[PATCH 3/4] clk: add clock driver for SCMI agents

[Peng Fan]

> Subject: [PATCH 3/4] clk: add clock driver for SCMI agents
> 
> This change introduces a clock driver for SCMI agent devices. When SCMI
> agent and SCMI clock drivers are enabled, SCMI agent binds a clock device for
> each SCMI clock protocol devices enabled in the FDT.
> 
> SCMI clock driver is embedded upon CONFIG_CLK_SCMI=y. If enabled,
> CONFIG_SCMI_AGENT is also enabled.
> 
> SCMI Clock protocol is defined in the SCMI specification [1].
> 
> Links: [1]
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdevelo
> per.arm.com%2Farchitectures%2Fsystem-architectures%2Fsoftware-standar
> ds%2Fscmi&data=02%7C01%7Cpeng.fan%40nxp.com%7C6a1c6d1e102
> 94e81e47708d82a6777b9%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%
> 7C0%7C637305971176347870&sdata=4pKZGL17y7QUY%2Bi9XRutLOCe
> 5jBs1y9gMW7vNoUIcC0%3D&reserved=0
> Signed-off-by: Etienne Carriere <etienne.carriere at linaro.org>
> ---
> 
>  drivers/clk/Kconfig     |   8 +++
>  drivers/clk/Makefile    |   1 +
>  drivers/clk/clk_scmi.c  | 152
> ++++++++++++++++++++++++++++++++++++++++
>  drivers/firmware/scmi.c |   3 +
>  4 files changed, 164 insertions(+)
>  create mode 100644 drivers/clk/clk_scmi.c
> 
> diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig index
> 82cb1874e19..234d6035202 100644
> --- a/drivers/clk/Kconfig
> +++ b/drivers/clk/Kconfig
> @@ -152,6 +152,14 @@ config CLK_CDCE9XX
>  	   Enable the clock synthesizer driver for CDCE913/925/937/949
>  	   series of chips.
> 
> +config CLK_SCMI
> +	bool "Enable SCMI clock driver"
> +	select SCMI_FIRMWARE
> +	help
> +	  Enable this option if you want to support clock devices exposed
> +	  by a SCMI agent based on SCMI clock protocol communication
> +	  with a SCMI server.
> +
>  source "drivers/clk/analogbits/Kconfig"
>  source "drivers/clk/at91/Kconfig"
>  source "drivers/clk/exynos/Kconfig"
> diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile index
> d9119545810..76bba77d1f0 100644
> --- a/drivers/clk/Makefile
> +++ b/drivers/clk/Makefile
> @@ -31,6 +31,7 @@ obj-$(CONFIG_CLK_K210) += kendryte/
>  obj-$(CONFIG_CLK_MPC83XX) += mpc83xx_clk.o
>  obj-$(CONFIG_CLK_OWL) += owl/
>  obj-$(CONFIG_CLK_RENESAS) += renesas/
> +obj-$(CONFIG_CLK_SCMI) += clk_scmi.o
>  obj-$(CONFIG_CLK_SIFIVE) += sifive/
>  obj-$(CONFIG_ARCH_SUNXI) += sunxi/
>  obj-$(CONFIG_CLK_STM32F) += clk_stm32f.o diff --git
> a/drivers/clk/clk_scmi.c b/drivers/clk/clk_scmi.c new file mode 100644 index
> 00000000000..efe64a6a38f
> --- /dev/null
> +++ b/drivers/clk/clk_scmi.c
> @@ -0,0 +1,152 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (C) 2019-2020 Linaro Limited  */ #include <common.h>
> +#include <clk-uclass.h> #include <dm.h> #include <scmi.h> #include
> +<asm/types.h>
> +
> +enum scmi_clock_message_id {
> +	SCMI_CLOCK_RATE_SET = 0x5,
> +	SCMI_CLOCK_RATE_GET = 0x6,
> +	SCMI_CLOCK_CONFIG_SET = 0x7,
> +};
> +
> +#define SCMI_CLK_RATE_ASYNC_NOTIFY	BIT(0)
> +#define SCMI_CLK_RATE_ASYNC_NORESP	(BIT(0) | BIT(1))
> +#define SCMI_CLK_RATE_ROUND_DOWN	0
> +#define SCMI_CLK_RATE_ROUND_UP		BIT(2)
> +#define SCMI_CLK_RATE_ROUND_CLOSEST	BIT(3)
> +
> +struct scmi_clk_state_in {
> +	u32 clock_id;
> +	u32 attributes;
> +};
> +
> +struct scmi_clk_state_out {
> +	s32 status;
> +};
> +
> +static int scmi_clk_gate(struct clk *clk, int enable) {
> +	struct scmi_clk_state_in in = {
> +		.clock_id = clk->id,
> +		.attributes = enable,
> +	};
> +	struct scmi_clk_state_out out;
> +	struct scmi_msg scmi_msg = {
> +		.protocol_id = SCMI_PROTOCOL_ID_CLOCK,
> +		.message_id = SCMI_CLOCK_CONFIG_SET,
> +		.in_msg = (u8 *)&in,
> +		.in_msg_sz = sizeof(in),
> +		.out_msg = (u8 *)&out,
> +		.out_msg_sz = sizeof(out),
> +	};
> +	int rc;
> +
> +	rc = scmi_send_and_process_msg(clk->dev->parent, &scmi_msg);
> +	if (rc)
> +		return rc;
> +
> +	return scmi_to_linux_errno(out.status); }
> +
> +static int scmi_clk_enable(struct clk *clk) {
> +	return scmi_clk_gate(clk, 1);
> +}
> +
> +static int scmi_clk_disable(struct clk *clk) {
> +	return scmi_clk_gate(clk, 0);
> +}
> +
> +struct scmi_clk_rate_get_in {
> +	u32 clock_id;
> +};
> +
> +struct scmi_clk_rate_get_out {
> +	s32 status;
> +	u32 rate_lsb;
> +	u32 rate_msb;
> +};
> +
> +static ulong scmi_clk_get_rate(struct clk *clk) {
> +	struct scmi_clk_rate_get_in in = {
> +		.clock_id = clk->id,
> +	};
> +	struct scmi_clk_rate_get_out out;
> +	struct scmi_msg scmi_msg = {
> +		.protocol_id = SCMI_PROTOCOL_ID_CLOCK,
> +		.message_id = SCMI_CLOCK_RATE_GET,
> +		.in_msg = (u8 *)&in,
> +		.in_msg_sz = sizeof(in),
> +		.out_msg = (u8 *)&out,
> +		.out_msg_sz = sizeof(out),
> +	};
> +	int rc;
> +
> +	rc = scmi_send_and_process_msg(clk->dev->parent, &scmi_msg);
> +	if (rc)
> +		return 0;
> +
> +	rc = scmi_to_linux_errno(out.status);
> +	if (rc)
> +		return 0;
> +
> +	return (ulong)(((u64)out.rate_msb << 32) | out.rate_lsb); }
> +
> +struct scmi_clk_rate_set_in {
> +	u32 clock_id;
> +	u32 flags;
> +	u32 rate_lsb;
> +	u32 rate_msb;
> +};
> +
> +struct scmi_clk_rate_set_out {
> +	s32 status;
> +};
> +
> +static ulong scmi_clk_set_rate(struct clk *clk, ulong rate) {
> +	struct scmi_clk_rate_set_in in = {
> +		.clock_id = clk->id,
> +		.flags = SCMI_CLK_RATE_ASYNC_NORESP |

This will use async, but how if sync?

Thanks,
Peng.

> +			 SCMI_CLK_RATE_ROUND_CLOSEST,
> +		.rate_lsb = (u32)rate,
> +		.rate_msb = (u32)((u64)rate >> 32),
> +	};
> +	struct scmi_clk_rate_set_out out;
> +	struct scmi_msg scmi_msg = {
> +		.protocol_id = SCMI_PROTOCOL_ID_CLOCK,
> +		.message_id = SCMI_CLOCK_RATE_SET,
> +		.in_msg = (u8 *)&in,
> +		.in_msg_sz = sizeof(in),
> +		.out_msg = (u8 *)&out,
> +		.out_msg_sz = sizeof(out),
> +	};
> +	int rc;
> +
> +	rc = scmi_send_and_process_msg(clk->dev->parent, &scmi_msg);
> +	if (rc)
> +		return 0;
> +
> +	return scmi_to_linux_errno(out.status); }
> +
> +static const struct clk_ops scmi_clk_ops = {
> +	.enable = scmi_clk_enable,
> +	.disable = scmi_clk_disable,
> +	.get_rate = scmi_clk_get_rate,
> +	.set_rate = scmi_clk_set_rate,
> +};
> +
> +U_BOOT_DRIVER(scmi_clock) = {
> +	.name = "scmi_clk",
> +	.id = UCLASS_CLK,
> +	.ops = &scmi_clk_ops,
> +};
> diff --git a/drivers/firmware/scmi.c b/drivers/firmware/scmi.c index
> fa8a91c3f3d..9f06718df51 100644
> --- a/drivers/firmware/scmi.c
> +++ b/drivers/firmware/scmi.c
> @@ -399,6 +399,9 @@ static int scmi_bind(struct udevice *dev)
>  			continue;
> 
>  		switch (protocol_id) {
> +		case SCMI_PROTOCOL_ID_CLOCK:
> +			drv = DM_GET_DRIVER(scmi_clock);
> +			break;
>  		default:
>  			dev_info(dev, "Ignore unsupported SCMI protocol %u\n",
>  				 protocol_id);
> --
> 2.17.1