chan, param->slave_id);
+ if (!cfg)
+ return -EINVAL;
+
+ if (test_and_set_bit(param->slave_id, sh_dmae_slave_used))
+ return -EBUSY;
+
+ param->config = cfg;
+
+ dmae_set_dmars(sh_chan, cfg->mid_rid);
+ dmae_set_chcr(sh_chan, cfg->chcr);
+ } else {
+ if ((sh_dmae_readl(sh_chan, CHCR) & 0x700) != 0x400)
+ dmae_set_chcr(sh_chan, RS_DEFAULT);
+ }
spin_lock_bh(&sh_chan->desc_lock);
while (sh_chan->descs_allocated < NR_DESCS_PER_CHANNEL) {
@@ -289,10 +324,18 @@ static void sh_dmae_free_chan_resources(struct dma_chan *chan)
struct sh_desc *desc, *_desc;
LIST_HEAD(list);
+ dmae_halt(sh_chan);
+
/* Prepared and not submitted descriptors can still be on the queue */
if (!list_empty(&sh_chan->ld_queue))
sh_dmae_chan_ld_cleanup(sh_chan, true);
+ if (chan->private) {
+ /* The caller is holding dma_list_mutex */
+ struct sh_dmae_slave *param = chan->private;
+ clear_bit(param->slave_id, sh_dmae_slave_used);
+ }
+
spin_lock_bh(&sh_chan->desc_lock);
list_splice_init(&sh_chan->ld_free, &list);
@@ -304,7 +347,7 @@ static void sh_dmae_free_chan_resources(struct dma_chan *chan)
kfree(desc);
}
-/*
+/**
* sh_dmae_add_desc - get, set up and return one transfer descriptor
* @sh_chan: DMA channel
* @flags: DMA transfer flags
@@ -351,12 +394,14 @@ static struct sh_desc *sh_dmae_add_desc(struct sh_dmae_chan *sh_chan,
new->async_tx.cookie = -EINVAL;
}
- dev_dbg(sh_chan->dev, "chaining (%u/%u)@%x -> %x with %p, cookie %d\n",
+ dev_dbg(sh_chan->dev,
+ "chaining (%u/%u)@%x -> %x with %p, cookie %d, shift %d\n",
copy_size, *len, *src, *dest, &new->async_tx,
- new->async_tx.cookie);
+ new->async_tx.cookie, sh_chan->xmit_shift);
new->mark = DESC_PREPARED;
new->async_tx.flags = flags;
+ new->direction = direction;
*len -= copy_size;
if (direction = DMA_BIDIRECTIONAL || direction = DMA_TO_DEVICE)
@@ -465,6 +510,8 @@ static struct dma_async_tx_descriptor *sh_dmae_prep_memcpy(
if (!chan || !len)
return NULL;
+ chan->private = NULL;
+
sh_chan = to_sh_chan(chan);
sg_init_table(&sg, 1);
@@ -477,6 +524,44 @@ static struct dma_async_tx_descriptor *sh_dmae_prep_memcpy(
flags);
}
+static struct dma_async_tx_descriptor *sh_dmae_prep_slave_sg(
+ struct dma_chan *chan, struct scatterlist *sgl, unsigned int sg_len,
+ enum dma_data_direction direction, unsigned long flags)
+{
+ struct sh_dmae_slave *param;
+ struct sh_dmae_chan *sh_chan;
+
+ if (!chan)
+ return NULL;
+
+ sh_chan = to_sh_chan(chan);
+ param = chan->private;
+
+ /* Someone calling slave DMA on a public channel? */
+ if (!param || !sg_len) {
+ dev_warn(sh_chan->dev, "%s: bad parameter: %p, %d, %d\n",
+ __func__, param, sg_len, param ? param->slave_id : -1);
+ return NULL;
+ }
+
+ /*
+ * if (param != NULL), this is a successfully requested slave channel,
+ * therefore param->config != NULL too.
+ */
+ return sh_dmae_prep_sg(sh_chan, sgl, sg_len, ¶m->config->addr,
+ direction, flags);
+}
+
+static void sh_dmae_terminate_all(struct dma_chan *chan)
+{
+ struct sh_dmae_chan *sh_chan = to_sh_chan(chan);
+
+ if (!chan)
+ return;
+
+ sh_dmae_chan_ld_cleanup(sh_chan, true);
+}
+
static dma_async_tx_callback __ld_cleanup(struct sh_dmae_chan *sh_chan, bool all)
{
struct sh_desc *desc, *_desc;
@@ -508,7 +593,11 @@ static dma_async_tx_callback __ld_cleanup(struct sh_dmae_chan *sh_chan, bool all
cookie = tx->cookie;
if (desc->mark = DESC_COMPLETED && desc->chunks = 1) {
- BUG_ON(sh_chan->completed_cookie != desc->cookie - 1);
+ if (sh_chan->completed_cookie != desc->cookie - 1)
+ dev_dbg(sh_chan->dev,
+ "Completing cookie %d, expected %d\n",
+ desc->cookie,
+ sh_chan->completed_cookie + 1);
sh_chan->completed_cookie = desc->cookie;
}
@@ -581,7 +670,7 @@ static void sh_chan_xfer_ld_queue(struct sh_dmae_chan *sh_chan)
return;
}
- /* Find the first un-transfer desciptor */
+ /* Find the first not transferred desciptor */
list_for_each_entry(sd, &sh_chan->ld_queue, node)
if (sd->mark = DESC_SUBMITTED) {
/* Get the ld start address from ld_queue */
@@ -685,11 +774,14 @@ static void dmae_do_tasklet(unsigned long data)
struct sh_dmae_chan *sh_chan = (struct sh_dmae_chan *)data;
struct sh_desc *desc;
u32 sar_buf = sh_dmae_readl(sh_chan, SAR);
+ u32 dar_buf = sh_dmae_readl(sh_chan, DAR);
spin_lock(&sh_chan->desc_lock);
list_for_each_entry(desc, &sh_chan->ld_queue, node) {
- if ((desc->hw.sar + desc->hw.tcr) = sar_buf &&
- desc->mark = DESC_SUBMITTED) {
+ if (desc->mark = DESC_SUBMITTED &&
+ ((desc->direction = DMA_FROM_DEVICE &&
+ (desc->hw.dar + desc->hw.tcr) = dar_buf) ||
+ (desc->hw.sar + desc->hw.tcr) = sar_buf)) {
dev_dbg(sh_chan->dev, "done #%d@%p dst %u\n",
desc->async_tx.cookie, &desc->async_tx,
desc->hw.dar);
@@ -762,7 +854,7 @@ static int __devinit sh_dmae_chan_probe(struct sh_dmae_device *shdev, int id)
}
snprintf(new_sh_chan->dev_id, sizeof(new_sh_chan->dev_id),
- "sh-dmae%d", new_sh_chan->id);
+ "sh-dmae%d", new_sh_chan->id);
/* set up channel irq */
err = request_irq(irq, &sh_dmae_interrupt, irqflags,
@@ -773,11 +865,6 @@ static int __devinit sh_dmae_chan_probe(struct sh_dmae_device *shdev, int id)
goto err_no_irq;
}
- /* CHCR register control function */
- new_sh_chan->set_chcr = dmae_set_chcr;
- /* DMARS register control function */
- new_sh_chan->set_dmars = dmae_set_dmars;
-
shdev->chan[id] = new_sh_chan;
return 0;
@@ -848,12 +935,19 @@ static int __init sh_dmae_probe(struct platform_device *pdev)
INIT_LIST_HEAD(&shdev->common.channels);
dma_cap_set(DMA_MEMCPY, shdev->common.cap_mask);
+ dma_cap_set(DMA_SLAVE, shdev->common.cap_mask);
+
shdev->common.device_alloc_chan_resources
= sh_dmae_alloc_chan_resources;
shdev->common.device_free_chan_resources = sh_dmae_free_chan_resources;
shdev->common.device_prep_dma_memcpy = sh_dmae_prep_memcpy;
shdev->common.device_is_tx_complete = sh_dmae_is_complete;
shdev->common.device_issue_pending = sh_dmae_memcpy_issue_pending;
+
+ /* Compulsory for DMA_SLAVE fields */
+ shdev->common.device_prep_slave_sg = sh_dmae_prep_slave_sg;
+ shdev->common.device_terminate_all = sh_dmae_terminate_all;
+
shdev->common.dev = &pdev->dev;
/* Default transfer size of 32 bytes requires 32-byte alignment */
shdev->common.copy_align = 5;
diff --git a/drivers/dma/shdma.h b/drivers/dma/shdma.h
index 108f1cf..7e227f3 100644
--- a/drivers/dma/shdma.h
+++ b/drivers/dma/shdma.h
@@ -29,6 +29,7 @@ struct sh_desc {
struct sh_dmae_regs hw;
struct list_head node;
struct dma_async_tx_descriptor async_tx;
+ enum dma_data_direction direction;
dma_cookie_t cookie;
int chunks;
int mark;
@@ -45,13 +46,9 @@ struct sh_dmae_chan {
struct device *dev; /* Channel device */
struct tasklet_struct tasklet; /* Tasklet */
int descs_allocated; /* desc count */
+ int xmit_shift; /* log_2(bytes_per_xfer) */
int id; /* Raw id of this channel */
char dev_id[16]; /* unique name per DMAC of channel */
-
- /* Set chcr */
- int (*set_chcr)(struct sh_dmae_chan *sh_chan, u32 regs);
- /* Set DMA resource */
- int (*set_dmars)(struct sh_dmae_chan *sh_chan, u16 res);
};
struct sh_dmae_device {
--
1.6.2.4
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH 3/3 v2] sh: implement DMA_SLAVE capability in SH dmaengine
2010-01-19 7:27 [PATCH 3/3 v2] sh: implement DMA_SLAVE capability in SH dmaengine Guennadi Liakhovetski
2010-02-01 19:05 ` Guennadi Liakhovetski
@ 2010-02-03 0:34 ` Dan Williams
2010-02-03 0:36 ` Dan Williams
2 siblings, 0 replies; 4+ messages in thread
From: Dan Williams @ 2010-02-03 0:34 UTC (permalink / raw)
To: linux-sh
Guennadi Liakhovetski wrote:
> Tested to work with a SIU ASoC driver on sh7722 (migor).
>
> Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
> ---
[..]
> + /*
> + * Called under dma_list_mutex, take care to perform all slave channel
> + * ID manipulations under that lock.
> + */
Not that I think we will ever see scalability patches aimed at breaking
up the "big dma_list_mutex lock", but it makes me a bit uneasy that this
relies on an internal implementation detail of dmaengine. Please add a
private lock here.
Thanks,
Dan
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH 3/3 v2] sh: implement DMA_SLAVE capability in SH dmaengine
2010-01-19 7:27 [PATCH 3/3 v2] sh: implement DMA_SLAVE capability in SH dmaengine Guennadi Liakhovetski
2010-02-01 19:05 ` Guennadi Liakhovetski
2010-02-03 0:34 ` Dan Williams
@ 2010-02-03 0:36 ` Dan Williams
2 siblings, 0 replies; 4+ messages in thread
From: Dan Williams @ 2010-02-03 0:36 UTC (permalink / raw)
To: linux-sh
Dan Williams wrote:
> Guennadi Liakhovetski wrote:
>> Tested to work with a SIU ASoC driver on sh7722 (migor).
>>
>> Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
>> ---
> [..]
>> + /*
>> + * Called under dma_list_mutex, take care to perform all slave channel
>> + * ID manipulations under that lock.
>> + */
>
> Not that I think we will ever see scalability patches aimed at breaking
> up the "big dma_list_mutex lock", but it makes me a bit uneasy that this
> relies on an internal implementation detail of dmaengine. Please add a
> private lock here.
>
...or perhaps change the comment to say that this relies on the
guarantee from dmaengine that alloc_chan_resources never runs
concurrently with itself or free_chan_resources. Which is an externally
visible guarantee of dmaengine.
--
Dan
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2010-02-03 0:36 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2010-01-19 7:27 [PATCH 3/3 v2] sh: implement DMA_SLAVE capability in SH dmaengine Guennadi Liakhovetski
2010-02-01 19:05 ` Guennadi Liakhovetski
2010-02-03 0:34 ` Dan Williams
2010-02-03 0:36 ` Dan Williams
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