Messages in this thread | | | Date | Mon, 9 Jan 2023 10:04:32 -0800 (PST) | From | matthew.gerlach@linux ... | Subject | Re: [PATCH v9 3/4] fpga: dfl: add basic support for DFHv1 |
| |
On Mon, 9 Jan 2023, Xu Yilun wrote:
> On 2023-01-04 at 15:22:52 -0800, matthew.gerlach@linux.intel.com wrote: >> From: Matthew Gerlach <matthew.gerlach@linux.intel.com> >> >> Version 1 of the Device Feature Header (DFH) definition adds >> functionality to the Device Feature List (DFL) bus. >> >> A DFHv1 header may have one or more parameter blocks that >> further describes the HW to SW. Add support to the DFL bus >> to parse the MSI-X parameter. >> >> The location of a feature's register set is explicitly >> described in DFHv1 and can be relative to the base of the DFHv1 >> or an absolute address. Parse the location and pass the information >> to DFL driver. >> >> Signed-off-by: Matthew Gerlach <matthew.gerlach@linux.intel.com> >> Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> >> > > [...] > >> +static u64 *find_param(u64 *params, resource_size_t max, int param_id) >> +{ >> + u64 *end = params + max / sizeof(u64); >> + u64 v, next; >> + >> + while (params < end) { >> + v = *params; >> + if (param_id == FIELD_GET(DFHv1_PARAM_HDR_ID, v)) >> + return params; >> + >> + if (FIELD_GET(DFHv1_PARAM_HDR_NEXT_EOP, v)) >> + break; >> + >> + next = FIELD_GET(DFHv1_PARAM_HDR_NEXT_OFFSET, v); >> + params += next; >> + } >> + >> + return NULL; >> +} >> + >> +/** >> + * dfh_find_param() - find parameter block for the given parameter id >> + * @dfl_dev: dfl device >> + * @param_id: id of dfl parameter >> + * @pcount: destination to store size of parameter data in u64 bit words > > As I mentioned before, could the size of the parameter data just be number > of bytes? This is the most common way for a data block.
returning a void* and a size_t in bytes would be more consistent. I will make your suggested change.
Thanks, Matthew Gerlach
> > Thanks, > Yilun > >> + * >> + * Return: pointer to start of parameter data, PTR_ERR otherwise. >> + */ >> +void *dfh_find_param(struct dfl_device *dfl_dev, int param_id, size_t *pcount) >> +{ >> + u64 *phdr = find_param(dfl_dev->params, dfl_dev->param_size, param_id); >> + >> + if (!phdr) >> + return ERR_PTR(-ENOENT); >> + >> + if (pcount) >> + *pcount = FIELD_GET(DFHv1_PARAM_HDR_NEXT_OFFSET, *phdr) - 1; >> + >> + return phdr + 1; >> +} >> +EXPORT_SYMBOL_GPL(dfh_find_param); >
| |