ACMD22 is used to verify the previously write operation. Normally, it
returns the number of written sectors as u32. SDUC, however, returns it
as u64. This is not a superfluous requirement, because SDUC writes may
exceeds 2TB. For Linux mmc however, the previously write operation
could not be more than the block layer limits, thus we make room for a
u64 and cast the returning value to u32.
Moreover, SD cards expect to be allowed the full 500msec busy period
post write operations. This is true for standard capacity SD, and even
more so for high volume SD cards, specifically SDUC. If CMD13 return an
error bit, the recovery flow is entered regardless of the busy period.
Thus, better enforce the busy period for SDUC, otherwise it might return
a bogus bytes written.
Signed-off-by: Avri Altman <avri.altman@xxxxxxx>
---
drivers/mmc/core/block.c | 43 ++++++++++++++++++++++++++++++++++------
1 file changed, 37 insertions(+), 6 deletions(-)
diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index 30cb8b0d5742..cc5ec94a4be1 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -48,6 +48,7 @@
#include <linux/mmc/sd.h>
#include <linux/uaccess.h>
+#include <asm/unaligned.h>
#include "queue.h"
#include "block.h"
@@ -948,13 +949,20 @@ static int mmc_sd_num_wr_blocks(struct mmc_card *card, u32 *written_blocks)
int err;
u32 result;
__be32 *blocks;
-
+ u8 resp_sz;
struct mmc_request mrq = {};
struct mmc_command cmd = {};
struct mmc_data data = {};
-
struct scatterlist sg;
+ /*
+ * SD cards, specifically high volume cards, expect to be allowed with the
+ * full 500msec busy period post write. Otherwise, they may not indicate
+ * correctly the number of bytes written.
+ */
+ if (mmc_card_is_sduc(card->host))
+ mmc_delay(500);
+
err = mmc_app_cmd(card->host, card);
if (err)
return err;
@@ -963,7 +971,14 @@ static int mmc_sd_num_wr_blocks(struct mmc_card *card, u32 *written_blocks)
cmd.arg = 0;
cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_ADTC;
- data.blksz = 4;
+ /*
+ * Normally, ACMD22 returns the number of written sectors as u32.
+ * SDUC, however, returns it as u64. This is not a superfluous
+ * requirement, because SDUC writes may exceed 2TB.
+ */
+ resp_sz = mmc_card_is_sduc(card->host) ? 8 : 4;
+
+ data.blksz = resp_sz;
data.blocks = 1;
data.flags = MMC_DATA_READ;
data.sg = &sg;
@@ -973,15 +988,31 @@ static int mmc_sd_num_wr_blocks(struct mmc_card *card, u32 *written_blocks)
mrq.cmd = &cmd;
mrq.data = &data;
- blocks = kmalloc(4, GFP_KERNEL);
+ blocks = kmalloc(resp_sz, GFP_KERNEL);
if (!blocks)
return -ENOMEM;
- sg_init_one(&sg, blocks, 4);
+ sg_init_one(&sg, blocks, resp_sz);
mmc_wait_for_req(card->host, &mrq);
- result = ntohl(*blocks);
+ if (mmc_card_is_sduc(card->host)) {
+ u64 blocks_64 = get_unaligned_be64(blocks);
+ /*
+ * For Linux mmc however, the previously write operation could
+ * not be more than the block layer limits, thus just make room
+ * for a u64 and cast the response back to u32.
+ */
+
+ if (blocks_64 > UINT_MAX) {
+ /* avoid any test robot warnings */
+ result = UINT_MAX;
+ } else {
+ result = (u32)blocks_64;
+ }
+ } else {
+ result = ntohl(*blocks);
+ }
kfree(blocks);
if (cmd.error || data.error)
--
2.25.1
