mmc: core: sd: implement proper support for sd3.0 au sizes

This reverts and updates commit 77776fd0a4cc541b9 ("mmc: sd: fix the
maximum au_size for SD3.0"). The au_size for SD3.0 cannot be achieved
by a simple bit shift, so this needs to be implemented differently.
Also, don't print the warning in case of 0 since 'not defined' is
different from 'invalid'.

Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Jaehoon Chung <jh80.chung@samsung.com>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: stable <stable@vger.kernel.org> # [3.12, 3.13]
Signed-off-by: Chris Ball <chris@printf.net>

diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index 6f42050..692fdb1 100644 (file)
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -11,6 +11,7 @@
  */
 
 #include <linux/err.h>
+#include <linux/sizes.h>
 #include <linux/slab.h>
 #include <linux/stat.h>
 #include <linux/pm_runtime.h>
@@ -45,6 +46,13 @@ static const unsigned int tacc_mant[] = {
        35,     40,     45,     50,     55,     60,     70,     80,
 };
 
+static const unsigned int sd_au_size[] = {
+       0,              SZ_16K / 512,           SZ_32K / 512,   SZ_64K / 512,
+       SZ_128K / 512,  SZ_256K / 512,          SZ_512K / 512,  SZ_1M / 512,
+       SZ_2M / 512,    SZ_4M / 512,            SZ_8M / 512,    (SZ_8M + SZ_4M) / 512,
+       SZ_16M / 512,   (SZ_16M + SZ_8M) / 512, SZ_32M / 512,   SZ_64M / 512,
+};
+
 #define UNSTUFF_BITS(resp,start,size)                                  \
        ({                                                              \
                const int __size = size;                                \
@@ -216,7 +224,7 @@ static int mmc_decode_scr(struct mmc_card *card)
 static int mmc_read_ssr(struct mmc_card *card)
 {
        unsigned int au, es, et, eo;
-       int err, i, max_au;
+       int err, i;
        u32 *ssr;
 
        if (!(card->csd.cmdclass & CCC_APP_SPEC)) {
@@ -240,26 +248,25 @@ static int mmc_read_ssr(struct mmc_card *card)
        for (i = 0; i < 16; i++)
                ssr[i] = be32_to_cpu(ssr[i]);
 
-       /* SD3.0 increases max AU size to 64MB (0xF) from 4MB (0x9) */
-       max_au = card->scr.sda_spec3 ? 0xF : 0x9;
-
        /*
         * UNSTUFF_BITS only works with four u32s so we have to offset the
         * bitfield positions accordingly.
         */
        au = UNSTUFF_BITS(ssr, 428 - 384, 4);
-       if (au > 0 && au <= max_au) {
-               card->ssr.au = 1 << (au + 4);
-               es = UNSTUFF_BITS(ssr, 408 - 384, 16);
-               et = UNSTUFF_BITS(ssr, 402 - 384, 6);
-               eo = UNSTUFF_BITS(ssr, 400 - 384, 2);
-               if (es && et) {
-                       card->ssr.erase_timeout = (et * 1000) / es;
-                       card->ssr.erase_offset = eo * 1000;
+       if (au) {
+               if (au <= 9 || card->scr.sda_spec3) {
+                       card->ssr.au = sd_au_size[au];
+                       es = UNSTUFF_BITS(ssr, 408 - 384, 16);
+                       et = UNSTUFF_BITS(ssr, 402 - 384, 6);
+                       if (es && et) {
+                               eo = UNSTUFF_BITS(ssr, 400 - 384, 2);
+                               card->ssr.erase_timeout = (et * 1000) / es;
+                               card->ssr.erase_offset = eo * 1000;
+                       }
+               } else {
+                       pr_warning("%s: SD Status: Invalid Allocation Unit size.\n",
+                                  mmc_hostname(card->host));
                }
-       } else {
-               pr_warning("%s: SD Status: Invalid Allocation Unit "
-                       "size.\n", mmc_hostname(card->host));
        }
 out:
        kfree(ssr);