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Commit a28e3517 authored by Jean Delvare's avatar Jean Delvare Committed by Wolfram Sang
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i2c: piix4: Fix SB800 locking 



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: default avatarJean Delvare <jdelvare@suse.de>
Tested-by: default avatarChristian Fetzer <fetzer.ch@gmail.com>
Reviewed-by: default avatarMika Westerberg <mika.westerberg@linux.intel.com>
[wsa: made mutex static]
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent 92e963f5

drivers/i2c/busses/i2c-piix4.c

+6 −16
Original line number Diff line number Diff line
@@ -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 @@ static int piix4_add_adapters_sb800(struct pci_dev *dev, unsigned short smba) 
		}

	}



	kfree(mutex);



	return retval;

}
@@ -798,11 +790,9 @@ 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);

	}