Re: [PATCH 4/8] soc: imx: add icc paths for i.MX8MP media blk ctrl

[Lucas Stach <l.stach@pengutronix.de>]

Am Mittwoch, dem 01.06.2022 um 17:45 +0800 schrieb Peng Fan (OSS):
> From: Peng Fan <peng.fan@nxp.com>
> 
> Add interconnect paths for i.MX8MP media blk ctrl
> 
> Signed-off-by: Peng Fan <peng.fan@nxp.com>
> ---
>  arch/arm64/boot/dts/freescale/imx8mp.dtsi |  1 +
>  drivers/soc/imx/imx8m-blk-ctrl.c          | 31 +++++++++++++++++++++++
>  2 files changed, 32 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/freescale/imx8mp.dtsi b/arch/arm64/boot/dts/freescale/imx8mp.dtsi
> index d9542dfff83f..2a1c6ff37e03 100644
> --- a/arch/arm64/boot/dts/freescale/imx8mp.dtsi
> +++ b/arch/arm64/boot/dts/freescale/imx8mp.dtsi
> @@ -4,6 +4,7 @@
>   */
>  
>  #include <dt-bindings/clock/imx8mp-clock.h>
> +#include <dt-bindings/interconnect/fsl,imx8mp.h>
>  #include <dt-bindings/power/imx8mp-power.h>
>  #include <dt-bindings/gpio/gpio.h>
>  #include <dt-bindings/input/input.h>
> diff --git a/drivers/soc/imx/imx8m-blk-ctrl.c b/drivers/soc/imx/imx8m-blk-ctrl.c
> index 7f49385ed2f8..423cac0c9cb6 100644
> --- a/drivers/soc/imx/imx8m-blk-ctrl.c
> +++ b/drivers/soc/imx/imx8m-blk-ctrl.c
> @@ -5,6 +5,7 @@
>   */
>  
>  #include <linux/device.h>
> +#include <linux/interconnect.h>
>  #include <linux/module.h>
>  #include <linux/of_device.h>
>  #include <linux/platform_device.h>
> @@ -37,6 +38,8 @@ struct imx8m_blk_ctrl_domain_data {
>  	const char *name;
>  	const char * const *clk_names;
>  	int num_clks;
> +	const char * const *path_names;
> +	int num_paths;
>  	const char *gpc_name;
>  	u32 rst_mask;
>  	u32 clk_mask;
> @@ -52,11 +55,13 @@ struct imx8m_blk_ctrl_domain_data {
>  };
>  
>  #define DOMAIN_MAX_CLKS 4
> +#define DOMAIN_MAX_PATHS 4
>  
>  struct imx8m_blk_ctrl_domain {
>  	struct generic_pm_domain genpd;
>  	const struct imx8m_blk_ctrl_domain_data *data;
>  	struct clk_bulk_data clks[DOMAIN_MAX_CLKS];
> +	struct icc_bulk_data paths[DOMAIN_MAX_PATHS];
>  	struct device *power_dev;
>  	struct imx8m_blk_ctrl *bc;
>  };
> @@ -117,6 +122,10 @@ static int imx8m_blk_ctrl_power_on(struct generic_pm_domain *genpd)
>  	if (data->mipi_phy_rst_mask)
>  		regmap_set_bits(bc->regmap, BLK_MIPI_RESET_DIV, data->mipi_phy_rst_mask);
>  
> +	ret = icc_bulk_set_bw(data->num_paths, domain->paths);
> +	if (ret)
> +		dev_err(bc->dev, "failed to set icc bw\n");
> +
>  	/* disable upstream clocks */
>  	clk_bulk_disable_unprepare(data->num_clks, domain->clks);
>  
> @@ -228,6 +237,18 @@ static int imx8m_blk_ctrl_probe(struct platform_device *pdev)
>  		for (j = 0; j < data->num_clks; j++)
>  			domain->clks[j].id = data->clk_names[j];
>  
> +		for (j = 0; j < data->num_paths; j++) {
> +			domain->paths[j].name = data->path_names[j];
> +			domain->paths[j].avg_bw = INT_MAX;
> +			domain->paths[j].peak_bw = INT_MAX;
> +		}
> +
> +		ret = devm_of_icc_bulk_get(dev, data->num_paths, domain->paths);
> +		if (ret) {
> +			dev_err_probe(dev, ret, "failed to get noc entries\n");

I don't like that this introduces a new requirement to the kernel
config and DT, which is a backwards compat breaking change. Now one
could argue that the NoC configuration is pretty critical and should
not be skipped, but it has the potential to break currently working
systems.

I think it would be better do a
if (ret != -EPROBE_DEFER)
	dev_warn_once(dev, "Could not get interconnect paths, NoC will stay unconfigured!\n");

here and ignore the error to allow the blk-ctrl to probe even if the
interconnect paths couldn't be found due to lacking kernel config or
DT.

Regards,
Lucas

> +			goto cleanup_pds;
> +		}
> +
>  		ret = devm_clk_bulk_get(dev, data->num_clks, domain->clks);
>  		if (ret) {
>  			dev_err_probe(dev, ret, "failed to get clock\n");
> @@ -647,6 +668,8 @@ static const struct imx8m_blk_ctrl_domain_data imx8mp_media_blk_ctl_domain_data[
>  		.gpc_name = "lcdif1",
>  		.rst_mask = BIT(4) | BIT(5) | BIT(23),
>  		.clk_mask = BIT(4) | BIT(5) | BIT(23),
> +		.path_names = (const char *[]){"lcdif-rd", "lcdif-wr"},
> +		.num_paths = 2,
>  	},
>  	[IMX8MP_MEDIABLK_PD_ISI] = {
>  		.name = "mediablk-isi",
> @@ -655,6 +678,8 @@ static const struct imx8m_blk_ctrl_domain_data imx8mp_media_blk_ctl_domain_data[
>  		.gpc_name = "isi",
>  		.rst_mask = BIT(6) | BIT(7),
>  		.clk_mask = BIT(6) | BIT(7),
> +		.path_names = (const char *[]){"isi0", "isi1", "isi2"},
> +		.num_paths = 3,
>  	},
>  	[IMX8MP_MEDIABLK_PD_MIPI_CSI2_2] = {
>  		.name = "mediablk-mipi-csi2-2",
> @@ -672,6 +697,8 @@ static const struct imx8m_blk_ctrl_domain_data imx8mp_media_blk_ctl_domain_data[
>  		.gpc_name = "lcdif2",
>  		.rst_mask = BIT(11) | BIT(12) | BIT(24),
>  		.clk_mask = BIT(11) | BIT(12) | BIT(24),
> +		.path_names = (const char *[]){"lcdif-rd", "lcdif-wr"},
> +		.num_paths = 2,
>  	},
>  	[IMX8MP_MEDIABLK_PD_ISP] = {
>  		.name = "mediablk-isp",
> @@ -680,6 +707,8 @@ static const struct imx8m_blk_ctrl_domain_data imx8mp_media_blk_ctl_domain_data[
>  		.gpc_name = "isp",
>  		.rst_mask = BIT(16) | BIT(17) | BIT(18),
>  		.clk_mask = BIT(16) | BIT(17) | BIT(18),
> +		.path_names = (const char *[]){"isp0", "isp1"},
> +		.num_paths = 2,
>  	},
>  	[IMX8MP_MEDIABLK_PD_DWE] = {
>  		.name = "mediablk-dwe",
> @@ -688,6 +717,8 @@ static const struct imx8m_blk_ctrl_domain_data imx8mp_media_blk_ctl_domain_data[
>  		.gpc_name = "dwe",
>  		.rst_mask = BIT(19) | BIT(20) | BIT(21),
>  		.clk_mask = BIT(19) | BIT(20) | BIT(21),
> +		.path_names = (const char *[]){"dwe"},
> +		.num_paths = 1,
>  	},
>  	[IMX8MP_MEDIABLK_PD_MIPI_DSI_2] = {
>  		.name = "mediablk-mipi-dsi-2",