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SubjectRe: [PATCH v2 4/6] fpga: dfl: add generic support for MSIX interrupts


On Fri, 30 Sep 2022, Xu Yilun wrote:

> On 2022-09-23 at 05:17:43 -0700, matthew.gerlach@linux.intel.com wrote:
>> From: Matthew Gerlach <matthew.gerlach@linux.intel.com>
>>
>> Define and use a DFHv1 parameter to add generic support for MSIX
>> interrupts for DFL devices.
>>
>> Signed-off-by: Matthew Gerlach <matthew.gerlach@linux.intel.com>
>> ---
>> v2: fix kernel doc
>> clarify use of DFH_VERSION field
>> ---
>> drivers/fpga/dfl.c | 60 +++++++++++++++++++++++++++++++++++++++++----
>> include/linux/dfl.h | 14 +++++++++++
>> 2 files changed, 69 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c
>> index 1132f3c10440..dfd3f563c92d 100644
>> --- a/drivers/fpga/dfl.c
>> +++ b/drivers/fpga/dfl.c
>> @@ -941,23 +941,22 @@ static int parse_feature_irqs(struct build_feature_devs_info *binfo,
>> void __iomem *base = binfo->ioaddr + ofst;
>> unsigned int i, ibase, inr = 0;
>> enum dfl_id_type type;
>> - int virq;
>> + int virq, off;
>> u64 v;
>>
>> type = feature_dev_id_type(binfo->feature_dev);
>>
>> /*
>> * Ideally DFL framework should only read info from DFL header, but
>> - * current version DFL only provides mmio resources information for
>> + * current version, DFHv0, only provides mmio resources information for
>
> With this patchset, it's not 'current version' anymore.

I will update the comment. Thanks.

>
>> * each feature in DFL Header, no field for interrupt resources.
>> * Interrupt resource information is provided by specific mmio
>> * registers of each private feature which supports interrupt. So in
>> * order to parse and assign irq resources, DFL framework has to look
>> * into specific capability registers of these private features.
>> *
>> - * Once future DFL version supports generic interrupt resource
>> - * information in common DFL headers, the generic interrupt parsing
>> - * code will be added. But in order to be compatible to old version
>> + * DFHv1 supports generic interrupt resource information in DFHv1
>> + * parameter blocks. But in order to be compatible to old version
>> * DFL, the driver may still fall back to these quirks.
>> */
>> if (type == PORT_ID) {
>> @@ -981,6 +980,36 @@ static int parse_feature_irqs(struct build_feature_devs_info *binfo,
>> }
>> }
>>
>> + if (fid != FEATURE_ID_AFU && fid != PORT_FEATURE_ID_ERROR &&
>> + fid != PORT_FEATURE_ID_UINT && fid != FME_FEATURE_ID_GLOBAL_ERR) {
>> +
>> + v = FIELD_GET(DFH_VERSION, readq(base));
>> + switch (v) {
>> + case 0:
>> + break;
>
> In last version, you mentioned that there will be no quirk for DFLv1, so
> how about:
>
> v = FIELD_GET(DFH_VERSION, readq(base));
>
> if (v == 0) {
> /* quirks */
> } else {
> /* parse PARAM MSIX */
> }
>
> No need to check specific feature ids again.

With v3 changes I will use a switch state and not need quirks for v1.

>
> Thanks,
> Yilun
>
>> +
>> + case 1:
>> + v = readq(base + DFHv1_CSR_SIZE_GRP);
>> + if (FIELD_GET(DFHv1_CSR_SIZE_GRP_HAS_PARAMS, v)) {
>> + off = dfl_find_param(base + DFHv1_PARAM_HDR, ofst,
>> + DFHv1_PARAM_ID_MSIX);
>> + if (off >= 0) {
>> + ibase = readl(base + DFHv1_PARAM_HDR +
>> + off + DFHv1_PARAM_MSIX_STARTV);
>> + inr = readl(base + DFHv1_PARAM_HDR +
>> + off + DFHv1_PARAM_MSIX_NUMV);
>> + dev_dbg(binfo->dev, "start %d num %d fid 0x%x\n",
>> + ibase, inr, fid);
>> + }
>> + }
>> + break;
>> +
>> + default:
>> + dev_warn(binfo->dev, "unexpected DFH version %lld\n", v);
>> + break;
>> + }
>> + }
>> +
>> if (!inr) {
>> *irq_base = 0;
>> *nr_irqs = 0;
>> @@ -1879,6 +1908,27 @@ long dfl_feature_ioctl_set_irq(struct platform_device *pdev,
>> }
>> EXPORT_SYMBOL_GPL(dfl_feature_ioctl_set_irq);
>>
>> +int dfl_find_param(void __iomem *base, resource_size_t max, int param)
>> +{
>> + int off = 0;
>> + u64 v, next;
>> +
>> + while (off < max) {
>> + v = readq(base + off);
>> + if (param == FIELD_GET(DFHv1_PARAM_HDR_ID, v))
>> + return off;
>> +
>> + next = FIELD_GET(DFHv1_PARAM_HDR_NEXT_OFFSET, v);
>> + if (!next)
>> + break;
>> +
>> + off += next;
>> + }
>> +
>> + return -ENOENT;
>> +}
>> +EXPORT_SYMBOL_GPL(dfl_find_param);
>> +
>> static void __exit dfl_fpga_exit(void)
>> {
>> dfl_chardev_uinit();
>> diff --git a/include/linux/dfl.h b/include/linux/dfl.h
>> index 1e53468ba8d8..33e21c360671 100644
>> --- a/include/linux/dfl.h
>> +++ b/include/linux/dfl.h
>> @@ -63,6 +63,10 @@
>> #define DFHv1_PARAM_HDR_VERSION GENMASK_ULL(31, 16) /* Version Param */
>> #define DFHv1_PARAM_HDR_NEXT_OFFSET GENMASK_ULL(63, 32) /* Offset of next Param */
>>
>> +#define DFHv1_PARAM_ID_MSIX 0x1
>> +#define DFHv1_PARAM_MSIX_STARTV 0x8
>> +#define DFHv1_PARAM_MSIX_NUMV 0xc
>> +
>> /**
>> * enum dfl_id_type - define the DFL FIU types
>> */
>> @@ -136,4 +140,14 @@ void dfl_driver_unregister(struct dfl_driver *dfl_drv);
>> module_driver(__dfl_driver, dfl_driver_register, \
>> dfl_driver_unregister)
>>
>> +/**
>> + * dfl_find_param() - find the offset of the given parameter
>> + * @base: base pointer to start of dfl parameters in DFH
>> + * @max: maximum offset to search
>> + * @param: id of dfl parameter
>> + *
>> + * Return: positive offset on success, negative error code otherwise.
>> + */
>> +int dfl_find_param(void __iomem *base, resource_size_t max, int param);
>> +
>> #endif /* __LINUX_DFL_H */
>> --
>> 2.25.1
>>
>

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