[PATCH V4 2/9] platform/x86/intel/sdsi: Combine read and write mailbox flows

David E. Box
2024-04-11T02:59:05Z

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>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
V4 - no changes

V3 - no changes

V2 - In sdsi_cmd_read() remove unnecessary check for non-zero packet_size
in do loop since the loop is exited earlier when packet_size is
zero.

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..d80c2dc0ce71 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 (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 = {};
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;

--
2.34.1