clk: tegra: Workaround for Tegra114 MSENC problem

Workaround a hardware bug in MSENC during clock enable.
Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Acked-by: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Stephen Warren <swarren@nvidia.com>

drivers/clk/tegra/clk-periph-gate.c

@@ -43,6 +43,8 @@ static DEFINE_SPINLOCK(periph_ref_lock);
 
 #define periph_clk_to_bit(gate) (1 << (gate->clk_num % 32))
 
+#define LVL2_CLK_GATE_OVRE 0x554
+
 /* Peripheral gate clock ops */
 static int clk_periph_is_enabled(struct clk_hw *hw)
 {
@@ -83,6 +85,13 @@ static int clk_periph_enable(struct clk_hw *hw)
 		}
 	}
 
+	if (gate->flags & TEGRA_PERIPH_WAR_1005168) {
+		writel_relaxed(0, gate->clk_base + LVL2_CLK_GATE_OVRE);
+		writel_relaxed(BIT(22), gate->clk_base + LVL2_CLK_GATE_OVRE);
+		udelay(1);
+		writel_relaxed(0, gate->clk_base + LVL2_CLK_GATE_OVRE);
+	}
+
 	spin_unlock_irqrestore(&periph_ref_lock, flags);
 
 	return 0;

drivers/clk/tegra/clk.h

@@ -358,6 +358,7 @@ struct tegra_clk_periph_regs {
  * TEGRA_PERIPH_ON_APB - If peripheral is in the APB bus then read the
  *     bus to flush the write operation in apb bus. This flag indicates
  *     that this peripheral is in apb bus.
+ * TEGRA_PERIPH_WAR_1005168 - Apply workaround for Tegra114 MSENC bug
  */
 struct tegra_clk_periph_gate {
 	u32			magic;
@@ -377,6 +378,7 @@ struct tegra_clk_periph_gate {
 #define TEGRA_PERIPH_NO_RESET BIT(0)
 #define TEGRA_PERIPH_MANUAL_RESET BIT(1)
 #define TEGRA_PERIPH_ON_APB BIT(2)
+#define TEGRA_PERIPH_WAR_1005168 BIT(3)
 
 void tegra_periph_reset(struct tegra_clk_periph_gate *gate, bool assert);
 extern const struct clk_ops tegra_clk_periph_gate_ops;