[PATCH] clk: tegra: add Tegra210 special resets

From: Peter De Schrijver
Date: Wed Mar 15 2017 - 08:42:17 EST


Tegra210 has 2 special resets which don't follow the normal pattern:
DVCO and ADSP. Add them in this patch.

Signed-off-by: Peter De Schrijver <pdeschrijver@xxxxxxxxxx>
---
drivers/clk/tegra/clk-tegra210.c | 85 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 85 insertions(+)

diff --git a/drivers/clk/tegra/clk-tegra210.c b/drivers/clk/tegra/clk-tegra210.c
index 2a84897..a41733d 100644
--- a/drivers/clk/tegra/clk-tegra210.c
+++ b/drivers/clk/tegra/clk-tegra210.c
@@ -24,6 +24,7 @@
#include <linux/export.h>
#include <linux/clk/tegra.h>
#include <dt-bindings/clock/tegra210-car.h>
+#include <dt-bindings/reset/tegra210-car.h>
#include <linux/iopoll.h>

#include "clk.h"
@@ -218,6 +219,12 @@
#define CLK_M_DIVISOR_SHIFT 2
#define CLK_M_DIVISOR_MASK 0x3

+#define RST_DFLL_DVCO 0x2f4
+#define DVFS_DFLL_RESET_SHIFT 0
+
+#define CLK_RST_CONTROLLER_RST_DEV_Y_SET 0x2a8
+#define CLK_RST_CONTROLLER_RST_DEV_Y_CLR 0x2ac
+
/*
* SDM fractional divisor is 16-bit 2's complement signed number within
* (-2^12 ... 2^12-1) range. Represented in PLL data structure as unsigned
@@ -2984,6 +2991,81 @@ static void __init tegra210_clock_apply_init_table(void)
}

/**
+ * tegra210_car_barrier - wait for pending writes to the CAR to complete
+ *
+ * Wait for any outstanding writes to the CAR MMIO space from this CPU
+ * to complete before continuing execution. No return value.
+ */
+static void tegra210_car_barrier(void)
+{
+ readl_relaxed(clk_base + RST_DFLL_DVCO);
+}
+
+/**
+ * tegra210_clock_assert_dfll_dvco_reset - assert the DFLL's DVCO reset
+ *
+ * Assert the reset line of the DFLL's DVCO. No return value.
+ */
+static void tegra210_clock_assert_dfll_dvco_reset(void)
+{
+ u32 v;
+
+ v = readl_relaxed(clk_base + RST_DFLL_DVCO);
+ v |= (1 << DVFS_DFLL_RESET_SHIFT);
+ writel_relaxed(v, clk_base + RST_DFLL_DVCO);
+ tegra210_car_barrier();
+}
+
+/**
+ * tegra210_clock_deassert_dfll_dvco_reset - deassert the DFLL's DVCO reset
+ *
+ * Deassert the reset line of the DFLL's DVCO, allowing the DVCO to
+ * operate. No return value.
+ */
+static void tegra210_clock_deassert_dfll_dvco_reset(void)
+{
+ u32 v;
+
+ v = readl_relaxed(clk_base + RST_DFLL_DVCO);
+ v &= ~(1 << DVFS_DFLL_RESET_SHIFT);
+ writel_relaxed(v, clk_base + RST_DFLL_DVCO);
+ tegra210_car_barrier();
+}
+
+static int tegra210_reset_assert(unsigned long id)
+{
+ if (id == TEGRA210_RST_DFLL_DVCO)
+ tegra210_clock_assert_dfll_dvco_reset();
+ else if (id == TEGRA210_RST_ADSP)
+ writel(GENMASK(26, 21) | BIT(7),
+ clk_base + CLK_RST_CONTROLLER_RST_DEV_Y_SET);
+ else
+ return -EINVAL;
+
+ return 0;
+}
+
+static int tegra210_reset_deassert(unsigned long id)
+{
+ if (id == TEGRA210_RST_DFLL_DVCO)
+ tegra210_clock_deassert_dfll_dvco_reset();
+ else if (id == TEGRA210_RST_ADSP) {
+ writel(BIT(21), clk_base + CLK_RST_CONTROLLER_RST_DEV_Y_CLR);
+ /*
+ * Considering adsp cpu clock (min: 12.5MHZ, max: 1GHz)
+ * a delay of 5us ensures that it's at least
+ * 6 * adsp_cpu_cycle_period long.
+ */
+ udelay(5);
+ writel(GENMASK(26, 22) | BIT(7),
+ clk_base + CLK_RST_CONTROLLER_RST_DEV_Y_CLR);
+ } else
+ return -EINVAL;
+
+ return 0;
+}
+
+/**
* tegra210_clock_init - Tegra210-specific clock initialization
* @np: struct device_node * of the DT node for the SoC CAR IP block
*
@@ -3047,6 +3129,9 @@ static void __init tegra210_clock_init(struct device_node *np)

tegra_super_clk_gen5_init(clk_base, pmc_base, tegra210_clks,
&pll_x_params);
+ tegra_init_special_resets(2, tegra210_reset_assert,
+ tegra210_reset_deassert);
+
tegra_add_of_provider(np);
tegra_register_devclks(devclks, ARRAY_SIZE(devclks));

--
1.9.1