[PATCH V1 04/12] clk: tegra: add support for peripheral clock suspend and resume

Sowjanya Komatineni
2019-05-21T23:31:59Z

This patch implements peripheral clock context save and restore
to support system suspend and resume operation.

Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
---
drivers/clk/tegra/clk.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++++-
drivers/clk/tegra/clk.h | 3 ++
2 files changed, 76 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/tegra/clk.c b/drivers/clk/tegra/clk.c
index 6f2862eddad7..08b788766564 100644
--- a/drivers/clk/tegra/clk.c
+++ b/drivers/clk/tegra/clk.c
@@ -81,6 +81,10 @@ static struct clk **clks;
static int clk_num;
static struct clk_onecell_data clk_data;

+#ifdef CONFIG_PM_SLEEP
+static u32 *periph_ctx;
+#endif
+
/* Handlers for SoC-specific reset lines */
static int (*special_reset_assert)(unsigned long);
static int (*special_reset_deassert)(unsigned long);
@@ -210,6 +214,65 @@ const struct tegra_clk_periph_regs *get_reg_bank(int clkid)
}
}

+#ifdef CONFIG_PM_SLEEP
+void tegra_clk_periph_suspend(void __iomem *clk_base)
+{
+ int i, idx;
+
+ idx = 0;
+ for (i = 0; i < periph_banks; i++, idx++)
+ periph_ctx[idx] =
+ readl_relaxed(clk_base + periph_regs[i].rst_reg);
+
+ for (i = 0; i < periph_banks; i++, idx++)
+ periph_ctx[idx] =
+ readl_relaxed(clk_base + periph_regs[i].enb_reg);
+}
+
+void tegra_clk_periph_force_on(u32 *clks_on, int count, void __iomem *clk_base)
+{
+ int i;
+
+ WARN_ON(count != periph_banks);
+
+ for (i = 0; i < count; i++)
+ writel_relaxed(clks_on[i], clk_base + periph_regs[i].enb_reg);
+}
+
+void tegra_clk_periph_resume(void __iomem *clk_base)
+{
+ int i, idx;
+
+ idx = 0;
+ for (i = 0; i < periph_banks; i++, idx++)
+ writel_relaxed(periph_ctx[idx],
+ clk_base + periph_regs[i].rst_reg);
+
+ /* ensure all resets have propagated */
+ fence_udelay(2, clk_base);
+ tegra_read_chipid();
+
+ for (i = 0; i < periph_banks; i++, idx++)
+ writel_relaxed(periph_ctx[idx],
+ clk_base + periph_regs[i].enb_reg);
+
+ /* ensure all enables have propagated */
+ fence_udelay(2, clk_base);
+ tegra_read_chipid();
+}
+
+static int tegra_clk_suspend_ctx_init(int banks)
+{
+ int err = 0;
+
+ periph_ctx = kzalloc(2 * banks * sizeof(*periph_ctx), GFP_KERNEL);
+ if (!periph_ctx)
+ err = -ENOMEM;
+
+ return err;
+}
+#endif
+
struct clk ** __init tegra_clk_init(void __iomem *regs, int num, int banks)
{
clk_base = regs;
@@ -226,11 +289,20 @@ struct clk ** __init tegra_clk_init(void __iomem *regs, int num, int banks)
periph_banks = banks;

clks = kcalloc(num, sizeof(struct clk *), GFP_KERNEL);
- if (!clks)
+ if (!clks) {
kfree(periph_clk_enb_refcnt);
+ return NULL;
+ }

clk_num = num;

+#ifdef CONFIG_PM_SLEEP
+ if (tegra_clk_suspend_ctx_init(banks)) {
+ kfree(periph_clk_enb_refcnt);
+ kfree(clks);
+ return NULL;
+ }
+#endif
return clks;
}

diff --git a/drivers/clk/tegra/clk.h b/drivers/clk/tegra/clk.h
index c82633686820..ef444648fcb1 100644
--- a/drivers/clk/tegra/clk.h
+++ b/drivers/clk/tegra/clk.h
@@ -853,6 +853,9 @@ void tegra_clk_pll_out_resume(struct clk *clk, unsigned long rate);
void tegra_clk_plle_tegra210_resume(struct clk *c);
void tegra_clk_sync_state_pll(struct clk *c);
void tegra_clk_sync_state_pll_out(struct clk *clk);
+void tegra_clk_periph_suspend(void __iomem *clk_base);
+void tegra_clk_periph_resume(void __iomem *clk_base);
+void tegra_clk_periph_force_on(u32 *clks_on, int count, void __iomem *clk_base);
#endif

--
2.7.4