Re: [PATCH v5] soc: imx: Add SoC device register for i.MX9

[Stefan Wahren]

Hi Alice,

these are the new comments

Am 11.11.24 um 04:23 schrieb alice.guo@xxxxxxxxxxx:
> From: "alice.guo" <alice.guo@xxxxxxx>
>
> i.MX9 SoCs have SoC ID, SoC revision number and chip unique identifier
> which are provided by the corresponding ARM trusted firmware API. This
> patch intends to use SMC call to obtain these information and then
> register i.MX9 SoC as a device.
>
> Signed-off-by: Alice Guo <alice.guo@xxxxxxx>
> Tested-by: Alexander Stein <alexander.stein@xxxxxxxxxxxxxxx>
> Reviewed-by: Stefan Wahren <wahrenst@xxxxxxx>
> ---
>
> Changes for v2:
>   - refine error log print
> Changes for v3:
>   - return -EINVAL when arm_smccc_smc failed
>   - fix the build warning caused by pr_err("%s: SMC failed: %d\n", __func__, res.a0);
>   - drop the pr_err in imx9_soc_init
>   - free the memory in the reverse order of allocation
>   - use of_match_node instead of of_machine_is_compatible
> Changes for v4:
>   - fix the build warning: 'imx9_soc_match' defined but not used [-Wunused-const-variable=]
>   - add Tested-by and Reviewed-by
> Changes for v5:
>   - probe imx9 soc driver as a platform driver
>
>   drivers/soc/imx/Makefile   |   2 +-
>   drivers/soc/imx/soc-imx9.c | 124 +++++++++++++++++++++++++++++++++++++
>   2 files changed, 125 insertions(+), 1 deletion(-)
>   create mode 100644 drivers/soc/imx/soc-imx9.c
>
> diff --git a/drivers/soc/imx/Makefile b/drivers/soc/imx/Makefile
> index 3ad321ca608a..ca6a5fa1618f 100644
> --- a/drivers/soc/imx/Makefile
> +++ b/drivers/soc/imx/Makefile
> @@ -3,4 +3,4 @@ ifeq ($(CONFIG_ARM),y)
>   obj-$(CONFIG_ARCH_MXC) += soc-imx.o
>   endif
>   obj-$(CONFIG_SOC_IMX8M) += soc-imx8m.o
> -obj-$(CONFIG_SOC_IMX9) += imx93-src.o
> +obj-$(CONFIG_SOC_IMX9) += imx93-src.o soc-imx9.o
> diff --git a/drivers/soc/imx/soc-imx9.c b/drivers/soc/imx/soc-imx9.c
> new file mode 100644
> index 000000000000..4ef92260e8f9
> --- /dev/null
> +++ b/drivers/soc/imx/soc-imx9.c
> @@ -0,0 +1,124 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright 2024 NXP
> + */
> +
> +#include <linux/arm-smccc.h>
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +#include <linux/sys_soc.h>
> +
> +#define IMX_SIP_GET_SOC_INFO	0xc2000006
> +#define SOC_ID(x)		(((x) & 0xFFFF) >> 8)
> +#define SOC_REV_MAJOR(x)	((((x) >> 28) & 0xF) - 0x9)
> +#define SOC_REV_MINOR(x)	(((x) >> 24) & 0xF)
> +
> +static int imx9_soc_probe(struct platform_device *pdev)
> +{
> +	struct soc_device_attribute *attr;
> +	struct arm_smccc_res res;
> +	struct soc_device *sdev;
> +	u32 soc_id, rev_major, rev_minor;
> +	u64 uid127_64, uid63_0;
> +	int err;
> +
> +	attr = kzalloc(sizeof(*attr), GFP_KERNEL);
> +	if (!attr)
> +		return -ENOMEM;
> +
> +	err = of_property_read_string(of_root, "model", &attr->machine);
> +	if (err) {
> +		pr_err("%s: missing model property: %d\n", __func__, err);
> +		goto attr;
> +	}
> +
> +	attr->family = kasprintf(GFP_KERNEL, "Freescale i.MX");
> +
> +	/*
> +	 * Retrieve the soc id, rev & uid info:
> +	 * res.a1[31:16]: soc revision;
> +	 * res.a1[15:0]: soc id;
> +	 * res.a2: uid[127:64];
> +	 * res.a3: uid[63:0];
> +	 */
> +	arm_smccc_smc(IMX_SIP_GET_SOC_INFO, 0, 0, 0, 0, 0, 0, 0, &res);
> +	if (res.a0 != SMCCC_RET_SUCCESS) {
> +		pr_err("%s: SMC failed: 0x%lx\n", __func__, res.a0);
> +		err = -EINVAL;
> +		goto family;
> +	}
I like it that soc-imx8m.c handles the corner case
CONFIG_HAVE_ARM_SMCCC=n in order to increase build coverage.

Is it possible to adapt this driver accordingly?
> +
> +	soc_id = SOC_ID(res.a1);
> +	rev_major = SOC_REV_MAJOR(res.a1);
> +	rev_minor = SOC_REV_MINOR(res.a1);
> +
> +	attr->soc_id = kasprintf(GFP_KERNEL, "i.MX%2x", soc_id);
> +	attr->revision = kasprintf(GFP_KERNEL, "%d.%d", rev_major, rev_minor);
> +
> +	uid127_64 = res.a2;
> +	uid63_0 = res.a3;
> +	attr->serial_number = kasprintf(GFP_KERNEL, "%016llx%016llx", uid127_64, uid63_0);
> +
> +	sdev = soc_device_register(attr);
> +	if (IS_ERR(sdev)) {
> +		err = PTR_ERR(sdev);
> +		pr_err("%s failed to register SoC as a device: %d\n", __func__, err);
> +		goto serial_number;
> +	}
> +
> +	return 0;
> +
> +serial_number:
> +	kfree(attr->serial_number);
> +	kfree(attr->revision);
> +	kfree(attr->soc_id);
> +family:
> +	kfree(attr->family);
> +attr:
> +	kfree(attr);
> +	return err;
> +}
> +
> +static __maybe_unused const struct of_device_id imx9_soc_match[] = {
> +	{ .compatible = "fsl,imx93", },
> +	{ .compatible = "fsl,imx95", },
> +	{ }
> +};
> +
> +static struct platform_driver imx9_soc_driver = {
> +	.probe = imx9_soc_probe,
> +	.driver.name = "imx9-soc",
Just a nit:

.driver = {
    .name = "imx9-soc",
},

This makes it easier to extend later. Maybe we can use a define also for
"imx9-soc" and use it
> +};
> +
> +static int __init imx9_soc_init(void)
> +{
> +	int ret;
> +	struct platform_device *pdev;
> +
> +	/* No match means it is not an i.MX 9 series SoC, do nothing. */
> +	if (!of_match_node(imx9_soc_match, of_root))
> +		return 0;
> +
> +	ret = platform_driver_register(&imx9_soc_driver);
> +	if (ret) {
> +		pr_err("failed to register imx9_soc platform driver: %d\n", ret);
> +		return ret;
> +	}
> +
> +	pdev = platform_device_register_simple("imx9-soc", -1, NULL, 0);
here too

Regards
> +	if (IS_ERR(pdev)) {
> +		pr_err("failed to register imx9_soc platform device: %ld\n", PTR_ERR(pdev));
> +		platform_driver_unregister(&imx9_soc_driver);
> +		return PTR_ERR(pdev);
> +	}
> +
> +	return 0;
> +}
> +device_initcall(imx9_soc_init);
> +
> +MODULE_AUTHOR("NXP");
> +MODULE_DESCRIPTION("NXP i.MX9 SoC");
> +MODULE_LICENSE("GPL");