[RFC PATCH v3.1 07/27] mmc: core: UHS-II support, set APP_CMD bit if necessary

AKASHI Takahiro
2020-11-06T02:28:22Z

In UHS-II mode, MMC_APP_CMD command need not to be sent.
Instead, APP_CMD bit in a packet should be set.

Signed-off-by: Ben Chuang <ben.chuang@genesyslogic.com.tw>
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
---
drivers/mmc/core/sd_ops.c | 9 +++++++++
drivers/mmc/core/uhs2.c | 4 ++++
2 files changed, 13 insertions(+)

diff --git a/drivers/mmc/core/sd_ops.c b/drivers/mmc/core/sd_ops.c
index f58bb50872f6..9dc296356928 100644
--- a/drivers/mmc/core/sd_ops.c
+++ b/drivers/mmc/core/sd_ops.c
@@ -26,6 +26,15 @@ int mmc_app_cmd(struct mmc_host *host, struct mmc_card *card)
if (WARN_ON(card && card->host != host))
return -EINVAL;

+ /* UHS2 packet has APP bit so only set APP_CMD flag here.
+ * Will set the APP bit when assembling UHS2 packet.
+ */
+ if (host->flags & MMC_UHS2_SUPPORT &&
+ host->flags & MMC_UHS2_INITIALIZED) {
+ host->flags |= MMC_UHS2_APP_CMD;
+ return 0;
+ }
+
cmd.opcode = MMC_APP_CMD;

if (card) {
diff --git a/drivers/mmc/core/uhs2.c b/drivers/mmc/core/uhs2.c
index 1f6d0e0cf355..c0d61e7d9e4b 100644
--- a/drivers/mmc/core/uhs2.c
+++ b/drivers/mmc/core/uhs2.c
@@ -835,6 +835,10 @@ int uhs2_prepare_sd_cmd(struct mmc_host *host, struct mmc_request *mrq)
header |= UHS2_PACKET_TYPE_CCMD;

arg = cmd->opcode << UHS2_SD_CMD_INDEX_POS;
+ if (host->flags & MMC_UHS2_APP_CMD) {
+ arg |= UHS2_SD_CMD_APP;
+ host->flags &= ~MMC_UHS2_APP_CMD;
+ }

uhs2_cmd = cmd->uhs2_cmd;
payload = uhs2_cmd->payload;
--
2.28.0