[PATCH v2 1/4] mmc: dw_mmc: split out preparation of desc for IDMAC32 and IDMAC64

From: Shawn Lin
Date: Fri Sep 02 2016 - 00:20:26 EST


We intend to add more check for descriptors when
preparing desc. Let's spilt out the separate body
to make the dw_mci_translate_sglist not so lengthy.
After spliting out these two functions, we could
remove dw_mci_translate_sglist and call both of them
when staring idmac.

Signed-off-by: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>

---

Changes in v2:
- remove dw_mci_translate_sglist

drivers/mmc/host/dw_mmc.c | 149 ++++++++++++++++++++++++----------------------
1 file changed, 79 insertions(+), 70 deletions(-)

diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index 22dacae..782b303 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -467,112 +467,121 @@ static void dw_mci_dmac_complete_dma(void *arg)
}
}

-static void dw_mci_translate_sglist(struct dw_mci *host, struct mmc_data *data,
- unsigned int sg_len)
+static inline void dw_mci_prepare_desc64(struct dw_mci *host,
+ struct mmc_data *data,
+ unsigned int sg_len)
{
unsigned int desc_len;
+ struct idmac_desc_64addr *desc_first, *desc_last, *desc;
int i;

- if (host->dma_64bit_address == 1) {
- struct idmac_desc_64addr *desc_first, *desc_last, *desc;
-
- desc_first = desc_last = desc = host->sg_cpu;
+ desc_first = desc_last = desc = host->sg_cpu;

- for (i = 0; i < sg_len; i++) {
- unsigned int length = sg_dma_len(&data->sg[i]);
+ for (i = 0; i < sg_len; i++) {
+ unsigned int length = sg_dma_len(&data->sg[i]);

- u64 mem_addr = sg_dma_address(&data->sg[i]);
+ u64 mem_addr = sg_dma_address(&data->sg[i]);

- for ( ; length ; desc++) {
- desc_len = (length <= DW_MCI_DESC_DATA_LENGTH) ?
- length : DW_MCI_DESC_DATA_LENGTH;
+ for ( ; length ; desc++) {
+ desc_len = (length <= DW_MCI_DESC_DATA_LENGTH) ?
+ length : DW_MCI_DESC_DATA_LENGTH;

- length -= desc_len;
+ length -= desc_len;

- /*
- * Set the OWN bit and disable interrupts
- * for this descriptor
- */
- desc->des0 = IDMAC_DES0_OWN | IDMAC_DES0_DIC |
- IDMAC_DES0_CH;
+ /*
+ * Set the OWN bit and disable interrupts
+ * for this descriptor
+ */
+ desc->des0 = IDMAC_DES0_OWN | IDMAC_DES0_DIC |
+ IDMAC_DES0_CH;

- /* Buffer length */
- IDMAC_64ADDR_SET_BUFFER1_SIZE(desc, desc_len);
+ /* Buffer length */
+ IDMAC_64ADDR_SET_BUFFER1_SIZE(desc, desc_len);

- /* Physical address to DMA to/from */
- desc->des4 = mem_addr & 0xffffffff;
- desc->des5 = mem_addr >> 32;
+ /* Physical address to DMA to/from */
+ desc->des4 = mem_addr & 0xffffffff;
+ desc->des5 = mem_addr >> 32;

- /* Update physical address for the next desc */
- mem_addr += desc_len;
+ /* Update physical address for the next desc */
+ mem_addr += desc_len;

- /* Save pointer to the last descriptor */
- desc_last = desc;
- }
+ /* Save pointer to the last descriptor */
+ desc_last = desc;
}
+ }

- /* Set first descriptor */
- desc_first->des0 |= IDMAC_DES0_FD;
+ /* Set first descriptor */
+ desc_first->des0 |= IDMAC_DES0_FD;

- /* Set last descriptor */
- desc_last->des0 &= ~(IDMAC_DES0_CH | IDMAC_DES0_DIC);
- desc_last->des0 |= IDMAC_DES0_LD;
+ /* Set last descriptor */
+ desc_last->des0 &= ~(IDMAC_DES0_CH | IDMAC_DES0_DIC);
+ desc_last->des0 |= IDMAC_DES0_LD;
+}

- } else {
- struct idmac_desc *desc_first, *desc_last, *desc;

- desc_first = desc_last = desc = host->sg_cpu;
+static inline void dw_mci_prepare_desc32(struct dw_mci *host,
+ struct mmc_data *data,
+ unsigned int sg_len)
+{
+ unsigned int desc_len;
+ struct idmac_desc *desc_first, *desc_last, *desc;
+ int i;

- for (i = 0; i < sg_len; i++) {
- unsigned int length = sg_dma_len(&data->sg[i]);
+ desc_first = desc_last = desc = host->sg_cpu;

- u32 mem_addr = sg_dma_address(&data->sg[i]);
+ for (i = 0; i < sg_len; i++) {
+ unsigned int length = sg_dma_len(&data->sg[i]);

- for ( ; length ; desc++) {
- desc_len = (length <= DW_MCI_DESC_DATA_LENGTH) ?
- length : DW_MCI_DESC_DATA_LENGTH;
+ u32 mem_addr = sg_dma_address(&data->sg[i]);

- length -= desc_len;
+ for ( ; length ; desc++) {
+ desc_len = (length <= DW_MCI_DESC_DATA_LENGTH) ?
+ length : DW_MCI_DESC_DATA_LENGTH;

- /*
- * Set the OWN bit and disable interrupts
- * for this descriptor
- */
- desc->des0 = cpu_to_le32(IDMAC_DES0_OWN |
- IDMAC_DES0_DIC |
- IDMAC_DES0_CH);
+ length -= desc_len;

- /* Buffer length */
- IDMAC_SET_BUFFER1_SIZE(desc, desc_len);
+ /*
+ * Set the OWN bit and disable interrupts
+ * for this descriptor
+ */
+ desc->des0 = cpu_to_le32(IDMAC_DES0_OWN |
+ IDMAC_DES0_DIC |
+ IDMAC_DES0_CH);

- /* Physical address to DMA to/from */
- desc->des2 = cpu_to_le32(mem_addr);
+ /* Buffer length */
+ IDMAC_SET_BUFFER1_SIZE(desc, desc_len);

- /* Update physical address for the next desc */
- mem_addr += desc_len;
+ /* Physical address to DMA to/from */
+ desc->des2 = cpu_to_le32(mem_addr);

- /* Save pointer to the last descriptor */
- desc_last = desc;
- }
- }
-
- /* Set first descriptor */
- desc_first->des0 |= cpu_to_le32(IDMAC_DES0_FD);
+ /* Update physical address for the next desc */
+ mem_addr += desc_len;

- /* Set last descriptor */
- desc_last->des0 &= cpu_to_le32(~(IDMAC_DES0_CH |
- IDMAC_DES0_DIC));
- desc_last->des0 |= cpu_to_le32(IDMAC_DES0_LD);
+ /* Save pointer to the last descriptor */
+ desc_last = desc;
+ }
}

- wmb(); /* drain writebuffer */
+ /* Set first descriptor */
+ desc_first->des0 |= cpu_to_le32(IDMAC_DES0_FD);
+
+ /* Set last descriptor */
+ desc_last->des0 &= cpu_to_le32(~(IDMAC_DES0_CH |
+ IDMAC_DES0_DIC));
+ desc_last->des0 |= cpu_to_le32(IDMAC_DES0_LD);
}

static int dw_mci_idmac_start_dma(struct dw_mci *host, unsigned int sg_len)
{
u32 temp;

- dw_mci_translate_sglist(host, host->data, sg_len);
+ if (host->dma_64bit_address == 1)
+ dw_mci_prepare_desc64(host, host->data, sg_len);
+ else
+ dw_mci_prepare_desc32(host, host->data, sg_len);
+
+ /* drain writebuffer */
+ wmb();

/* Make sure to reset DMA in case we did PIO before this */
dw_mci_ctrl_reset(host, SDMMC_CTRL_DMA_RESET);
--
2.3.7