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| author | Aidan MacDonald <aidanmacdonald.0x0@gmail.com> | 2022-04-28 17:44:53 +0100 |
|---|---|---|
| committer | Stephen Boyd <sboyd@kernel.org> | 2022-05-18 13:56:22 -0700 |
| commit | ca54d06fcacfdeb0b07acb4c6469a96fb02a9b44 (patch) | |
| tree | 096e8d883fa8a0e6d9defd626fa28ff720d78181 /drivers/clk/ingenic/x1000-cgu.c | |
| parent | bacf743e925d10076c0ba9b9289d0e827c3db7f1 (diff) | |
| download | linux-stable-ca54d06fcacfdeb0b07acb4c6469a96fb02a9b44.tar.gz linux-stable-ca54d06fcacfdeb0b07acb4c6469a96fb02a9b44.tar.bz2 linux-stable-ca54d06fcacfdeb0b07acb4c6469a96fb02a9b44.zip | |
clk: ingenic: Mark critical clocks in Ingenic SoCs
Consider CPU, L2 cache, and memory clocks as critical to prevent
them -- and the parent clocks -- from being automatically gated,
since nothing calls clk_get() on these clocks.
Gating the CPU clock hangs the processor, and gating memory makes
external DRAM inaccessible. Normal kernel code can't hope to deal
with either situation so those clocks have to be critical.
The L2 cache is required only if caches are running, and could be
gated if the kernel takes care to flush and disable caches before
gating the clock. There's no mechanism to do this, and probably no
reason to do it, so it's simpler to mark the L2 cache as critical.
Signed-off-by: Aidan MacDonald <aidanmacdonald.0x0@gmail.com>
Reviewed-by: Paul Cercueil <paul@crapouillou.net>
Link: https://lore.kernel.org/r/20220428164454.17908-3-aidanmacdonald.0x0@gmail.com
Tested-by: 周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com> # On X1000 and X1830
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Diffstat (limited to 'drivers/clk/ingenic/x1000-cgu.c')
| -rw-r--r-- | drivers/clk/ingenic/x1000-cgu.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/drivers/clk/ingenic/x1000-cgu.c b/drivers/clk/ingenic/x1000-cgu.c index 3c4d5a77ccbd..b2ce3fb83f54 100644 --- a/drivers/clk/ingenic/x1000-cgu.c +++ b/drivers/clk/ingenic/x1000-cgu.c @@ -251,6 +251,11 @@ static const struct ingenic_cgu_clk_info x1000_cgu_clocks[] = { [X1000_CLK_CPU] = { "cpu", CGU_CLK_DIV | CGU_CLK_GATE, + /* + * Disabling the CPU clock or any parent clocks will hang the + * system; mark it critical. + */ + .flags = CLK_IS_CRITICAL, .parents = { X1000_CLK_CPUMUX, -1, -1, -1 }, .div = { CGU_REG_CPCCR, 0, 1, 4, 22, -1, -1 }, .gate = { CGU_REG_CLKGR, 30 }, @@ -258,6 +263,11 @@ static const struct ingenic_cgu_clk_info x1000_cgu_clocks[] = { [X1000_CLK_L2CACHE] = { "l2cache", CGU_CLK_DIV, + /* + * The L2 cache clock is critical if caches are enabled and + * disabling it or any parent clocks will hang the system. + */ + .flags = CLK_IS_CRITICAL, .parents = { X1000_CLK_CPUMUX, -1, -1, -1 }, .div = { CGU_REG_CPCCR, 4, 1, 4, 22, -1, -1 }, }, @@ -290,6 +300,11 @@ static const struct ingenic_cgu_clk_info x1000_cgu_clocks[] = { [X1000_CLK_DDR] = { "ddr", CGU_CLK_MUX | CGU_CLK_DIV | CGU_CLK_GATE, + /* + * Disabling DDR clock or its parents will render DRAM + * inaccessible; mark it critical. + */ + .flags = CLK_IS_CRITICAL, .parents = { -1, X1000_CLK_SCLKA, X1000_CLK_MPLL, -1 }, .mux = { CGU_REG_DDRCDR, 30, 2 }, .div = { CGU_REG_DDRCDR, 0, 1, 4, 29, 28, 27 }, |