platform/x86: amd-pmc: Fix command completion code

The protocol to submit a job request to SMU is to wait for
AMD_PMC_REGISTER_RESPONSE to return 1,meaning SMU is ready to take
requests. PMC driver has to make sure that the response code is always
AMD_PMC_RESULT_OK before making any command submissions.

When we submit a message to SMU, we have to wait until it processes
the request. Adding a read_poll_timeout() check as this was missing in
the existing code.

Also, add a mutex to protect amd_pmc_send_cmd() calls to SMU.

Fixes: 156ec4731cb2 ("platform/x86: amd-pmc: Add AMD platform support for S2Idle")
Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
Acked-by: Raul E Rangel <rrangel@chromium.org>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20210629084803.248498-2-Shyam-sundar.S-k@amd.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

diff --git a/drivers/platform/x86/amd-pmc.c b/drivers/platform/x86/amd-pmc.c
index b9da58ee9b1e3b144ebb107705c2f36eb0112c8e..1b5f149932c1c33bb1c4a2f6d40081ec38448a48 100644 (file)
--- a/drivers/platform/x86/amd-pmc.c
+++ b/drivers/platform/x86/amd-pmc.c
@@ -68,6 +68,7 @@ struct amd_pmc_dev {
        u32 base_addr;
        u32 cpu_id;
        struct device *dev;
+       struct mutex lock; /* generic mutex lock */
 #if IS_ENABLED(CONFIG_DEBUG_FS)
        struct dentry *dbgfs_dir;
 #endif /* CONFIG_DEBUG_FS */
@@ -138,9 +139,10 @@ static int amd_pmc_send_cmd(struct amd_pmc_dev *dev, bool set)
        u8 msg;
        u32 val;
 
+       mutex_lock(&dev->lock);
        /* Wait until we get a valid response */
        rc = readx_poll_timeout(ioread32, dev->regbase + AMD_PMC_REGISTER_RESPONSE,
-                               val, val > 0, PMC_MSG_DELAY_MIN_US,
+                               val, val != 0, PMC_MSG_DELAY_MIN_US,
                                PMC_MSG_DELAY_MIN_US * RESPONSE_REGISTER_LOOP_MAX);
        if (rc) {
                dev_err(dev->dev, "failed to talk to SMU\n");
@@ -156,7 +158,37 @@ static int amd_pmc_send_cmd(struct amd_pmc_dev *dev, bool set)
        /* Write message ID to message ID register */
        msg = (dev->cpu_id == AMD_CPU_ID_RN) ? MSG_OS_HINT_RN : MSG_OS_HINT_PCO;
        amd_pmc_reg_write(dev, AMD_PMC_REGISTER_MESSAGE, msg);
-       return 0;
+       /* Wait until we get a valid response */
+       rc = readx_poll_timeout(ioread32, dev->regbase + AMD_PMC_REGISTER_RESPONSE,
+                               val, val != 0, PMC_MSG_DELAY_MIN_US,
+                               PMC_MSG_DELAY_MIN_US * RESPONSE_REGISTER_LOOP_MAX);
+       if (rc) {
+               dev_err(dev->dev, "SMU response timed out\n");
+               goto out_unlock;
+       }
+
+       switch (val) {
+       case AMD_PMC_RESULT_OK:
+               break;
+       case AMD_PMC_RESULT_CMD_REJECT_BUSY:
+               dev_err(dev->dev, "SMU not ready. err: 0x%x\n", val);
+               rc = -EBUSY;
+               goto out_unlock;
+       case AMD_PMC_RESULT_CMD_UNKNOWN:
+               dev_err(dev->dev, "SMU cmd unknown. err: 0x%x\n", val);
+               rc = -EINVAL;
+               goto out_unlock;
+       case AMD_PMC_RESULT_CMD_REJECT_PREREQ:
+       case AMD_PMC_RESULT_FAILED:
+       default:
+               dev_err(dev->dev, "SMU cmd failed. err: 0x%x\n", val);
+               rc = -EIO;
+               goto out_unlock;
+       }
+
+out_unlock:
+       mutex_unlock(&dev->lock);
+       return rc;
 }
 
 static int __maybe_unused amd_pmc_suspend(struct device *dev)
@@ -259,6 +291,7 @@ static int amd_pmc_probe(struct platform_device *pdev)
 
        amd_pmc_dump_registers(dev);
 
+       mutex_init(&dev->lock);
        platform_set_drvdata(pdev, dev);
        amd_pmc_dbgfs_register(dev);
        return 0;
@@ -269,6 +302,7 @@ static int amd_pmc_remove(struct platform_device *pdev)
        struct amd_pmc_dev *dev = platform_get_drvdata(pdev);
 
        amd_pmc_dbgfs_unregister(dev);
+       mutex_destroy(&dev->lock);
        return 0;
 }