platform/x86/amd/pmf: Move out of BIOS SMN pair for driver probe

The current SMN index used for the driver probe seems to be meant
for the BIOS pair and there are potential concurrency problems that can
occur with an inopportune SMI.

It is been advised to use SMN_INDEX_0 instead of SMN_INDEX_2, which is
what amd_nb.c provides and this function has protections to ensure that
only one caller can use it at a time.

Fixes: da5ce22 ("platform/x86/amd/pmf: Add support for PMF core layer")
Co-developed-by: Patil Rajesh Reddy <Patil.Reddy@amd.com>
Signed-off-by: Patil Rajesh Reddy <Patil.Reddy@amd.com>
Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
Link: https://lore.kernel.org/r/20230406164807.50969-4-Shyam-sundar.S-k@amd.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

drivers/platform/x86/amd/pmf/Kconfig

@@ -7,6 +7,7 @@ config AMD_PMF
 	tristate "AMD Platform Management Framework"
 	depends on ACPI && PCI
 	depends on POWER_SUPPLY
+	depends on AMD_NB
 	select ACPI_PLATFORM_PROFILE
 	help
 	  This driver provides support for the AMD Platform Management Framework.

drivers/platform/x86/amd/pmf/core.c

@@ -8,6 +8,7 @@
  * Author: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
  */
 
+#include <asm/amd_nb.h>
 #include <linux/debugfs.h>
 #include <linux/iopoll.h>
 #include <linux/module.h>
@@ -22,8 +23,6 @@
 #define AMD_PMF_REGISTER_ARGUMENT	0xA58
 
 /* Base address of SMU for mapping physical address to virtual address */
-#define AMD_PMF_SMU_INDEX_ADDRESS	0xB8
-#define AMD_PMF_SMU_INDEX_DATA		0xBC
 #define AMD_PMF_MAPPING_SIZE		0x01000
 #define AMD_PMF_BASE_ADDR_OFFSET	0x10000
 #define AMD_PMF_BASE_ADDR_LO		0x13B102E8
@@ -348,30 +347,19 @@ static int amd_pmf_probe(struct platform_device *pdev)
 	}
 
 	dev->cpu_id = rdev->device;
-	err = pci_write_config_dword(rdev, AMD_PMF_SMU_INDEX_ADDRESS, AMD_PMF_BASE_ADDR_LO);
-	if (err) {
-		dev_err(dev->dev, "error writing to 0x%x\n", AMD_PMF_SMU_INDEX_ADDRESS);
-		pci_dev_put(rdev);
-		return pcibios_err_to_errno(err);
-	}
 
-	err = pci_read_config_dword(rdev, AMD_PMF_SMU_INDEX_DATA, &val);
+	err = amd_smn_read(0, AMD_PMF_BASE_ADDR_LO, &val);
 	if (err) {
+		dev_err(dev->dev, "error in reading from 0x%x\n", AMD_PMF_BASE_ADDR_LO);
 		pci_dev_put(rdev);
 		return pcibios_err_to_errno(err);
 	}
 
 	base_addr_lo = val & AMD_PMF_BASE_ADDR_HI_MASK;
 
-	err = pci_write_config_dword(rdev, AMD_PMF_SMU_INDEX_ADDRESS, AMD_PMF_BASE_ADDR_HI);
-	if (err) {
-		dev_err(dev->dev, "error writing to 0x%x\n", AMD_PMF_SMU_INDEX_ADDRESS);
-		pci_dev_put(rdev);
-		return pcibios_err_to_errno(err);
-	}
-
-	err = pci_read_config_dword(rdev, AMD_PMF_SMU_INDEX_DATA, &val);
+	err = amd_smn_read(0, AMD_PMF_BASE_ADDR_HI, &val);
 	if (err) {
+		dev_err(dev->dev, "error in reading from 0x%x\n", AMD_PMF_BASE_ADDR_HI);
 		pci_dev_put(rdev);
 		return pcibios_err_to_errno(err);
 	}