Messages in this thread | | | Date | Tue, 22 Aug 2023 16:08:21 +0200 | From | Greg KH <> | Subject | Re: [PATCH v3 3/5] cdx: add support for bus enable and disable |
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On Mon, Aug 14, 2023 at 03:52:21PM +0530, Abhijit Gangurde wrote: > CDX bus needs to be disabled before updating/writing devices > in the FPGA. Once the devices are written, the bus shall be > rescanned. This change provides sysfs entry to enable/disable the > CDX bus. > > Co-developed-by: Nipun Gupta <nipun.gupta@amd.com> > Signed-off-by: Nipun Gupta <nipun.gupta@amd.com> > Signed-off-by: Abhijit Gangurde <abhijit.gangurde@amd.com> > Reviewed-by: Pieter Jansen van Vuuren <pieter.jansen-van-vuuren@amd.com> > Tested-by: Nikhil Agarwal <nikhil.agarwal@amd.com> > --- > Documentation/ABI/testing/sysfs-bus-cdx | 27 +++++++ > drivers/cdx/cdx.c | 94 +++++++++++++++++++++++++ > drivers/cdx/controller/cdx_controller.c | 50 +++++++++++++ > drivers/cdx/controller/mc_cdx_pcol.h | 54 ++++++++++++++ > drivers/cdx/controller/mcdi_functions.c | 24 +++++++ > drivers/cdx/controller/mcdi_functions.h | 18 +++++ > include/linux/cdx/cdx_bus.h | 12 ++++ > 7 files changed, 279 insertions(+) > > diff --git a/Documentation/ABI/testing/sysfs-bus-cdx b/Documentation/ABI/testing/sysfs-bus-cdx > index 7af477f49998..04c8dfe7e201 100644 > --- a/Documentation/ABI/testing/sysfs-bus-cdx > +++ b/Documentation/ABI/testing/sysfs-bus-cdx > @@ -11,6 +11,33 @@ Description: > > # echo 1 > /sys/bus/cdx/rescan > > +What: /sys/bus/cdx/enable > +Date: July 2023 > +Contact: nipun.gupta@amd.com > +Description: > + Writing bus number in hex to this file will attempt to enable > + the CDX bus. The bus number for the cdx devices can be found > + at /sys/bus/cdx/devices/cdx-BB:DD, where BB denotes the bus > + number for the respective device. > + > + For example :: > + > + # echo 00 > /sys/bus/cdx/enable > + > +What: /sys/bus/cdx/disable > +Date: July 2023 > +Contact: nipun.gupta@amd.com > +Description: > + Writing bus number in hex to this file will attempt to disable > + the CDX bus. CDX bus should be disabled before updating the > + devices in FPGA. The bus number for the cdx devices can be > + found at /sys/bus/cdx/devices/cdx-BB:DD, where BB denotes the > + bus number for the respective device. > + > + For example :: > + > + # echo 00 > /sys/bus/cdx/disable > + > What: /sys/bus/cdx/devices/.../vendor > Date: March 2023 > Contact: nipun.gupta@amd.com > diff --git a/drivers/cdx/cdx.c b/drivers/cdx/cdx.c > index 50df061f4537..411beb035fdd 100644 > --- a/drivers/cdx/cdx.c > +++ b/drivers/cdx/cdx.c > @@ -70,6 +70,10 @@ > #define CDX_DEFAULT_DMA_MASK (~0ULL) > #define MAX_CDX_CONTROLLERS 16 > > +#define CONTROLLER_ID(X) \ > + (((X) & CDX_CONTROLLER_ID_MASK) >> CDX_CONTROLLER_ID_SHIFT) > +#define BUS_ID(X) ((X) & CDX_BUS_NUM_MASK) > + > /* IDA for CDX controllers registered with the CDX bus */ > DEFINE_IDA(cdx_controller_ida); > /* Lock to protect controller ops */ > @@ -384,6 +388,94 @@ static struct attribute *cdx_dev_attrs[] = { > }; > ATTRIBUTE_GROUPS(cdx_dev); > > +static struct cdx_controller *cdx_find_controller(u8 controller_id) > +{ > + struct cdx_controller *cdx = NULL; > + struct platform_device *pd; > + struct device_node *np; > + > + for_each_compatible_node(np, NULL, compat_node_name) { > + if (!np) > + return NULL; > + > + pd = of_find_device_by_node(np); > + if (!pd) > + return NULL; > + > + cdx = platform_get_drvdata(pd); > + if (cdx && cdx->controller_registered && cdx->id == controller_id) { > + put_device(&pd->dev); > + break; > + } > + > + put_device(&pd->dev);
Where is the locking if a platform device is removed?
> + } > + > + return cdx; > +} > + > +static ssize_t enable_store(const struct bus_type *bus, > + const char *buf, size_t count) > +{ > + unsigned long controller_id; > + struct cdx_controller *cdx; > + u8 bus_id; > + int ret; > + > + if (kstrtou8(buf, 16, &bus_id)) > + return -EINVAL; > + > + controller_id = CONTROLLER_ID(bus_id); > + bus_id = BUS_ID(bus_id); > + > + mutex_lock(&cdx_controller_lock); > + > + cdx = cdx_find_controller(controller_id);
You lock before you call this function? Is the lock required before you call it? If so, please document that and enforce it with the proper sparse marking.
thanks,
greg k-h
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