--- /dev/null
+From 35306211392a8c17ba6cde2a6b5d1beb61ca7d54 Mon Sep 17 00:00:00 2001
+From: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
+Date: Wed, 12 Jun 2019 20:24:54 +0200
+Subject: [PATCH] clk: bcm283x: add driver interfacing with Raspberry
+ Pi's firmware
+
+Commit 4e85e535e6cc6e8a96350e8ee684d0f22eb8629e upstream.
+
+Raspberry Pi's firmware offers an interface though which update it's
+clock's frequencies. This is specially useful in order to change the CPU
+clock (pllb_arm) which is 'owned' by the firmware and we're unable to
+scale using the register interface provided by clk-bcm2835.
+
+Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
+Acked-by: Eric Anholt <eric@anholt.net>
+Signed-off-by: Stephen Boyd <sboyd@kernel.org>
+---
+ drivers/clk/bcm/Kconfig | 7 +
+ drivers/clk/bcm/Makefile | 1 +
+ drivers/clk/bcm/clk-raspberrypi.c | 300 ++++++++++++++++++++++++++++++
+ 3 files changed, 308 insertions(+)
+ create mode 100644 drivers/clk/bcm/clk-raspberrypi.c
+
+--- a/drivers/clk/bcm/Kconfig
++++ b/drivers/clk/bcm/Kconfig
+@@ -63,3 +63,10 @@ config CLK_BCM_SR
+ default ARCH_BCM_IPROC
+ help
+ Enable common clock framework support for the Broadcom Stingray SoC
++
++config CLK_RASPBERRYPI
++ tristate "Raspberry Pi firmware based clock support"
++ depends on RASPBERRYPI_FIRMWARE || (COMPILE_TEST && !RASPBERRYPI_FIRMWARE)
++ help
++ Enable common clock framework support for Raspberry Pi's firmware
++ dependent clocks
+--- a/drivers/clk/bcm/Makefile
++++ b/drivers/clk/bcm/Makefile
+@@ -7,6 +7,7 @@ obj-$(CONFIG_CLK_BCM_KONA) += clk-bcm216
+ obj-$(CONFIG_COMMON_CLK_IPROC) += clk-iproc-armpll.o clk-iproc-pll.o clk-iproc-asiu.o
+ obj-$(CONFIG_ARCH_BCM2835) += clk-bcm2835.o
+ obj-$(CONFIG_ARCH_BCM2835) += clk-bcm2835-aux.o
++obj-$(CONFIG_CLK_RASPBERRYPI) += clk-raspberrypi.o
+ obj-$(CONFIG_ARCH_BCM_53573) += clk-bcm53573-ilp.o
+ obj-$(CONFIG_CLK_BCM_CYGNUS) += clk-cygnus.o
+ obj-$(CONFIG_CLK_BCM_HR2) += clk-hr2.o
+--- /dev/null
++++ b/drivers/clk/bcm/clk-raspberrypi.c
+@@ -0,0 +1,300 @@
++// SPDX-License-Identifier: GPL-2.0+
++/*
++ * Raspberry Pi driver for firmware controlled clocks
++ *
++ * Even though clk-bcm2835 provides an interface to the hardware registers for
++ * the system clocks we've had to factor out 'pllb' as the firmware 'owns' it.
++ * We're not allowed to change it directly as we might race with the
++ * over-temperature and under-voltage protections provided by the firmware.
++ *
++ * Copyright (C) 2019 Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
++ */
++
++#include <linux/clkdev.h>
++#include <linux/clk-provider.h>
++#include <linux/io.h>
++#include <linux/module.h>
++#include <linux/platform_device.h>
++
++#include <soc/bcm2835/raspberrypi-firmware.h>
++
++#define RPI_FIRMWARE_ARM_CLK_ID 0x00000003
++
++#define RPI_FIRMWARE_STATE_ENABLE_BIT BIT(0)
++#define RPI_FIRMWARE_STATE_WAIT_BIT BIT(1)
++
++/*
++ * Even though the firmware interface alters 'pllb' the frequencies are
++ * provided as per 'pllb_arm'. We need to scale before passing them trough.
++ */
++#define RPI_FIRMWARE_PLLB_ARM_DIV_RATE 2
++
++#define A2W_PLL_FRAC_BITS 20
++
++struct raspberrypi_clk {
++ struct device *dev;
++ struct rpi_firmware *firmware;
++
++ unsigned long min_rate;
++ unsigned long max_rate;
++
++ struct clk_hw pllb;
++ struct clk_hw *pllb_arm;
++ struct clk_lookup *pllb_arm_lookup;
++};
++
++/*
++ * Structure of the message passed to Raspberry Pi's firmware in order to
++ * change clock rates. The 'disable_turbo' option is only available to the ARM
++ * clock (pllb) which we enable by default as turbo mode will alter multiple
++ * clocks at once.
++ *
++ * Even though we're able to access the clock registers directly we're bound to
++ * use the firmware interface as the firmware ultimately takes care of
++ * mitigating overheating/undervoltage situations and we would be changing
++ * frequencies behind his back.
++ *
++ * For more information on the firmware interface check:
++ * https://github.com/raspberrypi/firmware/wiki/Mailbox-property-interface
++ */
++struct raspberrypi_firmware_prop {
++ __le32 id;
++ __le32 val;
++ __le32 disable_turbo;
++} __packed;
++
++static int raspberrypi_clock_property(struct rpi_firmware *firmware, u32 tag,
++ u32 clk, u32 *val)
++{
++ struct raspberrypi_firmware_prop msg = {
++ .id = cpu_to_le32(clk),
++ .val = cpu_to_le32(*val),
++ .disable_turbo = cpu_to_le32(1),
++ };
++ int ret;
++
++ ret = rpi_firmware_property(firmware, tag, &msg, sizeof(msg));
++ if (ret)
++ return ret;
++
++ *val = le32_to_cpu(msg.val);
++
++ return 0;
++}
++
++static int raspberrypi_fw_pll_is_on(struct clk_hw *hw)
++{
++ struct raspberrypi_clk *rpi = container_of(hw, struct raspberrypi_clk,
++ pllb);
++ u32 val = 0;
++ int ret;
++
++ ret = raspberrypi_clock_property(rpi->firmware,
++ RPI_FIRMWARE_GET_CLOCK_STATE,
++ RPI_FIRMWARE_ARM_CLK_ID, &val);
++ if (ret)
++ return 0;
++
++ return !!(val & RPI_FIRMWARE_STATE_ENABLE_BIT);
++}
++
++
++static unsigned long raspberrypi_fw_pll_get_rate(struct clk_hw *hw,
++ unsigned long parent_rate)
++{
++ struct raspberrypi_clk *rpi = container_of(hw, struct raspberrypi_clk,
++ pllb);
++ u32 val = 0;
++ int ret;
++
++ ret = raspberrypi_clock_property(rpi->firmware,
++ RPI_FIRMWARE_GET_CLOCK_RATE,
++ RPI_FIRMWARE_ARM_CLK_ID,
++ &val);
++ if (ret)
++ return ret;
++
++ return val * RPI_FIRMWARE_PLLB_ARM_DIV_RATE;
++}
++
++static int raspberrypi_fw_pll_set_rate(struct clk_hw *hw, unsigned long rate,
++ unsigned long parent_rate)
++{
++ struct raspberrypi_clk *rpi = container_of(hw, struct raspberrypi_clk,
++ pllb);
++ u32 new_rate = rate / RPI_FIRMWARE_PLLB_ARM_DIV_RATE;
++ int ret;
++
++ ret = raspberrypi_clock_property(rpi->firmware,
++ RPI_FIRMWARE_SET_CLOCK_RATE,
++ RPI_FIRMWARE_ARM_CLK_ID,
++ &new_rate);
++ if (ret)
++ dev_err_ratelimited(rpi->dev, "Failed to change %s frequency: %d",
++ clk_hw_get_name(hw), ret);
++
++ return ret;
++}
++
++/*
++ * Sadly there is no firmware rate rounding interface. We borrowed it from
++ * clk-bcm2835.
++ */
++static int raspberrypi_pll_determine_rate(struct clk_hw *hw,
++ struct clk_rate_request *req)
++{
++ struct raspberrypi_clk *rpi = container_of(hw, struct raspberrypi_clk,
++ pllb);
++ u64 div, final_rate;
++ u32 ndiv, fdiv;
++
++ /* We can't use req->rate directly as it would overflow */
++ final_rate = clamp(req->rate, rpi->min_rate, rpi->max_rate);
++
++ div = (u64)final_rate << A2W_PLL_FRAC_BITS;
++ do_div(div, req->best_parent_rate);
++
++ ndiv = div >> A2W_PLL_FRAC_BITS;
++ fdiv = div & ((1 << A2W_PLL_FRAC_BITS) - 1);
++
++ final_rate = ((u64)req->best_parent_rate *
++ ((ndiv << A2W_PLL_FRAC_BITS) + fdiv));
++
++ req->rate = final_rate >> A2W_PLL_FRAC_BITS;
++
++ return 0;
++}
++
++static const struct clk_ops raspberrypi_firmware_pll_clk_ops = {
++ .is_prepared = raspberrypi_fw_pll_is_on,
++ .recalc_rate = raspberrypi_fw_pll_get_rate,
++ .set_rate = raspberrypi_fw_pll_set_rate,
++ .determine_rate = raspberrypi_pll_determine_rate,
++};
++
++static int raspberrypi_register_pllb(struct raspberrypi_clk *rpi)
++{
++ u32 min_rate = 0, max_rate = 0;
++ struct clk_init_data init;
++ int ret;
++
++ memset(&init, 0, sizeof(init));
++
++ /* All of the PLLs derive from the external oscillator. */
++ init.parent_names = (const char *[]){ "osc" };
++ init.num_parents = 1;
++ init.name = "pllb";
++ init.ops = &raspberrypi_firmware_pll_clk_ops;
++ init.flags = CLK_GET_RATE_NOCACHE | CLK_IGNORE_UNUSED;
++
++ /* Get min & max rates set by the firmware */
++ ret = raspberrypi_clock_property(rpi->firmware,
++ RPI_FIRMWARE_GET_MIN_CLOCK_RATE,
++ RPI_FIRMWARE_ARM_CLK_ID,
++ &min_rate);
++ if (ret) {
++ dev_err(rpi->dev, "Failed to get %s min freq: %d\n",
++ init.name, ret);
++ return ret;
++ }
++
++ ret = raspberrypi_clock_property(rpi->firmware,
++ RPI_FIRMWARE_GET_MAX_CLOCK_RATE,
++ RPI_FIRMWARE_ARM_CLK_ID,
++ &max_rate);
++ if (ret) {
++ dev_err(rpi->dev, "Failed to get %s max freq: %d\n",
++ init.name, ret);
++ return ret;
++ }
++
++ if (!min_rate || !max_rate) {
++ dev_err(rpi->dev, "Unexpected frequency range: min %u, max %u\n",
++ min_rate, max_rate);
++ return -EINVAL;
++ }
++
++ dev_info(rpi->dev, "CPU frequency range: min %u, max %u\n",
++ min_rate, max_rate);
++
++ rpi->min_rate = min_rate * RPI_FIRMWARE_PLLB_ARM_DIV_RATE;
++ rpi->max_rate = max_rate * RPI_FIRMWARE_PLLB_ARM_DIV_RATE;
++
++ rpi->pllb.init = &init;
++
++ return devm_clk_hw_register(rpi->dev, &rpi->pllb);
++}
++
++static int raspberrypi_register_pllb_arm(struct raspberrypi_clk *rpi)
++{
++ rpi->pllb_arm = clk_hw_register_fixed_factor(rpi->dev,
++ "pllb_arm", "pllb",
++ CLK_SET_RATE_PARENT | CLK_GET_RATE_NOCACHE,
++ 1, 2);
++ if (IS_ERR(rpi->pllb_arm)) {
++ dev_err(rpi->dev, "Failed to initialize pllb_arm\n");
++ return PTR_ERR(rpi->pllb_arm);
++ }
++
++ rpi->pllb_arm_lookup = clkdev_hw_create(rpi->pllb_arm, NULL, "cpu0");
++ if (!rpi->pllb_arm_lookup) {
++ dev_err(rpi->dev, "Failed to initialize pllb_arm_lookup\n");
++ clk_hw_unregister_fixed_factor(rpi->pllb_arm);
++ return -ENOMEM;
++ }
++
++ return 0;
++}
++
++static int raspberrypi_clk_probe(struct platform_device *pdev)
++{
++ struct device_node *firmware_node;
++ struct device *dev = &pdev->dev;
++ struct rpi_firmware *firmware;
++ struct raspberrypi_clk *rpi;
++ int ret;
++
++ firmware_node = of_find_compatible_node(NULL, NULL,
++ "raspberrypi,bcm2835-firmware");
++ if (!firmware_node) {
++ dev_err(dev, "Missing firmware node\n");
++ return -ENOENT;
++ }
++
++ firmware = rpi_firmware_get(firmware_node);
++ of_node_put(firmware_node);
++ if (!firmware)
++ return -EPROBE_DEFER;
++
++ rpi = devm_kzalloc(dev, sizeof(*rpi), GFP_KERNEL);
++ if (!rpi)
++ return -ENOMEM;
++
++ rpi->dev = dev;
++ rpi->firmware = firmware;
++
++ ret = raspberrypi_register_pllb(rpi);
++ if (ret) {
++ dev_err(dev, "Failed to initialize pllb, %d\n", ret);
++ return ret;
++ }
++
++ ret = raspberrypi_register_pllb_arm(rpi);
++ if (ret)
++ return ret;
++
++ return 0;
++}
++
++static struct platform_driver raspberrypi_clk_driver = {
++ .driver = {
++ .name = "raspberrypi-clk",
++ },
++ .probe = raspberrypi_clk_probe,
++};
++module_platform_driver(raspberrypi_clk_driver);
++
++MODULE_AUTHOR("Nicolas Saenz Julienne <nsaenzjulienne@suse.de>");
++MODULE_DESCRIPTION("Raspberry Pi firmware clock driver");
++MODULE_LICENSE("GPL");
++MODULE_ALIAS("platform:raspberrypi-clk");
projects / openwrt / staging / wigyori.git / blobdiff