From 66ee50c6e23432efded0c34ea71428f97cac808a Mon Sep 17 00:00:00 2001 From: Dmitry Osipenko Date: Tue, 2 Mar 2021 15:25:00 +0300 Subject: [PATCH] soc/tegra: pmc: Ensure that clock rates aren't too high Switch all clocks of a power domain to a safe rate which is suitable for all possible voltages in order to ensure that hardware constraints aren't violated when power domain state toggles. Tested-by: Peter Geis # Ouya T30 Tested-by: Nicolas Chauvet # PAZ00 T20 and TK1 T124 Tested-by: Matt Merhar # Ouya T30 Signed-off-by: Dmitry Osipenko Signed-off-by: Thierry Reding --- drivers/soc/tegra/pmc.c | 92 +++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 90 insertions(+), 2 deletions(-) diff --git a/drivers/soc/tegra/pmc.c b/drivers/soc/tegra/pmc.c index 1c601dc..8245fba 100644 --- a/drivers/soc/tegra/pmc.c +++ b/drivers/soc/tegra/pmc.c @@ -258,6 +258,7 @@ struct tegra_powergate { unsigned int id; struct clk **clks; unsigned int num_clks; + unsigned long *clk_rates; struct reset_control *reset; }; @@ -663,6 +664,57 @@ out: return 0; } +static int tegra_powergate_prepare_clocks(struct tegra_powergate *pg) +{ + unsigned long safe_rate = 100 * 1000 * 1000; + unsigned int i; + int err; + + for (i = 0; i < pg->num_clks; i++) { + pg->clk_rates[i] = clk_get_rate(pg->clks[i]); + + if (!pg->clk_rates[i]) { + err = -EINVAL; + goto out; + } + + if (pg->clk_rates[i] <= safe_rate) + continue; + + /* + * We don't know whether voltage state is okay for the + * current clock rate, hence it's better to temporally + * switch clock to a safe rate which is suitable for + * all voltages, before enabling the clock. + */ + err = clk_set_rate(pg->clks[i], safe_rate); + if (err) + goto out; + } + + return 0; + +out: + while (i--) + clk_set_rate(pg->clks[i], pg->clk_rates[i]); + + return err; +} + +static int tegra_powergate_unprepare_clocks(struct tegra_powergate *pg) +{ + unsigned int i; + int err; + + for (i = 0; i < pg->num_clks; i++) { + err = clk_set_rate(pg->clks[i], pg->clk_rates[i]); + if (err) + return err; + } + + return 0; +} + static void tegra_powergate_disable_clocks(struct tegra_powergate *pg) { unsigned int i; @@ -713,10 +765,14 @@ static int tegra_powergate_power_up(struct tegra_powergate *pg, usleep_range(10, 20); - err = tegra_powergate_enable_clocks(pg); + err = tegra_powergate_prepare_clocks(pg); if (err) goto powergate_off; + err = tegra_powergate_enable_clocks(pg); + if (err) + goto unprepare_clks; + usleep_range(10, 20); err = __tegra_powergate_remove_clamping(pg->pmc, pg->id); @@ -739,12 +795,19 @@ static int tegra_powergate_power_up(struct tegra_powergate *pg, if (disable_clocks) tegra_powergate_disable_clocks(pg); + err = tegra_powergate_unprepare_clocks(pg); + if (err) + return err; + return 0; disable_clks: tegra_powergate_disable_clocks(pg); usleep_range(10, 20); +unprepare_clks: + tegra_powergate_unprepare_clocks(pg); + powergate_off: tegra_powergate_set(pg->pmc, pg->id, false); @@ -755,10 +818,14 @@ static int tegra_powergate_power_down(struct tegra_powergate *pg) { int err; - err = tegra_powergate_enable_clocks(pg); + err = tegra_powergate_prepare_clocks(pg); if (err) return err; + err = tegra_powergate_enable_clocks(pg); + if (err) + goto unprepare_clks; + usleep_range(10, 20); err = reset_control_assert(pg->reset); @@ -775,6 +842,10 @@ static int tegra_powergate_power_down(struct tegra_powergate *pg) if (err) goto assert_resets; + err = tegra_powergate_unprepare_clocks(pg); + if (err) + return err; + return 0; assert_resets: @@ -786,6 +857,9 @@ assert_resets: disable_clks: tegra_powergate_disable_clocks(pg); +unprepare_clks: + tegra_powergate_unprepare_clocks(pg); + return err; } @@ -903,6 +977,12 @@ int tegra_powergate_sequence_power_up(unsigned int id, struct clk *clk, if (!pg) return -ENOMEM; + pg->clk_rates = kzalloc(sizeof(*pg->clk_rates), GFP_KERNEL); + if (!pg->clk_rates) { + kfree(pg->clks); + return -ENOMEM; + } + pg->id = id; pg->clks = &clk; pg->num_clks = 1; @@ -914,6 +994,7 @@ int tegra_powergate_sequence_power_up(unsigned int id, struct clk *clk, dev_err(pmc->dev, "failed to turn on partition %d: %d\n", id, err); + kfree(pg->clk_rates); kfree(pg); return err; @@ -1064,6 +1145,12 @@ static int tegra_powergate_of_get_clks(struct tegra_powergate *pg, if (!pg->clks) return -ENOMEM; + pg->clk_rates = kcalloc(count, sizeof(*pg->clk_rates), GFP_KERNEL); + if (!pg->clk_rates) { + kfree(pg->clks); + return -ENOMEM; + } + for (i = 0; i < count; i++) { pg->clks[i] = of_clk_get(np, i); if (IS_ERR(pg->clks[i])) { @@ -1080,6 +1167,7 @@ err: while (i--) clk_put(pg->clks[i]); + kfree(pg->clk_rates); kfree(pg->clks); return err; -- 2.7.4