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authorBen Dooks <ben-linux@fluff.org>2010-03-05 16:43:29 -0500
committerLinus Torvalds <torvalds@linux-foundation.org>2010-03-06 14:26:36 -0500
commit9e506f35b1dc327c448d4791bc098f07b9b2efe9 (patch)
tree4b38fa8120d28737f37fd665b160c67ed51e94a5 /drivers
parent118cd17d4137f34c747c32765c1cb4d3910c04d4 (diff)
sdhci: improve sdhci sdhci_set_adma_desc() code
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@fluff.org> Cc: Pierre Ossman <pierre@ossman.eu> Cc: <linux-mmc@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/mmc/host/sdhci.c16
1 files changed, 8 insertions, 8 deletions
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index fcdd00785033..6c866b43b03c 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)
378 378
379static void sdhci_set_adma_desc(u8 *desc, u32 addr, int len, unsigned cmd) 379static void sdhci_set_adma_desc(u8 *desc, u32 addr, int len, unsigned cmd)
380{ 380{
381 desc[7] = (addr >> 24) & 0xff; 381 __le32 *dataddr = (__le32 __force *)(desc + 4);
382 desc[6] = (addr >> 16) & 0xff; 382 __le16 *cmdlen = (__le16 __force *)desc;
383 desc[5] = (addr >> 8) & 0xff;
384 desc[4] = (addr >> 0) & 0xff;
385 383
386 desc[3] = (len >> 8) & 0xff; 384 /* SDHCI specification says ADMA descriptors should be 4 byte
387 desc[2] = (len >> 0) & 0xff; 385 * aligned, so using 16 or 32bit operations should be safe. */
388 386
389 desc[0] = cmd & 0xff; 387 cmdlen[0] = cpu_to_le16(cmd);
390 desc[1] = cmd >> 8; 388 cmdlen[1] = cpu_to_le16(len);
389
390 dataddr[0] = cpu_to_le32(addr);
391} 391}
392 392
393static int sdhci_adma_table_pre(struct sdhci_host *host, 393static int sdhci_adma_table_pre(struct sdhci_host *host,