On Tue, Jan 28, 2020 at 07:14:19PM +0800, John Garry wrote:
> Add a generic driver for platforms which populate their ACPI PPTT
> processor package ID Type Structure according to suggestion in the ACPI
> spec - see ACPI 6.2, section 5.2.29.3 ID structure Type 2.
>
> The soc_id is from member LEVEL_2_ID.
>
> For this, we need to use a whitelist of platforms which are known to
> populate the structure as suggested.
>
> For now, only the vendor and soc_id fields are exposed.
>
> Signed-off-by: John Garry <john.garry@xxxxxxxxxx>
> ---
> drivers/soc/Makefile | 1 +
> drivers/soc/acpi_generic.c | 102 +++++++++++++++++++++++++++++++++++++
> 2 files changed, 103 insertions(+)
> create mode 100644 drivers/soc/acpi_generic.c
>
> diff --git a/drivers/soc/Makefile b/drivers/soc/Makefile
> index 8b49d782a1ab..2a59a30a22cd 100644
> --- a/drivers/soc/Makefile
> +++ b/drivers/soc/Makefile
> @@ -3,6 +3,7 @@
> # Makefile for the Linux Kernel SOC specific device drivers.
> #
>
> +obj-$(CONFIG_ACPI_PPTT) += acpi_generic.o
> obj-$(CONFIG_ARCH_ACTIONS) += actions/
> obj-$(CONFIG_SOC_ASPEED) += aspeed/
> obj-$(CONFIG_ARCH_AT91) += atmel/
> diff --git a/drivers/soc/acpi_generic.c b/drivers/soc/acpi_generic.c
> new file mode 100644
> index 000000000000..34a1f5f8e063
> --- /dev/null
> +++ b/drivers/soc/acpi_generic.c
> @@ -0,0 +1,102 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) John Garry, john.garry@xxxxxxxxxx
> + */
> +
> +#define pr_fmt(fmt) "SOC ACPI GENERIC: " fmt
You have a device, why do you need pr_fmt()?
> +
> +#include <linux/acpi.h>
> +#include <linux/sys_soc.h>
> +
> +/*
> + * Known platforms that fill in PPTT package ID structures according to
> + * ACPI spec examples, that being:
> + * - Custom driver attribute is in ID Type Structure VENDOR_ID member
> + * - SoC id is in ID Type Structure LEVEL_2_ID member
> + * See ACPI SPEC 6.2 Table 5-154 for PPTT ID Type Structure
> + */
> +static struct acpi_platform_list plat_list[] = {
> + {"HISI ", "HIP08 ", 0, ACPI_SIG_PPTT, all_versions},
> + { } /* End */
> +};
> +
> +struct acpi_generic_soc_struct {
> + struct soc_device_attribute dev_attr;
> + u32 vendor;
> +};
> +
> +static ssize_t vendor_show(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + struct acpi_generic_soc_struct *soc = dev_get_drvdata(dev);
> + u8 vendor_id[5] = {};
> +
> + *(u32 *)vendor_id = soc->vendor;
> +
> + return sprintf(buf, "%s\n", vendor_id);
> +}
> +
> +static DEVICE_ATTR_RO(vendor);
> +
> +static __init int soc_acpi_generic_init(void)
> +{
> + int index;
> +
> + index = acpi_match_platform_list(plat_list);
> + if (index < 0)
> + return -ENOENT;
> +
> + index = 0;
> + while (true) {
> + struct acpi_pptt_package_info info;
> +
> + if (!acpi_pptt_get_package_info(index, &info)) {
> + struct soc_device_attribute *soc_dev_attr;
> + struct acpi_generic_soc_struct *soc;
> + struct soc_device *soc_dev;
> + u8 soc_id[9] = {};
> +
> + *(u64 *)soc_id = info.LEVEL_2_ID;
> +
> + soc = kzalloc(sizeof(*soc), GFP_KERNEL);
> + if (!soc)
> + return -ENOMEM;
> +
> + soc_dev_attr = &soc->dev_attr;
> + soc_dev_attr->soc_id = kasprintf(GFP_KERNEL, "%s",
> + soc_id);
> + if (!soc_dev_attr->soc_id) {
> + kfree(soc);
> + return -ENOMEM;
> + }
> + soc->vendor = info.vendor_id;
> +
> + soc_dev = soc_device_register(soc_dev_attr);
> + if (IS_ERR(soc_dev)) {
> + int ret = PTR_ERR(soc_dev);
> +
> + pr_info("could not register soc (%d) index=%d\n",
> + ret, index);
pr_err()?
And shouldn't the core print out the error, not the person who calls it?
> + kfree(soc_dev_attr->soc_id);
> + kfree(soc);
> + return ret;
> + }
> + dev_set_drvdata(soc_device_to_device(soc_dev), soc);
> + device_create_file(soc_device_to_device(soc_dev),
> + &dev_attr_vendor);
You just raced with userspace and lost. Use the built-in api that I
made _just_ because of SOC drivers to do this correctly.
thanks,
greg k-h
