clock: add Tegra186 clock driver

In Tegra186, on-SoC clocks are manipulated using IPC requests to the BPMP
(Boot and Power Management Processor). This change implements a driver
that does that. A tegra/ sub-directory is created to follow the existing
pattern. It is unconditionally selected by CONFIG_TEGRA186 since virtually
any Tegra186 build of U-Boot will need the feature.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>

arch/arm/mach-tegra/Kconfig

@@ -64,9 +64,11 @@ config TEGRA210
 
 config TEGRA186
 	bool "Tegra186 family"
+	select CLK
 	select DM_MAILBOX
 	select MISC
 	select TEGRA186_BPMP
+	select TEGRA186_CLOCK
 	select TEGRA186_GPIO
 	select TEGRA_ARMV8_COMMON
 	select TEGRA_HSP

drivers/clk/Kconfig

@@ -20,6 +20,7 @@ config SPL_CLK
 	  setting up clocks within SPL, and allows the same drivers to be
 	  used as U-Boot proper.
 
+source "drivers/clk/tegra/Kconfig"
 source "drivers/clk/uniphier/Kconfig"
 source "drivers/clk/exynos/Kconfig"
 

drivers/clk/Makefile

@@ -10,5 +10,7 @@ obj-$(CONFIG_ARCH_ROCKCHIP) += rockchip/
 obj-$(CONFIG_SANDBOX) += clk_sandbox.o
 obj-$(CONFIG_SANDBOX) += clk_sandbox_test.o
 obj-$(CONFIG_MACH_PIC32) += clk_pic32.o
+
+obj-y += tegra/
 obj-$(CONFIG_CLK_UNIPHIER) += uniphier/
 obj-$(CONFIG_CLK_EXYNOS) += exynos/

drivers/clk/tegra/Kconfig

@@ -0,0 +1,6 @@
+config TEGRA186_CLOCK
+	bool "Enable Tegra186 BPMP-based clock driver"
+	depends on TEGRA186_BPMP
+	help
+	  Enable support for manipulating Tegra's on-SoC clocks via IPC
+	  requests to the BPMP (Boot and Power Management Processor).

drivers/clk/tegra/Makefile

@@ -0,0 +1,5 @@
+# Copyright (c) 2016, NVIDIA CORPORATION.
+#
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_TEGRA186_CLOCK) += tegra186-clk.o

drivers/clk/tegra/tegra186-clk.c

@@ -0,0 +1,104 @@
+/*
+ * Copyright (c) 2016, NVIDIA CORPORATION.
+ *
+ * SPDX-License-Identifier: GPL-2.0
+ */
+
+#include <common.h>
+#include <clk-uclass.h>
+#include <dm.h>
+#include <misc.h>
+#include <asm/arch-tegra/bpmp_abi.h>
+
+static ulong tegra186_clk_get_rate(struct clk *clk)
+{
+	struct mrq_clk_request req;
+	struct mrq_clk_response resp;
+	int ret;
+
+	debug("%s(clk=%p) (dev=%p, id=%lu)\n", __func__, clk, clk->dev,
+	      clk->id);
+
+	req.cmd_and_id = (CMD_CLK_GET_RATE << 24) | clk->id;
+
+	ret = misc_call(clk->dev->parent, MRQ_CLK, &req, sizeof(req), &resp,
+			sizeof(resp));
+	if (ret < 0)
+		return ret;
+
+	return resp.clk_get_rate.rate;
+}
+
+static ulong tegra186_clk_set_rate(struct clk *clk, ulong rate)
+{
+	struct mrq_clk_request req;
+	struct mrq_clk_response resp;
+	int ret;
+
+	debug("%s(clk=%p, rate=%lu) (dev=%p, id=%lu)\n", __func__, clk, rate,
+	      clk->dev, clk->id);
+
+	req.cmd_and_id = (CMD_CLK_SET_RATE << 24) | clk->id;
+	req.clk_set_rate.rate = rate;
+
+	ret = misc_call(clk->dev->parent, MRQ_CLK, &req, sizeof(req), &resp,
+			sizeof(resp));
+	if (ret < 0)
+		return ret;
+
+	return resp.clk_set_rate.rate;
+}
+
+static int tegra186_clk_en_dis(struct clk *clk,
+			       enum mrq_reset_commands cmd)
+{
+	struct mrq_clk_request req;
+	struct mrq_clk_response resp;
+	int ret;
+
+	req.cmd_and_id = (cmd << 24) | clk->id;
+
+	ret = misc_call(clk->dev->parent, MRQ_CLK, &req, sizeof(req), &resp,
+			sizeof(resp));
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int tegra186_clk_enable(struct clk *clk)
+{
+	debug("%s(clk=%p) (dev=%p, id=%lu)\n", __func__, clk, clk->dev,
+	      clk->id);
+
+	return tegra186_clk_en_dis(clk, CMD_CLK_ENABLE);
+}
+
+static int tegra186_clk_disable(struct clk *clk)
+{
+	debug("%s(clk=%p) (dev=%p, id=%lu)\n", __func__, clk, clk->dev,
+	      clk->id);
+
+	return tegra186_clk_en_dis(clk, CMD_CLK_DISABLE);
+}
+
+static struct clk_ops tegra186_clk_ops = {
+	.get_rate = tegra186_clk_get_rate,
+	.set_rate = tegra186_clk_set_rate,
+	.enable = tegra186_clk_enable,
+	.disable = tegra186_clk_disable,
+};
+
+static int tegra186_clk_probe(struct udevice *dev)
+{
+	debug("%s(dev=%p)\n", __func__, dev);
+
+	return 0;
+}
+
+U_BOOT_DRIVER(tegra186_clk) = {
+	.name		= "tegra186_clk",
+	.id		= UCLASS_CLK,
+	.probe		= tegra186_clk_probe,
+	.ops = &tegra186_clk_ops,
+};