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

Ilpo Järvinen
2024-02-08T13:38:07Z

On Wed, 31 Jan 2024, 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;
> + }
> +
> /* 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) {

Why you check for packet_size here if you break earlier for !packet_size?

> + 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;
> }

--
i.