From: Sam Protsenko <semen.protsenko@linaro.org> To: "Krzysztof Kozlowski" <krzysztof.kozlowski@canonical.com>, "Sylwester Nawrocki" <s.nawrocki@samsung.com>, "Paweł Chmiel" <pawel.mikolaj.chmiel@gmail.com>, "Chanwoo Choi" <cw00.choi@samsung.com>, "Tomasz Figa" <tomasz.figa@gmail.com>, "Rob Herring" <robh+dt@kernel.org>, "Stephen Boyd" <sboyd@kernel.org>, "Michael Turquette" <mturquette@baylibre.com> Cc: Sumit Semwal <sumit.semwal@linaro.org>, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org, linux-samsung-soc@vger.kernel.org Subject: [PATCH v2 1/1] clk: samsung: exynos850: Register clocks early Date: Mon, 25 Oct 2021 19:12:54 +0300 [thread overview] Message-ID: <20211025161254.5575-1-semen.protsenko@linaro.org> (raw) 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_DRIVER(), and do all stuff relying on "struct dev" object (like runtime PM and enabling bus clock) later in platform driver probe. Basically CLK_OF_DECLARE_DRIVER() matches CMU compatible, but clears OF_POPULATED flag, which allows the same device to be matched again later. Similar issue was discussed at [1] and addressed in commit 1f7db7bbf031 ("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> --- Changes in v2: - Register only CMU_PERI clocks early Notes: - This patch should be applied on top of CMU_APM series (clk: samsung: exynos850: Implement CMU_APM domain) drivers/clk/samsung/clk-exynos850.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff --git a/drivers/clk/samsung/clk-exynos850.c b/drivers/clk/samsung/clk-exynos850.c index 95e373d17b42..ecffa5c7a081 100644 --- a/drivers/clk/samsung/clk-exynos850.c +++ b/drivers/clk/samsung/clk-exynos850.c @@ -753,6 +753,15 @@ static const struct samsung_cmu_info peri_cmu_info __initconst = { .clk_name = "dout_peri_bus", }; +static void __init exynos850_cmu_peri_init(struct device_node *np) +{ + exynos850_init_clocks(np, peri_clk_regs, ARRAY_SIZE(peri_clk_regs)); + samsung_cmu_register_one(np, &peri_cmu_info); +} + +CLK_OF_DECLARE_DRIVER(exynos850_cmu_peri, "samsung,exynos850-cmu-peri", + exynos850_cmu_peri_init); + /* ---- CMU_CORE ------------------------------------------------------------ */ /* Register Offset definitions for CMU_CORE (0x12000000) */ @@ -920,8 +929,12 @@ static int __init exynos850_cmu_probe(struct platform_device *pdev) struct device_node *np = dev->of_node; info = of_device_get_match_data(dev); - exynos850_init_clocks(np, info->clk_regs, info->nr_clk_regs); - samsung_cmu_register_one(np, info); + + /* Early clocks are already registered using CLK_OF_DECLARE_DRIVER() */ + if (info != &peri_cmu_info) { + exynos850_init_clocks(np, info->clk_regs, info->nr_clk_regs); + samsung_cmu_register_one(np, info); + } /* Keep bus clock running, so it's possible to access CMU registers */ if (info->clk_name) { -- 2.30.2
WARNING: multiple messages have this Message-ID (diff)
From: Sam Protsenko <semen.protsenko@linaro.org> To: "Krzysztof Kozlowski" <krzysztof.kozlowski@canonical.com>, "Sylwester Nawrocki" <s.nawrocki@samsung.com>, "Paweł Chmiel" <pawel.mikolaj.chmiel@gmail.com>, "Chanwoo Choi" <cw00.choi@samsung.com>, "Tomasz Figa" <tomasz.figa@gmail.com>, "Rob Herring" <robh+dt@kernel.org>, "Stephen Boyd" <sboyd@kernel.org>, "Michael Turquette" <mturquette@baylibre.com> Cc: Sumit Semwal <sumit.semwal@linaro.org>, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org, linux-samsung-soc@vger.kernel.org Subject: [PATCH v2 1/1] clk: samsung: exynos850: Register clocks early Date: Mon, 25 Oct 2021 19:12:54 +0300 [thread overview] Message-ID: <20211025161254.5575-1-semen.protsenko@linaro.org> (raw) 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_DRIVER(), and do all stuff relying on "struct dev" object (like runtime PM and enabling bus clock) later in platform driver probe. Basically CLK_OF_DECLARE_DRIVER() matches CMU compatible, but clears OF_POPULATED flag, which allows the same device to be matched again later. Similar issue was discussed at [1] and addressed in commit 1f7db7bbf031 ("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> --- Changes in v2: - Register only CMU_PERI clocks early Notes: - This patch should be applied on top of CMU_APM series (clk: samsung: exynos850: Implement CMU_APM domain) drivers/clk/samsung/clk-exynos850.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff --git a/drivers/clk/samsung/clk-exynos850.c b/drivers/clk/samsung/clk-exynos850.c index 95e373d17b42..ecffa5c7a081 100644 --- a/drivers/clk/samsung/clk-exynos850.c +++ b/drivers/clk/samsung/clk-exynos850.c @@ -753,6 +753,15 @@ static const struct samsung_cmu_info peri_cmu_info __initconst = { .clk_name = "dout_peri_bus", }; +static void __init exynos850_cmu_peri_init(struct device_node *np) +{ + exynos850_init_clocks(np, peri_clk_regs, ARRAY_SIZE(peri_clk_regs)); + samsung_cmu_register_one(np, &peri_cmu_info); +} + +CLK_OF_DECLARE_DRIVER(exynos850_cmu_peri, "samsung,exynos850-cmu-peri", + exynos850_cmu_peri_init); + /* ---- CMU_CORE ------------------------------------------------------------ */ /* Register Offset definitions for CMU_CORE (0x12000000) */ @@ -920,8 +929,12 @@ static int __init exynos850_cmu_probe(struct platform_device *pdev) struct device_node *np = dev->of_node; info = of_device_get_match_data(dev); - exynos850_init_clocks(np, info->clk_regs, info->nr_clk_regs); - samsung_cmu_register_one(np, info); + + /* Early clocks are already registered using CLK_OF_DECLARE_DRIVER() */ + if (info != &peri_cmu_info) { + exynos850_init_clocks(np, info->clk_regs, info->nr_clk_regs); + samsung_cmu_register_one(np, info); + } /* Keep bus clock running, so it's possible to access CMU registers */ if (info->clk_name) { -- 2.30.2 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next reply other threads:[~2021-10-25 16:13 UTC|newest] Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top [not found] <CGME20211025161302eucas1p2f50ef29a0bba69c13deaf1ad31a8439c@eucas1p2.samsung.com> 2021-10-25 16:12 ` Sam Protsenko [this message] 2021-10-25 16:12 ` [PATCH v2 1/1] clk: samsung: exynos850: Register clocks early Sam Protsenko 2021-10-26 14:53 ` Krzysztof Kozlowski 2021-10-26 14:53 ` Krzysztof Kozlowski 2021-11-20 12:49 ` Sylwester Nawrocki 2021-11-20 12:49 ` Sylwester Nawrocki 2021-11-20 16:47 ` Sam Protsenko 2021-11-20 16:47 ` Sam Protsenko 2021-11-20 17:38 ` Sylwester Nawrocki 2021-11-20 17:38 ` Sylwester Nawrocki 2021-11-21 22:50 ` Sam Protsenko 2021-11-21 22:50 ` Sam Protsenko [not found] <CGME20211122144217eucas1p21c5f4930563ee051d625bb8e3a932a4a@eucas1p2.samsung.com> 2021-11-22 14:42 ` Sam Protsenko 2021-11-22 14:42 ` Sam Protsenko 2021-11-22 22:04 ` Sylwester Nawrocki 2021-11-22 22:04 ` Sylwester Nawrocki
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