dw_dmac: autoconfigure block_size or use platform data

The maximum block size is a configurable parameter for the chip. So, driver
will try to get it from the encoded component parameters. Otherwise it will
come from the platform data.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>

5 files changed, 28 insertions, 16 deletions

diff --git a/arch/arm/mach-spear13xx/spear13xx.c b/arch/arm/mach-spear13xx/spear13xx.c
index cf936b106e27..c64d8123518f 100644
--- a/arch/arm/mach-spear13xx/spear13xx.c
+++ b/arch/arm/mach-spear13xx/spear13xx.c
@@ -78,6 +78,7 @@ struct dw_dma_platform_data dmac_plat_data = {
         .nr_channels = 8,
         .chan_allocation_order = CHAN_ALLOCATION_DESCENDING,
         .chan_priority = CHAN_PRIORITY_DESCENDING,
+        .block_size = 4095U,
 };
 
 void __init spear13xx_l2x0_init(void)
diff --git a/arch/avr32/mach-at32ap/at32ap700x.c b/arch/avr32/mach-at32ap/at32ap700x.c
index 0445c4fd67e3..2c4aefeb86b5 100644
--- a/arch/avr32/mach-at32ap/at32ap700x.c
+++ b/arch/avr32/mach-at32ap/at32ap700x.c
@@ -605,6 +605,7 @@ static void __init genclk_init_parent(struct clk *clk)
 
 static struct dw_dma_platform_data dw_dmac0_data = {
         .nr_channels    = 3,
+        .block_size     = 4095U,
 };
 
 static struct resource dw_dmac0_resource[] = {
diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c
index d71bc7167891..c143b7e40716 100644
--- a/drivers/dma/dw_dmac.c
+++ b/drivers/dma/dw_dmac.c
@@ -56,16 +56,6 @@
         })
 
 /*
- * This is configuration-dependent and usually a funny size like 4095.
- *
- * Note that this is a transfer count, i.e. if we transfer 32-bit
- * words, we can do 16380 bytes per descriptor.
- *
- * This parameter is also system-specific.
- */
-#define DWC_MAX_COUNT   4095U
-
-/*
  * Number of descriptors to allocate for each channel. This should be
  * made configurable somehow; preferably, the clients (at least the
  * ones using slave transfers) should be able to give us a hint.
@@ -672,7 +662,7 @@ dwc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
 
         for (offset = 0; offset < len; offset += xfer_count << src_width) {
                 xfer_count = min_t(size_t, (len - offset) >> src_width,
-                                DWC_MAX_COUNT);
+                                           dwc->block_size);
 
                 desc = dwc_desc_get(dwc);
                 if (!desc)
@@ -773,8 +763,8 @@ slave_sg_todev_fill_desc:
                         desc->lli.sar = mem;
                         desc->lli.dar = reg;
                         desc->lli.ctllo = ctllo | DWC_CTLL_SRC_WIDTH(mem_width);
-                        if ((len >> mem_width) > DWC_MAX_COUNT) {
-                                dlen = DWC_MAX_COUNT << mem_width;
+                        if ((len >> mem_width) > dwc->block_size) {
+                                dlen = dwc->block_size << mem_width;
                                 mem += dlen;
                                 len -= dlen;
                         } else {
@@ -833,8 +823,8 @@ slave_sg_fromdev_fill_desc:
                         desc->lli.sar = reg;
                         desc->lli.dar = mem;
                         desc->lli.ctllo = ctllo | DWC_CTLL_DST_WIDTH(mem_width);
-                        if ((len >> reg_width) > DWC_MAX_COUNT) {
-                                dlen = DWC_MAX_COUNT << reg_width;
+                        if ((len >> reg_width) > dwc->block_size) {
+                                dlen = dwc->block_size << reg_width;
                                 mem += dlen;
                                 len -= dlen;
                         } else {
@@ -1217,7 +1207,7 @@ struct dw_cyclic_desc *dw_dma_cyclic_prep(struct dma_chan *chan,
         periods = buf_len / period_len;
 
         /* Check for too big/unaligned periods and unaligned DMA buffer. */
-        if (period_len > (DWC_MAX_COUNT << reg_width))
+        if (period_len > (dwc->block_size << reg_width))
                 goto out_err;
         if (unlikely(period_len & ((1 << reg_width) - 1)))
                 goto out_err;
@@ -1383,6 +1373,7 @@ static int __devinit dw_probe(struct platform_device *pdev)
         bool                    autocfg;
         unsigned int            dw_params;
         unsigned int            nr_channels;
+        unsigned int            max_blk_size = 0;
         int                     irq;
         int                     err;
         int                     i;
@@ -1423,6 +1414,10 @@ static int __devinit dw_probe(struct platform_device *pdev)
 
         dw->regs = regs;
 
+        /* get hardware configuration parameters */
+        if (autocfg)
+                max_blk_size = dma_readl(dw, MAX_BLK_SIZE);
+
         /* Calculate all channel mask before DMA setup */
         dw->all_chan_mask = (1 << nr_channels) - 1;
 
@@ -1468,6 +1463,16 @@ static int __devinit dw_probe(struct platform_device *pdev)
                 INIT_LIST_HEAD(&dwc->free_list);
 
                 channel_clear_bit(dw, CH_EN, dwc->mask);
+
+                /* hardware configuration */
+                if (autocfg)
+                        /* Decode maximum block size for given channel. The
+                         * stored 4 bit value represents blocks from 0x00 for 3
+                         * up to 0x0a for 4095. */
+                        dwc->block_size =
+                                (4 << ((max_blk_size >> 4 * i) & 0xf)) - 1;
+                else
+                        dwc->block_size = pdata->block_size;
         }
 
         /* Clear all interrupts on all channels. */
diff --git a/drivers/dma/dw_dmac_regs.h b/drivers/dma/dw_dmac_regs.h
index 8a3a81adbf78..2a1cc533f0c8 100644
--- a/drivers/dma/dw_dmac_regs.h
+++ b/drivers/dma/dw_dmac_regs.h
@@ -193,6 +193,9 @@ struct dw_dma_chan {
 
         unsigned int            descs_allocated;
 
+        /* hardware configuration */
+        unsigned int            block_size;
+
         /* configuration passed via DMA_SLAVE_CONFIG */
         struct dma_slave_config dma_sconfig;
 };
diff --git a/include/linux/dw_dmac.h b/include/linux/dw_dmac.h
index 2412e02d7c0f..3315ef9c785b 100644
--- a/include/linux/dw_dmac.h
+++ b/include/linux/dw_dmac.h
@@ -19,6 +19,7 @@
  * @nr_channels: Number of channels supported by hardware (max 8)
  * @is_private: The device channels should be marked as private and not for
  *      by the general purpose DMA channel allocator.
+ * @block_size: Maximum block size supported by the controller
  */
 struct dw_dma_platform_data {
         unsigned int    nr_channels;
@@ -29,6 +30,7 @@ struct dw_dma_platform_data {
 #define CHAN_PRIORITY_ASCENDING         0       /* chan0 highest */
 #define CHAN_PRIORITY_DESCENDING        1       /* chan7 highest */
         unsigned char   chan_priority;
+        unsigned short  block_size;
 };
 
 /* bursts size */