[PATCH v3 4/5] platform/x86: amd-pmc: Move to later in the suspend process

[Mario Limonciello <mario.limonciello@amd.com>]

The `OS_HINT` message is supposed to indicate that everything else
that is supposed to go into the deepest state has done so.

This assumption is invalid as:
1) The CPUs will still go in and out of the deepest state
2) Other devices may still run their `noirq` suspend routines
3) The LPS0 ACPI device will still run

To more closely mirror how this works on other operating systems,
move the `amd-pmc` suspend to the very last thing before the s2idle
loop via an lps0 callback.

Fixes: 8d89835b0467 ("PM: suspend: Do not pause cpuidle in the suspend-to-idle path")
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
changes from v2->v3:
 * no changes
changes from v1->v2:
 * adjust for changes in previous patches
 * display a debugging message for constraints

 drivers/platform/x86/amd-pmc.c | 42 +++++++++++++++++++++-------------
 1 file changed, 26 insertions(+), 16 deletions(-)

diff --git a/drivers/platform/x86/amd-pmc.c b/drivers/platform/x86/amd-pmc.c
index 971aaabaa9c8..752a99d759d2 100644
--- a/drivers/platform/x86/amd-pmc.c
+++ b/drivers/platform/x86/amd-pmc.c
@@ -639,13 +639,16 @@ static int amd_pmc_verify_czn_rtc(struct amd_pmc_dev *pdev, u32 *arg)
 	return rc;
 }
 
-static int __maybe_unused amd_pmc_suspend(struct device *dev)
+static int amd_pmc_suspend(void *context, bool constraints)
 {
-	struct amd_pmc_dev *pdev = dev_get_drvdata(dev);
+	struct amd_pmc_dev *pdev = dev_get_drvdata((struct device *)context);
 	int rc;
 	u8 msg;
 	u32 arg = 1;
 
+	/* for enabling constraints checking in the future */
+	dev_dbg(pdev->dev, "LPI constraints were%smet.\n", constraints ? " " : " not ");
+
 	/* Reset and Start SMU logging - to monitor the s0i3 stats */
 	amd_pmc_send_cmd(pdev, 0, NULL, SMU_MSG_LOG_RESET, 0);
 	amd_pmc_send_cmd(pdev, 0, NULL, SMU_MSG_LOG_START, 0);
@@ -658,7 +661,7 @@ static int __maybe_unused amd_pmc_suspend(struct device *dev)
 	}
 
 	/* Dump the IdleMask before we send hint to SMU */
-	amd_pmc_idlemask_read(pdev, dev, NULL);
+	amd_pmc_idlemask_read(pdev, pdev->dev, NULL);
 	msg = amd_pmc_get_os_hint(pdev);
 	rc = amd_pmc_send_cmd(pdev, arg, NULL, msg, 0);
 	if (rc) {
@@ -681,28 +684,28 @@ static int __maybe_unused amd_pmc_suspend(struct device *dev)
 	return rc;
 }
 
-static int __maybe_unused amd_pmc_resume(struct device *dev)
+static void amd_pmc_resume(void *context)
 {
-	struct amd_pmc_dev *pdev = dev_get_drvdata(dev);
+	struct amd_pmc_dev *pdev = dev_get_drvdata((struct device *)context);
 	int rc;
 	u8 msg;
 
 	msg = amd_pmc_get_os_hint(pdev);
 	rc = amd_pmc_send_cmd(pdev, 0, NULL, msg, 0);
 	if (rc)
-		dev_err(pdev->dev, "resume failed\n");
+		dev_err(pdev->dev, "resume failed: %d\n", rc);
 
 	/* Let SMU know that we are looking for stats */
 	amd_pmc_send_cmd(pdev, 0, NULL, SMU_MSG_LOG_DUMP_DATA, 0);
 
 	/* Dump the IdleMask to see the blockers */
-	amd_pmc_idlemask_read(pdev, dev, NULL);
+	amd_pmc_idlemask_read(pdev, pdev->dev, NULL);
 
 	/* Write data incremented by 1 to distinguish in stb_read */
 	if (enable_stb)
 		rc = amd_pmc_write_stb(pdev, AMD_PMC_STB_PREDEF + 1);
 	if (rc)
-		dev_err(pdev->dev, "error writing to STB\n");
+		dev_err(pdev->dev, "error writing to STB: %d\n", rc);
 
 	/* Restore the QoS request back to defaults if it was set */
 	if (pdev->cpu_id == AMD_CPU_ID_CZN)
@@ -711,15 +714,8 @@ static int __maybe_unused amd_pmc_resume(struct device *dev)
 
 	/* Notify on failed entry */
 	amd_pmc_validate_deepest(pdev);
-
-	return rc;
 }
 
-static const struct dev_pm_ops amd_pmc_pm_ops = {
-	.suspend_noirq = amd_pmc_suspend,
-	.resume_noirq = amd_pmc_resume,
-};
-
 static const struct pci_device_id pmc_pci_ids[] = {
 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, AMD_CPU_ID_YC) },
 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, AMD_CPU_ID_CZN) },
@@ -805,6 +801,11 @@ static int amd_pmc_read_stb(struct amd_pmc_dev *dev, u32 *buf)
 static int amd_pmc_probe(struct platform_device *pdev)
 {
 	struct amd_pmc_dev *dev = &pmc;
+	struct lps0_callback_handler lps0_handler = {
+		.prepare_late_callback = amd_pmc_suspend,
+		.restore_early_callback = amd_pmc_resume,
+		.context = &pdev->dev,
+	};
 	struct pci_dev *rdev;
 	u32 base_addr_lo, base_addr_hi;
 	u64 base_addr, fch_phys_addr;
@@ -884,6 +885,10 @@ static int amd_pmc_probe(struct platform_device *pdev)
 
 	amd_pmc_get_smu_version(dev);
 	platform_set_drvdata(pdev, dev);
+	err = acpi_register_lps0_callbacks(&lps0_handler);
+	if (err)
+		goto err_pci_dev_put;
+
 	amd_pmc_dbgfs_register(dev);
 	cpu_latency_qos_add_request(&dev->amd_pmc_pm_qos_req, PM_QOS_DEFAULT_VALUE);
 	return 0;
@@ -896,7 +901,13 @@ static int amd_pmc_probe(struct platform_device *pdev)
 static int amd_pmc_remove(struct platform_device *pdev)
 {
 	struct amd_pmc_dev *dev = platform_get_drvdata(pdev);
+	struct lps0_callback_handler lps0_handler = {
+		.prepare_late_callback = amd_pmc_suspend,
+		.restore_early_callback = amd_pmc_resume,
+		.context = &pdev->dev,
+	};
 
+	acpi_unregister_lps0_callbacks(&lps0_handler);
 	amd_pmc_dbgfs_unregister(dev);
 	pci_dev_put(dev->rdev);
 	mutex_destroy(&dev->lock);
@@ -917,7 +928,6 @@ static struct platform_driver amd_pmc_driver = {
 	.driver = {
 		.name = "amd_pmc",
 		.acpi_match_table = amd_pmc_acpi_ids,
-		.pm = &amd_pmc_pm_ops,
 	},
 	.probe = amd_pmc_probe,
 	.remove = amd_pmc_remove,
-- 
2.34.1