[PATCH v3 4/4] platform/x86/amd: pmc: Add an extra STB message for checking s2idle entry

[Mario Limonciello]

The `check` callback is run right before the cores are put into HLT.
This will allow checking synchronization problems with other software
that writes into the STB.

Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
---
v2->v3:
 * Update for changes in patch 1/4.

 drivers/platform/x86/amd/pmc.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/platform/x86/amd/pmc.c b/drivers/platform/x86/amd/pmc.c
index fba42036682d..32887687f888 100644
--- a/drivers/platform/x86/amd/pmc.c
+++ b/drivers/platform/x86/amd/pmc.c
@@ -41,6 +41,7 @@
 #define AMD_PMC_STB_PMI_0		0x03E30600
 #define AMD_PMC_STB_S2IDLE_PREPARE	0xC6000001
 #define AMD_PMC_STB_S2IDLE_RESTORE	0xC6000002
+#define AMD_PMC_STB_S2IDLE_CHECK	0xC6000003
 
 /* STB S2D(Spill to DRAM) has different message port offset */
 #define STB_SPILL_TO_DRAM		0xBE
@@ -706,6 +707,16 @@ static void amd_pmc_s2idle_prepare(void)
 		dev_err(pdev->dev, "error writing to STB: %d\n", rc);
 }
 
+static void amd_pmc_s2idle_check(void)
+{
+	struct amd_pmc_dev *pdev = &pmc;
+	int rc;
+
+	rc = amd_pmc_write_stb(pdev, AMD_PMC_STB_S2IDLE_CHECK);
+	if (rc)
+		dev_err(pdev->dev, "error writing to STB: %d\n", rc);
+}
+
 static void amd_pmc_s2idle_restore(void)
 {
 	struct amd_pmc_dev *pdev = &pmc;
@@ -733,6 +744,7 @@ static void amd_pmc_s2idle_restore(void)
 
 static struct acpi_s2idle_dev_ops amd_pmc_s2idle_dev_ops = {
 	.prepare = amd_pmc_s2idle_prepare,
+	.check = amd_pmc_s2idle_check,
 	.restore = amd_pmc_s2idle_restore,
 };
 #endif
-- 
2.34.1