Unverified Commit 919d6924 authored by Maíra Canal's avatar Maíra Canal Committed by Stephen Boyd
Browse files

clk: bcm: rpi: Turn firmware clock on/off when preparing/unpreparing 

Currently, when we prepare or unprepare RPi's clocks, we don't actually
enable/disable the firmware clock. This means that
`clk_disable_unprepare()` doesn't actually change the clock state at
all, nor does it lowers the clock rate.

From the Mailbox Property Interface documentation [1], we can see that
we should use `RPI_FIRMWARE_SET_CLOCK_STATE` to set the clock state
off/on. Therefore, use `RPI_FIRMWARE_SET_CLOCK_STATE` to create a
prepare and an unprepare hook for RPi's firmware clock.

As now the clocks are actually turned off, some of them are now marked
CLK_IS_CRITICAL, as those are required to be on during the whole system
operation.

Link: https://github.com/raspberrypi/firmware/wiki/Mailbox-property-interface

 [1]
Signed-off-by: default avatarMaíra Canal <mcanal@igalia.com>
Reviewed-by: default avatarStefan Wahren <wahrenst@gmx.net>
Signed-off-by: default avatarStephen Boyd <sboyd@kernel.org>
parent 072ce917

drivers/clk/bcm/clk-raspberrypi.c

+55 −1
Original line number Diff line number Diff line
@@ -68,6 +68,7 @@ struct raspberrypi_clk_variant { 
	char		*clkdev;

	unsigned long	min_rate;

	bool		minimize;

	u32		flags;

};



static struct raspberrypi_clk_variant
@@ -75,6 +76,7 @@ raspberrypi_clk_variants[RPI_FIRMWARE_NUM_CLK_ID] = { 
	[RPI_FIRMWARE_ARM_CLK_ID] = {

		.export = true,

		.clkdev = "cpu0",

		.flags = CLK_IS_CRITICAL,

	},

	[RPI_FIRMWARE_CORE_CLK_ID] = {

		.export = true,
@@ -90,6 +92,12 @@ raspberrypi_clk_variants[RPI_FIRMWARE_NUM_CLK_ID] = { 
		 * always use the minimum the drivers will let us.

		 */

		.minimize = true,



		/*

		 * It should never be disabled as it drives the bus for

		 * everything else.

		 */

		.flags = CLK_IS_CRITICAL,

	},

	[RPI_FIRMWARE_M2MC_CLK_ID] = {

		.export = true,
@@ -115,6 +123,15 @@ raspberrypi_clk_variants[RPI_FIRMWARE_NUM_CLK_ID] = { 
		 * drivers will let us.

		 */

		.minimize = true,



		/*

		 * As mentioned above, this clock is disabled during boot,

		 * the firmware will skip the HSM initialization, resulting

		 * in a bus lockup. Therefore, make sure it's enabled

		 * during boot, but after it, it can be enabled/disabled

		 * by the driver.

		 */

		.flags = CLK_IGNORE_UNUSED,

	},

	[RPI_FIRMWARE_V3D_CLK_ID] = {

		.export = true,
@@ -123,10 +140,12 @@ raspberrypi_clk_variants[RPI_FIRMWARE_NUM_CLK_ID] = { 
	[RPI_FIRMWARE_PIXEL_CLK_ID] = {

		.export = true,

		.minimize = true,

		.flags = CLK_IS_CRITICAL,

	},

	[RPI_FIRMWARE_HEVC_CLK_ID] = {

		.export = true,

		.minimize = true,

		.flags = CLK_IS_CRITICAL,

	},

	[RPI_FIRMWARE_ISP_CLK_ID] = {

		.export = true,
@@ -135,6 +154,7 @@ raspberrypi_clk_variants[RPI_FIRMWARE_NUM_CLK_ID] = { 
	[RPI_FIRMWARE_PIXEL_BVB_CLK_ID] = {

		.export = true,

		.minimize = true,

		.flags = CLK_IS_CRITICAL,

	},

	[RPI_FIRMWARE_VEC_CLK_ID] = {

		.export = true,
@@ -265,7 +285,41 @@ static int raspberrypi_fw_dumb_determine_rate(struct clk_hw *hw, 
	return 0;

}



static int raspberrypi_fw_prepare(struct clk_hw *hw)

{

	const struct raspberrypi_clk_data *data = clk_hw_to_data(hw);

	struct raspberrypi_clk *rpi = data->rpi;

	u32 state = RPI_FIRMWARE_STATE_ENABLE_BIT;

	int ret;



	ret = raspberrypi_clock_property(rpi->firmware, data,

					 RPI_FIRMWARE_SET_CLOCK_STATE, &state);

	if (ret)

		dev_err_ratelimited(rpi->dev,

				    "Failed to set clock %s state to on: %d\n",

				    clk_hw_get_name(hw), ret);



	return ret;

}



static void raspberrypi_fw_unprepare(struct clk_hw *hw)

{

	const struct raspberrypi_clk_data *data = clk_hw_to_data(hw);

	struct raspberrypi_clk *rpi = data->rpi;

	u32 state = 0;

	int ret;



	ret = raspberrypi_clock_property(rpi->firmware, data,

					 RPI_FIRMWARE_SET_CLOCK_STATE, &state);

	if (ret)

		dev_err_ratelimited(rpi->dev,

				    "Failed to set clock %s state to off: %d\n",

				    clk_hw_get_name(hw), ret);

}



static const struct clk_ops raspberrypi_firmware_clk_ops = {

	.prepare        = raspberrypi_fw_prepare,

	.unprepare      = raspberrypi_fw_unprepare,

	.is_prepared	= raspberrypi_fw_is_prepared,

	.recalc_rate	= raspberrypi_fw_get_rate,

	.determine_rate	= raspberrypi_fw_dumb_determine_rate,
@@ -295,7 +349,7 @@ static struct clk_hw *raspberrypi_clk_register(struct raspberrypi_clk *rpi, 
	if (!init.name)

		return ERR_PTR(-ENOMEM);

	init.ops = &raspberrypi_firmware_clk_ops;

	init.flags = CLK_GET_RATE_NOCACHE;

	init.flags = variant->flags | CLK_GET_RATE_NOCACHE;



	data->hw.init = &init;