We need a single mutex for all 4 shared SMBus ports on the SB800. A
per-port mutex doesn't protect us from concurrent access.
In theory the mutex should be per PCI device, however in practice we
know that there's only ever a single instance of the device in a given
system so we can use a global.
Also take the mutex during initialization, as first port may be already
in use when second port is initialized.
Signed-off-by: Jean Delvare <jdelvare@xxxxxxx>
Cc: Christian Fetzer <fetzer.ch@xxxxxxxxx>
Cc: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
Cc: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Cc: Wolfram Sang <wsa@xxxxxxxxxxxxx>
---
drivers/i2c/busses/i2c-piix4.c | 22 ++++++----------------
1 file changed, 6 insertions(+), 16 deletions(-)
--- linux-4.5-rc0.orig/drivers/i2c/busses/i2c-piix4.c 2016-01-22 13:51:27.500458587 +0100
+++ linux-4.5-rc0/drivers/i2c/busses/i2c-piix4.c 2016-01-22 13:56:13.210960522 +0100
@@ -137,6 +137,7 @@ static const struct dmi_system_id piix4_
};
/* SB800 globals */
+DEFINE_MUTEX(piix4_mutex_sb800);
static const char *piix4_main_port_names_sb800[PIIX4_MAX_ADAPTERS] = {
"SDA0", "SDA2", "SDA3", "SDA4"
};
@@ -148,7 +149,6 @@ struct i2c_piix4_adapdata {
/* SB800 */
bool sb800_main;
unsigned short port;
- struct mutex *mutex;
};
static int piix4_setup(struct pci_dev *PIIX4_dev,
@@ -275,10 +275,12 @@ static int piix4_setup_sb800(struct pci_
else
smb_en = (aux) ? 0x28 : 0x2c;
+ mutex_lock(&piix4_mutex_sb800);
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);
+ mutex_unlock(&piix4_mutex_sb800);
if (!smb_en) {
smb_en_status = smba_en_lo & 0x10;
@@ -559,7 +561,7 @@ static s32 piix4_access_sb800(struct i2c
u8 port;
int retval;
- mutex_lock(adapdata->mutex);
+ mutex_lock(&piix4_mutex_sb800);
outb_p(SB800_PIIX4_PORT_IDX, SB800_PIIX4_SMB_IDX);
smba_en_lo = inb_p(SB800_PIIX4_SMB_IDX + 1);
@@ -574,7 +576,7 @@ static s32 piix4_access_sb800(struct i2c
outb_p(smba_en_lo, SB800_PIIX4_SMB_IDX + 1);
- mutex_unlock(adapdata->mutex);
+ mutex_unlock(&piix4_mutex_sb800);
return retval;
}
@@ -673,17 +675,10 @@ static int piix4_add_adapter(struct pci_
static int piix4_add_adapters_sb800(struct pci_dev *dev, unsigned short smba)
{
- struct mutex *mutex;
struct i2c_piix4_adapdata *adapdata;
int port;
int retval;
- mutex = kzalloc(sizeof(*mutex), GFP_KERNEL);
- if (mutex == NULL)
- return -ENOMEM;
-
- mutex_init(mutex);
-
for (port = 0; port < PIIX4_MAX_ADAPTERS; port++) {
retval = piix4_add_adapter(dev, smba,
piix4_main_port_names_sb800[port],
@@ -696,7 +691,6 @@ static int piix4_add_adapters_sb800(stru
adapdata = i2c_get_adapdata(piix4_main_adapters[port]);
adapdata->sb800_main = true;
adapdata->port = port;
- adapdata->mutex = mutex;
}
return retval;
@@ -714,8 +708,6 @@ error:
}
}
- kfree(mutex);
-
return retval;
}
@@ -798,10 +790,8 @@ static void piix4_adap_remove(struct i2c
i2c_del_adapter(adap);
if (adapdata->port == 0) {
release_region(adapdata->smba, SMBIOSIZE);
- if (adapdata->sb800_main) {
- kfree(adapdata->mutex);
+ if (adapdata->sb800_main)
release_region(SB800_PIIX4_SMB_IDX, 2);
- }
}
kfree(adapdata);
kfree(adap);
--
Jean Delvare
SUSE L3 Support
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