[RFC PATCH v3 5/8] firmware: Add legacy SCPI protocol driver

[sudeep.holla@arm.com (Sudeep Holla)]

Hi Neil,

On 09/08/16 11:29, Neil Armstrong wrote:
> Add legacy protocol driver for an early published SCPI implementation
> by supporting old command indexes and structure.
> This driver also supports vendor messages and rockchip specific
> mailbox data structure for message passing to SCP.
>

Sorry for the delay but I expected some attempts to reduce the
duplication of code we have here. I really don't like the duplication of
the code. As I mentioned earlier it can be reduced. I see lot of scope
for that and I see that you made zero attempts since v2.

> Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
> ---
>  drivers/firmware/Kconfig       |  20 ++
>  drivers/firmware/Makefile      |   1 +
>  drivers/firmware/legacy_scpi.c | 710 +++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 731 insertions(+)
>  create mode 100644 drivers/firmware/legacy_scpi.c
>
> diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig
> index ff85511..f6226b7 100644
> --- a/drivers/firmware/Kconfig
> +++ b/drivers/firmware/Kconfig
> @@ -40,6 +40,26 @@ config ARM_SCPI_POWER_DOMAIN
>  	  This enables support for the SCPI power domains which can be
>  	  enabled or disabled via the SCP firmware
>
> +config LEGACY_SCPI_PROTOCOL
> +	bool "Legacy System Control and Power Interface (SCPI) Message Protocol"
> +	default y if ARCH_MESON
> +	select SCPI_FW
> +	help
> +	  System Control and Power Interface (SCPI) Message Protocol is
> +	  defined for the purpose of communication between the Application
> +	  Cores(AP) and the System Control Processor(SCP). The MHU peripheral
> +	  provides a mechanism for inter-processor communication between SCP
> +	  and AP.
> +
> +	  SCP controls most of the power managament on the Application
> +	  Processors. It offers control and management of: the core/cluster
> +	  power states, various power domain DVFS including the core/cluster,
> +	  certain system clocks configuration, thermal sensors and many
> +	  others.
> +
> +	  This protocol library provides interface for all the client drivers
> +	  making use of the features offered by the legacy SCP protocol.
> +

Why do we need this ? If we plan to enable this in defconfig, I would
rather not introduce this as it serves nothing extra over the
compatible. We need runtime check for this with DT compatibles.


[...]


> +enum legacy_scpi_client_id {
> +	SCPI_CL_NONE,
> +	SCPI_CL_CLOCKS,
> +	SCPI_CL_DVFS,
> +	SCPI_CL_POWER,
> +	SCPI_CL_THERMAL,
> +	SCPI_MAX,
> +};
> +

As I said before these values were introduced by me initially and I
reckon firmware doesn't depend on that. Have you really tested dropping
them ? This must go as they are useless and we now have tokens which are
much better.

I will stop here and ask why can't you start with simple change like
below ? Then we can add or re-define the structures/enums when
absolutely needed. Please don't just copy the entire driver and make
changes where-ever needed or please try to adapt to the new driver and
try to deviate as less as required by the firmware.

Regards,
Sudeep

--->8

diff --git i/drivers/firmware/arm_scpi.c w/drivers/firmware/arm_scpi.c
index 438893762076..b394ffb5939c 100644
--- i/drivers/firmware/arm_scpi.c
+++ w/drivers/firmware/arm_scpi.c
@@ -82,6 +82,9 @@

  #define MAX_RX_TIMEOUT		(msecs_to_jiffies(30))

+typedef int (*scpi_send_msg_func)(u8 cmd, void *tx_buf, unsigned int 
tx_len,
+				  void *rx_buf, unsigned int rx_len);
+
  enum scpi_error_codes {
  	SCPI_SUCCESS = 0, /* Success */
  	SCPI_ERR_PARAM = 1, /* Invalid parameter(s) */
@@ -162,6 +165,7 @@ struct scpi_drvinfo {
  	u32 firmware_version;
  	int num_chans;
  	atomic_t next_chan;
+	scpi_send_msg_func send_msg;
  	struct scpi_ops *scpi_ops;
  	struct scpi_chan *channels;
  	struct scpi_dvfs_info *dvfs[MAX_DVFS_DOMAINS];
@@ -397,8 +401,8 @@ scpi_clk_get_range(u16 clk_id, unsigned long *min, 
unsigned long *max)
  	struct clk_get_info clk;
  	__le16 le_clk_id = cpu_to_le16(clk_id);

-	ret = scpi_send_message(SCPI_CMD_GET_CLOCK_INFO, &le_clk_id,
-				sizeof(le_clk_id), &clk, sizeof(clk));
+	ret = scpi_info->send_msg(SCPI_CMD_GET_CLOCK_INFO, &le_clk_id,
+				  sizeof(le_clk_id), &clk, sizeof(clk));
  	if (!ret) {
  		*min = le32_to_cpu(clk.min_rate);
  		*max = le32_to_cpu(clk.max_rate);
@@ -412,8 +416,8 @@ static unsigned long scpi_clk_get_val(u16 clk_id)
  	struct clk_get_value clk;
  	__le16 le_clk_id = cpu_to_le16(clk_id);

-	ret = scpi_send_message(SCPI_CMD_GET_CLOCK_VALUE, &le_clk_id,
-				sizeof(le_clk_id), &clk, sizeof(clk));
+	ret = scpi_info->send_msg(SCPI_CMD_GET_CLOCK_VALUE, &le_clk_id,
+				  sizeof(le_clk_id), &clk, sizeof(clk));
  	return ret ? ret : le32_to_cpu(clk.rate);
  }

@@ -425,8 +429,8 @@ static int scpi_clk_set_val(u16 clk_id, unsigned 
long rate)
  		.rate = cpu_to_le32(rate)
  	};

-	return scpi_send_message(SCPI_CMD_SET_CLOCK_VALUE, &clk, sizeof(clk),
-				 &stat, sizeof(stat));
+	return scpi_info->send_msg(SCPI_CMD_SET_CLOCK_VALUE, &clk, sizeof(clk),
+				   &stat, sizeof(stat));
  }

  static int scpi_dvfs_get_idx(u8 domain)
@@ -434,8 +438,8 @@ static int scpi_dvfs_get_idx(u8 domain)
  	int ret;
  	u8 dvfs_idx;

-	ret = scpi_send_message(SCPI_CMD_GET_DVFS, &domain, sizeof(domain),
-				&dvfs_idx, sizeof(dvfs_idx));
+	ret = scpi_info->send_msg(SCPI_CMD_GET_DVFS, &domain, sizeof(domain),
+				  &dvfs_idx, sizeof(dvfs_idx));
  	return ret ? ret : dvfs_idx;
  }

@@ -444,8 +448,8 @@ static int scpi_dvfs_set_idx(u8 domain, u8 index)
  	int stat;
  	struct dvfs_set dvfs = {domain, index};

-	return scpi_send_message(SCPI_CMD_SET_DVFS, &dvfs, sizeof(dvfs),
-				 &stat, sizeof(stat));
+	return scpi_info->send_msg(SCPI_CMD_SET_DVFS, &dvfs, sizeof(dvfs),
+				   &stat, sizeof(stat));
  }

  static int opp_cmp_func(const void *opp1, const void *opp2)
@@ -468,8 +472,8 @@ static struct scpi_dvfs_info *scpi_dvfs_get_info(u8 
domain)
  	if (scpi_info->dvfs[domain])	/* data already populated */
  		return scpi_info->dvfs[domain];

-	ret = scpi_send_message(SCPI_CMD_GET_DVFS_INFO, &domain, sizeof(domain),
-				&buf, sizeof(buf));
+	ret = scpi_info->send_msg(SCPI_CMD_GET_DVFS_INFO, &domain,
+				  sizeof(domain), &buf, sizeof(buf));

  	if (ret)
  		return ERR_PTR(ret);
@@ -503,8 +507,8 @@ static int scpi_sensor_get_capability(u16 *sensors)
  	struct sensor_capabilities cap_buf;
  	int ret;

-	ret = scpi_send_message(SCPI_CMD_SENSOR_CAPABILITIES, NULL, 0, &cap_buf,
-				sizeof(cap_buf));
+	ret = scpi_info->send_msg(SCPI_CMD_SENSOR_CAPABILITIES, NULL, 0,
+				  &cap_buf, sizeof(cap_buf));
  	if (!ret)
  		*sensors = le16_to_cpu(cap_buf.sensors);

@@ -517,8 +521,8 @@ static int scpi_sensor_get_info(u16 sensor_id, 
struct scpi_sensor_info *info)
  	struct _scpi_sensor_info _info;
  	int ret;

-	ret = scpi_send_message(SCPI_CMD_SENSOR_INFO, &id, sizeof(id),
-				&_info, sizeof(_info));
+	ret = scpi_info->send_msg(SCPI_CMD_SENSOR_INFO, &id, sizeof(id),
+				  &_info, sizeof(_info));
  	if (!ret) {
  		memcpy(info, &_info, sizeof(*info));
  		info->sensor_id = le16_to_cpu(_info.sensor_id);
@@ -533,8 +537,8 @@ static int scpi_sensor_get_value(u16 sensor, u64 *val)
  	struct sensor_value buf;
  	int ret;

-	ret = scpi_send_message(SCPI_CMD_SENSOR_VALUE, &id, sizeof(id),
-				&buf, sizeof(buf));
+	ret = scpi_info->send_msg(SCPI_CMD_SENSOR_VALUE, &id, sizeof(id),
+				  &buf, sizeof(buf));
  	if (!ret)
  		*val = (u64)le32_to_cpu(buf.hi_val) << 32 |
  			le32_to_cpu(buf.lo_val);
@@ -548,8 +552,8 @@ static int scpi_device_get_power_state(u16 dev_id)
  	u8 pstate;
  	__le16 id = cpu_to_le16(dev_id);

-	ret = scpi_send_message(SCPI_CMD_GET_DEVICE_PWR_STATE, &id,
-				sizeof(id), &pstate, sizeof(pstate));
+	ret = scpi_info->send_msg(SCPI_CMD_GET_DEVICE_PWR_STATE, &id,
+				  sizeof(id), &pstate, sizeof(pstate));
  	return ret ? ret : pstate;
  }

@@ -561,8 +565,8 @@ static int scpi_device_set_power_state(u16 dev_id, 
u8 pstate)
  		.pstate = pstate,
  	};

-	return scpi_send_message(SCPI_CMD_SET_DEVICE_PWR_STATE, &dev_set,
-				 sizeof(dev_set), &stat, sizeof(stat));
+	return scpi_info->send_msg(SCPI_CMD_SET_DEVICE_PWR_STATE, &dev_set,
+				   sizeof(dev_set), &stat, sizeof(stat));
  }

  static struct scpi_ops scpi_ops = {
@@ -591,8 +595,8 @@ static int scpi_init_versions(struct scpi_drvinfo *info)
  	int ret;
  	struct scp_capabilities caps;

-	ret = scpi_send_message(SCPI_CMD_SCPI_CAPABILITIES, NULL, 0,
-				&caps, sizeof(caps));
+	ret = scpi_info->send_msg(SCPI_CMD_SCPI_CAPABILITIES, NULL, 0,
+				  &caps, sizeof(caps));
  	if (!ret) {
  		info->protocol_version = le32_to_cpu(caps.protocol_version);
  		info->firmware_version = le32_to_cpu(caps.platform_version);
@@ -681,6 +685,14 @@ static int scpi_alloc_xfer_list(struct device *dev, 
struct scpi_chan *ch)
  	return 0;
  }

+static const struct of_device_id scpi_of_match[] = {
+	{.compatible = "arm,scpi", .data = scpi_send_message},
+	{.compatible = "arm,scpi-legacy", .data = scpi_send_message},
+	{},
+};
+
+MODULE_DEVICE_TABLE(of, scpi_of_match);
+
  static int scpi_probe(struct platform_device *pdev)
  {
  	int count, idx, ret;
@@ -688,11 +700,15 @@ static int scpi_probe(struct platform_device *pdev)
  	struct scpi_chan *scpi_chan;
  	struct device *dev = &pdev->dev;
  	struct device_node *np = dev->of_node;
+	const struct of_device_id *match;

  	scpi_info = devm_kzalloc(dev, sizeof(*scpi_info), GFP_KERNEL);
  	if (!scpi_info)
  		return -ENOMEM;

+	match = of_match_device(scpi_of_match, dev);
+	scpi_info->send_msg = match->data;
+
  	count = of_count_phandle_with_args(np, "mboxes", "#mbox-cells");
  	if (count < 0) {
  		dev_err(dev, "no mboxes property in '%s'\n", np->full_name);
@@ -778,13 +794,6 @@ static int scpi_probe(struct platform_device *pdev)
  	return of_platform_populate(dev->of_node, NULL, NULL, dev);
  }

-static const struct of_device_id scpi_of_match[] = {
-	{.compatible = "arm,scpi"},
-	{},
-};
-
-MODULE_DEVICE_TABLE(of, scpi_of_match);
-
  static struct platform_driver scpi_driver = {
  	.driver = {
  		.name = "scpi_protocol",