The Exynos Chip ID driver on Exynos SoCs has so far only informational
purpose - to expose the SoC device in sysfs. No other drivers depend on
it so there is really no benefit of initializing it early.
The code would be the most flexible if converted to a regular driver.
However there is already another driver - Exynos ASV (Adaptive Supply
Voltage) - which binds to the device node of Chip ID.
The solution is to convert the Exynos Chip ID to a built in driver and
merge the Exynos ASV into it.
This has several benefits:
1. Although the Exynos ASV driver binds to a device node present in all
Exynos DTS (generic compatible), it fails to probe except on the
supported ones (only Exynos5422). This means that the regular boot
process has a planned/normal device probe failure.
Merging the ASV into Chip ID will remove this probe failure because
the final driver will always bind, just with disabled ASV features.
2. Allows to use dev_info() as the SoC bus is present (since
core_initcall).
3. Could speed things up because of execution of Chip ID code in a SMP
environment (after bringing up secondary CPUs, unlike early_initcall),
This reduces the amount of work to be done early, when the kernel has
to bring up critical devices.
5. Makes the Chip ID code defer-probe friendly,
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20201207190517.262051-5-krzk@kernel.org
Reviewed-by: Pankaj Dubey <pankaj.dubey@samsung.com>
If regmap_read() fails, the product_id local variable will contain
random value from the stack. Do not try to parse such value and fail
the ASV driver probe.
Fixes: 5ea428595c ("soc: samsung: Add Exynos Adaptive Supply Voltage driver")
Cc: <stable@vger.kernel.org>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Pankaj Dubey <pankaj.dubey@samsung.com>
Link: https://lore.kernel.org/r/20201207190517.262051-3-krzk@kernel.org
Check if the SoC is really supported before gathering the needed
resources. This fixes endless deferred probe on some SoCs other than
Exynos5422 (like Exynos5410).
Fixes: 5ea428595c ("soc: samsung: Add Exynos Adaptive Supply Voltage driver")
Cc: <stable@vger.kernel.org>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Pankaj Dubey <pankaj.dubey@samsung.com>
Link: https://lore.kernel.org/r/20201207190517.262051-2-krzk@kernel.org
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
The OPP core manages various resources, e.g. clocks or interconnect paths.
These resources are looked up when the OPP table is allocated once
dev_pm_opp_get_opp_table() is called the first time (either directly
or indirectly through one of the many helper functions).
At this point, the resources may not be available yet, i.e. looking them
up will result in -EPROBE_DEFER. Unfortunately, dev_pm_opp_get_opp_table()
is currently unable to propagate this error code since it only returns
the allocated OPP table or NULL.
This means that all consumers of the OPP core are required to make sure
that all necessary resources are available. Usually this happens by
requesting them, checking the result and releasing them immediately after.
For example, we have added "dev_pm_opp_of_find_icc_paths(dev, NULL)" to
several drivers now just to make sure the interconnect providers are
ready before the OPP table is allocated. If this call is missing,
the OPP core will only warn about this and then attempt to continue
without interconnect. This will eventually fail horribly, e.g.:
cpu cpu0: _allocate_opp_table: Error finding interconnect paths: -517
... later ...
of: _read_bw: Mismatch between opp-peak-kBps and paths (1 0)
cpu cpu0: _opp_add_static_v2: opp key field not found
cpu cpu0: _of_add_opp_table_v2: Failed to add OPP, -22
This example happens when trying to use interconnects for a CPU OPP
table together with qcom-cpufreq-nvmem.c. qcom-cpufreq-nvmem calls
dev_pm_opp_set_supported_hw(), which ends up allocating the OPP table
early. To fix the problem with the current approach we would need to add
yet another call to dev_pm_opp_of_find_icc_paths(dev, NULL).
But actually qcom-cpufreq-nvmem.c has nothing to do with interconnects...
This commit attempts to make this more robust by allowing
dev_pm_opp_get_opp_table() to return an error pointer. Fixing all
the usages is trivial because the function is usually used indirectly
through another helper (e.g. dev_pm_opp_set_supported_hw() above).
These other helpers already return an error pointer.
The example above then works correctly because set_supported_hw() will
return -EPROBE_DEFER, and qcom-cpufreq-nvmem.c already propagates that
error. It should also be possible to remove the remaining usages of
"dev_pm_opp_of_find_icc_paths(dev, NULL)" from other drivers as well.
Note that this commit currently only handles -EPROBE_DEFER for the
clock/interconnects within _allocate_opp_table(). Other errors are just
ignored as before. Eventually those should be propagated as well.
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Acked-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
[ Viresh: skip checking return value of dev_pm_opp_get_opp_table() for
EPROBE_DEFER in domain.c, fix NULL return value and reorder
code a bit in core.c, and update exynos-asv.c ]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
The dev_pm_opp_get_opp_table() returns error pointers if it's disabled
in the config and it returns NULL if there is an error. This code only
checks for error pointers so it could lead to an Oops inside the
dev_pm_opp_put_opp_table() function.
Fixes: 5ea428595c ("soc: samsung: Add Exynos Adaptive Supply Voltage driver")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
The Adaptive Supply Voltage (ASV) driver adjusts CPU cluster operating
points depending on exact revision of an SoC retrieved from the CHIPID
block or the OTP memory. This allows for some power saving as for some
CPU clock frequencies we can lower CPU cluster's supply voltage comparing
to safe values common to all the SoC revisions.
This patch adds support for Exynos5422/5800 SoC, it is partially based
on code from https://github.com/hardkernel/linux repository,
branch odroidxu4-4.14.y, files: arch/arm/mach-exynos/exynos5422-asv.[ch].
Tested on Odroid XU3, XU4, XU3 Lite.
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
