Re: [PATCH v4 3/4] fpga: dfl: add basic support DFHv1

matthew.gerlach
2022-10-29T14:47:42Z

On Sat, 29 Oct 2022, Xu Yilun wrote:

> On 2022-10-20 at 14:26:09 -0700, matthew.gerlach@linux.intel.com wrote:
>> From: Matthew Gerlach <matthew.gerlach@linux.intel.com>
>>
>> Add generic support for MSI-X interrupts for DFL devices.
>
> The first paragraph of the commit message should be the summary of the
> whole change. But this seems one of the changes. Please add the proper
> summary at the beginning.

This is a very good suggestion. It will be addressed in the next
revision.

>
>>
>> The location of a feature's registers 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>
>> ---
>> v4: s/MSIX/MSI_X
>> move kernel doc to implementation
>> use structure assignment
>> fix decode of absolute address
>> clean up comment in parse_feature_irqs
>> remove use of csr_res
>>
>> v3: remove unneeded blank line
>> use clearer variable name
>> pass finfo into parse_feature_irqs()
>> refactor code for better indentation
>> use switch statement for irq parsing
>> squash in code parsing register location
>>
>> v2: fix kernel doc
>> clarify use of DFH_VERSION field
>> ---
>> drivers/fpga/dfl.c | 234 ++++++++++++++++++++++++++++++++++----------
>> drivers/fpga/dfl.h | 5 +
>> include/linux/dfl.h | 4 +
>> 3 files changed, 194 insertions(+), 49 deletions(-)
>>
>> diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c
>> index b9aae85ba930..37f995e66436 100644
>> --- a/drivers/fpga/dfl.c
>> +++ b/drivers/fpga/dfl.c
>> @@ -342,6 +342,8 @@ static void release_dfl_dev(struct device *dev)
>> if (ddev->mmio_res.parent)
>> release_resource(&ddev->mmio_res);
>>
>> + kfree(ddev->params);
>> +
>> ida_free(&dfl_device_ida, ddev->id);
>> kfree(ddev->irqs);
>> kfree(ddev);
>> @@ -380,7 +382,16 @@ dfl_dev_add(struct dfl_feature_platform_data *pdata,
>> ddev->type = feature_dev_id_type(pdev);
>> ddev->feature_id = feature->id;
>> ddev->revision = feature->revision;
>> + ddev->dfh_version = feature->dfh_version;
>> ddev->cdev = pdata->dfl_cdev;
>> + if (feature->param_size) {
>> + ddev->params = kmemdup(feature->params, feature->param_size, GFP_KERNEL);
>> + if (!ddev->params) {
>> + ret = -ENOMEM;
>> + goto put_dev;
>> + }
>> + ddev->param_size = feature->param_size;
>> + }
>>
>> /* add mmio resource */
>> parent_res = &pdev->resource[feature->resource_index];
>> @@ -708,20 +719,27 @@ struct build_feature_devs_info {
>> * struct dfl_feature_info - sub feature info collected during feature dev build
>> *
>> * @fid: id of this sub feature.
>> + * @revision: revision of this sub feature
>> + * @dfh_version: version of Device Feature Header (DFH)
>> * @mmio_res: mmio resource of this sub feature.
>> * @ioaddr: mapped base address of mmio resource.
>> * @node: node in sub_features linked list.
>> * @irq_base: start of irq index in this sub feature.
>> * @nr_irqs: number of irqs of this sub feature.
>> + * @param_size: size DFH parameters.
>> + * @params: DFH parameter data.
>> */
>> struct dfl_feature_info {
>> u16 fid;
>> u8 revision;
>> + u8 dfh_version;
>> struct resource mmio_res;
>> void __iomem *ioaddr;
>> struct list_head node;
>> unsigned int irq_base;
>> unsigned int nr_irqs;
>> + unsigned int param_size;
>> + u64 params[];
>> };
>>
>> static void dfl_fpga_cdev_add_port_dev(struct dfl_fpga_cdev *cdev,
>> @@ -797,7 +815,17 @@ static int build_info_commit_dev(struct build_feature_devs_info *binfo)
>> feature->dev = fdev;
>> feature->id = finfo->fid;
>> feature->revision = finfo->revision;
>> + feature->dfh_version = finfo->dfh_version;
>>
>> + if (finfo->param_size) {
>> + feature->params = devm_kmemdup(binfo->dev,
>> + finfo->params, finfo->param_size,
>> + GFP_KERNEL);
>> + if (!feature->params)
>> + return -ENOMEM;
>> +
>> + feature->param_size = finfo->param_size;
>> + }
>> /*
>> * the FIU header feature has some fundamental functions (sriov
>> * set, port enable/disable) needed for the dfl bus device and
>> @@ -934,56 +962,108 @@ static u16 feature_id(u64 value)
>> return 0;
>> }
>>
>> +static void *find_param(void *base, resource_size_t max, int param)
>> +{
>> + int off = 0;
>> + u64 v, next;
>> +
>> + while (off < max) {
>> + v = *(u64 *)(base + off);
>> + if (param == FIELD_GET(DFHv1_PARAM_HDR_ID, v))
>> + return base + off + DFHv1_PARAM_DATA;
>> +
>> + next = FIELD_GET(DFHv1_PARAM_HDR_NEXT_OFFSET, v);
>> + off += next & ~DFHv1_PARAM_HDR_NEXT_MASK;
>> + if (next & DFHv1_PARAM_HDR_NEXT_EOL)
>> + break;
>> +
>> + }
>> +
>> + return NULL;
>> +}
>> +
>> +/**
>> + * dfh_find_param() - find data for the given parameter id
>> + * @dfl_dev: dfl device
>> + * @param: id of dfl parameter
>> + *
>> + * Return: pointer to parameter data on success, NULL otherwise.
>> + */
>> +void *dfh_find_param(struct dfl_device *dfl_dev, int param)
>> +{
>> + return find_param(dfl_dev->params, dfl_dev->param_size, param);
>> +}
>> +EXPORT_SYMBOL_GPL(dfh_find_param);
>> +
>> static int parse_feature_irqs(struct build_feature_devs_info *binfo,
>> - resource_size_t ofst, u16 fid,
>> - unsigned int *irq_base, unsigned int *nr_irqs)
>> + resource_size_t ofst, struct dfl_feature_info *finfo)
>> {
>> void __iomem *base = binfo->ioaddr + ofst;
>> unsigned int i, ibase, inr = 0;
>> + void *params = finfo->params;
>> enum dfl_id_type type;
>> + u16 fid = finfo->fid;
>> int virq;
>> + u32 *p;
>> u64 v;
>>
>> - type = feature_dev_id_type(binfo->feature_dev);
>> + switch (finfo->dfh_version) {
>> + case 0:
>> + /*
>> + * DFHv0 only provides mmio resource information for each feature
>> + * in the DFL header. There is no generic interrupt information.
>> + * Instead, features with interrupt functionality provide
>> + * the information in feature specific registers.
>> + */
>> + type = feature_dev_id_type(binfo->feature_dev);
>> + if (type == PORT_ID) {
>> + switch (fid) {
>> + case PORT_FEATURE_ID_UINT:
>> + v = readq(base + PORT_UINT_CAP);
>> + ibase = FIELD_GET(PORT_UINT_CAP_FST_VECT, v);
>> + inr = FIELD_GET(PORT_UINT_CAP_INT_NUM, v);
>> + break;
>> + case PORT_FEATURE_ID_ERROR:
>> + v = readq(base + PORT_ERROR_CAP);
>> + ibase = FIELD_GET(PORT_ERROR_CAP_INT_VECT, v);
>> + inr = FIELD_GET(PORT_ERROR_CAP_SUPP_INT, v);
>> + break;
>> + }
>> + } else if (type == FME_ID) {
>> + switch (fid) {
>> + case FME_FEATURE_ID_GLOBAL_ERR:
>> + v = readq(base + FME_ERROR_CAP);
>> + ibase = FIELD_GET(FME_ERROR_CAP_INT_VECT, v);
>> + inr = FIELD_GET(FME_ERROR_CAP_SUPP_INT, v);
>> + break;
>> + }
>> + }
>> + break;
>>
>> - /*
>> - * Ideally DFL framework should only read info from DFL header, but
>> - * current version DFL only provides mmio resources information for
>> - * 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
>> - * DFL, the driver may still fall back to these quirks.
>> - */
>> - if (type == PORT_ID) {
>> - switch (fid) {
>> - case PORT_FEATURE_ID_UINT:
>> - v = readq(base + PORT_UINT_CAP);
>> - ibase = FIELD_GET(PORT_UINT_CAP_FST_VECT, v);
>> - inr = FIELD_GET(PORT_UINT_CAP_INT_NUM, v);
>> + case 1:
>> + /*
>> + * DFHv1 provides interrupt resource information in DFHv1
>> + * parameter blocks.
>> + */
>> + if (!finfo->param_size)
>> break;
>> - case PORT_FEATURE_ID_ERROR:
>> - v = readq(base + PORT_ERROR_CAP);
>> - ibase = FIELD_GET(PORT_ERROR_CAP_INT_VECT, v);
>> - inr = FIELD_GET(PORT_ERROR_CAP_SUPP_INT, v);
>> +
>> + p = find_param(params, finfo->param_size, DFHv1_PARAM_ID_MSI_X);
>> + if (!p)
>> break;
>> - }
>> - } else if (type == FME_ID) {
>> - if (fid == FME_FEATURE_ID_GLOBAL_ERR) {
>> - v = readq(base + FME_ERROR_CAP);
>> - ibase = FIELD_GET(FME_ERROR_CAP_INT_VECT, v);
>> - inr = FIELD_GET(FME_ERROR_CAP_SUPP_INT, v);
>> - }
>> +
>> + ibase = *p++;
>> + inr = *p;
>> + break;
>> +
>> + default:
>> + dev_warn(binfo->dev, "unexpected DFH version %d\n", finfo->dfh_version);
>> + break;
>> }
>>
>> if (!inr) {
>> - *irq_base = 0;
>> - *nr_irqs = 0;
>> + finfo->irq_base = 0;
>> + finfo->nr_irqs = 0;
>> return 0;
>> }
>>
>> @@ -1006,12 +1086,37 @@ static int parse_feature_irqs(struct build_feature_devs_info *binfo,
>> }
>> }
>>
>> - *irq_base = ibase;
>> - *nr_irqs = inr;
>> + finfo->irq_base = ibase;
>> + finfo->nr_irqs = inr;
>>
>> return 0;
>> }
>>
>> +static int dfh_get_psize(void __iomem *dfh_base, resource_size_t max)
>> +{
>> + int size = 0;
>> + u64 v, next;
>> +
>> + if (!FIELD_GET(DFHv1_CSR_SIZE_GRP_HAS_PARAMS,
>> + readq(dfh_base + DFHv1_CSR_SIZE_GRP)))
>> + return 0;
>> +
>> + while (size + DFHv1_PARAM_HDR < max) {
>> + v = readq(dfh_base + DFHv1_PARAM_HDR + size);
>> +
>> + next = FIELD_GET(DFHv1_PARAM_HDR_NEXT_OFFSET, v);
>> + if (!(next & ~DFHv1_PARAM_HDR_NEXT_MASK))
>> + return -EINVAL;
>> +
>> + size += next & ~DFHv1_PARAM_HDR_NEXT_MASK;
>> +
>> + if (next & DFHv1_PARAM_HDR_NEXT_EOL)
>> + return size;
>> + }
>> +
>> + return -ENOENT;
>> +}
>> +
>> /*
>> * when create sub feature instances, for private features, it doesn't need
>> * to provide resource size and feature id as they could be read from DFH
>> @@ -1023,39 +1128,70 @@ static int
>> create_feature_instance(struct build_feature_devs_info *binfo,
>> resource_size_t ofst, resource_size_t size, u16 fid)
>> {
>> - unsigned int irq_base, nr_irqs;
>> struct dfl_feature_info *finfo;
>> + int dfh_psize = 0;
>> u8 revision = 0;
>> + u8 dfh_ver = 0;
>> int ret;
>> u64 v;
>>
>> if (fid != FEATURE_ID_AFU) {
>> v = readq(binfo->ioaddr + ofst);
>> revision = FIELD_GET(DFH_REVISION, v);
>> -
>> + dfh_ver = FIELD_GET(DFH_VERSION, v);
>> /* read feature size and id if inputs are invalid */
>> size = size ? size : feature_size(v);
>> fid = fid ? fid : feature_id(v);
>> + if (dfh_ver == 1) {
>> + dfh_psize = dfh_get_psize(binfo->ioaddr + ofst, size);
>> + if (dfh_psize < 0) {
>> + dev_err(binfo->dev,
>> + "failed to read size of DFHv1 parameters %d\n",
>> + dfh_psize);
>> + return dfh_psize;
>> + }
>> + dev_dbg(binfo->dev, "dfhv1_psize %d\n", dfh_psize);
>> + }
>> }
>>
>> if (binfo->len - ofst < size)
>> return -EINVAL;
>>
>> - ret = parse_feature_irqs(binfo, ofst, fid, &irq_base, &nr_irqs);
>> - if (ret)
>> - return ret;
>> -
>> - finfo = kzalloc(sizeof(*finfo), GFP_KERNEL);
>> + finfo = kzalloc(sizeof(*finfo) + dfh_psize, GFP_KERNEL);
>
> The u64 flexible array in the structure, but seems dfh_get_psize could
> not garantee 64bit aligned size.
>
> What's the mandatory alignment of param data? If 64bit aligned, bit 33-34
> of PARAM_HDR should be reserved. If 32bit aligned, finfo:params should be
> u32[].
>
> Thanks,
> Yilun

The mandatory alignment alignment is 64. The documentation and field
definitions will be updated accordingly in the next revision.

>
>> if (!finfo)
>> return -ENOMEM;
>>
>> + if (dfh_psize > 0) {
>> + memcpy_fromio(finfo->params,
>> + binfo->ioaddr + ofst + DFHv1_PARAM_HDR, dfh_psize);
>> + finfo->param_size = dfh_psize;
>> + }
>> +
>> finfo->fid = fid;
>> finfo->revision = revision;
>> - finfo->mmio_res.start = binfo->start + ofst;
>> - finfo->mmio_res.end = finfo->mmio_res.start + size - 1;
>> + finfo->dfh_version = dfh_ver;
>> finfo->mmio_res.flags = IORESOURCE_MEM;
>> - finfo->irq_base = irq_base;
>> - finfo->nr_irqs = nr_irqs;
>> + if (dfh_ver == 1) {
>> + v = readq(binfo->ioaddr + ofst + DFHv1_CSR_ADDR);
>> + if (v & DFHv1_CSR_ADDR_REL)
>> + finfo->mmio_res.start = v & ~DFHv1_CSR_ADDR_REL;
>> + else
>> + finfo->mmio_res.start = binfo->start + ofst +
>> + FIELD_GET(DFHv1_CSR_ADDR_MASK, v);
>> +
>> + v = readq(binfo->ioaddr + ofst + DFHv1_CSR_SIZE_GRP);
>> + finfo->mmio_res.end = finfo->mmio_res.start +
>> + FIELD_GET(DFHv1_CSR_SIZE_GRP_SIZE, v) - 1;
>
> So for dflv1, no feature header resource for dfl_device, is it a problem
> for dfl_uio? Does userspace driver need the raw feature header?
These are two very good questions. The dfl_uio driver question is
particularly relevent because user space is looking at the GUIDs.

>
>> + } else {
>> + finfo->mmio_res.start = binfo->start + ofst;
>> + finfo->mmio_res.end = finfo->mmio_res.start + size - 1;
>> + }
>> +
>> + ret = parse_feature_irqs(binfo, ofst, finfo);
>> + if (ret) {
>> + kfree(finfo);
>> + return ret;
>> + }
>>
>> list_add_tail(&finfo->node, &binfo->sub_features);
>> binfo->feature_num++;
>> diff --git a/drivers/fpga/dfl.h b/drivers/fpga/dfl.h
>> index 45e6e1359a67..1ea7f40c1af6 100644
>> --- a/drivers/fpga/dfl.h
>> +++ b/drivers/fpga/dfl.h
>> @@ -273,11 +273,14 @@ struct dfl_feature_irq_ctx {
>> * @ops: ops of this sub feature.
>> * @ddev: ptr to the dfl device of this sub feature.
>> * @priv: priv data of this feature.
>> + * @param_size: size of dfh parameters
>> + * @params: point to memory copy of dfh parameters
>> */
>> struct dfl_feature {
>> struct platform_device *dev;
>> u16 id;
>> u8 revision;
>> + u8 dfh_version;
>> int resource_index;
>> void __iomem *ioaddr;
>> struct dfl_feature_irq_ctx *irq_ctx;
>> @@ -285,6 +288,8 @@ struct dfl_feature {
>> const struct dfl_feature_ops *ops;
>> struct dfl_device *ddev;
>> void *priv;
>> + unsigned int param_size;
>> + void *params;
>> };
>>
>> #define FEATURE_DEV_ID_UNUSED (-1)
>> diff --git a/include/linux/dfl.h b/include/linux/dfl.h
>> index fea9e16d35b6..d00787e870b7 100644
>> --- a/include/linux/dfl.h
>> +++ b/include/linux/dfl.h
>> @@ -50,9 +50,12 @@ struct dfl_device {
>> u16 type;
>> u16 feature_id;
>> u8 revision;
>> + u8 dfh_version;
>> struct resource mmio_res;
>> int *irqs;
>> unsigned int num_irqs;
>> + unsigned int param_size;
>> + void *params;
>> struct dfl_fpga_cdev *cdev;
>> const struct dfl_device_id *id_entry;
>> };
>> @@ -95,4 +98,5 @@ void dfl_driver_unregister(struct dfl_driver *dfl_drv);
>> module_driver(__dfl_driver, dfl_driver_register, \
>> dfl_driver_unregister)
>>
>> +void *dfh_find_param(struct dfl_device *dfl_dev, int param);
>
> int param_id is better?

param_id would be better.

>
> Thanks,
> Yilun
>
>> #endif /* __LINUX_DFL_H */
>> --
>> 2.25.1
>>
>