174 lines
5.0 KiB
Diff
174 lines
5.0 KiB
Diff
From 54276fe20c0735dd18d298891b71b664ea54962d Mon Sep 17 00:00:00 2001
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From: Maxime Ripard <maxime@cerno.tech>
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Date: Mon, 10 Feb 2020 14:06:09 +0100
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Subject: [PATCH] clk: bcm: rpi: Discover the firmware clocks
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The RaspberryPi4 firmware actually exposes more clocks than are currently
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handled by the driver and we will need to change some of them directly
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based on the pixel rate for the display related clocks, or the load for the
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GPU.
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This rate change can have a number of side-effects, including adjusting the
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various PLL voltages or the PLL parents. The firmware will also update
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those clocks by itself for example if the SoC runs too hot.
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In order to make Linux play as nice as possible with those constraints, it
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makes sense to rely on the firmware clocks as much as possible.
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Fortunately,t he firmware has an interface to discover the clocks it
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exposes.
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Let's use it to discover, register the clocks in the clocks framework and
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then expose them through the device tree for consumers to use them.
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Cc: Michael Turquette <mturquette@baylibre.com>
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Cc: Stephen Boyd <sboyd@kernel.org>
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Cc: linux-clk@vger.kernel.org
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Signed-off-by: Maxime Ripard <maxime@cerno.tech>
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---
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drivers/clk/bcm/clk-raspberrypi.c | 104 ++++++++++++++++++---
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include/soc/bcm2835/raspberrypi-firmware.h | 5 +
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2 files changed, 97 insertions(+), 12 deletions(-)
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--- a/drivers/clk/bcm/clk-raspberrypi.c
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+++ b/drivers/clk/bcm/clk-raspberrypi.c
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@@ -285,6 +285,95 @@ static struct clk_hw *raspberrypi_regist
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return &raspberrypi_clk_pllb_arm.hw;
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}
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+static long raspberrypi_fw_dumb_round_rate(struct clk_hw *hw,
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+ unsigned long rate,
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+ unsigned long *parent_rate)
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+{
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+ /*
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+ * The firmware will do the rounding but that isn't part of
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+ * the interface with the firmware, so we just do our best
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+ * here.
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+ */
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+ return rate;
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+}
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+
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+static const struct clk_ops raspberrypi_firmware_clk_ops = {
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+ .is_prepared = raspberrypi_fw_is_prepared,
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+ .recalc_rate = raspberrypi_fw_get_rate,
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+ .round_rate = raspberrypi_fw_dumb_round_rate,
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+ .set_rate = raspberrypi_fw_set_rate,
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+};
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+
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+static struct clk_hw *raspberrypi_clk_register(struct raspberrypi_clk *rpi,
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+ unsigned int parent,
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+ unsigned int id)
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+{
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+ struct raspberrypi_clk_data *data;
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+ struct clk_init_data init = {};
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+ int ret;
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+
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+ if (id == RPI_FIRMWARE_ARM_CLK_ID) {
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+ struct clk_hw *hw;
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+
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+ hw = raspberrypi_register_pllb(rpi);
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+ if (IS_ERR(hw)) {
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+ dev_err(rpi->dev, "Failed to initialize pllb, %ld\n",
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+ PTR_ERR(hw));
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+ return hw;
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+ }
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+
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+ return raspberrypi_register_pllb_arm(rpi);
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+ }
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+
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+ data = devm_kzalloc(rpi->dev, sizeof(*data), GFP_KERNEL);
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+ if (!data)
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+ return ERR_PTR(-ENOMEM);
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+ data->rpi = rpi;
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+ data->id = id;
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+
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+ init.name = devm_kasprintf(rpi->dev, GFP_KERNEL, "fw-clk-%u", id);
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+ init.ops = &raspberrypi_firmware_clk_ops;
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+ init.flags = CLK_GET_RATE_NOCACHE;
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+
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+ data->hw.init = &init;
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+
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+ ret = devm_clk_hw_register(rpi->dev, &data->hw);
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+ if (ret)
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+ return ERR_PTR(ret);
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+
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+ return &data->hw;
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+}
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+
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+static int raspberrypi_discover_clocks(struct raspberrypi_clk *rpi,
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+ struct clk_hw_onecell_data *data)
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+{
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+ struct rpi_firmware_get_clocks_response *clks;
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+ int ret;
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+
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+ clks = devm_kcalloc(rpi->dev, sizeof(*clks), NUM_FW_CLKS, GFP_KERNEL);
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+ if (!clks)
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+ return -ENOMEM;
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+
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+ ret = rpi_firmware_property(rpi->firmware, RPI_FIRMWARE_GET_CLOCKS,
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+ clks, sizeof(*clks) * NUM_FW_CLKS);
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+ if (ret)
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+ return ret;
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+
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+ while (clks->id) {
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+ struct clk_hw *hw;
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+
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+ hw = raspberrypi_clk_register(rpi, clks->parent, clks->id);
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+ if (IS_ERR(hw))
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+ return PTR_ERR(hw);
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+
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+ data->hws[clks->id] = hw;
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+ data->num = clks->id + 1;
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+ clks++;
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+ }
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+
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+ return 0;
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+}
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+
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static int raspberrypi_clk_probe(struct platform_device *pdev)
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{
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struct clk_hw_onecell_data *clk_data;
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@@ -292,7 +381,6 @@ static int raspberrypi_clk_probe(struct
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struct device *dev = &pdev->dev;
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struct rpi_firmware *firmware;
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struct raspberrypi_clk *rpi;
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- struct clk_hw *hw;
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int ret;
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firmware_node = of_parse_phandle(dev->of_node, "raspberrypi,firmware", 0);
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@@ -318,17 +406,9 @@ static int raspberrypi_clk_probe(struct
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if (!clk_data)
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return -ENOMEM;
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- hw = raspberrypi_register_pllb(rpi);
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- if (IS_ERR(hw)) {
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- dev_err(dev, "Failed to initialize pllb, %ld\n", PTR_ERR(hw));
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- return PTR_ERR(hw);
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- }
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-
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- hw = raspberrypi_register_pllb_arm(rpi);
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- if (IS_ERR(hw))
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- return PTR_ERR(hw);
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- clk_data->hws[RPI_FIRMWARE_ARM_CLK_ID] = hw;
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- clk_data->num = RPI_FIRMWARE_ARM_CLK_ID + 1;
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+ ret = raspberrypi_discover_clocks(rpi, clk_data);
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+ if (ret)
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+ return ret;
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ret = devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get,
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clk_data);
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--- a/include/soc/bcm2835/raspberrypi-firmware.h
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+++ b/include/soc/bcm2835/raspberrypi-firmware.h
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@@ -160,6 +160,11 @@ enum rpi_firmware_property_tag {
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#define GET_DISPLAY_SETTINGS_PAYLOAD_SIZE 64
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+struct rpi_firmware_get_clocks_response {
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+ __le32 parent;
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+ __le32 id;
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+};
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+
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#if IS_ENABLED(CONFIG_RASPBERRYPI_FIRMWARE)
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int rpi_firmware_property(struct rpi_firmware *fw,
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u32 tag, void *data, size_t len);
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