ENGR00233569 SDMA: Add support for SDMA M2M copy

Our SDMA code did not support SDMA M2M copy function before, we add
SDMA M2M copy function in this patch, you can use 'sg' to use this
function, you can refer to 'linux-test/module_test/mxc_sdma_memcopy_test.c'
for how to use this function.

Signed-off-by: Ge Lei <b42127@freescale.com>

diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c
index 68cacbffb071cf3ca9e1c7ace96d18a2db493d1b..6b7af2cc047e7cbacad4849bbd7ea14f36c2c0ed 100644 (file)
--- a/drivers/dma/imx-sdma.c
+++ b/drivers/dma/imx-sdma.c
@@ -266,6 +266,7 @@ struct sdma_channel {
        unsigned int                    pc_to_device;
        unsigned int                    device_to_device;
        unsigned int                    other_script;
+       unsigned int                    pc_to_pc;
        enum sdma_mode                  mode;
        dma_addr_t                      per_address, per_address2;
        u32                             event_mask0, event_mask1;
@@ -591,6 +592,7 @@ static void sdma_get_pc(struct sdma_channel *sdmac,
        sdmac->pc_to_device = 0;
        sdmac->device_to_device = 0;
        sdmac->other_script = 0;
+       sdmac->pc_to_pc = 0;
 
        switch (peripheral_type) {
        case IMX_DMATYPE_MEMORY:
@@ -663,6 +665,7 @@ static void sdma_get_pc(struct sdma_channel *sdmac,
        sdmac->pc_to_device = emi_2_per;
        sdmac->device_to_device = per_2_per;
        sdmac->other_script = other;
+       sdmac->pc_to_pc = emi_2_emi;
 }
 
 static int sdma_set_context_reg(struct sdma_channel *sdmac,
@@ -701,6 +704,8 @@ static int sdma_load_context(struct sdma_channel *sdmac)
                load_address = sdmac->device_to_device;
        else if (sdmac->direction == DMA_MEM_TO_DEV)
                load_address = sdmac->pc_to_device;
+       else if (sdmac->direction == DMA_MEM_TO_MEM)
+               load_address = sdmac->pc_to_pc;
        else
                load_address = sdmac->other_script;
 
@@ -1056,8 +1061,20 @@ static struct dma_async_tx_descriptor *sdma_prep_slave_sg(
        int channel = sdmac->channel;
        struct scatterlist *sg;
 
-       if (sdmac->status == DMA_IN_PROGRESS)
-               return NULL;
+       /*
+        * For SDMA M2M use, we need 2 scatterlists, the src addresses are
+        * stored in the first sg, and the dst addresses are stored in the
+        * second sg. In the former code, when the first sg entered 'sdma_
+        * prep_slave_sg', 'sdmac->status' would be set to 'DMA_IN_PROGRESS',
+        * and the second sg would return 'NULL' when entered 'sdma_prep_slave
+        * _sg'. To avoid this error, in the code, we check if for M2M use,
+        * the second sg will not return 'NULL' when enters 'sdma_prep_slave
+        * _sg'.
+        */
+       if (!((direction == DMA_MEM_TO_MEM) && (flags == 0))) {
+               if (sdmac->status == DMA_IN_PROGRESS)
+                       return NULL;
+       }
        sdmac->status = DMA_IN_PROGRESS;
 
        sdmac->mode = SDMA_MODE_NORMAL;
@@ -1082,6 +1099,12 @@ static struct dma_async_tx_descriptor *sdma_prep_slave_sg(
                struct sdma_buffer_descriptor *bd = &sdmac->bd[i];
                int param;
 
+               if (sdmac->direction == DMA_MEM_TO_MEM) {
+                       if (flags == 1)
+                               bd->buffer_addr = sg->dma_address;
+                       if (flags == 0)
+                               bd->ext_buffer_addr = sg->dma_address;
+               } else
                bd->buffer_addr = sg->dma_address;
 
                count = sg->length;
@@ -1268,6 +1291,8 @@ static int sdma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
                        sdmac->per_address = dmaengine_cfg->dst_addr;
                        sdmac->watermark_level = dmaengine_cfg->dst_maxburst;
                        sdmac->word_size = dmaengine_cfg->dst_addr_width;
+               } else if (dmaengine_cfg->direction == DMA_MEM_TO_MEM) {
+                       sdmac->word_size = dmaengine_cfg->dst_addr_width;
                }
                sdmac->direction = dmaengine_cfg->direction;
                return sdma_config_channel(sdmac);