[RFC PATCH v3.1 06/27] mmc: core: UHS-II support, generate UHS-II SD command packet

AKASHI Takahiro
2020-11-06T02:28:25Z

In SD-TRAN protocol, legacy SD commands should be "encapsulated" in SD
packets as described in SD specification.
Please see section 7.1 and 7.2.1 in "UHS-II Simplified Addendum."

Signed-off-by: Ben Chuang <ben.chuang@genesyslogic.com.tw>
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
---
drivers/mmc/core/core.c | 18 +++++++++++
drivers/mmc/core/uhs2.c | 70 +++++++++++++++++++++++++++++++++++++++++
drivers/mmc/core/uhs2.h | 1 +
3 files changed, 89 insertions(+)

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index a08cb1c0f6d2..ac43e93033e6 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -337,6 +337,8 @@ static int mmc_mrq_prep(struct mmc_host *host, struct mmc_request *mrq)

int mmc_start_request(struct mmc_host *host, struct mmc_request *mrq)
{
+ struct uhs2_command uhs2_cmd;
+ u32 payload[4]; /* for maximum size */
int err;

init_completion(&mrq->cmd_completion);
@@ -354,6 +356,13 @@ int mmc_start_request(struct mmc_host *host, struct mmc_request *mrq)
if (err)
return err;

+ if (host->flags & MMC_UHS2_SUPPORT &&
+ host->flags & MMC_UHS2_INITIALIZED) {
+ uhs2_cmd.payload = payload;
+ mrq->cmd->uhs2_cmd = &uhs2_cmd;
+ uhs2_prepare_sd_cmd(host, mrq);
+ }
+
led_trigger_event(host->led, LED_FULL);
__mmc_start_request(host, mrq);

@@ -433,6 +442,8 @@ EXPORT_SYMBOL(mmc_wait_for_req_done);
*/
int mmc_cqe_start_req(struct mmc_host *host, struct mmc_request *mrq)
{
+ struct uhs2_command uhs2_cmd;
+ u32 payload[4]; /* for maximum size */
int err;

/*
@@ -453,6 +464,13 @@ int mmc_cqe_start_req(struct mmc_host *host, struct mmc_request *mrq)
if (err)
goto out_err;

+ if (host->flags & MMC_UHS2_SUPPORT &&
+ host->flags & MMC_UHS2_INITIALIZED) {
+ uhs2_cmd.payload = payload;
+ mrq->cmd->uhs2_cmd = &uhs2_cmd;
+ uhs2_prepare_sd_cmd(host, mrq);
+ }
+
err = host->cqe_ops->cqe_request(host, mrq);
if (err)
goto out_err;
diff --git a/drivers/mmc/core/uhs2.c b/drivers/mmc/core/uhs2.c
index acb46b5b57ef..1f6d0e0cf355 100644
--- a/drivers/mmc/core/uhs2.c
+++ b/drivers/mmc/core/uhs2.c
@@ -807,3 +807,73 @@ int mmc_uhs2_rescan_try_freq(struct mmc_host *host, unsigned int freq)
return err;
}
EXPORT_SYMBOL_GPL(mmc_uhs2_rescan_try_freq);
+
+/**
+ * uhs2_prepare_sd_cmd - prepare for SD command packet
+ * @host: MMC host
+ * @mrq: MMC request
+ *
+ * Initialize and fill in a header and a payload of SD command packet.
+ * The caller should allocate uhs2_command in host->cmd->uhs2_cmd in
+ * advance.
+ *
+ * Return: 0 on success, non-zero error on failure
+ */
+int uhs2_prepare_sd_cmd(struct mmc_host *host, struct mmc_request *mrq)
+{
+ struct mmc_command *cmd;
+ struct uhs2_command *uhs2_cmd;
+ u16 header = 0, arg = 0;
+ u32 *payload;
+ u8 plen = 0;
+
+ cmd = mrq->cmd;
+ header = host->uhs2_dev_prop.node_id;
+ if ((cmd->flags & MMC_CMD_MASK) == MMC_CMD_ADTC)
+ header |= UHS2_PACKET_TYPE_DCMD;
+ else
+ header |= UHS2_PACKET_TYPE_CCMD;
+
+ arg = cmd->opcode << UHS2_SD_CMD_INDEX_POS;
+
+ uhs2_cmd = cmd->uhs2_cmd;
+ payload = uhs2_cmd->payload;
+ plen = 2; /* at the maximum */
+
+ if ((cmd->flags & MMC_CMD_MASK) == MMC_CMD_ADTC &&
+ !cmd->uhs2_tmode0_flag) {
+ if (host->flags & MMC_UHS2_2L_HD)
+ arg |= UHS2_DCMD_2L_HD_MODE;
+
+ arg |= UHS2_DCMD_LM_TLEN_EXIST;
+
+ if (cmd->data->blocks == 1 &&
+ cmd->data->blksz != 512 &&
+ cmd->opcode != MMC_READ_SINGLE_BLOCK &&
+ cmd->opcode != MMC_WRITE_BLOCK) {
+ arg |= UHS2_DCMD_TLUM_BYTE_MODE;
+ payload[1] = uhs2_dcmd_convert_msb(cmd->data->blksz);
+ } else {
+ payload[1] = uhs2_dcmd_convert_msb(cmd->data->blocks);
+ }
+
+ if (cmd->opcode == SD_IO_RW_EXTENDED) {
+ arg &= ~(UHS2_DCMD_LM_TLEN_EXIST |
+ UHS2_DCMD_TLUM_BYTE_MODE |
+ UHS2_NATIVE_DCMD_DAM_IO);
+ payload[1] = 0;
+ plen = 1;
+ }
+ } else {
+ plen = 1;
+ }
+
+ payload[0] = uhs2_dcmd_convert_msb(cmd->arg);
+ pr_debug("%s: %s: sd_cmd->arg = 0x%x, payload[0]= 0x%x.\n",
+ mmc_hostname(host), __func__, cmd->arg, payload[0]);
+
+ uhs2_cmd_assemble(cmd, uhs2_cmd, header, arg, payload, plen, NULL, 0);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(uhs2_prepare_sd_cmd);
diff --git a/drivers/mmc/core/uhs2.h b/drivers/mmc/core/uhs2.h
index e3389d4dda3b..48486ba21062 100644
--- a/drivers/mmc/core/uhs2.h
+++ b/drivers/mmc/core/uhs2.h
@@ -16,5 +16,6 @@
#define UHS2_PHY_INIT_ERR 1

int mmc_uhs2_rescan_try_freq(struct mmc_host *host, unsigned int freq);
+int uhs2_prepare_sd_cmd(struct mmc_host *host, struct mmc_request *mrq);

#endif /* MMC_UHS2_H */
--
2.28.0