[RFC,7/9] apple-gmux: add sysfs interface
Commit Message
Allow reading gmux ports from userspace. When the unsafe module
parameter allow_user_writes is true, writing 1 byte
values is also allowed.
For example:
cd /sys/bus/acpi/devices/APP000B:00/physical_node/
echo 4 > gmux_selected_port
cat gmux_selected_port_data | xxd -p
Will show the gmux version information (00000005 in this case)
Signed-off-by: Orlando Chamberlain <orlandoch.dev@gmail.com>
---
drivers/platform/x86/apple-gmux.c | 129 ++++++++++++++++++++++++++++++
1 file changed, 129 insertions(+)
Comments
Hi,
On 2/10/23 05:48, Orlando Chamberlain wrote:
> Allow reading gmux ports from userspace. When the unsafe module
> parameter allow_user_writes is true, writing 1 byte
> values is also allowed.
>
> For example:
>
> cd /sys/bus/acpi/devices/APP000B:00/physical_node/
> echo 4 > gmux_selected_port
> cat gmux_selected_port_data | xxd -p
>
> Will show the gmux version information (00000005 in this case)
Please use debugfs for this and as part of the conversion
drop the #ifdef-s (debugfs has stubs for when not enabled)
and drop all the error checking of creating the files, debugfs
is deliberately designed to not have any error checking in
the setup / teardown code.
This also removes the need for the allow_user_writes parameter
replacing it with the new kernel lockdown mechanism. debugfs
will automatically block access to writable files when
the kernel is in lockdown mode.
Regards,
Hans
> Signed-off-by: Orlando Chamberlain <orlandoch.dev@gmail.com>
> ---
> drivers/platform/x86/apple-gmux.c | 129 ++++++++++++++++++++++++++++++
> 1 file changed, 129 insertions(+)
>
> diff --git a/drivers/platform/x86/apple-gmux.c b/drivers/platform/x86/apple-gmux.c
> index c38d6ef0c15a..756059d48393 100644
> --- a/drivers/platform/x86/apple-gmux.c
> +++ b/drivers/platform/x86/apple-gmux.c
> @@ -66,6 +66,11 @@ struct apple_gmux_data {
> enum vga_switcheroo_client_id switch_state_external;
> enum vga_switcheroo_state power_state;
> struct completion powerchange_done;
> +
> +#ifdef CONFIG_SYSFS
> + /* sysfs data */
> + int selected_port;
> +#endif /* CONFIG_SYSFS */
> };
>
> static struct apple_gmux_data *apple_gmux_data;
> @@ -651,6 +656,121 @@ static void gmux_notify_handler(acpi_handle device, u32 value, void *context)
> complete(&gmux_data->powerchange_done);
> }
>
> +/**
> + * DOC: Sysfs Interface
> + *
> + * gmux ports can be read from userspace as a sysfs interface. For example:
> + *
> + * # echo 4 > /sys/bus/acpi/devices/APP000B:00/physical_node/gmux_selected_port
> + * # cat /sys/bus/acpi/devices/APP000B:00/physical_node/gmux_selected_port_data | xxd -p
> + * 00000005
> + *
> + * Reads 4 bytes from port 4 (GMUX_PORT_VERSION_MAJOR).
> + *
> + * Single byte writes are also supported, however this must be enabled with the
> + * unsafe allow_user_writes module parameter.
> + *
> + */
> +
> +#ifdef CONFIG_SYSFS
> +
> +static bool allow_user_writes;
> +module_param_unsafe(allow_user_writes, bool, 0);
> +MODULE_PARM_DESC(allow_user_writes, "Allow userspace to write to gmux ports (default: false) (bool)");
> +
> +static ssize_t gmux_selected_port_store(struct device *dev,
> + struct device_attribute *attr, const char *sysfsbuf, size_t count)
> +{
> + struct apple_gmux_data *gmux_data = dev_get_drvdata(dev);
> + u8 port;
> +
> + if (kstrtou8(sysfsbuf, 10, &port) < 0)
> + return -EINVAL;
> +
> + /* On pio gmux's, make sure the user doesn't access too high of a port. */
> + if ((gmux_data->config == &apple_gmux_pio) &&
> + port > (gmux_data->iolen - 4))
> + return -EINVAL;
> +
> + gmux_data->selected_port = port;
> + return count;
> +}
> +
> +static ssize_t gmux_selected_port_show(struct device *dev,
> + struct device_attribute *attr, char *sysfsbuf)
> +{
> + struct apple_gmux_data *gmux_data = dev_get_drvdata(dev);
> +
> + return sysfs_emit(sysfsbuf, "%d\n", gmux_data->selected_port);
> +}
> +
> +DEVICE_ATTR_RW(gmux_selected_port);
> +
> +static ssize_t gmux_selected_port_data_store(struct device *dev,
> + struct device_attribute *attr, const char *sysfsbuf, size_t count)
> +{
> + struct apple_gmux_data *gmux_data = dev_get_drvdata(dev);
> +
> + if (count == 1)
> + gmux_write8(gmux_data, gmux_data->selected_port, *sysfsbuf);
> + else
> + return -EINVAL;
> +
> + return count;
> +}
> +
> +static ssize_t gmux_selected_port_data_show(struct device *dev,
> + struct device_attribute *attr, char *sysfsbuf)
> +{
> + struct apple_gmux_data *gmux_data = dev_get_drvdata(dev);
> + u32 data;
> +
> + data = gmux_read32(gmux_data, gmux_data->selected_port);
> + memcpy(sysfsbuf, &data, sizeof(data));
> +
> + return sizeof(data);
> +}
> +
> +struct device_attribute dev_attr_gmux_selected_port_data_rw = __ATTR_RW(gmux_selected_port_data);
> +struct device_attribute dev_attr_gmux_selected_port_data_ro = __ATTR_RO(gmux_selected_port_data);
> +
> +static int gmux_init_sysfs(struct pnp_dev *pnp)
> +{
> + int ret;
> +
> + ret = device_create_file(&pnp->dev, &dev_attr_gmux_selected_port);
> + if (ret)
> + return ret;
> + if (allow_user_writes)
> + ret = device_create_file(&pnp->dev, &dev_attr_gmux_selected_port_data_rw);
> + else
> + ret = device_create_file(&pnp->dev, &dev_attr_gmux_selected_port_data_ro);
> + if (ret)
> + device_remove_file(&pnp->dev, &dev_attr_gmux_selected_port);
> + return ret;
> +}
> +
> +static void gmux_fini_sysfs(struct pnp_dev *pnp)
> +{
> + device_remove_file(&pnp->dev, &dev_attr_gmux_selected_port);
> + if (allow_user_writes)
> + device_remove_file(&pnp->dev, &dev_attr_gmux_selected_port_data_rw);
> + else
> + device_remove_file(&pnp->dev, &dev_attr_gmux_selected_port_data_ro);
> +}
> +
> +#else
> +
> +static int gmux_init_sysfs(struct pnp_dev *pnp)
> +{
> + return 0;
> +}
> +static void gmux_fini_sysfs(struct pnp_dev *pnp)
> +{
> +}
> +
> +#endif /* CONFIG_SYSFS */
> +
> static int gmux_suspend(struct device *dev)
> {
> struct pnp_dev *pnp = to_pnp_dev(dev);
> @@ -846,8 +966,16 @@ static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
> goto err_register_handler;
> }
>
> + ret = gmux_init_sysfs(pnp);
> + if (ret) {
> + pr_err("Failed to register gmux sysfs entries\n");
> + goto err_sysfs;
> + }
> +
> return 0;
>
> +err_sysfs:
> + vga_switcheroo_unregister_handler();
> err_register_handler:
> gmux_disable_interrupts(gmux_data);
> apple_gmux_data = NULL;
> @@ -877,6 +1005,7 @@ static void gmux_remove(struct pnp_dev *pnp)
> {
> struct apple_gmux_data *gmux_data = pnp_get_drvdata(pnp);
>
> + gmux_fini_sysfs(pnp);
> vga_switcheroo_unregister_handler();
> gmux_disable_interrupts(gmux_data);
> if (gmux_data->gpe >= 0) {
Hi,
On 2/10/23 21:15, Hans de Goede wrote:
> Hi,
>
> On 2/10/23 05:48, Orlando Chamberlain wrote:
>> Allow reading gmux ports from userspace. When the unsafe module
>> parameter allow_user_writes is true, writing 1 byte
>> values is also allowed.
>>
>> For example:
>>
>> cd /sys/bus/acpi/devices/APP000B:00/physical_node/
>> echo 4 > gmux_selected_port
>> cat gmux_selected_port_data | xxd -p
>>
>> Will show the gmux version information (00000005 in this case)
>
> Please use debugfs for this and as part of the conversion
> drop the #ifdef-s (debugfs has stubs for when not enabled)
> and drop all the error checking of creating the files, debugfs
> is deliberately designed to not have any error checking in
> the setup / teardown code.
>
> This also removes the need for the allow_user_writes parameter
> replacing it with the new kernel lockdown mechanism. debugfs
> will automatically block access to writable files when
> the kernel is in lockdown mode.
>
> Regards,
>
> Hans
p.s.
I just realized I forgot my usual thank you for contributing
to the kernel reply to the cover letter before diving into
the review (oops).
So let me correct that: thank you very much for your work on this!
Regards,
Hans
>> Signed-off-by: Orlando Chamberlain <orlandoch.dev@gmail.com>
>> ---
>> drivers/platform/x86/apple-gmux.c | 129 ++++++++++++++++++++++++++++++
>> 1 file changed, 129 insertions(+)
>>
>> diff --git a/drivers/platform/x86/apple-gmux.c b/drivers/platform/x86/apple-gmux.c
>> index c38d6ef0c15a..756059d48393 100644
>> --- a/drivers/platform/x86/apple-gmux.c
>> +++ b/drivers/platform/x86/apple-gmux.c
>> @@ -66,6 +66,11 @@ struct apple_gmux_data {
>> enum vga_switcheroo_client_id switch_state_external;
>> enum vga_switcheroo_state power_state;
>> struct completion powerchange_done;
>> +
>> +#ifdef CONFIG_SYSFS
>> + /* sysfs data */
>> + int selected_port;
>> +#endif /* CONFIG_SYSFS */
>> };
>>
>> static struct apple_gmux_data *apple_gmux_data;
>> @@ -651,6 +656,121 @@ static void gmux_notify_handler(acpi_handle device, u32 value, void *context)
>> complete(&gmux_data->powerchange_done);
>> }
>>
>> +/**
>> + * DOC: Sysfs Interface
>> + *
>> + * gmux ports can be read from userspace as a sysfs interface. For example:
>> + *
>> + * # echo 4 > /sys/bus/acpi/devices/APP000B:00/physical_node/gmux_selected_port
>> + * # cat /sys/bus/acpi/devices/APP000B:00/physical_node/gmux_selected_port_data | xxd -p
>> + * 00000005
>> + *
>> + * Reads 4 bytes from port 4 (GMUX_PORT_VERSION_MAJOR).
>> + *
>> + * Single byte writes are also supported, however this must be enabled with the
>> + * unsafe allow_user_writes module parameter.
>> + *
>> + */
>> +
>> +#ifdef CONFIG_SYSFS
>> +
>> +static bool allow_user_writes;
>> +module_param_unsafe(allow_user_writes, bool, 0);
>> +MODULE_PARM_DESC(allow_user_writes, "Allow userspace to write to gmux ports (default: false) (bool)");
>> +
>> +static ssize_t gmux_selected_port_store(struct device *dev,
>> + struct device_attribute *attr, const char *sysfsbuf, size_t count)
>> +{
>> + struct apple_gmux_data *gmux_data = dev_get_drvdata(dev);
>> + u8 port;
>> +
>> + if (kstrtou8(sysfsbuf, 10, &port) < 0)
>> + return -EINVAL;
>> +
>> + /* On pio gmux's, make sure the user doesn't access too high of a port. */
>> + if ((gmux_data->config == &apple_gmux_pio) &&
>> + port > (gmux_data->iolen - 4))
>> + return -EINVAL;
>> +
>> + gmux_data->selected_port = port;
>> + return count;
>> +}
>> +
>> +static ssize_t gmux_selected_port_show(struct device *dev,
>> + struct device_attribute *attr, char *sysfsbuf)
>> +{
>> + struct apple_gmux_data *gmux_data = dev_get_drvdata(dev);
>> +
>> + return sysfs_emit(sysfsbuf, "%d\n", gmux_data->selected_port);
>> +}
>> +
>> +DEVICE_ATTR_RW(gmux_selected_port);
>> +
>> +static ssize_t gmux_selected_port_data_store(struct device *dev,
>> + struct device_attribute *attr, const char *sysfsbuf, size_t count)
>> +{
>> + struct apple_gmux_data *gmux_data = dev_get_drvdata(dev);
>> +
>> + if (count == 1)
>> + gmux_write8(gmux_data, gmux_data->selected_port, *sysfsbuf);
>> + else
>> + return -EINVAL;
>> +
>> + return count;
>> +}
>> +
>> +static ssize_t gmux_selected_port_data_show(struct device *dev,
>> + struct device_attribute *attr, char *sysfsbuf)
>> +{
>> + struct apple_gmux_data *gmux_data = dev_get_drvdata(dev);
>> + u32 data;
>> +
>> + data = gmux_read32(gmux_data, gmux_data->selected_port);
>> + memcpy(sysfsbuf, &data, sizeof(data));
>> +
>> + return sizeof(data);
>> +}
>> +
>> +struct device_attribute dev_attr_gmux_selected_port_data_rw = __ATTR_RW(gmux_selected_port_data);
>> +struct device_attribute dev_attr_gmux_selected_port_data_ro = __ATTR_RO(gmux_selected_port_data);
>> +
>> +static int gmux_init_sysfs(struct pnp_dev *pnp)
>> +{
>> + int ret;
>> +
>> + ret = device_create_file(&pnp->dev, &dev_attr_gmux_selected_port);
>> + if (ret)
>> + return ret;
>> + if (allow_user_writes)
>> + ret = device_create_file(&pnp->dev, &dev_attr_gmux_selected_port_data_rw);
>> + else
>> + ret = device_create_file(&pnp->dev, &dev_attr_gmux_selected_port_data_ro);
>> + if (ret)
>> + device_remove_file(&pnp->dev, &dev_attr_gmux_selected_port);
>> + return ret;
>> +}
>> +
>> +static void gmux_fini_sysfs(struct pnp_dev *pnp)
>> +{
>> + device_remove_file(&pnp->dev, &dev_attr_gmux_selected_port);
>> + if (allow_user_writes)
>> + device_remove_file(&pnp->dev, &dev_attr_gmux_selected_port_data_rw);
>> + else
>> + device_remove_file(&pnp->dev, &dev_attr_gmux_selected_port_data_ro);
>> +}
>> +
>> +#else
>> +
>> +static int gmux_init_sysfs(struct pnp_dev *pnp)
>> +{
>> + return 0;
>> +}
>> +static void gmux_fini_sysfs(struct pnp_dev *pnp)
>> +{
>> +}
>> +
>> +#endif /* CONFIG_SYSFS */
>> +
>> static int gmux_suspend(struct device *dev)
>> {
>> struct pnp_dev *pnp = to_pnp_dev(dev);
>> @@ -846,8 +966,16 @@ static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
>> goto err_register_handler;
>> }
>>
>> + ret = gmux_init_sysfs(pnp);
>> + if (ret) {
>> + pr_err("Failed to register gmux sysfs entries\n");
>> + goto err_sysfs;
>> + }
>> +
>> return 0;
>>
>> +err_sysfs:
>> + vga_switcheroo_unregister_handler();
>> err_register_handler:
>> gmux_disable_interrupts(gmux_data);
>> apple_gmux_data = NULL;
>> @@ -877,6 +1005,7 @@ static void gmux_remove(struct pnp_dev *pnp)
>> {
>> struct apple_gmux_data *gmux_data = pnp_get_drvdata(pnp);
>>
>> + gmux_fini_sysfs(pnp);
>> vga_switcheroo_unregister_handler();
>> gmux_disable_interrupts(gmux_data);
>> if (gmux_data->gpe >= 0) {
>
On Fri, 10 Feb 2023 21:23:15 +0100
Hans de Goede <hdegoede@redhat.com> wrote:
> Hi,
>
> On 2/10/23 21:15, Hans de Goede wrote:
> > Hi,
> >
> > On 2/10/23 05:48, Orlando Chamberlain wrote:
> >> Allow reading gmux ports from userspace. When the unsafe module
> >> parameter allow_user_writes is true, writing 1 byte
> >> values is also allowed.
> >>
> >> For example:
> >>
> >> cd /sys/bus/acpi/devices/APP000B:00/physical_node/
> >> echo 4 > gmux_selected_port
> >> cat gmux_selected_port_data | xxd -p
> >>
> >> Will show the gmux version information (00000005 in this case)
> >
> > Please use debugfs for this and as part of the conversion
> > drop the #ifdef-s (debugfs has stubs for when not enabled)
> > and drop all the error checking of creating the files, debugfs
> > is deliberately designed to not have any error checking in
> > the setup / teardown code.
> >
> > This also removes the need for the allow_user_writes parameter
> > replacing it with the new kernel lockdown mechanism. debugfs
> > will automatically block access to writable files when
> > the kernel is in lockdown mode.
I'll change it to use debugfs instead of sysfs in v2.
> >
> > Regards,
> >
> > Hans
>
> p.s.
>
> I just realized I forgot my usual thank you for contributing
> to the kernel reply to the cover letter before diving into
> the review (oops).
>
> So let me correct that: thank you very much for your work on this!
thank you for maintaining and reviewing!
>
> Regards,
>
> Hans
>
>
>
>
>
>
> >> Signed-off-by: Orlando Chamberlain <orlandoch.dev@gmail.com>
> >> ---
> >> drivers/platform/x86/apple-gmux.c | 129
> >> ++++++++++++++++++++++++++++++ 1 file changed, 129 insertions(+)
> >>
> >> diff --git a/drivers/platform/x86/apple-gmux.c
> >> b/drivers/platform/x86/apple-gmux.c index
> >> c38d6ef0c15a..756059d48393 100644 ---
> >> a/drivers/platform/x86/apple-gmux.c +++
> >> b/drivers/platform/x86/apple-gmux.c @@ -66,6 +66,11 @@ struct
> >> apple_gmux_data { enum vga_switcheroo_client_id
> >> switch_state_external; enum vga_switcheroo_state power_state;
> >> struct completion powerchange_done;
> >> +
> >> +#ifdef CONFIG_SYSFS
> >> + /* sysfs data */
> >> + int selected_port;
> >> +#endif /* CONFIG_SYSFS */
> >> };
> >>
> >> static struct apple_gmux_data *apple_gmux_data;
> >> @@ -651,6 +656,121 @@ static void gmux_notify_handler(acpi_handle
> >> device, u32 value, void *context)
> >> complete(&gmux_data->powerchange_done); }
> >>
> >> +/**
> >> + * DOC: Sysfs Interface
> >> + *
> >> + * gmux ports can be read from userspace as a sysfs interface.
> >> For example:
> >> + *
> >> + * # echo 4 >
> >> /sys/bus/acpi/devices/APP000B:00/physical_node/gmux_selected_port
> >> + * # cat
> >> /sys/bus/acpi/devices/APP000B:00/physical_node/gmux_selected_port_data
> >> | xxd -p
> >> + * 00000005
> >> + *
> >> + * Reads 4 bytes from port 4 (GMUX_PORT_VERSION_MAJOR).
> >> + *
> >> + * Single byte writes are also supported, however this must be
> >> enabled with the
> >> + * unsafe allow_user_writes module parameter.
> >> + *
> >> + */
> >> +
> >> +#ifdef CONFIG_SYSFS
> >> +
> >> +static bool allow_user_writes;
> >> +module_param_unsafe(allow_user_writes, bool, 0);
> >> +MODULE_PARM_DESC(allow_user_writes, "Allow userspace to write to
> >> gmux ports (default: false) (bool)"); +
> >> +static ssize_t gmux_selected_port_store(struct device *dev,
> >> + struct device_attribute *attr, const char
> >> *sysfsbuf, size_t count) +{
> >> + struct apple_gmux_data *gmux_data = dev_get_drvdata(dev);
> >> + u8 port;
> >> +
> >> + if (kstrtou8(sysfsbuf, 10, &port) < 0)
> >> + return -EINVAL;
> >> +
> >> + /* On pio gmux's, make sure the user doesn't access too
> >> high of a port. */
> >> + if ((gmux_data->config == &apple_gmux_pio) &&
> >> + port > (gmux_data->iolen - 4))
> >> + return -EINVAL;
> >> +
> >> + gmux_data->selected_port = port;
> >> + return count;
> >> +}
> >> +
> >> +static ssize_t gmux_selected_port_show(struct device *dev,
> >> + struct device_attribute *attr, char *sysfsbuf)
> >> +{
> >> + struct apple_gmux_data *gmux_data = dev_get_drvdata(dev);
> >> +
> >> + return sysfs_emit(sysfsbuf, "%d\n",
> >> gmux_data->selected_port); +}
> >> +
> >> +DEVICE_ATTR_RW(gmux_selected_port);
> >> +
> >> +static ssize_t gmux_selected_port_data_store(struct device *dev,
> >> + struct device_attribute *attr, const char
> >> *sysfsbuf, size_t count) +{
> >> + struct apple_gmux_data *gmux_data = dev_get_drvdata(dev);
> >> +
> >> + if (count == 1)
> >> + gmux_write8(gmux_data, gmux_data->selected_port,
> >> *sysfsbuf);
> >> + else
> >> + return -EINVAL;
> >> +
> >> + return count;
> >> +}
> >> +
> >> +static ssize_t gmux_selected_port_data_show(struct device *dev,
> >> + struct device_attribute *attr, char *sysfsbuf)
> >> +{
> >> + struct apple_gmux_data *gmux_data = dev_get_drvdata(dev);
> >> + u32 data;
> >> +
> >> + data = gmux_read32(gmux_data, gmux_data->selected_port);
> >> + memcpy(sysfsbuf, &data, sizeof(data));
> >> +
> >> + return sizeof(data);
> >> +}
> >> +
> >> +struct device_attribute dev_attr_gmux_selected_port_data_rw =
> >> __ATTR_RW(gmux_selected_port_data); +struct device_attribute
> >> dev_attr_gmux_selected_port_data_ro =
> >> __ATTR_RO(gmux_selected_port_data); + +static int
> >> gmux_init_sysfs(struct pnp_dev *pnp) +{
> >> + int ret;
> >> +
> >> + ret = device_create_file(&pnp->dev,
> >> &dev_attr_gmux_selected_port);
> >> + if (ret)
> >> + return ret;
> >> + if (allow_user_writes)
> >> + ret = device_create_file(&pnp->dev,
> >> &dev_attr_gmux_selected_port_data_rw);
> >> + else
> >> + ret = device_create_file(&pnp->dev,
> >> &dev_attr_gmux_selected_port_data_ro);
> >> + if (ret)
> >> + device_remove_file(&pnp->dev,
> >> &dev_attr_gmux_selected_port);
> >> + return ret;
> >> +}
> >> +
> >> +static void gmux_fini_sysfs(struct pnp_dev *pnp)
> >> +{
> >> + device_remove_file(&pnp->dev,
> >> &dev_attr_gmux_selected_port);
> >> + if (allow_user_writes)
> >> + device_remove_file(&pnp->dev,
> >> &dev_attr_gmux_selected_port_data_rw);
> >> + else
> >> + device_remove_file(&pnp->dev,
> >> &dev_attr_gmux_selected_port_data_ro); +}
> >> +
> >> +#else
> >> +
> >> +static int gmux_init_sysfs(struct pnp_dev *pnp)
> >> +{
> >> + return 0;
> >> +}
> >> +static void gmux_fini_sysfs(struct pnp_dev *pnp)
> >> +{
> >> +}
> >> +
> >> +#endif /* CONFIG_SYSFS */
> >> +
> >> static int gmux_suspend(struct device *dev)
> >> {
> >> struct pnp_dev *pnp = to_pnp_dev(dev);
> >> @@ -846,8 +966,16 @@ static int gmux_probe(struct pnp_dev *pnp,
> >> const struct pnp_device_id *id) goto err_register_handler;
> >> }
> >>
> >> + ret = gmux_init_sysfs(pnp);
> >> + if (ret) {
> >> + pr_err("Failed to register gmux sysfs entries\n");
> >> + goto err_sysfs;
> >> + }
> >> +
> >> return 0;
> >>
> >> +err_sysfs:
> >> + vga_switcheroo_unregister_handler();
> >> err_register_handler:
> >> gmux_disable_interrupts(gmux_data);
> >> apple_gmux_data = NULL;
> >> @@ -877,6 +1005,7 @@ static void gmux_remove(struct pnp_dev *pnp)
> >> {
> >> struct apple_gmux_data *gmux_data = pnp_get_drvdata(pnp);
> >>
> >> + gmux_fini_sysfs(pnp);
> >> vga_switcheroo_unregister_handler();
> >> gmux_disable_interrupts(gmux_data);
> >> if (gmux_data->gpe >= 0) {
> >
>
@@ -66,6 +66,11 @@ struct apple_gmux_data {
enum vga_switcheroo_client_id switch_state_external;
enum vga_switcheroo_state power_state;
struct completion powerchange_done;
+
+#ifdef CONFIG_SYSFS
+ /* sysfs data */
+ int selected_port;
+#endif /* CONFIG_SYSFS */
};
static struct apple_gmux_data *apple_gmux_data;
@@ -651,6 +656,121 @@ static void gmux_notify_handler(acpi_handle device, u32 value, void *context)
complete(&gmux_data->powerchange_done);
}
+/**
+ * DOC: Sysfs Interface
+ *
+ * gmux ports can be read from userspace as a sysfs interface. For example:
+ *
+ * # echo 4 > /sys/bus/acpi/devices/APP000B:00/physical_node/gmux_selected_port
+ * # cat /sys/bus/acpi/devices/APP000B:00/physical_node/gmux_selected_port_data | xxd -p
+ * 00000005
+ *
+ * Reads 4 bytes from port 4 (GMUX_PORT_VERSION_MAJOR).
+ *
+ * Single byte writes are also supported, however this must be enabled with the
+ * unsafe allow_user_writes module parameter.
+ *
+ */
+
+#ifdef CONFIG_SYSFS
+
+static bool allow_user_writes;
+module_param_unsafe(allow_user_writes, bool, 0);
+MODULE_PARM_DESC(allow_user_writes, "Allow userspace to write to gmux ports (default: false) (bool)");
+
+static ssize_t gmux_selected_port_store(struct device *dev,
+ struct device_attribute *attr, const char *sysfsbuf, size_t count)
+{
+ struct apple_gmux_data *gmux_data = dev_get_drvdata(dev);
+ u8 port;
+
+ if (kstrtou8(sysfsbuf, 10, &port) < 0)
+ return -EINVAL;
+
+ /* On pio gmux's, make sure the user doesn't access too high of a port. */
+ if ((gmux_data->config == &apple_gmux_pio) &&
+ port > (gmux_data->iolen - 4))
+ return -EINVAL;
+
+ gmux_data->selected_port = port;
+ return count;
+}
+
+static ssize_t gmux_selected_port_show(struct device *dev,
+ struct device_attribute *attr, char *sysfsbuf)
+{
+ struct apple_gmux_data *gmux_data = dev_get_drvdata(dev);
+
+ return sysfs_emit(sysfsbuf, "%d\n", gmux_data->selected_port);
+}
+
+DEVICE_ATTR_RW(gmux_selected_port);
+
+static ssize_t gmux_selected_port_data_store(struct device *dev,
+ struct device_attribute *attr, const char *sysfsbuf, size_t count)
+{
+ struct apple_gmux_data *gmux_data = dev_get_drvdata(dev);
+
+ if (count == 1)
+ gmux_write8(gmux_data, gmux_data->selected_port, *sysfsbuf);
+ else
+ return -EINVAL;
+
+ return count;
+}
+
+static ssize_t gmux_selected_port_data_show(struct device *dev,
+ struct device_attribute *attr, char *sysfsbuf)
+{
+ struct apple_gmux_data *gmux_data = dev_get_drvdata(dev);
+ u32 data;
+
+ data = gmux_read32(gmux_data, gmux_data->selected_port);
+ memcpy(sysfsbuf, &data, sizeof(data));
+
+ return sizeof(data);
+}
+
+struct device_attribute dev_attr_gmux_selected_port_data_rw = __ATTR_RW(gmux_selected_port_data);
+struct device_attribute dev_attr_gmux_selected_port_data_ro = __ATTR_RO(gmux_selected_port_data);
+
+static int gmux_init_sysfs(struct pnp_dev *pnp)
+{
+ int ret;
+
+ ret = device_create_file(&pnp->dev, &dev_attr_gmux_selected_port);
+ if (ret)
+ return ret;
+ if (allow_user_writes)
+ ret = device_create_file(&pnp->dev, &dev_attr_gmux_selected_port_data_rw);
+ else
+ ret = device_create_file(&pnp->dev, &dev_attr_gmux_selected_port_data_ro);
+ if (ret)
+ device_remove_file(&pnp->dev, &dev_attr_gmux_selected_port);
+ return ret;
+}
+
+static void gmux_fini_sysfs(struct pnp_dev *pnp)
+{
+ device_remove_file(&pnp->dev, &dev_attr_gmux_selected_port);
+ if (allow_user_writes)
+ device_remove_file(&pnp->dev, &dev_attr_gmux_selected_port_data_rw);
+ else
+ device_remove_file(&pnp->dev, &dev_attr_gmux_selected_port_data_ro);
+}
+
+#else
+
+static int gmux_init_sysfs(struct pnp_dev *pnp)
+{
+ return 0;
+}
+static void gmux_fini_sysfs(struct pnp_dev *pnp)
+{
+}
+
+#endif /* CONFIG_SYSFS */
+
static int gmux_suspend(struct device *dev)
{
struct pnp_dev *pnp = to_pnp_dev(dev);
@@ -846,8 +966,16 @@ static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
goto err_register_handler;
}
+ ret = gmux_init_sysfs(pnp);
+ if (ret) {
+ pr_err("Failed to register gmux sysfs entries\n");
+ goto err_sysfs;
+ }
+
return 0;
+err_sysfs:
+ vga_switcheroo_unregister_handler();
err_register_handler:
gmux_disable_interrupts(gmux_data);
apple_gmux_data = NULL;
@@ -877,6 +1005,7 @@ static void gmux_remove(struct pnp_dev *pnp)
{
struct apple_gmux_data *gmux_data = pnp_get_drvdata(pnp);
+ gmux_fini_sysfs(pnp);
vga_switcheroo_unregister_handler();
gmux_disable_interrupts(gmux_data);
if (gmux_data->gpe >= 0) {