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kernel-ark/drivers/i2c/busses/i2c-mpc.c
Sylvain Munaut 7f02d56e54 [PATCH] i2c: Race fix for i2c-mpc.c 
i2c: Race fix for i2c-mpc.c

The problem was that the clock speed and driver data is
initialized after the i2c adapter was added. This caused
the i2c bus to start working at a wrong speed. (Mostly
noticable on the second bus on mpc5200)

With this patch we've tried to keep the i2c adapter
working perfectly all the time it is included in the system.
Initialize before added, Remove garbage after deleleted.

Submitted-by: Asier Llano Palacios
Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
Signed-off-by: Kumar Gala <kumar.gala@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-06-21 21:52:01 -07:00

499 lines
11 KiB
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/*
* (C) Copyright 2003-2004
* Humboldt Solutions Ltd, adrian@humboldt.co.uk.
* This is a combined i2c adapter and algorithm driver for the
* MPC107/Tsi107 PowerPC northbridge and processors that include
* the same I2C unit (8240, 8245, 85xx).
*
* Release 0.8
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*/
#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/pci.h>
#include <asm/io.h>
#ifdef CONFIG_FSL_OCP
#include <asm/ocp.h>
#define FSL_I2C_DEV_SEPARATE_DFSRR FS_I2C_SEPARATE_DFSRR
#define FSL_I2C_DEV_CLOCK_5200 FS_I2C_CLOCK_5200
#else
#include <linux/fsl_devices.h>
#endif
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#define MPC_I2C_ADDR 0x00
#define MPC_I2C_FDR 0x04
#define MPC_I2C_CR 0x08
#define MPC_I2C_SR 0x0c
#define MPC_I2C_DR 0x10
#define MPC_I2C_DFSRR 0x14
#define MPC_I2C_REGION 0x20
#define CCR_MEN 0x80
#define CCR_MIEN 0x40
#define CCR_MSTA 0x20
#define CCR_MTX 0x10
#define CCR_TXAK 0x08
#define CCR_RSTA 0x04
#define CSR_MCF 0x80
#define CSR_MAAS 0x40
#define CSR_MBB 0x20
#define CSR_MAL 0x10
#define CSR_SRW 0x04
#define CSR_MIF 0x02
#define CSR_RXAK 0x01
struct mpc_i2c {
void __iomem *base;
u32 interrupt;
wait_queue_head_t queue;
struct i2c_adapter adap;
int irq;
u32 flags;
};
static __inline__ void writeccr(struct mpc_i2c *i2c, u32 x)
{
writeb(x, i2c->base + MPC_I2C_CR);
}
static irqreturn_t mpc_i2c_isr(int irq, void *dev_id, struct pt_regs *regs)
{
struct mpc_i2c *i2c = dev_id;
if (readb(i2c->base + MPC_I2C_SR) & CSR_MIF) {
/* Read again to allow register to stabilise */
i2c->interrupt = readb(i2c->base + MPC_I2C_SR);
writeb(0, i2c->base + MPC_I2C_SR);
wake_up_interruptible(&i2c->queue);
}
return IRQ_HANDLED;
}
static int i2c_wait(struct mpc_i2c *i2c, unsigned timeout, int writing)
{
unsigned long orig_jiffies = jiffies;
u32 x;
int result = 0;
if (i2c->irq == 0)
{
while (!(readb(i2c->base + MPC_I2C_SR) & CSR_MIF)) {
schedule();
if (time_after(jiffies, orig_jiffies + timeout)) {
pr_debug("I2C: timeout\n");
result = -EIO;
break;
}
}
x = readb(i2c->base + MPC_I2C_SR);
writeb(0, i2c->base + MPC_I2C_SR);
} else {
/* Interrupt mode */
result = wait_event_interruptible_timeout(i2c->queue,
(i2c->interrupt & CSR_MIF), timeout * HZ);
if (unlikely(result < 0))
pr_debug("I2C: wait interrupted\n");
else if (unlikely(!(i2c->interrupt & CSR_MIF))) {
pr_debug("I2C: wait timeout\n");
result = -ETIMEDOUT;
}
x = i2c->interrupt;
i2c->interrupt = 0;
}
if (result < 0)
return result;
if (!(x & CSR_MCF)) {
pr_debug("I2C: unfinished\n");
return -EIO;
}
if (x & CSR_MAL) {
pr_debug("I2C: MAL\n");
return -EIO;
}
if (writing && (x & CSR_RXAK)) {
pr_debug("I2C: No RXAK\n");
/* generate stop */
writeccr(i2c, CCR_MEN);
return -EIO;
}
return 0;
}
static void mpc_i2c_setclock(struct mpc_i2c *i2c)
{
/* Set clock and filters */
if (i2c->flags & FSL_I2C_DEV_SEPARATE_DFSRR) {
writeb(0x31, i2c->base + MPC_I2C_FDR);
writeb(0x10, i2c->base + MPC_I2C_DFSRR);
} else if (i2c->flags & FSL_I2C_DEV_CLOCK_5200)
writeb(0x3f, i2c->base + MPC_I2C_FDR);
else
writel(0x1031, i2c->base + MPC_I2C_FDR);
}
static void mpc_i2c_start(struct mpc_i2c *i2c)
{
/* Clear arbitration */
writeb(0, i2c->base + MPC_I2C_SR);
/* Start with MEN */
writeccr(i2c, CCR_MEN);
}
static void mpc_i2c_stop(struct mpc_i2c *i2c)
{
writeccr(i2c, CCR_MEN);
}
static int mpc_write(struct mpc_i2c *i2c, int target,
const u8 * data, int length, int restart)
{
int i;
unsigned timeout = i2c->adap.timeout;
u32 flags = restart ? CCR_RSTA : 0;
/* Start with MEN */
if (!restart)
writeccr(i2c, CCR_MEN);
/* Start as master */
writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_MTX | flags);
/* Write target byte */
writeb((target << 1), i2c->base + MPC_I2C_DR);
if (i2c_wait(i2c, timeout, 1) < 0)
return -1;
for (i = 0; i < length; i++) {
/* Write data byte */
writeb(data[i], i2c->base + MPC_I2C_DR);
if (i2c_wait(i2c, timeout, 1) < 0)
return -1;
}
return 0;
}
static int mpc_read(struct mpc_i2c *i2c, int target,
u8 * data, int length, int restart)
{
unsigned timeout = i2c->adap.timeout;
int i;
u32 flags = restart ? CCR_RSTA : 0;
/* Start with MEN */
if (!restart)
writeccr(i2c, CCR_MEN);
/* Switch to read - restart */
writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_MTX | flags);
/* Write target address byte - this time with the read flag set */
writeb((target << 1) | 1, i2c->base + MPC_I2C_DR);
if (i2c_wait(i2c, timeout, 1) < 0)
return -1;
if (length) {
if (length == 1)
writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_TXAK);
else
writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA);
/* Dummy read */
readb(i2c->base + MPC_I2C_DR);
}
for (i = 0; i < length; i++) {
if (i2c_wait(i2c, timeout, 0) < 0)
return -1;
/* Generate txack on next to last byte */
if (i == length - 2)
writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_TXAK);
/* Generate stop on last byte */
if (i == length - 1)
writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_TXAK);
data[i] = readb(i2c->base + MPC_I2C_DR);
}
return length;
}
static int mpc_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
{
struct i2c_msg *pmsg;
int i;
int ret = 0;
unsigned long orig_jiffies = jiffies;
struct mpc_i2c *i2c = i2c_get_adapdata(adap);
mpc_i2c_start(i2c);
/* Allow bus up to 1s to become not busy */
while (readb(i2c->base + MPC_I2C_SR) & CSR_MBB) {
if (signal_pending(current)) {
pr_debug("I2C: Interrupted\n");
return -EINTR;
}
if (time_after(jiffies, orig_jiffies + HZ)) {
pr_debug("I2C: timeout\n");
return -EIO;
}
schedule();
}
for (i = 0; ret >= 0 && i < num; i++) {
pmsg = &msgs[i];
pr_debug("Doing %s %d bytes to 0x%02x - %d of %d messages\n",
pmsg->flags & I2C_M_RD ? "read" : "write",
pmsg->len, pmsg->addr, i + 1, num);
if (pmsg->flags & I2C_M_RD)
ret =
mpc_read(i2c, pmsg->addr, pmsg->buf, pmsg->len, i);
else
ret =
mpc_write(i2c, pmsg->addr, pmsg->buf, pmsg->len, i);
}
mpc_i2c_stop(i2c);
return (ret < 0) ? ret : num;
}
static u32 mpc_functionality(struct i2c_adapter *adap)
{
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}
static struct i2c_algorithm mpc_algo = {
.name = "MPC algorithm",
.id = I2C_ALGO_MPC107,
.master_xfer = mpc_xfer,
.functionality = mpc_functionality,
};
static struct i2c_adapter mpc_ops = {
.owner = THIS_MODULE,
.name = "MPC adapter",
.id = I2C_ALGO_MPC107 | I2C_HW_MPC107,
.algo = &mpc_algo,
.class = I2C_CLASS_HWMON,
.timeout = 1,
.retries = 1
};
#ifdef CONFIG_FSL_OCP
static int __devinit mpc_i2c_probe(struct ocp_device *ocp)
{
int result = 0;
struct mpc_i2c *i2c;
if (!(i2c = kmalloc(sizeof(*i2c), GFP_KERNEL))) {
return -ENOMEM;
}
memset(i2c, 0, sizeof(*i2c));
i2c->irq = ocp->def->irq;
i2c->flags = ((struct ocp_fs_i2c_data *)ocp->def->additions)->flags;
init_waitqueue_head(&i2c->queue);
if (!request_mem_region(ocp->def->paddr, MPC_I2C_REGION, "i2c-mpc")) {
printk(KERN_ERR "i2c-mpc - resource unavailable\n");
return -ENODEV;
}
i2c->base = ioremap(ocp->def->paddr, MPC_I2C_REGION);
if (!i2c->base) {
printk(KERN_ERR "i2c-mpc - failed to map controller\n");
result = -ENOMEM;
goto fail_map;
}
if (i2c->irq != OCP_IRQ_NA)
{
if ((result = request_irq(ocp->def->irq, mpc_i2c_isr,
SA_SHIRQ, "i2c-mpc", i2c)) < 0) {
printk(KERN_ERR
"i2c-mpc - failed to attach interrupt\n");
goto fail_irq;
}
} else
i2c->irq = 0;
mpc_i2c_setclock(i2c);
ocp_set_drvdata(ocp, i2c);
i2c->adap = mpc_ops;
i2c_set_adapdata(&i2c->adap, i2c);
if ((result = i2c_add_adapter(&i2c->adap)) < 0) {
printk(KERN_ERR "i2c-mpc - failed to add adapter\n");
goto fail_add;
}
return result;
fail_add:
if (ocp->def->irq != OCP_IRQ_NA)
free_irq(ocp->def->irq, 0);
fail_irq:
iounmap(i2c->base);
fail_map:
release_mem_region(ocp->def->paddr, MPC_I2C_REGION);
kfree(i2c);
return result;
}
static void __devexit mpc_i2c_remove(struct ocp_device *ocp)
{
struct mpc_i2c *i2c = ocp_get_drvdata(ocp);
i2c_del_adapter(&i2c->adap);
ocp_set_drvdata(ocp, NULL);
if (ocp->def->irq != OCP_IRQ_NA)
free_irq(i2c->irq, i2c);
iounmap(i2c->base);
release_mem_region(ocp->def->paddr, MPC_I2C_REGION);
kfree(i2c);
}
static struct ocp_device_id mpc_iic_ids[] __devinitdata = {
{.vendor = OCP_VENDOR_FREESCALE,.function = OCP_FUNC_IIC},
{.vendor = OCP_VENDOR_INVALID}
};
MODULE_DEVICE_TABLE(ocp, mpc_iic_ids);
static struct ocp_driver mpc_iic_driver = {
.name = "iic",
.id_table = mpc_iic_ids,
.probe = mpc_i2c_probe,
.remove = __devexit_p(mpc_i2c_remove)
};
static int __init iic_init(void)
{
return ocp_register_driver(&mpc_iic_driver);
}
static void __exit iic_exit(void)
{
ocp_unregister_driver(&mpc_iic_driver);
}
module_init(iic_init);
module_exit(iic_exit);
#else
static int fsl_i2c_probe(struct device *device)
{
int result = 0;
struct mpc_i2c *i2c;
struct platform_device *pdev = to_platform_device(device);
struct fsl_i2c_platform_data *pdata;
struct resource *r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
pdata = (struct fsl_i2c_platform_data *) pdev->dev.platform_data;
if (!(i2c = kmalloc(sizeof(*i2c), GFP_KERNEL))) {
return -ENOMEM;
}
memset(i2c, 0, sizeof(*i2c));
i2c->irq = platform_get_irq(pdev, 0);
i2c->flags = pdata->device_flags;
init_waitqueue_head(&i2c->queue);
i2c->base = ioremap((phys_addr_t)r->start, MPC_I2C_REGION);
if (!i2c->base) {
printk(KERN_ERR "i2c-mpc - failed to map controller\n");
result = -ENOMEM;
goto fail_map;
}
if (i2c->irq != 0)
if ((result = request_irq(i2c->irq, mpc_i2c_isr,
SA_SHIRQ, "i2c-mpc", i2c)) < 0) {
printk(KERN_ERR
"i2c-mpc - failed to attach interrupt\n");
goto fail_irq;
}
mpc_i2c_setclock(i2c);
dev_set_drvdata(device, i2c);
i2c->adap = mpc_ops;
i2c_set_adapdata(&i2c->adap, i2c);
i2c->adap.dev.parent = &pdev->dev;
if ((result = i2c_add_adapter(&i2c->adap)) < 0) {
printk(KERN_ERR "i2c-mpc - failed to add adapter\n");
goto fail_add;
}
return result;
fail_add:
if (i2c->irq != 0)
free_irq(i2c->irq, NULL);
fail_irq:
iounmap(i2c->base);
fail_map:
kfree(i2c);
return result;
};
static int fsl_i2c_remove(struct device *device)
{
struct mpc_i2c *i2c = dev_get_drvdata(device);
i2c_del_adapter(&i2c->adap);
dev_set_drvdata(device, NULL);
if (i2c->irq != 0)
free_irq(i2c->irq, i2c);
iounmap(i2c->base);
kfree(i2c);
return 0;
};
/* Structure for a device driver */
static struct device_driver fsl_i2c_driver = {
.name = "fsl-i2c",
.bus = &platform_bus_type,
.probe = fsl_i2c_probe,
.remove = fsl_i2c_remove,
};
static int __init fsl_i2c_init(void)
{
return driver_register(&fsl_i2c_driver);
}
static void __exit fsl_i2c_exit(void)
{
driver_unregister(&fsl_i2c_driver);
}
module_init(fsl_i2c_init);
module_exit(fsl_i2c_exit);
#endif /* CONFIG_FSL_OCP */
MODULE_AUTHOR("Adrian Cox <adrian@humboldt.co.uk>");
MODULE_DESCRIPTION
("I2C-Bus adapter for MPC107 bridge and MPC824x/85xx/52xx processors");
MODULE_LICENSE("GPL");
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