Re: [PATCH 2/8] platform/x86/intel/sdsi: Combine read and write mailbox flows

Kuppuswamy Sathyanarayanan
2024-02-01T17:31:32Z

On 1/31/24 5:07 PM, David E. Box wrote:
> The current mailbox commands are either read-only or write-only and the
> flow is different for each. New commands will need to send and receive
> data. In preparation for these commands, create a common polling function
> to handle sending data and receiving in the same transaction.
>
> Signed-off-by: David E. Box <david.e.box@linux.intel.com>
> ---
> drivers/platform/x86/intel/sdsi.c | 79 +++++++++++++++++--------------
> 1 file changed, 44 insertions(+), 35 deletions(-)
>
> diff --git a/drivers/platform/x86/intel/sdsi.c b/drivers/platform/x86/intel/sdsi.c
> index a70c071de6e2..05a35f2f85b6 100644
> --- a/drivers/platform/x86/intel/sdsi.c
> +++ b/drivers/platform/x86/intel/sdsi.c
> @@ -15,6 +15,7 @@
> #include <linux/iopoll.h>
> #include <linux/kernel.h>
> #include <linux/module.h>
> +#include <linux/overflow.h>
> #include <linux/pci.h>
> #include <linux/slab.h>
> #include <linux/sysfs.h>
> @@ -156,8 +157,8 @@ static int sdsi_status_to_errno(u32 status)
> }
> }
>
> -static int sdsi_mbox_cmd_read(struct sdsi_priv *priv, struct sdsi_mbox_info *info,
> - size_t *data_size)
> +static int sdsi_mbox_poll(struct sdsi_priv *priv, struct sdsi_mbox_info *info,
> + size_t *data_size)
> {
> struct device *dev = priv->dev;
> u32 total, loop, eom, status, message_size;
> @@ -166,18 +167,10 @@ static int sdsi_mbox_cmd_read(struct sdsi_priv *priv, struct sdsi_mbox_info *inf
>
> lockdep_assert_held(&priv->mb_lock);
>
> - /* Format and send the read command */
> - control = FIELD_PREP(CTRL_EOM, 1) |
> - FIELD_PREP(CTRL_SOM, 1) |
> - FIELD_PREP(CTRL_RUN_BUSY, 1) |
> - FIELD_PREP(CTRL_PACKET_SIZE, info->size);
> - writeq(control, priv->control_addr);
> -
> /* For reads, data sizes that are larger than the mailbox size are read in packets. */
> total = 0;
> loop = 0;
> do {
> - void *buf = info->buffer + (SDSI_SIZE_MAILBOX * loop);
> u32 packet_size;
>
> /* Poll on ready bit */
> @@ -195,6 +188,11 @@ static int sdsi_mbox_cmd_read(struct sdsi_priv *priv, struct sdsi_mbox_info *inf
> if (ret)
> break;
>
> + if (!packet_size) {
> + sdsi_complete_transaction(priv);
> + break;
> + }
> +

It seems to be a generic check. Is this related to converting to a read/write function or
a common fix you added together in this patch.

> /* Only the last packet can be less than the mailbox size. */
> if (!eom && packet_size != SDSI_SIZE_MAILBOX) {
> dev_err(dev, "Invalid packet size\n");
> @@ -208,9 +206,13 @@ static int sdsi_mbox_cmd_read(struct sdsi_priv *priv, struct sdsi_mbox_info *inf
> break;
> }
>
> - sdsi_memcpy64_fromio(buf, priv->mbox_addr, round_up(packet_size, SDSI_SIZE_CMD));
> + if (packet_size && info->buffer) {
> + void *buf = info->buffer + array_size(SDSI_SIZE_MAILBOX, loop);
>
> - total += packet_size;
> + sdsi_memcpy64_fromio(buf, priv->mbox_addr,
> + round_up(packet_size, SDSI_SIZE_CMD));
> + total += packet_size;
> + }
>
> sdsi_complete_transaction(priv);
> } while (!eom && ++loop < MBOX_MAX_PACKETS);
> @@ -230,16 +232,33 @@ static int sdsi_mbox_cmd_read(struct sdsi_priv *priv, struct sdsi_mbox_info *inf
> dev_warn(dev, "Read count %u differs from expected count %u\n",
> total, message_size);
>
> - *data_size = total;
> + if (data_size)
> + *data_size = total;
>
> return 0;
> }
>
> -static int sdsi_mbox_cmd_write(struct sdsi_priv *priv, struct sdsi_mbox_info *info)
> +static int sdsi_mbox_cmd_read(struct sdsi_priv *priv, struct sdsi_mbox_info *info,
> + size_t *data_size)
> +{
> + u64 control;
> +
> + lockdep_assert_held(&priv->mb_lock);
> +
> + /* Format and send the read command */
> + control = FIELD_PREP(CTRL_EOM, 1) |
> + FIELD_PREP(CTRL_SOM, 1) |
> + FIELD_PREP(CTRL_RUN_BUSY, 1) |
> + FIELD_PREP(CTRL_PACKET_SIZE, info->size);
> + writeq(control, priv->control_addr);
> +
> + return sdsi_mbox_poll(priv, info, data_size);
> +}
> +
> +static int sdsi_mbox_cmd_write(struct sdsi_priv *priv, struct sdsi_mbox_info *info,
> + size_t *data_size)
> {
> u64 control;
> - u32 status;
> - int ret;
>
> lockdep_assert_held(&priv->mb_lock);
>
> @@ -256,20 +275,7 @@ static int sdsi_mbox_cmd_write(struct sdsi_priv *priv, struct sdsi_mbox_info *in
> FIELD_PREP(CTRL_PACKET_SIZE, info->size);
> writeq(control, priv->control_addr);
>
> - /* Poll on ready bit */
> - ret = readq_poll_timeout(priv->control_addr, control, control & CTRL_READY,
> - MBOX_POLLING_PERIOD_US, MBOX_TIMEOUT_US);
> -
> - if (ret)
> - goto release_mbox;
> -
> - status = FIELD_GET(CTRL_STATUS, control);
> - ret = sdsi_status_to_errno(status);
> -
> -release_mbox:
> - sdsi_complete_transaction(priv);
> -
> - return ret;
> + return sdsi_mbox_poll(priv, info, data_size);
> }
>
> static int sdsi_mbox_acquire(struct sdsi_priv *priv, struct sdsi_mbox_info *info)
> @@ -313,7 +319,8 @@ static int sdsi_mbox_acquire(struct sdsi_priv *priv, struct sdsi_mbox_info *info
> return ret;
> }
>
> -static int sdsi_mbox_write(struct sdsi_priv *priv, struct sdsi_mbox_info *info)
> +static int sdsi_mbox_write(struct sdsi_priv *priv, struct sdsi_mbox_info *info,
> + size_t *data_size)
> {
> int ret;
>
> @@ -323,7 +330,7 @@ static int sdsi_mbox_write(struct sdsi_priv *priv, struct sdsi_mbox_info *info)
> if (ret)
> return ret;
>
> - return sdsi_mbox_cmd_write(priv, info);
> + return sdsi_mbox_cmd_write(priv, info, data_size);
> }
>
> static int sdsi_mbox_read(struct sdsi_priv *priv, struct sdsi_mbox_info *info, size_t *data_size)
> @@ -342,7 +349,7 @@ static int sdsi_mbox_read(struct sdsi_priv *priv, struct sdsi_mbox_info *info, s
> static ssize_t sdsi_provision(struct sdsi_priv *priv, char *buf, size_t count,
> enum sdsi_command command)
> {
> - struct sdsi_mbox_info info;
> + struct sdsi_mbox_info info = {};

This change also looks like an independent fix. Is this related to common function usage
you mentioned in the commit log.

> int ret;
>
> if (count > (SDSI_SIZE_WRITE_MSG - SDSI_SIZE_CMD))
> @@ -364,7 +371,9 @@ static ssize_t sdsi_provision(struct sdsi_priv *priv, char *buf, size_t count,
> ret = mutex_lock_interruptible(&priv->mb_lock);
> if (ret)
> goto free_payload;
> - ret = sdsi_mbox_write(priv, &info);
> +
> + ret = sdsi_mbox_write(priv, &info, NULL);
> +
> mutex_unlock(&priv->mb_lock);
>
> free_payload:
> @@ -408,7 +417,7 @@ static ssize_t
> certificate_read(u64 command, struct sdsi_priv *priv, char *buf, loff_t off,
> size_t count)
> {
> - struct sdsi_mbox_info info;
> + struct sdsi_mbox_info info = {};
> size_t size;
> int ret;
>

--
Sathyanarayanan Kuppuswamy
Linux Kernel Developer