i2c: gpio: fault-injector: add 'inject_panic' injector

Add a fault injector simulating a Kernel panic happening after starting
a transfer. Read the docs for its usage.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

1 files changed, 30 insertions, 1 deletions

diff --git a/drivers/i2c/busses/i2c-gpio.c b/drivers/i2c/busses/i2c-gpio.c
index 76e43783f50f..bba5c4627de3 100644
--- a/drivers/i2c/busses/i2c-gpio.c
+++ b/drivers/i2c/busses/i2c-gpio.c
@@ -231,6 +231,32 @@ static int fops_lose_arbitration_set(void *data, u64 duration)
 }
 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);
@@ -256,9 +282,12 @@ static void i2c_gpio_fault_injector_init(struct platform_device *pdev)
                                    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)
+        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);
 }