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path: root/drivers/i2c/busses/i2c-piix4.c
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Diffstat (limited to 'drivers/i2c/busses/i2c-piix4.c')
-rw-r--r--drivers/i2c/busses/i2c-piix4.c26
1 files changed, 25 insertions, 1 deletions
diff --git a/drivers/i2c/busses/i2c-piix4.c b/drivers/i2c/busses/i2c-piix4.c
index c2268cdf38e8..c21ca7bf2efe 100644
--- a/drivers/i2c/busses/i2c-piix4.c
+++ b/drivers/i2c/busses/i2c-piix4.c
@@ -58,7 +58,7 @@
#define SMBSLVDAT (0xC + piix4_smba)
/* count for request_region */
-#define SMBIOSIZE 8
+#define SMBIOSIZE 9
/* PCI Address Constants */
#define SMBBA 0x090
@@ -585,12 +585,33 @@ static s32 piix4_access_sb800(struct i2c_adapter *adap, u16 addr,
u8 command, int size, union i2c_smbus_data *data)
{
struct i2c_piix4_adapdata *adapdata = i2c_get_adapdata(adap);
+ unsigned short piix4_smba = adapdata->smba;
+ int retries = MAX_TIMEOUT;
+ int smbslvcnt;
u8 smba_en_lo;
u8 port;
int retval;
mutex_lock(&piix4_mutex_sb800);
+ /* Request the SMBUS semaphore, avoid conflicts with the IMC */
+ smbslvcnt = inb_p(SMBSLVCNT);
+ do {
+ outb_p(smbslvcnt | 0x10, SMBSLVCNT);
+
+ /* Check the semaphore status */
+ smbslvcnt = inb_p(SMBSLVCNT);
+ if (smbslvcnt & 0x10)
+ break;
+
+ usleep_range(1000, 2000);
+ } while (--retries);
+ /* SMBus is still owned by the IMC, we give up */
+ if (!retries) {
+ mutex_unlock(&piix4_mutex_sb800);
+ return -EBUSY;
+ }
+
outb_p(piix4_port_sel_sb800, SB800_PIIX4_SMB_IDX);
smba_en_lo = inb_p(SB800_PIIX4_SMB_IDX + 1);
@@ -604,6 +625,9 @@ static s32 piix4_access_sb800(struct i2c_adapter *adap, u16 addr,
outb_p(smba_en_lo, SB800_PIIX4_SMB_IDX + 1);
+ /* Release the semaphore */
+ outb_p(smbslvcnt | 0x20, SMBSLVCNT);
+
mutex_unlock(&piix4_mutex_sb800);
return retval;