From: John Garry <john.garry@huawei.com>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: <rjw@rjwysocki.net>, <lenb@kernel.org>, <jeremy.linton@arm.com>,
<arnd@arndb.de>, <olof@lixom.net>, <linux-kernel@vger.kernel.org>,
<linux-acpi@vger.kernel.org>, <guohanjun@huawei.com>
Subject: Re: [PATCH RFC 2/2] soc: Add a basic ACPI generic driver
Date: Tue, 28 Jan 2020 13:33:48 +0000 [thread overview]
Message-ID: <ae2c9384-4fb9-b3ea-d6a8-aaa652ffdafc@huawei.com> (raw)
In-Reply-To: <20200128115629.GB2680602@kroah.com>
Hi Greg,
>> +
>> +#define pr_fmt(fmt) "SOC ACPI GENERIC: " fmt
>
> You have a device, why do you need pr_fmt()?
>
The only print in the code can be removed, below, so I need not worry
about this, i.e. remove it.
>> +
>> +#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()?
Yes, more appropriate.
>
> And shouldn't the core print out the error, not the person who calls it?
Sure, that would sounds reasonable, but I just wanted to get the index
at which we fail. I could live without 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.
>
Fine, there is the soc device custom attr group which I can use. But, as
Arnd said, maybe we can drop this custom file.
Cheers,
John
next prev parent reply other threads:[~2020-01-28 13:33 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-28 11:14 [PATCH RFC 0/2] Add basic generic ACPI soc driver John Garry
2020-01-28 11:14 ` [PATCH RFC 1/2] ACPI/PPTT: Add acpi_pptt_get_package_info() API John Garry
2020-01-28 12:34 ` Sudeep Holla
2020-01-28 14:04 ` John Garry
2020-01-28 14:54 ` Sudeep Holla
2020-01-29 11:03 ` John Garry
2020-01-30 11:23 ` Sudeep Holla
2020-01-30 16:12 ` John Garry
2020-01-30 17:41 ` Sudeep Holla
2020-01-31 10:58 ` John Garry
2020-01-28 11:14 ` [PATCH RFC 2/2] soc: Add a basic ACPI generic driver John Garry
2020-01-28 11:56 ` Greg KH
2020-01-28 13:33 ` John Garry [this message]
2020-01-28 12:50 ` Arnd Bergmann
2020-01-28 14:46 ` John Garry
2020-01-28 15:20 ` Sudeep Holla
2020-01-28 15:59 ` John Garry
2020-01-28 16:17 ` Sudeep Holla
2020-01-28 17:51 ` Olof Johansson
2020-01-28 18:22 ` John Garry
2020-01-28 19:11 ` Rafael J. Wysocki
2020-01-28 19:28 ` John Garry
2020-01-28 22:30 ` Rafael J. Wysocki
2020-01-29 10:27 ` John Garry
2020-01-28 20:06 ` Olof Johansson
2020-01-29 9:58 ` John Garry
2020-01-28 16:56 ` [PATCH RFC 0/2] Add basic generic ACPI soc driver Jeremy Linton
2020-01-28 17:28 ` John Garry
2020-01-28 19:04 ` Jeremy Linton
2020-01-28 20:07 ` John Garry
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