platform/x86/intel/sdsi: Combine read and write mailbox flows

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>
Link: https://lore.kernel.org/r/20240411025856.2782476-3-david.e.box@linux.intel.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

diff --git a/drivers/platform/x86/intel/sdsi.c b/drivers/platform/x86/intel/sdsi.c
index a70c071de6e284cd5ec56f75590c0683a76d28b2..d80c2dc0ce712f20e139b3a4582397d38855e988 100644 (file)
--- 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;