Provide a function to the MMC hosts to read some blocks of data as part
of their tuning. The card parameter is optional since it is not
available from the execute_tuning() operation, but present in
execute_hs400_tuning() and prepare_sd_hs_tuning().
This function only returns the status of the read operation, not the
data read.
Signed-off-by: Benoît Monin <benoit.monin@bootlin.com>
---
drivers/mmc/core/mmc_ops.c | 79 ++++++++++++++++++++++++++++++++++++++++++++++
include/linux/mmc/host.h | 2 ++
2 files changed, 81 insertions(+)
diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c
index 66283825513cb4ff993a1b2ec1f0b0cac4e74487..d29e5daf3e326ab37e61c99456421b1f66bcb0de 100644
--- a/drivers/mmc/core/mmc_ops.c
+++ b/drivers/mmc/core/mmc_ops.c
@@ -1077,3 +1077,82 @@ int mmc_sanitize(struct mmc_card *card, unsigned int timeout_ms)
return err;
}
EXPORT_SYMBOL_GPL(mmc_sanitize);
+
+/**
+ * mmc_read_tuning() - read data blocks from the mmc
+ * @card: mmc card to read from, can be NULL
+ * @host: mmc host doing the read
+ * @blksz: data block size
+ * @blocks: number of blocks to read
+ *
+ * Read one or more blocks of data from the beginning of the mmc. This is a
+ * low-level helper for tuning operation. If card is NULL, it is assumed that
+ * CMD23 can be used for multi-block read.
+ *
+ * Note: Allocate and free a temporary buffer to store the data read. The data
+ * is not available outside of the function, only the status of the read
+ * operation.
+ *
+ * Return: 0 in case of success, otherwise -EIO / -ENOMEM / -E2BIG
+ */
+int mmc_read_tuning(struct mmc_card *card, struct mmc_host *host,
+ unsigned int blksz, unsigned int blocks)
+{
+ struct mmc_request mrq = {};
+ struct mmc_command sbc = {};
+ struct mmc_command cmd = {};
+ struct mmc_command stop = {};
+ struct mmc_data data = {};
+ struct scatterlist sg;
+ void *buf;
+ unsigned int len;
+
+ if (blocks > 1) {
+ if (mmc_host_can_cmd23(host) &&
+ (!card || (mmc_card_can_cmd23(card) &&
+ !mmc_card_blk_no_cmd23(card)))) {
+ mrq.sbc = &sbc;
+ sbc.opcode = MMC_SET_BLOCK_COUNT;
+ sbc.arg = blocks;
+ sbc.flags = MMC_RSP_R1 | MMC_CMD_AC;
+ }
+ cmd.opcode = MMC_READ_MULTIPLE_BLOCK;
+ mrq.stop = &stop;
+ stop.opcode = MMC_STOP_TRANSMISSION;
+ stop.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_AC;
+ } else {
+ cmd.opcode = MMC_READ_SINGLE_BLOCK;
+ }
+
+ mrq.cmd = &cmd;
+ cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_ADTC;
+
+ mrq.data = &data;
+ data.flags = MMC_DATA_READ;
+ data.blksz = blksz;
+ data.blocks = blocks;
+ data.blk_addr = 0;
+ data.sg = &sg;
+ data.sg_len = 1;
+ if (card)
+ mmc_set_data_timeout(&data, card);
+ else
+ data.timeout_ns = 1000000000;
+
+ if (check_mul_overflow(blksz, blocks, &len))
+ return -E2BIG;
+ buf = kmalloc(len, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ sg_init_one(&sg, buf, len);
+
+ mmc_wait_for_req(host, &mrq);
+ kfree(buf);
+
+ if (sbc.error || cmd.error || data.error)
+ return -EIO;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(mmc_read_tuning);
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 68f09a955a902047ac517441b6820fa6e4166a13..5a6471a6219222b199a16afd9e6bd5ab74b05c86 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -743,5 +743,7 @@ int mmc_send_status(struct mmc_card *card, u32 *status);
int mmc_send_tuning(struct mmc_host *host, u32 opcode, int *cmd_error);
int mmc_send_abort_tuning(struct mmc_host *host, u32 opcode);
int mmc_get_ext_csd(struct mmc_card *card, u8 **new_ext_csd);
+int mmc_read_tuning(struct mmc_card *card, struct mmc_host *host,
+ unsigned int blksz, unsigned int blocks);
#endif /* LINUX_MMC_HOST_H */
--
2.50.1
On Wed, 16 Jul 2025 at 17:47, Benoît Monin <benoit.monin@bootlin.com> wrote:
>
> Provide a function to the MMC hosts to read some blocks of data as part
> of their tuning. The card parameter is optional since it is not
> available from the execute_tuning() operation, but present in
> execute_hs400_tuning() and prepare_sd_hs_tuning().
>
> This function only returns the status of the read operation, not the
> data read.
>
> Signed-off-by: Benoît Monin <benoit.monin@bootlin.com>
> ---
> drivers/mmc/core/mmc_ops.c | 79 ++++++++++++++++++++++++++++++++++++++++++++++
> include/linux/mmc/host.h | 2 ++
> 2 files changed, 81 insertions(+)
>
> diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c
> index 66283825513cb4ff993a1b2ec1f0b0cac4e74487..d29e5daf3e326ab37e61c99456421b1f66bcb0de 100644
> --- a/drivers/mmc/core/mmc_ops.c
> +++ b/drivers/mmc/core/mmc_ops.c
> @@ -1077,3 +1077,82 @@ int mmc_sanitize(struct mmc_card *card, unsigned int timeout_ms)
> return err;
> }
> EXPORT_SYMBOL_GPL(mmc_sanitize);
> +
> +/**
> + * mmc_read_tuning() - read data blocks from the mmc
> + * @card: mmc card to read from, can be NULL
> + * @host: mmc host doing the read
> + * @blksz: data block size
> + * @blocks: number of blocks to read
> + *
> + * Read one or more blocks of data from the beginning of the mmc. This is a
> + * low-level helper for tuning operation. If card is NULL, it is assumed that
> + * CMD23 can be used for multi-block read.
It makes sense to have a comment for this, but I would just just drop
the "struct mmc_card *card" as an in-parameter. If it turns out to be
needed later on, we would need additional changes to enable the caller
of mmc_read_tuning() to pass the "card" along.
> + *
> + * Note: Allocate and free a temporary buffer to store the data read. The data
> + * is not available outside of the function, only the status of the read
> + * operation.
> + *
> + * Return: 0 in case of success, otherwise -EIO / -ENOMEM / -E2BIG
> + */
> +int mmc_read_tuning(struct mmc_card *card, struct mmc_host *host,
> + unsigned int blksz, unsigned int blocks)
> +{
> + struct mmc_request mrq = {};
> + struct mmc_command sbc = {};
> + struct mmc_command cmd = {};
> + struct mmc_command stop = {};
> + struct mmc_data data = {};
> + struct scatterlist sg;
> + void *buf;
> + unsigned int len;
> +
> + if (blocks > 1) {
> + if (mmc_host_can_cmd23(host) &&
> + (!card || (mmc_card_can_cmd23(card) &&
> + !mmc_card_blk_no_cmd23(card)))) {
> + mrq.sbc = &sbc;
> + sbc.opcode = MMC_SET_BLOCK_COUNT;
> + sbc.arg = blocks;
> + sbc.flags = MMC_RSP_R1 | MMC_CMD_AC;
> + }
> + cmd.opcode = MMC_READ_MULTIPLE_BLOCK;
> + mrq.stop = &stop;
> + stop.opcode = MMC_STOP_TRANSMISSION;
> + stop.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_AC;
> + } else {
> + cmd.opcode = MMC_READ_SINGLE_BLOCK;
> + }
> +
> + mrq.cmd = &cmd;
> + cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_ADTC;
> +
> + mrq.data = &data;
> + data.flags = MMC_DATA_READ;
> + data.blksz = blksz;
> + data.blocks = blocks;
> + data.blk_addr = 0;
> + data.sg = &sg;
> + data.sg_len = 1;
> + if (card)
> + mmc_set_data_timeout(&data, card);
> + else
> + data.timeout_ns = 1000000000;
> +
> + if (check_mul_overflow(blksz, blocks, &len))
> + return -E2BIG;
> + buf = kmalloc(len, GFP_KERNEL);
> + if (!buf)
> + return -ENOMEM;
> +
> + sg_init_one(&sg, buf, len);
> +
> + mmc_wait_for_req(host, &mrq);
> + kfree(buf);
> +
> + if (sbc.error || cmd.error || data.error)
> + return -EIO;
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(mmc_read_tuning);
> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
> index 68f09a955a902047ac517441b6820fa6e4166a13..5a6471a6219222b199a16afd9e6bd5ab74b05c86 100644
> --- a/include/linux/mmc/host.h
> +++ b/include/linux/mmc/host.h
> @@ -743,5 +743,7 @@ int mmc_send_status(struct mmc_card *card, u32 *status);
> int mmc_send_tuning(struct mmc_host *host, u32 opcode, int *cmd_error);
> int mmc_send_abort_tuning(struct mmc_host *host, u32 opcode);
> int mmc_get_ext_csd(struct mmc_card *card, u8 **new_ext_csd);
> +int mmc_read_tuning(struct mmc_card *card, struct mmc_host *host,
> + unsigned int blksz, unsigned int blocks);
>
> #endif /* LINUX_MMC_HOST_H */
>
> --
> 2.50.1
>
Otherwise this looks good to me!
Kind regards
Uffe
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