This Patch adds the support for Dual Buffer Descriptor mode of
Operation for the dw_mmc driver.The patch also provides the configurability
Option for choosing DUAL_BUFFER mode or the chained modes through menuconfig.
The Menuconfig option for selecting Dual Buffer mode or chained mode
is selected only if Internal DMAC is enabled.
Signed-off-by: Shashidhar Hiremath <shashidh...@vayavyalabs.com>
---
v2:
* As per suggestions by Will Newton and James Hogan
-Config symbol Names prefixed with MMC_DW
-Added more Description for Config parameters added
-Removed unnecessary config opion IDMAC_DESC_MODE
-IDMAC_SET_BUFFER_SIZE chenged IDMAC_SET_BUFFER_SIZES
-fixed typos and indented commments correctly
-if ((i +1) <= sg_len changed to ((i +1) < sg_len
-duplication "desc->des0 = IDMAC_DES0_OWN | IDMAC_DES0_DIC" line removed
-fixed bug in making DSL value zero
-removed ANDing the des1 with zero before writing buffer lengths to it
-Added proper multiline comments
v3:
* As per suggestions by James Hogan
-Modified Config Symbol Names in the Driver File
-Fixed Bug in Clearing the DSL field of BMOD register
-Fixed bug in IDMAC_SET_BUFFER_SIZES
v4:
* After Testing the Dual Buffer Support
-Modified the dma_init sequence to support Dual Buffer Mode
drivers/mmc/host/Kconfig | 19 ++++++++++++++
drivers/mmc/host/dw_mmc.c | 58 ++++++++++++++++++++++++++++++++++++++++----
drivers/mmc/host/dw_mmc.h | 2 +
3 files changed, 73 insertions(+), 6 deletions(-)
diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
index 8c87096..dd0df83 100644
--- a/drivers/mmc/host/Kconfig
+++ b/drivers/mmc/host/Kconfig
@@ -534,6 +534,25 @@ config MMC_DW_IDMAC
Designware Mobile Storage IP block. This disables the external DMA
interface.
+choice
+ prompt "select IDMAC Descriptors Mode"
+ depends on MMC_DW_IDMAC
+
+config MMC_DW_CHAIN_DESC
+ bool "Chain Descriptor Structure"
+ help
+ Select this option to enable Chained Mode of Operation and the
+ Chained Mode operates in a mode where only one Buffer will be used
+ for each descriptor when the transfer is happening in DMA mode.
+
+config MMC_DW_DUAL_BUFFER_DESC
+ bool "Dual Buffer Descriptor Structure"
+ help
+ Select this option to enable Dual Buffer Desc Mode of Operation and
+ Dual Buffer Descriptor Mode or the Ring Mode indicates that two
+ buffers can be used for each descriptor during DMA mode transfer.
+endchoice
+
config MMC_SH_MMCIF
tristate "SuperH Internal MMCIF support"
depends on MMC_BLOCK && (SUPERH || ARCH_SHMOBILE)
diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index ff0f714..ba54bb8 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -63,6 +63,8 @@ struct idmac_desc {
u32 des1; /* Buffer sizes */
#define IDMAC_SET_BUFFER1_SIZE(d, s) \
((d)->des1 = ((d)->des1 & 0x03ffe000) | ((s) & 0x1fff))
+#define IDMAC_SET_BUFFER_SIZES(d, s1, s2) \
+ (d->des1 = (((s1) & 0x1fff) | (((s2) & 0x1fff) << 13)))
u32 des2; /* buffer 1 physical address */
@@ -347,18 +349,45 @@ static void dw_mci_translate_sglist(struct dw_mci *host,
struct mmc_data *data,
int i;
struct idmac_desc *desc = host->sg_cpu;
+#ifdef CONFIG_MMC_DW_DUAL_BUFFER_DESC
+ for (i = 0; i < sg_len; i += 2, desc++) {
+#endif
+#ifdef CONFIG_MMC_DW_CHAIN_DESC
for (i = 0; i < sg_len; i++, desc++) {
- unsigned int length = sg_dma_len(&data->sg[i]);
- u32 mem_addr = sg_dma_address(&data->sg[i]);
+#endif
+ unsigned int length1 = sg_dma_len(&data->sg[i]);
+ u32 mem_addr1 = sg_dma_address(&data->sg[i]);
+#ifdef CONFIG_MMC_DW_DUAL_BUFFER_DESC
+ unsigned int length2 = 0;
+ u32 mem_addr2;
+
+ if ((i+1) < sg_len) {
+ length2 = sg_dma_len(&data->sg[(i+1)]);
+ mem_addr2 = sg_dma_address(&data->sg[i+1]);
+ }
+
+ /* Set the OWN bit and disable interrupts for this descriptor
+ * and disable the Chained Mode
+ */
+ desc->des0 = (IDMAC_DES0_OWN | IDMAC_DES0_DIC) &
(~IDMAC_DES0_CH);
+ /* Buffer length1 and length2 */
+ IDMAC_SET_BUFFER_SIZES(desc, length1, length2);
+#endif
+#ifdef CONFIG_MMC_DW_CHAIN_DESC
/* Set the OWN bit and disable interrupts for this descriptor */
desc->des0 = IDMAC_DES0_OWN | IDMAC_DES0_DIC | IDMAC_DES0_CH;
- /* Buffer length */
- IDMAC_SET_BUFFER1_SIZE(desc, length);
+ /* Buffer length1 */
+ IDMAC_SET_BUFFER1_SIZE(desc, length1);
+#endif
/* Physical address to DMA to/from */
- desc->des2 = mem_addr;
+ desc->des2 = mem_addr1;
+#ifdef CONFIG_MMC_DW_DUAL_BUFFER_DESC
+ if ((i+1) < sg_len)
+ desc->des3 = mem_addr2;
+#endif
}
/* Set first descriptor */
@@ -366,8 +395,14 @@ static void dw_mci_translate_sglist(struct dw_mci *host,
struct mmc_data *data,
desc->des0 |= IDMAC_DES0_FD;
/* Set last descriptor */
+#ifdef CONFIG_MMC_DW_DUAL_BUFFER_DESC
+ desc = host->sg_cpu + ((i/2) - 1) * sizeof(struct idmac_desc);
+ desc->des0 &= (~IDMAC_DES0_DIC);
+#endif
+#ifdef CONFIG_MMC_DW_CHAIN_DESC
desc = host->sg_cpu + (i - 1) * sizeof(struct idmac_desc);
desc->des0 &= ~(IDMAC_DES0_CH | IDMAC_DES0_DIC);
+#endif
desc->des0 |= IDMAC_DES0_LD;
wmb();
@@ -388,6 +423,10 @@ static void dw_mci_idmac_start_dma(struct dw_mci *host,
unsigned int sg_len)
/* Enable the IDMAC */
temp = mci_readl(host, BMOD);
+#ifdef CONFIG_MMC_DW_DUAL_BUFFER_DESC
+ /* The Descriptor Skip length is made zero */
+ temp &= ~(SDMMC_BMOD_DSL(0x1f));
+#endif
temp |= SDMMC_IDMAC_ENABLE | SDMMC_IDMAC_FB;
mci_writel(host, BMOD, temp);
@@ -402,13 +441,20 @@ static int dw_mci_idmac_init(struct dw_mci *host)
/* Number of descriptors in the ring buffer */
host->ring_size = PAGE_SIZE / sizeof(struct idmac_desc);
-
+#ifdef CONFIG_MMC_DW_CHAIN_DESC
/* Forward link the descriptor list */
for (i = 0, p = host->sg_cpu; i < host->ring_size - 1; i++, p++)
p->des3 = host->sg_dma + (sizeof(struct idmac_desc) * (i + 1));
+#endif
+#ifdef CONFIG_MMC_DW_DUAL_BUFFER_DESC
+ for (i = 0, p = host->sg_cpu; i < host->ring_size - 1; i++)
+ p++;
+#endif
/* Set the last descriptor as the end-of-ring descriptor */
+#ifdef CONFIG_MMC_DW_CHAIN_DESC
p->des3 = host->sg_dma;
+#endif
p->des0 = IDMAC_DES0_ER;
/* Mask out interrupts - get Tx & Rx complete only */
diff --git a/drivers/mmc/host/dw_mmc.h b/drivers/mmc/host/dw_mmc.h
index 027d377..0520dc8 100644
--- a/drivers/mmc/host/dw_mmc.h
+++ b/drivers/mmc/host/dw_mmc.h
@@ -72,6 +72,8 @@
/* Clock Enable register defines */
#define SDMMC_CLKEN_LOW_PWR BIT(16)
#define SDMMC_CLKEN_ENABLE BIT(0)
+/* BMOD register defines */
+#define SDMMC_BMOD_DSL(n) _SBF(2, (n))
/* time-out register defines */
#define SDMMC_TMOUT_DATA(n) _SBF(8, (n))
#define SDMMC_TMOUT_DATA_MSK 0xFFFFFF00
--
1.7.2.3
--
To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
