i2c: piix4: Add EFCH MMIO support for SMBus port select

AMD processors include registers capable of selecting between 2 SMBus
ports. Port selection is made during each user access by writing to
FCH::PM::DECODEEN[smbus0sel]. Change the driver to use MMIO during
SMBus port selection because cd6h/cd7h port I/O is not available on
later AMD processors.

Signed-off-by: Terry Bowman <terry.bowman@amd.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

diff --git a/drivers/i2c/busses/i2c-piix4.c b/drivers/i2c/busses/i2c-piix4.c
index 7f31217..4789fc9 100644 (file)
--- a/drivers/i2c/busses/i2c-piix4.c
+++ b/drivers/i2c/busses/i2c-piix4.c
@@ -753,10 +753,19 @@ static void piix4_imc_wakeup(void)
        release_region(KERNCZ_IMC_IDX, 2);
 }
 
-static int piix4_sb800_port_sel(u8 port)
+static int piix4_sb800_port_sel(u8 port, struct sb800_mmio_cfg *mmio_cfg)
 {
        u8 smba_en_lo, val;
 
+       if (mmio_cfg->use_mmio) {
+               smba_en_lo = ioread8(mmio_cfg->addr + piix4_port_sel_sb800);
+               val = (smba_en_lo & ~piix4_port_mask_sb800) | port;
+               if (smba_en_lo != val)
+                       iowrite8(val, mmio_cfg->addr + piix4_port_sel_sb800);
+
+               return (smba_en_lo & piix4_port_mask_sb800);
+       }
+
        outb_p(piix4_port_sel_sb800, SB800_PIIX4_SMB_IDX);
        smba_en_lo = inb_p(SB800_PIIX4_SMB_IDX + 1);
 
@@ -843,12 +852,12 @@ static s32 piix4_access_sb800(struct i2c_adapter *adap, u16 addr,
                }
        }
 
-       prev_port = piix4_sb800_port_sel(adapdata->port);
+       prev_port = piix4_sb800_port_sel(adapdata->port, &adapdata->mmio_cfg);
 
        retval = piix4_access(adap, addr, flags, read_write,
                              command, size, data);
 
-       piix4_sb800_port_sel(prev_port);
+       piix4_sb800_port_sel(prev_port, &adapdata->mmio_cfg);
 
        /* Release the semaphore */
        outb_p(smbslvcnt | 0x20, SMBSLVCNT);