fpga: dfl: add basic support for DFHv1

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 <[e-mail]>
Reviewed-by: Ilpo Järvinen <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/fpga/dfl.c

···
 #include <linux/dfl.h>
 #include <linux/fpga-dfl.h>
 #include <linux/module.h>
+#include <linux/overflow.h>
 #include <linux/uaccess.h>
 
 #include "dfl.h"
···
 	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);
···
 	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];
···
  * 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,
···
 		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
···
 	return 0;
 }
 
+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
+ * @psize: destination to store size of parameter data in bytes
+ *
+ * Return: pointer to start of parameter data, PTR_ERR otherwise.
+ */
+void *dfh_find_param(struct dfl_device *dfl_dev, int param_id, size_t *psize)
+{
+	u64 *phdr = find_param(dfl_dev->params, dfl_dev->param_size, param_id);
+
+	if (!phdr)
+		return ERR_PTR(-ENOENT);
+
+	if (psize)
+		*psize = (FIELD_GET(DFHv1_PARAM_HDR_NEXT_OFFSET, *phdr) - 1) * sizeof(u64);
+
+	return phdr + 1;
+}
+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;
+	u64 *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.
+		 */
+		p = find_param(params, finfo->param_size, DFHv1_PARAM_ID_MSI_X);
+		if (!p)
 			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) {
-		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);
-		}
+
+		p++;
+		ibase = FIELD_GET(DFHv1_PARAM_MSI_X_STARTV, *p);
+		inr = FIELD_GET(DFHv1_PARAM_MSI_X_NUMV, *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;
 	}
 
···
 		}
 	}
 
-	*irq_base = ibase;
-	*nr_irqs = inr;
+	finfo->irq_base = ibase;
+	finfo->nr_irqs = inr;
 
 	return 0;
+}
+
+static int dfh_get_param_size(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)
+			return -EINVAL;
+
+		size += next * sizeof(u64);
+
+		if (FIELD_GET(DFHv1_PARAM_HDR_NEXT_EOP, v))
+			return size;
+	}
+
+	return -ENOENT;
 }
 
 /*
···
 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;
+	resource_size_t start, end;
+	int dfh_psize = 0;
 	u8 revision = 0;
+	u64 v, addr_off;
+	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_param_size(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(struct_size(finfo, params, dfh_psize / sizeof(u64)), GFP_KERNEL);
 	if (!finfo)
 		return -ENOMEM;
 
+	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;
+	if (dfh_ver == 1) {
+		v = readq(binfo->ioaddr + ofst + DFHv1_CSR_ADDR);
+		addr_off = FIELD_GET(DFHv1_CSR_ADDR_MASK, v);
+		if (FIELD_GET(DFHv1_CSR_ADDR_REL, v))
+			start = addr_off << 1;
+		else
+			start = binfo->start + ofst + addr_off;
+
+		v = readq(binfo->ioaddr + ofst + DFHv1_CSR_SIZE_GRP);
+		end = start + FIELD_GET(DFHv1_CSR_SIZE_GRP_SIZE, v) - 1;
+	} else {
+		start = binfo->start + ofst;
+		end = start + size - 1;
+	}
 	finfo->mmio_res.flags = IORESOURCE_MEM;
-	finfo->irq_base = irq_base;
-	finfo->nr_irqs = nr_irqs;
+	finfo->mmio_res.start = start;
+	finfo->mmio_res.end = end;
+
+	ret = parse_feature_irqs(binfo, ofst, finfo);
+	if (ret) {
+		kfree(finfo);
+		return ret;
+	}
 
 	list_add_tail(&finfo->node, &binfo->sub_features);
 	binfo->feature_num++;

drivers/fpga/dfl.h

···
 #define DFHv1_PARAM_HDR_NEXT_EOP	BIT_ULL(32)
 #define DFHv1_PARAM_DATA		0x08  /* Offset of Param data from Param header */
 
+#define DFHv1_PARAM_ID_MSI_X		0x1
+#define DFHv1_PARAM_MSI_X_NUMV		GENMASK_ULL(63, 32)
+#define DFHv1_PARAM_MSI_X_STARTV	GENMASK_ULL(31, 0)
+
 /* Next AFU Register Bitfield */
 #define NEXT_AFU_NEXT_DFH_OFST	GENMASK_ULL(23, 0)	/* Offset to next AFU */
 
···
  *
  * @dev: ptr to pdev of the feature device which has the sub feature.
  * @id: sub feature id.
+ * @revision: revisition of the instance of a feature.
  * @resource_index: each sub feature has one mmio resource for its registers.
  *		    this index is used to find its mmio resource from the
  *		    feature dev (platform device)'s resources.
···
  * @ops: ops of this sub feature.
  * @ddev: ptr to the dfl device of this sub feature.
  * @priv: priv data of this feature.
+ * @dfh_version: version of the DFH
+ * @param_size: size of dfh parameters
+ * @params: point to memory copy of dfh parameters
  */
 struct dfl_feature {
 	struct platform_device *dev;
···
 	const struct dfl_feature_ops *ops;
 	struct dfl_device *ddev;
 	void *priv;
+	u8 dfh_version;
+	unsigned int param_size;
+	void *params;
 };
 
 #define FEATURE_DEV_ID_UNUSED	(-1)

include/linux/dfl.h

···
  * @id: id of the dfl device.
  * @type: type of DFL FIU of the device. See enum dfl_id_type.
  * @feature_id: feature identifier local to its DFL FIU type.
+ * @revision: revision of this dfl device feature.
  * @mmio_res: mmio resource of this dfl device.
  * @irqs: list of Linux IRQ numbers of this dfl device.
  * @num_irqs: number of IRQs supported by this dfl device.
  * @cdev: pointer to DFL FPGA container device this dfl device belongs to.
  * @id_entry: matched id entry in dfl driver's id table.
+ * @dfh_version: version of DFH for the device
+ * @param_size: size of the block parameters in bytes
+ * @params: pointer to block of parameters copied memory
  */
 struct dfl_device {
 	struct device dev;
···
 	unsigned int num_irqs;
 	struct dfl_fpga_cdev *cdev;
 	const struct dfl_device_id *id_entry;
+	u8 dfh_version;
+	unsigned int param_size;
+	void *params;
 };
 
 /**
···
 	module_driver(__dfl_driver, dfl_driver_register, \
 		      dfl_driver_unregister)
 
+void *dfh_find_param(struct dfl_device *dfl_dev, int param_id, size_t *pcount);
 #endif /* __LINUX_DFL_H */