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i2c: piix4: Fix SB800 locking

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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@suse.de>
Tested-by: Christian Fetzer <fetzer.ch@gmail.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
[wsa: made mutex static]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Jean Delvare 2016-01-22 14:12:02 +01:00 committed by Wolfram Sang
parent 92e963f50f
commit a28e35171c
1 changed files with 6 additions and 16 deletions
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22
drivers/i2c/busses/i2c-piix4.c
View file

@ -137,6 +137,7 @@ static const struct dmi_system_id piix4_dmi_ibm[] = {
};
/* SB800 globals */
static 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_dev *PIIX4_dev,
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_adapter *adap, u16 addr,
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_adapter *adap, u16 addr,
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_dev *dev, unsigned short smba,
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(struct pci_dev *dev, unsigned short smba)
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_adapter *adap)
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);