[PATCH v2 01/12] scmi: refactor the code to hide a channel from devices

Etienne CARRIERE etienne.carriere at st.com
Thu Aug 3 11:24:51 CEST 2023


Hello Takahiro-san,

Sorry again for this late feedback.
Testing the series against stm32mp135f-dk board which is using SCMI resources, I see the board fails to boot.

> From: AKASHI Takahiro <takahiro.akashi at linaro.org>
> To: trini at konsulko.com, sjg at chromium.org
> Cc: etienne.carriere at st.com, u-boot at lists.denx.de,
> 	AKASHI Takahiro <takahiro.akashi at linaro.org>
> Subject: [PATCH v2 01/12] scmi: refactor the code to hide a channel from devices
> Date: Wed, 26 Jul 2023 17:37:57 +0900	[thread overview]
> Message-ID: <20230726083808.140780-2-takahiro.akashi at linaro.org> (raw)
> In-Reply-To: <20230726083808.140780-1-takahiro.akashi at linaro.org>
> 
> The commit 85dc58289238 ("firmware: scmi: prepare uclass to pass channel
> reference") added an explicit parameter, channel, but it seems to make
> the code complex.
> 
> Hiding this parameter will allow for adding a generic (protocol-agnostic)
> helper function, i.e. for PROTOCOL_VERSION, in a later patch.
> 
> Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
>
> ---
> v2
> * new patch
> ---
>  drivers/clk/clk_scmi.c                    | 27 ++-------
>  drivers/firmware/scmi/scmi_agent-uclass.c | 74 ++++++++++++++++++-----
>  drivers/power/regulator/scmi_regulator.c  | 27 +++------
>  drivers/reset/reset-scmi.c                | 19 +-----
>  include/scmi_agent.h                      | 15 +++--
>  5 files changed, 86 insertions(+), 76 deletions(-)
> 
> diff --git a/drivers/clk/clk_scmi.c b/drivers/clk/clk_scmi.c
> index d172fed24c9d..34a49363a51a 100644
> --- a/drivers/clk/clk_scmi.c
> +++ b/drivers/clk/clk_scmi.c
> @@ -13,17 +13,8 @@
>  #include <asm/types.h>
>  #include <linux/clk-provider.h>
>  
> -/**
> - * struct scmi_clk_priv - Private data for SCMI clocks
> - * @channel: Reference to the SCMI channel to use
> - */
> -struct scmi_clk_priv {
> -	struct scmi_channel *channel;
> -};
> -
>  static int scmi_clk_get_num_clock(struct udevice *dev, size_t *num_clocks)
>  {
> -	struct scmi_clk_priv *priv = dev_get_priv(dev);
>  	struct scmi_clk_protocol_attr_out out;
>  	struct scmi_msg msg = {
>  		.protocol_id = SCMI_PROTOCOL_ID_CLOCK,
> @@ -33,7 +24,7 @@ static int scmi_clk_get_num_clock(struct udevice *dev, size_t *num_clocks)
>  	};
>  	int ret;
>  
> -	ret = devm_scmi_process_msg(dev, priv->channel, &msg);
> +	ret = devm_scmi_process_msg(dev, &msg);
>  	if (ret)
>  		return ret;
>  
> @@ -44,7 +35,6 @@ static int scmi_clk_get_num_clock(struct udevice *dev, size_t *num_clocks)
>  
>  static int scmi_clk_get_attibute(struct udevice *dev, int clkid, char **name)
>  {
> -	struct scmi_clk_priv *priv = dev_get_priv(dev);
>  	struct scmi_clk_attribute_in in = {
>  		.clock_id = clkid,
>  	};
> @@ -59,7 +49,7 @@ static int scmi_clk_get_attibute(struct udevice *dev, int clkid, char **name)
>  	};
>  	int ret;
>  
> -	ret = devm_scmi_process_msg(dev, priv->channel, &msg);
> +	ret = devm_scmi_process_msg(dev, &msg);
>  	if (ret)
>  		return ret;
>  
> @@ -70,7 +60,6 @@ static int scmi_clk_get_attibute(struct udevice *dev, int clkid, char **name)
>  
>  static int scmi_clk_gate(struct clk *clk, int enable)
>  {
> -	struct scmi_clk_priv *priv = dev_get_priv(clk->dev);
>  	struct scmi_clk_state_in in = {
>  		.clock_id = clk->id,
>  		.attributes = enable,
> @@ -81,7 +70,7 @@ static int scmi_clk_gate(struct clk *clk, int enable)
>  					  in, out);
>  	int ret;
>  
> -	ret = devm_scmi_process_msg(clk->dev, priv->channel, &msg);
> +	ret = devm_scmi_process_msg(clk->dev, &msg);
>  	if (ret)
>  		return ret;
>  
> @@ -100,7 +89,6 @@ static int scmi_clk_disable(struct clk *clk)
>  
>  static ulong scmi_clk_get_rate(struct clk *clk)
>  {
> -	struct scmi_clk_priv *priv = dev_get_priv(clk->dev);
>  	struct scmi_clk_rate_get_in in = {
>  		.clock_id = clk->id,
>  	};
> @@ -110,7 +98,7 @@ static ulong scmi_clk_get_rate(struct clk *clk)
>  					  in, out);
>  	int ret;
>  
> -	ret = devm_scmi_process_msg(clk->dev, priv->channel, &msg);
> +	ret = devm_scmi_process_msg(clk->dev, &msg);
>  	if (ret < 0)
>  		return ret;
>  
> @@ -123,7 +111,6 @@ static ulong scmi_clk_get_rate(struct clk *clk)
>  
>  static ulong scmi_clk_set_rate(struct clk *clk, ulong rate)
>  {
> -	struct scmi_clk_priv *priv = dev_get_priv(clk->dev);
>  	struct scmi_clk_rate_set_in in = {
>  		.clock_id = clk->id,
>  		.flags = SCMI_CLK_RATE_ROUND_CLOSEST,
> @@ -136,7 +123,7 @@ static ulong scmi_clk_set_rate(struct clk *clk, ulong rate)
>  					  in, out);
>  	int ret;
>  
> -	ret = devm_scmi_process_msg(clk->dev, priv->channel, &msg);
> +	ret = devm_scmi_process_msg(clk->dev, &msg);
>  	if (ret < 0)
>  		return ret;
>  
> @@ -149,12 +136,11 @@ static ulong scmi_clk_set_rate(struct clk *clk, ulong rate)
>  
>  static int scmi_clk_probe(struct udevice *dev)
>  {
> -	struct scmi_clk_priv *priv = dev_get_priv(dev);
>  	struct clk *clk;
>  	size_t num_clocks, i;
>  	int ret;
>  
> -	ret = devm_scmi_of_get_channel(dev, &priv->channel);
> +	ret = devm_scmi_of_get_channel(dev);
>  	if (ret)
>  		return ret;
>  
> @@ -205,5 +191,4 @@ U_BOOT_DRIVER(scmi_clock) = {
>  	.id = UCLASS_CLK,
>  	.ops = &scmi_clk_ops,
>  	.probe = scmi_clk_probe,
> -	.priv_auto = sizeof(struct scmi_clk_priv *),
>  };
> diff --git a/drivers/firmware/scmi/scmi_agent-uclass.c b/drivers/firmware/scmi/scmi_agent-uclass.c
> index 02de692d66f3..39cf15c88f75 100644
> --- a/drivers/firmware/scmi/scmi_agent-uclass.c
> +++ b/drivers/firmware/scmi/scmi_agent-uclass.c
> @@ -8,6 +8,7 @@
>  #include <common.h>
>  #include <dm.h>
>  #include <errno.h>
> +#include <scmi_agent.h>
>  #include <scmi_agent-uclass.h>
>  #include <scmi_protocols.h>
>  #include <dm/device_compat.h>
> @@ -129,43 +130,88 @@ static const struct scmi_agent_ops *transport_dev_ops(struct udevice *dev)
>  	return (const struct scmi_agent_ops *)dev->driver->ops;
>  }
>  
> -int devm_scmi_of_get_channel(struct udevice *dev, struct scmi_channel **channel)
> +/**
> + * scmi_of_get_channel() - Get SCMI channel handle
> + *
> + * @dev:	SCMI agent device
> + * @channel:	Output reference to the SCMI channel upon success
> + *
> + * On return, @channel will be set.
> + * Return	0 on success and a negative errno on failure
> + */
> +static int scmi_of_get_channel(struct udevice *dev, struct scmi_channel **channel)
> +{
> +	const struct scmi_agent_ops *ops;
> +
> +	ops = transport_dev_ops(dev);
> +	if (ops->of_get_channel)
> +		return ops->of_get_channel(dev, channel);
> +	else
> +		return -EPROTONOSUPPORT;
> +}
> +
> +int devm_scmi_of_get_channel(struct udevice *dev)
>  {
>  	struct udevice *parent;
> +	struct scmi_agent_proto_priv *priv = dev_get_parent_priv(dev);

This parent lookup does not match when CONFIG_CLK_CCF is enabled. When so,
the scmi clock device is on the clock itself but a child udevice of some
udevice held by the common clock framework (CCF).
Platforms from the stm32mp13 family do enable SCMI clock and CCF.

It can propose a way to go, using find_scmi_transport_device() to provide
the agent's 1st child private data as an output argument:
//patch-start
-static struct udevice *find_scmi_transport_device(struct udevice *dev)
+static struct udevice *
+find_scmi_transport_device(struct udevice *dev,
+                          struct scmi_agent_proto_priv **priv)
 {
        struct udevice *parent = dev;
+       struct scmi_agent_proto_priv *parent_priv;
 
        do {
+               parent_priv = dev_get_parent_priv(parent);
                parent = dev_get_parent(parent);
        } while (parent && device_get_uclass_id(parent) != UCLASS_SCMI_AGENT);
 
        if (!parent)
                dev_err(dev, "Invalid SCMI device, agent not found\n");
+       else if (priv)
+               *priv = parent_priv;
 
        return parent;
 }
//end patch

Tested OK on stm32mp13 with the remaining patch series applied (minor conflics).

BR,
etienne


> +	int ret;
>  
>  	parent = find_scmi_transport_device(dev);
>  	if (!parent)
>  		return -ENODEV;
>  
> -	if (transport_dev_ops(parent)->of_get_channel)
> -		return transport_dev_ops(parent)->of_get_channel(parent, channel);
> +	ret = scmi_of_get_channel(parent, &priv->channel);
> +	if (ret == -EPROTONOSUPPORT) {
> +		/* Drivers without a get_channel operator don't need a channel ref */
> +		priv->channel = NULL;
>  
> -	/* Drivers without a get_channel operator don't need a channel ref */
> -	*channel = NULL;
> +		return 0;
> +	}
>  
> -	return 0;
> +	return ret;
>  }
>  
> -int devm_scmi_process_msg(struct udevice *dev, struct scmi_channel *channel,
> -			  struct scmi_msg *msg)
> +/**
> + * scmi_process_msg() - Send and process an SCMI message
> + *
> + * Send a message to an SCMI server.
> + * Caller sets scmi_msg::out_msg_sz to the output message buffer size.
> + *
> + * @dev:	SCMI agent device
> + * @channel:	Communication channel for the device
> + * @msg:	Message structure reference
> + *
> + * On return, scmi_msg::out_msg_sz stores the response payload size.
> + * Return:	0 on success and a negative errno on failure
> + */
> +static int scmi_process_msg(struct udevice *dev, struct scmi_channel *channel,
> +			    struct scmi_msg *msg)
>  {
>  	const struct scmi_agent_ops *ops;
> +
> +	ops = transport_dev_ops(dev);
> +	if (ops->process_msg)
> +		return ops->process_msg(dev, channel, msg);
> +	else
> +		return -EPROTONOSUPPORT;
> +}
> +
> +int devm_scmi_process_msg(struct udevice *dev, struct scmi_msg *msg)
> +{
>  	struct udevice *parent;
> +	struct scmi_agent_proto_priv *priv = dev_get_parent_priv(dev);
>  
>  	parent = find_scmi_transport_device(dev);
>  	if (!parent)
>  		return -ENODEV;
>  
> -	ops = transport_dev_ops(parent);
> -
> -	if (ops->process_msg)
> -		return ops->process_msg(parent, channel, msg);
> -
> -	return -EPROTONOSUPPORT;
> +	return scmi_process_msg(parent, priv->channel, msg);
>  }
>  
>  UCLASS_DRIVER(scmi_agent) = {
>  	.id		= UCLASS_SCMI_AGENT,
>  	.name		= "scmi_agent",
>  	.post_bind	= scmi_bind_protocols,
> +	.per_device_plat_auto = sizeof(struct scmi_agent_priv),

Typo: this added line belong to patch 04/12.

Regards,
Etienne

> +	.per_child_auto	= sizeof(struct scmi_agent_proto_priv *),
>  };
> diff --git a/drivers/power/regulator/scmi_regulator.c b/drivers/power/regulator/scmi_regulator.c
> index 801148036ff6..08918b20872c 100644
> --- a/drivers/power/regulator/scmi_regulator.c
> +++ b/drivers/power/regulator/scmi_regulator.c
> @@ -25,18 +25,9 @@ struct scmi_regulator_platdata {
>  	u32 domain_id;
>  };
>  
> -/**
> - * struct scmi_regulator_priv - Private data for SCMI voltage regulator
> - * @channel: Reference to the SCMI channel to use
> - */
> -struct scmi_regulator_priv {
> -	struct scmi_channel *channel;
> -};
> -
>  static int scmi_voltd_set_enable(struct udevice *dev, bool enable)
>  {
>  	struct scmi_regulator_platdata *pdata = dev_get_plat(dev);
> -	struct scmi_regulator_priv *priv = dev_get_priv(dev);
>  	struct scmi_voltd_config_set_in in = {
>  		.domain_id = pdata->domain_id,
>  		.config = enable ? SCMI_VOLTD_CONFIG_ON : SCMI_VOLTD_CONFIG_OFF,
> @@ -47,7 +38,7 @@ static int scmi_voltd_set_enable(struct udevice *dev, bool enable)
>  					  in, out);
>  	int ret;
>  
> -	ret = devm_scmi_process_msg(dev, priv->channel, &msg);
> +	ret = devm_scmi_process_msg(dev, &msg);
>  	if (ret)
>  		return ret;
>  
> @@ -57,7 +48,6 @@ static int scmi_voltd_set_enable(struct udevice *dev, bool enable)
>  static int scmi_voltd_get_enable(struct udevice *dev)
>  {
>  	struct scmi_regulator_platdata *pdata = dev_get_plat(dev);
> -	struct scmi_regulator_priv *priv = dev_get_priv(dev);
>  	struct scmi_voltd_config_get_in in = {
>  		.domain_id = pdata->domain_id,
>  	};
> @@ -67,7 +57,7 @@ static int scmi_voltd_get_enable(struct udevice *dev)
>  					  in, out);
>  	int ret;
>  
> -	ret = devm_scmi_process_msg(dev, priv->channel, &msg);
> +	ret = devm_scmi_process_msg(dev, &msg);
>  	if (ret < 0)
>  		return ret;
>  
> @@ -80,7 +70,6 @@ static int scmi_voltd_get_enable(struct udevice *dev)
>  
>  static int scmi_voltd_set_voltage_level(struct udevice *dev, int uV)
>  {
> -	struct scmi_regulator_priv *priv = dev_get_priv(dev);
>  	struct scmi_regulator_platdata *pdata = dev_get_plat(dev);
>  	struct scmi_voltd_level_set_in in = {
>  		.domain_id = pdata->domain_id,
> @@ -92,7 +81,7 @@ static int scmi_voltd_set_voltage_level(struct udevice *dev, int uV)
>  					  in, out);
>  	int ret;
>  
> -	ret = devm_scmi_process_msg(dev, priv->channel, &msg);
> +	ret = devm_scmi_process_msg(dev, &msg);
>  	if (ret < 0)
>  		return ret;
>  
> @@ -101,7 +90,6 @@ static int scmi_voltd_set_voltage_level(struct udevice *dev, int uV)
>  
>  static int scmi_voltd_get_voltage_level(struct udevice *dev)
>  {
> -	struct scmi_regulator_priv *priv = dev_get_priv(dev);
>  	struct scmi_regulator_platdata *pdata = dev_get_plat(dev);
>  	struct scmi_voltd_level_get_in in = {
>  		.domain_id = pdata->domain_id,
> @@ -112,7 +100,7 @@ static int scmi_voltd_get_voltage_level(struct udevice *dev)
>  					  in, out);
>  	int ret;
>  
> -	ret = devm_scmi_process_msg(dev, priv->channel, &msg);
> +	ret = devm_scmi_process_msg(dev, &msg);
>  	if (ret < 0)
>  		return ret;
>  
> @@ -140,7 +128,6 @@ static int scmi_regulator_of_to_plat(struct udevice *dev)
>  static int scmi_regulator_probe(struct udevice *dev)
>  {
>  	struct scmi_regulator_platdata *pdata = dev_get_plat(dev);
> -	struct scmi_regulator_priv *priv = dev_get_priv(dev);
>  	struct scmi_voltd_attr_in in = { 0 };
>  	struct scmi_voltd_attr_out out = { 0 };
>  	struct scmi_msg scmi_msg = {
> @@ -153,14 +140,14 @@ static int scmi_regulator_probe(struct udevice *dev)
>  	};
>  	int ret;
>  
> -	ret = devm_scmi_of_get_channel(dev->parent, &priv->channel);
> +	ret = devm_scmi_of_get_channel(dev);
>  	if (ret)
>  		return ret;
>  
>  	/* Check voltage domain is known from SCMI server */
>  	in.domain_id = pdata->domain_id;
>  
> -	ret = devm_scmi_process_msg(dev, priv->channel, &scmi_msg);
> +	ret = devm_scmi_process_msg(dev, &scmi_msg);
>  	if (ret) {
>  		dev_err(dev, "Failed to query voltage domain %u: %d\n",
>  			pdata->domain_id, ret);
> @@ -184,7 +171,6 @@ U_BOOT_DRIVER(scmi_regulator) = {
>  	.probe = scmi_regulator_probe,
>  	.of_to_plat = scmi_regulator_of_to_plat,
>  	.plat_auto = sizeof(struct scmi_regulator_platdata),
> -	.priv_auto = sizeof(struct scmi_regulator_priv *),
>  };
>  
>  static int scmi_regulator_bind(struct udevice *dev)
> @@ -209,4 +195,5 @@ U_BOOT_DRIVER(scmi_voltage_domain) = {
>  	.name = "scmi_voltage_domain",
>  	.id = UCLASS_NOP,
>  	.bind = scmi_regulator_bind,
> +	.per_child_auto = sizeof(struct scmi_agent_proto_priv *),
>  };
> diff --git a/drivers/reset/reset-scmi.c b/drivers/reset/reset-scmi.c
> index 122556162ec3..b76711f0a8fb 100644
> --- a/drivers/reset/reset-scmi.c
> +++ b/drivers/reset/reset-scmi.c
> @@ -13,17 +13,8 @@
>  #include <scmi_protocols.h>
>  #include <asm/types.h>
>  
> -/**
> - * struct scmi_reset_priv - Private data for SCMI reset controller
> - * @channel: Reference to the SCMI channel to use
> - */
> -struct scmi_reset_priv {
> -	struct scmi_channel *channel;
> -};
> -
>  static int scmi_reset_set_level(struct reset_ctl *rst, bool assert_not_deassert)
>  {
> -	struct scmi_reset_priv *priv = dev_get_priv(rst->dev);
>  	struct scmi_rd_reset_in in = {
>  		.domain_id = rst->id,
>  		.flags = assert_not_deassert ? SCMI_RD_RESET_FLAG_ASSERT : 0,
> @@ -35,7 +26,7 @@ static int scmi_reset_set_level(struct reset_ctl *rst, bool assert_not_deassert)
>  					  in, out);
>  	int ret;
>  
> -	ret = devm_scmi_process_msg(rst->dev, priv->channel, &msg);
> +	ret = devm_scmi_process_msg(rst->dev, &msg);
>  	if (ret)
>  		return ret;
>  
> @@ -54,7 +45,6 @@ static int scmi_reset_deassert(struct reset_ctl *rst)
>  
>  static int scmi_reset_request(struct reset_ctl *rst)
>  {
> -	struct scmi_reset_priv *priv = dev_get_priv(rst->dev);
>  	struct scmi_rd_attr_in in = {
>  		.domain_id = rst->id,
>  	};
> @@ -68,7 +58,7 @@ static int scmi_reset_request(struct reset_ctl *rst)
>  	 * We don't really care about the attribute, just check
>  	 * the reset domain exists.
>  	 */
> -	ret = devm_scmi_process_msg(rst->dev, priv->channel, &msg);
> +	ret = devm_scmi_process_msg(rst->dev, &msg);
>  	if (ret)
>  		return ret;
>  
> @@ -83,9 +73,7 @@ static const struct reset_ops scmi_reset_domain_ops = {
>  
>  static int scmi_reset_probe(struct udevice *dev)
>  {
> -	struct scmi_reset_priv *priv = dev_get_priv(dev);
> -
> -	return devm_scmi_of_get_channel(dev, &priv->channel);
> +	return devm_scmi_of_get_channel(dev);
>  }
>  
>  U_BOOT_DRIVER(scmi_reset_domain) = {
> @@ -93,5 +81,4 @@ U_BOOT_DRIVER(scmi_reset_domain) = {
>  	.id = UCLASS_RESET,
>  	.ops = &scmi_reset_domain_ops,
>  	.probe = scmi_reset_probe,
> -	.priv_auto = sizeof(struct scmi_reset_priv *),
>  };
> diff --git a/include/scmi_agent.h b/include/scmi_agent.h
> index ee6286366df7..577892029ff8 100644
> --- a/include/scmi_agent.h
> +++ b/include/scmi_agent.h
> @@ -15,6 +15,14 @@
>  struct udevice;
>  struct scmi_channel;
>  
> +/**
> + * struct scmi_agent_proto_priv - Private data in device for SCMI agent
> + * @channel: Reference to the SCMI channel to use
> + */
> +struct scmi_agent_proto_priv {
> +	struct scmi_channel *channel;
> +};
> +
>  /*
>   * struct scmi_msg - Context of a SCMI message sent and the response received
>   *
> @@ -49,10 +57,9 @@ struct scmi_msg {
>   * devm_scmi_of_get_channel() - Get SCMI channel handle from SCMI agent DT node
>   *
>   * @dev:	Device requesting a channel
> - * @channel:	Output reference to the SCMI channel upon success
>   * @return 0 on success and a negative errno on failure
>   */
> -int devm_scmi_of_get_channel(struct udevice *dev, struct scmi_channel **channel);
> +int devm_scmi_of_get_channel(struct udevice *dev);
>  
>  /**
>   * devm_scmi_process_msg() - Send and process an SCMI message
> @@ -62,12 +69,10 @@ int devm_scmi_of_get_channel(struct udevice *dev, struct scmi_channel **channel)
>   * On return, scmi_msg::out_msg_sz stores the response payload size.
>   *
>   * @dev:	SCMI device
> - * @channel:	Communication channel for the device
>   * @msg:	Message structure reference
>   * Return: 0 on success and a negative errno on failure
>   */
> -int devm_scmi_process_msg(struct udevice *dev, struct scmi_channel *channel,
> -			  struct scmi_msg *msg);
> +int devm_scmi_process_msg(struct udevice *dev, struct scmi_msg *msg);
>  
>  /**
>   * scmi_to_linux_errno() - Convert an SCMI error code into a Linux errno code
> -- 
> 2.41.0


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