diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-gpio.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-gpio.c | 134 |
1 files changed, 115 insertions, 19 deletions
diff --git a/drivers/i2c/busses/i2c-gpio.c b/drivers/i2c/busses/i2c-gpio.c index c008d209f0b8..bba5c4627de3 100644 --- a/drivers/i2c/busses/i2c-gpio.c +++ b/drivers/i2c/busses/i2c-gpio.c @@ -7,17 +7,19 @@ * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ +#include <linux/completion.h> #include <linux/debugfs.h> #include <linux/delay.h> -#include <linux/i2c.h> +#include <linux/gpio/consumer.h> #include <linux/i2c-algo-bit.h> -#include <linux/platform_data/i2c-gpio.h> +#include <linux/i2c.h> #include <linux/init.h> +#include <linux/interrupt.h> #include <linux/module.h> -#include <linux/slab.h> -#include <linux/platform_device.h> -#include <linux/gpio/consumer.h> #include <linux/of.h> +#include <linux/platform_data/i2c-gpio.h> +#include <linux/platform_device.h> +#include <linux/slab.h> struct i2c_gpio_private_data { struct gpio_desc *sda; @@ -27,6 +29,9 @@ struct i2c_gpio_private_data { struct i2c_gpio_platform_data pdata; #ifdef CONFIG_I2C_GPIO_FAULT_INJECTOR struct dentry *debug_dir; + /* these must be protected by bus lock */ + struct completion scl_irq_completion; + u64 scl_irq_data; #endif }; @@ -162,6 +167,96 @@ static int fops_incomplete_write_byte_set(void *data, u64 addr) } DEFINE_DEBUGFS_ATTRIBUTE(fops_incomplete_write_byte, NULL, fops_incomplete_write_byte_set, "%llu\n"); +static int i2c_gpio_fi_act_on_scl_irq(struct i2c_gpio_private_data *priv, + irqreturn_t handler(int, void*)) +{ + int ret, irq = gpiod_to_irq(priv->scl); + + if (irq < 0) + return irq; + + i2c_lock_bus(&priv->adap, I2C_LOCK_ROOT_ADAPTER); + + ret = gpiod_direction_input(priv->scl); + if (ret) + goto unlock; + + reinit_completion(&priv->scl_irq_completion); + + ret = request_irq(irq, handler, IRQF_TRIGGER_FALLING, + "i2c_gpio_fault_injector_scl_irq", priv); + if (ret) + goto output; + + wait_for_completion_interruptible(&priv->scl_irq_completion); + + free_irq(irq, priv); + output: + ret = gpiod_direction_output(priv->scl, 1) ?: ret; + unlock: + i2c_unlock_bus(&priv->adap, I2C_LOCK_ROOT_ADAPTER); + + return ret; +} + +static irqreturn_t lose_arbitration_irq(int irq, void *dev_id) +{ + struct i2c_gpio_private_data *priv = dev_id; + + setsda(&priv->bit_data, 0); + udelay(priv->scl_irq_data); + setsda(&priv->bit_data, 1); + + complete(&priv->scl_irq_completion); + + return IRQ_HANDLED; +} + +static int fops_lose_arbitration_set(void *data, u64 duration) +{ + struct i2c_gpio_private_data *priv = data; + + if (duration > 100 * 1000) + return -EINVAL; + + priv->scl_irq_data = duration; + /* + * Interrupt on falling SCL. This ensures that the master under test has + * really started the transfer. Interrupt on falling SDA did only + * exercise 'bus busy' detection on some HW but not 'arbitration lost'. + * Note that the interrupt latency may cause the first bits to be + * transmitted correctly. + */ + return i2c_gpio_fi_act_on_scl_irq(priv, lose_arbitration_irq); +} +DEFINE_DEBUGFS_ATTRIBUTE(fops_lose_arbitration, NULL, fops_lose_arbitration_set, "%llu\n"); + +static irqreturn_t inject_panic_irq(int irq, void *dev_id) +{ + struct i2c_gpio_private_data *priv = dev_id; + + udelay(priv->scl_irq_data); + panic("I2C fault injector induced panic"); + + return IRQ_HANDLED; +} + +static int fops_inject_panic_set(void *data, u64 duration) +{ + struct i2c_gpio_private_data *priv = data; + + if (duration > 100 * 1000) + return -EINVAL; + + priv->scl_irq_data = duration; + /* + * Interrupt on falling SCL. This ensures that the master under test has + * really started the transfer. + */ + return i2c_gpio_fi_act_on_scl_irq(priv, inject_panic_irq); +} +DEFINE_DEBUGFS_ATTRIBUTE(fops_inject_panic, NULL, fops_inject_panic_set, "%llu\n"); + static void i2c_gpio_fault_injector_init(struct platform_device *pdev) { struct i2c_gpio_private_data *priv = platform_get_drvdata(pdev); @@ -181,12 +276,20 @@ static void i2c_gpio_fault_injector_init(struct platform_device *pdev) if (!priv->debug_dir) return; - debugfs_create_file_unsafe("scl", 0600, priv->debug_dir, priv, &fops_scl); - debugfs_create_file_unsafe("sda", 0600, priv->debug_dir, priv, &fops_sda); + init_completion(&priv->scl_irq_completion); + debugfs_create_file_unsafe("incomplete_address_phase", 0200, priv->debug_dir, priv, &fops_incomplete_addr_phase); debugfs_create_file_unsafe("incomplete_write_byte", 0200, priv->debug_dir, priv, &fops_incomplete_write_byte); + if (priv->bit_data.getscl) { + debugfs_create_file_unsafe("inject_panic", 0200, priv->debug_dir, + priv, &fops_inject_panic); + debugfs_create_file_unsafe("lose_arbitration", 0200, priv->debug_dir, + priv, &fops_lose_arbitration); + } + debugfs_create_file_unsafe("scl", 0600, priv->debug_dir, priv, &fops_scl); + debugfs_create_file_unsafe("sda", 0600, priv->debug_dir, priv, &fops_sda); } static void i2c_gpio_fault_injector_exit(struct platform_device *pdev) @@ -286,11 +389,11 @@ static int i2c_gpio_probe(struct platform_device *pdev) /* * First get the GPIO pins; if it fails, we'll defer the probe. - * If the SDA line is marked from platform data or device tree as - * "open drain" it means something outside of our control is making - * this line being handled as open drain, and we should just handle - * it as any other output. Else we enforce open drain as this is - * required for an I2C bus. + * If the SCL/SDA lines are marked "open drain" by platform data or + * device tree then this means that something outside of our control is + * marking these lines to be handled as open drain, and we should just + * handle them as we handle any other output. Else we enforce open + * drain as this is required for an I2C bus. */ if (pdata->sda_is_open_drain) gflags = GPIOD_OUT_HIGH; @@ -300,13 +403,6 @@ static int i2c_gpio_probe(struct platform_device *pdev) if (IS_ERR(priv->sda)) return PTR_ERR(priv->sda); - /* - * If the SCL line is marked from platform data or device tree as - * "open drain" it means something outside of our control is making - * this line being handled as open drain, and we should just handle - * it as any other output. Else we enforce open drain as this is - * required for an I2C bus. - */ if (pdata->scl_is_open_drain) gflags = GPIOD_OUT_HIGH; else |