linux/drivers/amba
Saravana Kannan f2d3b9a46e ARM: 9220/1: amba: Remove deferred device addition
The uevents generated for an amba device need PID and CID information
that's available only when the amba device is powered on, clocked and
out of reset. So, if those resources aren't available, the information
can't be read to generate the uevents. To workaround this requirement,
if the resources weren't available, the device addition was deferred and
retried periodically.

However, this deferred addition retry isn't based on resources becoming
available. Instead, it's retried every 5 seconds and causes arbitrary
probe delays for amba devices and their consumers.

Also, maintaining a separate deferred-probe like mechanism is
maintenance headache.

With this commit, instead of deferring the device addition, we simply
defer the generation of uevents for the device and probing of the device
(because drivers needs PID and CID to match) until the PID and CID
information can be read. This allows us to delete all the amba specific
deferring code and also avoid the arbitrary probing delays.

Cc: Rob Herring <robh@kernel.org>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Saravana Kannan <saravanak@google.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Nicolas Saenz Julienne <nsaenz@kernel.org>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: patches@armlinux.org.uk
Signed-off-by: Saravana Kannan <saravanak@google.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Tested-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
2022-07-28 15:09:23 +01:00
..
bus.c ARM: 9220/1: amba: Remove deferred device addition 2022-07-28 15:09:23 +01:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Makefile treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
tegra-ahb.c ARM: tegra: Replace zero-length array with flexible-array 2020-06-15 23:08:28 -05:00