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authorRob Herring <robh@kernel.org>2020-04-29 15:58:12 -0500
committerRob Herring <robh@kernel.org>2020-05-05 11:43:01 -0500
commit039599c92d3b2e73689e8b6e519d653fd4770abb (patch)
treee0acc2f0d6b7d981eec7186a04de3a61069f625e /drivers/amba
parent6aec54a649576e59d20c7ed0b3f000b8b5dff56b (diff)
amba: Retry adding deferred devices at late_initcall
If amba bus devices defer when adding, the amba bus code simply retries adding the devices every 5 seconds. This doesn't work well as it completely unsynchronized with starting the init process which can happen in less than 5 secs. Add a retry during late_initcall. If the amba devices are added, then deferred probe takes over. If the dependencies have not probed at this point, then there's no improvement over previous behavior. To completely solve this, we'd need to retry after every successful probe as deferred probe does. The list_empty() check now happens outside the mutex, but the mutex wasn't necessary in the first place. This needed to use deferred probe instead of fragile initcall ordering on 32-bit VExpress systems where the apb_pclk has a number of probe dependencies (vexpress-sysregs, vexpress-config). Cc: John Stultz <john.stultz@linaro.org> Cc: Saravana Kannan <saravanak@google.com> Cc: Nicolas Saenz Julienne <nsaenzjulienne@suse.de> Cc: Geert Uytterhoeven <geert+renesas@glider.be> Cc: Russell King <linux@armlinux.org.uk> Tested-by: Sudeep Holla <sudeep.holla@arm.com> Reviewed-by: Sudeep Holla <sudeep.holla@arm.com> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Rob Herring <robh@kernel.org>
Diffstat (limited to 'drivers/amba')
-rw-r--r--drivers/amba/bus.c14
1 files changed, 11 insertions, 3 deletions
diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c
index fe1523664816..e797995fc65b 100644
--- a/drivers/amba/bus.c
+++ b/drivers/amba/bus.c
@@ -505,7 +505,7 @@ static DECLARE_DELAYED_WORK(deferred_retry_work, amba_deferred_retry_func);
#define DEFERRED_DEVICE_TIMEOUT (msecs_to_jiffies(5 * 1000))
-static void amba_deferred_retry_func(struct work_struct *dummy)
+static int amba_deferred_retry(void)
{
struct deferred_device *ddev, *tmp;
@@ -521,11 +521,19 @@ static void amba_deferred_retry_func(struct work_struct *dummy)
kfree(ddev);
}
+ mutex_unlock(&deferred_devices_lock);
+
+ return 0;
+}
+late_initcall(amba_deferred_retry);
+
+static void amba_deferred_retry_func(struct work_struct *dummy)
+{
+ amba_deferred_retry();
+
if (!list_empty(&deferred_devices))
schedule_delayed_work(&deferred_retry_work,
DEFERRED_DEVICE_TIMEOUT);
-
- mutex_unlock(&deferred_devices_lock);
}
/**