ARM: tegra: Implement powergate support

Implement the powergate API that allows various power partitions to be
power up and down.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>

2 files changed, 103 insertions, 0 deletions

diff --git a/arch/arm/cpu/tegra-common/Makefile b/arch/arm/cpu/tegra-common/Makefile
index a18c318..c7603ee 100644
--- a/arch/arm/cpu/tegra-common/Makefile
+++ b/arch/arm/cpu/tegra-common/Makefile
@@ -13,5 +13,6 @@ obj-y += cache.o
 obj-y += clock.o
 obj-y += lowlevel_init.o
 obj-y += pinmux-common.o
+obj-y += powergate.o
 obj-$(CONFIG_DISPLAY_CPUINFO) += sys_info.o
 obj-$(CONFIG_TEGRA124) += vpr.o
diff --git a/arch/arm/cpu/tegra-common/powergate.c b/arch/arm/cpu/tegra-common/powergate.c
new file mode 100644
index 0000000..439cff3
--- /dev/null
+++ b/arch/arm/cpu/tegra-common/powergate.c
@@ -0,0 +1,102 @@
+/*
+ * Copyright (c) 2014, NVIDIA CORPORATION.  All rights reserved.
+ *
+ * SPDX-License-Identifier: GPL-2.0
+ */
+
+#include <common.h>
+#include <errno.h>
+
+#include <asm/io.h>
+#include <asm/types.h>
+
+#include <asm/arch/powergate.h>
+#include <asm/arch/tegra.h>
+
+#define PWRGATE_TOGGLE 0x30
+#define  PWRGATE_TOGGLE_START (1 << 8)
+
+#define REMOVE_CLAMPING 0x34
+
+#define PWRGATE_STATUS 0x38
+
+static int tegra_powergate_set(enum tegra_powergate id, bool state)
+{
+	u32 value, mask = state ? (1 << id) : 0, old_mask;
+	unsigned long start, timeout = 25;
+
+	value = readl(NV_PA_PMC_BASE + PWRGATE_STATUS);
+	old_mask = value & (1 << id);
+
+	if (mask == old_mask)
+		return 0;
+
+	writel(PWRGATE_TOGGLE_START | id, NV_PA_PMC_BASE + PWRGATE_TOGGLE);
+
+	start = get_timer(0);
+
+	while (get_timer(start) < timeout) {
+		value = readl(NV_PA_PMC_BASE + PWRGATE_STATUS);
+		if ((value & (1 << id)) == mask)
+			return 0;
+	}
+
+	return -ETIMEDOUT;
+}
+
+static int tegra_powergate_power_on(enum tegra_powergate id)
+{
+	return tegra_powergate_set(id, true);
+}
+
+int tegra_powergate_power_off(enum tegra_powergate id)
+{
+	return tegra_powergate_set(id, false);
+}
+
+static int tegra_powergate_remove_clamping(enum tegra_powergate id)
+{
+	unsigned long value;
+
+	/*
+	 * The REMOVE_CLAMPING register has the bits for the PCIE and VDEC
+	 * partitions reversed. This was originally introduced on Tegra20 but
+	 * has since been carried forward for backwards-compatibility.
+	 */
+	if (id == TEGRA_POWERGATE_VDEC)
+		value = 1 << TEGRA_POWERGATE_PCIE;
+	else if (id == TEGRA_POWERGATE_PCIE)
+		value = 1 << TEGRA_POWERGATE_VDEC;
+	else
+		value = 1 << id;
+
+	writel(value, NV_PA_PMC_BASE + REMOVE_CLAMPING);
+
+	return 0;
+}
+
+int tegra_powergate_sequence_power_up(enum tegra_powergate id,
+				      enum periph_id periph)
+{
+	int err;
+
+	reset_set_enable(periph, 1);
+
+	err = tegra_powergate_power_on(id);
+	if (err < 0)
+		return err;
+
+	clock_enable(periph);
+
+	udelay(10);
+
+	err = tegra_powergate_remove_clamping(id);
+	if (err < 0)
+		return err;
+
+	udelay(10);
+
+	reset_set_enable(periph, 0);
+
+	return 0;
+}