[PATCH v2 6/8] i2c: piix4: Add EFCH MMIO support to SMBus base address detect

[Terry Bowman <terry.bowman@amd.com>]

The EFCH SMBus controller's base address is determined using details in
FCH::PM::DECODEEN[smbusasfiobase] and FCH::PM::DECODEEN[smbusasfioen].
This code also writes to FCH::PM::ISACONTROL[mmioen] to enable MMIO
decoding. These register fields were accessed using cd6h/cd7h port I/O.
cd6h/cd7h port I/O is no longer available in later AMD processors.
Change base address detection to use MMIO instead of port I/O cd6h/cd7h.

Signed-off-by: Terry Bowman <terry.bowman@amd.com>
To: Guenter Roeck <linux@roeck-us.net>
To: linux-watchdog@vger.kernel.org
To: Jean Delvare <jdelvare@suse.com>
To: linux-i2c@vger.kernel.org
To: Wolfram Sang <wsa@kernel.org>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
To: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: linux-kernel@vger.kernel.org
Cc: Wim Van Sebroeck <wim@linux-watchdog.org>
Cc: Robert Richter <rrichter@amd.com>
Cc: Thomas Lendacky <thomas.lendacky@amd.com>
---
 drivers/i2c/busses/i2c-piix4.c | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-piix4.c b/drivers/i2c/busses/i2c-piix4.c
index ffb1367dd852..2937f3254c31 100644
--- a/drivers/i2c/busses/i2c-piix4.c
+++ b/drivers/i2c/busses/i2c-piix4.c
@@ -98,6 +98,7 @@
 #define SB800_PIIX4_PORT_IDX_MASK_KERNCZ	0x18
 #define SB800_PIIX4_PORT_IDX_SHIFT_KERNCZ	3
 
+#define SB800_PIIX4_FCH_PM_DECODEEN_MMIO        BIT(1)
 #define SB800_PIIX4_FCH_PM_ADDR                 0xFED80300
 #define SB800_PIIX4_FCH_PM_SIZE                 8
 
@@ -344,10 +345,18 @@ static int piix4_setup_sb800_smba(struct pci_dev *PIIX4_dev,
 	if (retval)
 		return retval;
 
-	outb_p(smb_en, SB800_PIIX4_SMB_IDX);
-	smba_en_lo = inb_p(SB800_PIIX4_SMB_IDX + 1);
-	outb_p(smb_en + 1, SB800_PIIX4_SMB_IDX);
-	smba_en_hi = inb_p(SB800_PIIX4_SMB_IDX + 1);
+	if (mmio_cfg.use_mmio) {
+		iowrite32(ioread32(mmio_cfg.addr + 4) | SB800_PIIX4_FCH_PM_DECODEEN_MMIO,
+			  mmio_cfg.addr + 4);
+
+		smba_en_lo = ioread8(mmio_cfg.addr);
+		smba_en_hi = ioread8(mmio_cfg.addr + 1);
+	} else {
+		outb_p(smb_en, SB800_PIIX4_SMB_IDX);
+		smba_en_lo = inb_p(SB800_PIIX4_SMB_IDX + 1);
+		outb_p(smb_en + 1, SB800_PIIX4_SMB_IDX);
+		smba_en_hi = inb_p(SB800_PIIX4_SMB_IDX + 1);
+	}
 
 	piix4_sb800_region_release(&PIIX4_dev->dev, &mmio_cfg);
 
-- 
2.30.2