[PATCH 5.15 011/132] i2c: piix4: Add EFCH MMIO support for SMBus port select

Greg Kroah-Hartman
2022-05-23T17:32:37Z

From: Terry Bowman <terry.bowman@amd.com>

commit 381a3083c6747ae5cdbef9b176d57d1b966db49f upstream.

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>
Cc: Mario Limonciello <Mario.Limonciello@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/i2c/busses/i2c-piix4.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)

--- 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
}
}

- 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);