Hello.
Sudhakar Rajashekhara wrote:
On some platforms like DM355, the number of EDMA parameter
slots available for EDMA_SLOT_ANY usage are few. In such cases,
if MMC/SD uses 16 slots for each instance of MMC controller,
then the number of slots available for other modules will be
very few.
By passing the number of EDMA slots to be used in MMC driver
from platform data, EDMA slots available for other purposes
can be controlled.
Signed-off-by: Sudhakar Rajashekhara <sudhakar....@ti.com>
---
arch/arm/mach-davinci/include/mach/mmc.h | 3 +++
drivers/mmc/host/davinci_mmc.c | 22 +++++++++++++++-------
2 files changed, 18 insertions(+), 7 deletions(-)
diff --git a/arch/arm/mach-davinci/include/mach/mmc.h
b/arch/arm/mach-davinci/include/mach/mmc.h
index 5a85e24..384fc0e 100644
--- a/arch/arm/mach-davinci/include/mach/mmc.h
+++ b/arch/arm/mach-davinci/include/mach/mmc.h
@@ -22,6 +22,9 @@ struct davinci_mmc_config {
/* Version of the MMC/SD controller */
u8 version;
+
+ /* Number of sg segments */
+ u32 nr_sg;
Why waste 4 bytres if the maximum number is 16?
diff --git a/drivers/mmc/host/davinci_mmc.c b/drivers/mmc/host/davinci_mmc.c
index 3bd0ba2..19c050c 100644
--- a/drivers/mmc/host/davinci_mmc.c
+++ b/drivers/mmc/host/davinci_mmc.c
@@ -137,15 +137,15 @@
/*
* One scatterlist dma "segment" is at most MAX_CCNT rw_threshold units,
- * and we handle up to NR_SG segments. MMC_BLOCK_BOUNCE kicks in only
+ * and we handle up to MAX_NR_SG segments. MMC_BLOCK_BOUNCE kicks in only
* for drivers with max_hw_segs == 1, making the segments bigger (64KB)
- * than the page or two that's otherwise typical. NR_SG == 16 gives at
- * least the same throughput boost, using EDMA transfer linkage instead
- * of spending CPU time copying pages.
+ * than the page or two that's otherwise typical. nr_sg (passed from
+ * platform data) == 16 gives at least the same throughput boost, using
+ * EDMA transfer linkage instead of spending CPU time copying pages.
*/
#define MAX_CCNT ((1 << 16) - 1)
-#define NR_SG 16
+#define MAX_NR_SG 16
static unsigned rw_threshold = 32;
module_param(rw_threshold, uint, S_IRUGO);
@@ -192,7 +192,7 @@ struct mmc_davinci_host {
struct edmacc_param tx_template;
struct edmacc_param rx_template;
unsigned n_link;
- u32 links[NR_SG - 1];
+ u32 links[MAX_NR_SG - 1];
/* For PIO we walk scatterlists one segment at a time. */
unsigned int sg_len;
@@ -202,6 +202,8 @@ struct mmc_davinci_host {
u8 version;
/* for ns in one cycle calculation */
unsigned ns_in_one_cycle;
+ /* Number of sg segments */
+ u32 nr_sg;
Same question.
WBR, Sergei
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