The sdhci_set_adma_desc is using byte-writes to write data in a specified
order into memory. Change to using __le16 for the two byte and __le32 for
the four byte cases and use the cpu_to_{le16,le32} to do the conversion
before writing.
This will reduce the size of the code and the number of writes as we no
longer need to chop the data up before writing.
As an example on ARM S3C64XX SoC, in little-endian configuration:
000000d4 <sdhci_set_adma_desc>:
- d8: e1a0c423 lsr ip, r3, #8
- dc: e1a0ec21 lsr lr, r1, #24
- e0: e1a04821 lsr r4, r1, #16
- e4: e1a05421 lsr r5, r1, #8
- e8: e1a06442 asr r6, r2, #8
- ec: e5c0c001 strb ip, [r0, #1]
- f0: e5c0e007 strb lr, [r0, #7]
- f4: e5c04006 strb r4, [r0, #6]
- f8: e5c05005 strb r5, [r0, #5]
- fc: e5c01004 strb r1, [r0, #4]
- 100: e5c06003 strb r6, [r0, #3]
- 104: e5c02002 strb r2, [r0, #2]
- 108: e5c03000 strb r3, [r0]
+ d4: e5801004 str r1, [r0, #4]
+ d8: e1c030b0 strh r3, [r0]
+ dc: e1c020b2 strh r2, [r0, #2]
Signed-off-by: Ben Dooks <ben-linux@xxxxxxxxx>
---
drivers/mmc/host/sdhci.c | 16 ++++++++--------
1 files changed, 8 insertions(+), 8 deletions(-)
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 391eb08..d09a1d5 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -378,16 +378,16 @@ static void sdhci_kunmap_atomic(void *buffer, unsigned long *flags)
static void sdhci_set_adma_desc(u8 *desc, u32 addr, int len, unsigned cmd)
{
- desc[7] = (addr >> 24) & 0xff;
- desc[6] = (addr >> 16) & 0xff;
- desc[5] = (addr >> 8) & 0xff;
- desc[4] = (addr >> 0) & 0xff;
+ __le32 *dataddr = (__le32 __force *)(desc + 4);
+ __le16 *cmdlen = (__le16 __force *)desc;
- desc[3] = (len >> 8) & 0xff;
- desc[2] = (len >> 0) & 0xff;
+ /* SDHCI specification says ADMA descriptors should be 4 byte
+ * aligned, so using 16 or 32bit operations should be safe. */
- desc[0] = cmd & 0xff;
- desc[1] = cmd >> 8;
+ cmdlen[0] = cpu_to_le16(cmd);
+ cmdlen[1] = cpu_to_le16(len);
+
+ dataddr[0] = cpu_to_le32(addr);
}
static int sdhci_adma_table_pre(struct sdhci_host *host,
--
1.6.0.4
--
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