Rename exynos850_register_cmu to exynos_arm64_register_cmu and move it
to a new file called "clk-exynos-arm64.c".
This should have no functional changes, but it will allow this code to
be shared between other arm64 Exynos SoCs, like the Exynos7885 and
possibly ExynosAuto V9.
Signed-off-by: David Virag <virag.david003@gmail.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Reviewed-by: Sam Protsenko <semen.protsenko@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Link: https://lore.kernel.org/r/20211206153124.427102-5-virag.david003@gmail.com
System Register is used to configure system behavior, like USI protocol,
etc. SYSREG clocks should be provided to corresponding syscon nodes, to
make it possible to modify SYSREG registers.
While at it, add also missing PMU and GPIO clocks, which looks necessary
and might be needed for corresponding Exynos850 features soon.
Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
Link: https://lore.kernel.org/r/20211217161549.24836-3-semen.protsenko@linaro.org
Some clocks must be registered before init calls. For example MCT clock
(from CMU_PERI) is needed for MCT timer driver, which is registered
with TIMER_OF_DECLARE(). By the time we get to core_initcall() used for
clk-exynos850 platform driver init, it's already too late. Inability to
get "mct" clock in MCT driver leads to kernel panic, as functions
registered with *_OF_DECLARE() can't do deferred calls. MCT timer driver
can't be fixed either, as it's acting as a clock source and it's
essential to register it in start_kernel() -> time_init().
Let's register CMU_PERI clocks early, using CLK_OF_DECLARE(). CMU_TOP
generates clocks needed for CMU_PERI, but it's already registered early.
While at it, let's cleanup the code a bit, by extracting everything
related to CMU initialization and registration to the separate function.
Similar issue was discussed at [1] and addressed in commit 1f7db7bbf0
("clk: renesas: cpg-mssr: Add early clock support"), as well as in
drivers/clk/mediatek/clk-mt2712.c.
[1] https://patchwork.kernel.org/project/linux-renesas-soc/patch/20180829132954.64862-2-chris.brandt@renesas.com/
Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Link: https://lore.kernel.org/r/20211122144206.23134-1-semen.protsenko@linaro.org
Some clocks shouldn't be automatically disabled in clk_disable_unused(),
otherwise kernel hangs. Mark those clocks with:
- CLK_IS_CRITICAL flag, when there won't be any consumers for that
clock, but system can't function when it's gated
- CLK_IGNORE_UNUSED flag, when consumer driver will be probably added
later
That makes it possible to run the kernel without passing the
"clk_ignore_unused" param.
Next clocks were modified:
- "gout_dpu_cmu_dpu_pclk": CLK_IGNORE_UNUSED
Will be enabled later in DSIM driver (Display Serial Interface
Master).
- "gout_gpio_peri_pclk": CLK_IGNORE_UNUSED
"gout_gpio_cmgp_pclk": CLK_IGNORE_UNUSED
"gout_gpio_hsi_pclk": CLK_IGNORE_UNUSED
Should be probably enabled in corresponding GPIO driver later, or
made CLK_IS_CRITICAL. "gout_gpio_peri_clk" is actually used by LEDs
on Exynos850-based dev board, so kernel hangs if this clock is not
running. Other clocks were marked as "ignore unused" to prevent
similar issues for other use cases or boards that might be added
later.
- "gout_cci_aclk": CLK_IS_CRITICAL
CCI (Cache Coherent Interconnect): obviously is critical.
- "gout_gic_clk": CLK_IS_CRITICAL
GIC (Generic Interrupt Controller): obviously is critical.
Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Link: https://lore.kernel.org/r/20211121232741.6967-7-semen.protsenko@linaro.org
CMU_CMGP clock domain provides clocks for CMGP IP-core (Common GPIO).
CMGP module encapsulates next blocks:
- 8 GPIO lines
- 1 GPADC
- 2 USI blocks, each can be configured to provide one of
UART/SPI/HSI2C serial interfaces
Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Link: https://lore.kernel.org/r/20211121232741.6967-5-semen.protsenko@linaro.org
CMU_APM clock domain provides clocks for APM IP-core (Active Power
Management). According to Exynos850 TRM, CMU_APM generates I3C, Mailbox,
Speedy, Timer, WDT, RTC and PMU clocks for BLK_ALIVE.
This patch adds next clocks:
- bus clocks in CMU_TOP needed for CMU_APM
- all internal CMU_APM clocks
- leaf clocks for I3C, Speedy and RTC IP-cores
- bus clocks for CMU_CMGP and CMU_CHUB
CMU_APM doesn't belong to Power Domains, but platform driver is used for
its registration to keep its bus clock always running. Otherwise rtc-s3c
driver disables that clock and system freezes.
Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
Link: https://lore.kernel.org/r/20211121232741.6967-3-semen.protsenko@linaro.org
This is the initial implementation adding only basic clocks like UART,
MMC, I2C and corresponding parent clocks. Design is influenced by
Exynos5433 clock driver.
Bus clock is enabled by default (in probe function) for all CMUs except
CMU_TOP, the reasoning is as follows. By default if bus clock has no
users its "enable count" value is 0. It might be actually running if
it's already enabled in bootloader, but then in some cases it can be
disabled by mistake. For example, such case was observed when
dw_mci_probe() enabled the bus clock, then failed to do something and
disabled that bus clock on error path. After that, even the attempt to
read the 'clk_summary' file in DebugFS freezed forever, as CMU bus clock
ended up being disabled and it wasn't possible to access CMU registers
anymore.
To avoid such cases, CMU driver must increment the ref count for that
bus clock by running clk_prepare_enable(). There is already existing
'.clk_name' field in struct samsung_cmu_info, exactly for that reason.
It was added in commit 523d3de41f ("clk: samsung: exynos5433: Add
support for runtime PM"), with next mentioning in commit message:
> Also for each CMU there is one special parent clock, which has to be
> enabled all the time when any access to CMU registers is being done.
But that clock is actually only enabled in Exynos5433 clock driver right
now. So the same code is added to exynos850_cmu_probe() function,
As was described above, it might be helpful not only for PM reasons, but
also to prevent possible erroneous clock gating on error paths.
Another way to workaround that issue would be to use CLOCK_IS_CRITICAL
flag for corresponding gate clocks. But that might be not very good
design decision, as we might still want to disable that bus clock, e.g.
on PM suspend.
Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
Link: https://lore.kernel.org/r/20211008154352.19519-6-semen.protsenko@linaro.org
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
David Virag
Sam Protsenko