From: Stephen Boyd <swboyd@chromium.org>
To: linux-kernel@vger.kernel.org, patrick.rudolph@9elements.com
Cc: coreboot@coreboot.org,
Patrick Rudolph <patrick.rudolph@9elements.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Allison Randal <allison@lohutok.net>,
Alexios Zavras <alexios.zavras@intel.com>,
Julius Werner <jwerner@chromium.org>,
Samuel Holland <samuel@sholland.org>
Subject: Re: [PATCH v4 2/2] firmware: google: Expose coreboot tables over sysfs
Date: Thu, 25 Jun 2020 00:10:51 -0700 [thread overview]
Message-ID: <159306905194.62212.10204515187655751787@swboyd.mtv.corp.google.com> (raw)
In-Reply-To: <20200407082923.2001556-3-patrick.rudolph@9elements.com>
Quoting patrick.rudolph@9elements.com (2020-04-07 01:29:07)
> From: Patrick Rudolph <patrick.rudolph@9elements.com>
>
> Make all coreboot table entries available to userland. This is useful for
> tools that are currently using /dev/mem.
>
> Besides the tag and size also expose the raw table data itself.
>
> Update the ABI documentation to explain the new sysfs interface.
>
> Tools can easily scan for the right coreboot table by reading
> /sys/bus/coreboot/devices/coreboot*/attributes/id
> The binary table data can then be read from
> /sys/bus/coreboot/devices/coreboot*/attributes/data
>
> Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
> ---
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Minor nits below:
> -v2:
> - Add ABI documentation
> - Add 0x prefix on hex values
> - Remove wrong ioremap hint as found by CI
> -v3:
> - Use BIN_ATTR_RO
> -v4:
> - Updated ABI documentation
> ---
> Documentation/ABI/stable/sysfs-bus-coreboot | 30 +++++++++++
> drivers/firmware/google/coreboot_table.c | 58 +++++++++++++++++++++
> 2 files changed, 88 insertions(+)
>
> diff --git a/Documentation/ABI/stable/sysfs-bus-coreboot b/Documentation/ABI/stable/sysfs-bus-coreboot
> index 6055906f41f2..328153a1b3f4 100644
> --- a/Documentation/ABI/stable/sysfs-bus-coreboot
> +++ b/Documentation/ABI/stable/sysfs-bus-coreboot
> diff --git a/drivers/firmware/google/coreboot_table.c b/drivers/firmware/google/coreboot_table.c
> index 0205987a4fd4..d0fc3eb93f4f 100644
> --- a/drivers/firmware/google/coreboot_table.c
> +++ b/drivers/firmware/google/coreboot_table.c
> @@ -3,9 +3,11 @@
> * coreboot_table.c
> *
> * Module providing coreboot table access.
> + * Exports coreboot tables as attributes in sysfs.
> *
> * Copyright 2017 Google Inc.
> * Copyright 2017 Samuel Holland <samuel@sholland.org>
> + * Copyright 2019 9elements Agency GmbH
> */
>
> #include <linux/acpi.h>
> @@ -84,6 +86,60 @@ void coreboot_driver_unregister(struct coreboot_driver *driver)
> }
> EXPORT_SYMBOL(coreboot_driver_unregister);
>
> +static ssize_t id_show(struct device *dev,
> + struct device_attribute *attr, char *buffer)
> +{
> + struct coreboot_device *device = CB_DEV(dev);
Wouldn't hurt to throw const in front of these.
> +
> + return sprintf(buffer, "0x%08x\n", device->entry.tag);
> +}
> +
> +static ssize_t size_show(struct device *dev,
> + struct device_attribute *attr, char *buffer)
> +{
> + struct coreboot_device *device = CB_DEV(dev);
And these. But the function is so short probably doesn't really matter.
> +
> + return sprintf(buffer, "%u\n", device->entry.size);
> +}
> +
> +static DEVICE_ATTR_RO(id);
> +static DEVICE_ATTR_RO(size);
> +
> +static struct attribute *cb_dev_attrs[] = {
> + &dev_attr_id.attr,
> + &dev_attr_size.attr,
> + NULL
> +};
> +
> +static ssize_t data_read(struct file *filp, struct kobject *kobj,
> + struct bin_attribute *bin_attr,
> + char *buffer, loff_t offset, size_t count)
> +{
> + struct device *dev = kobj_to_dev(kobj);
> + struct coreboot_device *device = CB_DEV(dev);
> +
> + return memory_read_from_buffer(buffer, count, &offset,
> + &device->entry, device->entry.size);
> +}
> +
> +static BIN_ATTR_RO(data, 0);
Still no way to figure out the actual size? Can we add the bin_attribute
at runtime?
> +
> +static struct bin_attribute *cb_dev_bin_attrs[] = {
> + &bin_attr_data,
> + NULL
> +};
> +
prev parent reply other threads:[~2020-06-25 7:10 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-07 8:29 [PATCH v4 0/2] firmware: google: Expose coreboot tables and CBMEM patrick.rudolph
2020-04-07 8:29 ` [PATCH v4 1/2] firmware: google: Expose CBMEM over sysfs patrick.rudolph
2020-04-20 0:07 ` Samuel Holland
2020-06-25 7:05 ` Stephen Boyd
2020-06-25 20:51 ` Julius Werner
2020-06-26 7:27 ` Stephen Boyd
2020-07-01 0:22 ` Julius Werner
2020-04-07 8:29 ` [PATCH v4 2/2] firmware: google: Expose coreboot tables " patrick.rudolph
2020-04-20 0:07 ` Samuel Holland
2020-06-25 7:10 ` Stephen Boyd [this message]
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