wimax/i2400m: don't retry SDIO enable in probe() paths
The iwmc3200 has a quirk where retrying SDIO enable during the probe()
path causes bad interactions with the TOP function controller that
causes a reset storm. The workaround is simply not to retry an SDIO
enable in said path (and still do in the reset / reinitialization
paths).
The driver does so by checking i2400ms->debugfs_dentry to see if it
has been initialized; if not, it is in the probe() path. Document said
fact in i2400ms->debugfs_entry.
Signed-off-by: Inaky Perez-Gonzalez <inaky@linux.intel.com>
diff --git a/drivers/net/wimax/i2400m/i2400m-sdio.h b/drivers/net/wimax/i2400m/i2400m-sdio.h
index fba482c..b9c4bed 100644
--- a/drivers/net/wimax/i2400m/i2400m-sdio.h
+++ b/drivers/net/wimax/i2400m/i2400m-sdio.h
@@ -100,6 +100,14 @@
* @tx_workqueue: workqeueue used for data TX; we don't use the
* system's workqueue as that might cause deadlocks with code in
* the bus-generic driver.
+ *
+ * @debugfs_dentry: dentry for the SDIO specific debugfs files
+ *
+ * Note this value is set to NULL upon destruction; this is
+ * because some routinges use it to determine if we are inside the
+ * probe() path or some other path. When debugfs is disabled,
+ * creation sets the dentry to '(void*) -ENODEV', which is valid
+ * for the test.
*/
struct i2400ms {
struct i2400m i2400m; /* FIRST! See doc */
diff --git a/drivers/net/wimax/i2400m/sdio.c b/drivers/net/wimax/i2400m/sdio.c
index 079f900..e8ad85c 100644
--- a/drivers/net/wimax/i2400m/sdio.c
+++ b/drivers/net/wimax/i2400m/sdio.c
@@ -159,6 +159,10 @@
/*
* Setup minimal device communication infrastructure needed to at
* least be able to update the firmware.
+ *
+ * Note the ugly trick: if we are in the probe path
+ * (i2400ms->debugfs_dentry == NULL), we only retry function
+ * enablement one, to avoid racing with the iwmc3200 top controller.
*/
static
int i2400ms_bus_setup(struct i2400m *i2400m)
@@ -168,6 +172,7 @@
container_of(i2400m, struct i2400ms, i2400m);
struct device *dev = i2400m_dev(i2400m);
struct sdio_func *func = i2400ms->func;
+ int retries;
sdio_claim_host(func);
result = sdio_set_block_size(func, I2400MS_BLK_SIZE);
@@ -177,7 +182,11 @@
goto error_set_blk_size;
}
- result = i2400ms_enable_function(i2400ms, 1);
+ if (i2400ms->iwmc3200 && i2400ms->debugfs_dentry == NULL)
+ retries = 0;
+ else
+ retries = 1;
+ result = i2400ms_enable_function(i2400ms, retries);
if (result < 0) {
dev_err(dev, "Cannot enable SDIO function: %d\n", result);
goto error_func_enable;
@@ -415,6 +424,7 @@
error:
debugfs_remove_recursive(i2400ms->debugfs_dentry);
+ i2400ms->debugfs_dentry = NULL;
return result;
}
@@ -531,6 +541,7 @@
d_fnstart(3, dev, "SDIO func %p\n", func);
debugfs_remove_recursive(i2400ms->debugfs_dentry);
+ i2400ms->debugfs_dentry = NULL;
i2400m_release(i2400m);
sdio_set_drvdata(func, NULL);
free_netdev(net_dev);
