fpga: dfl: afu: add afu sub feature support

User Accelerated Function Unit sub feature exposes the MMIO region of
the AFU. After valid PR bitstream is programmed and the port is enabled,
then this MMIO region could be accessed.

This patch adds support to enumerate the AFU MMIO region and expose it
to userspace via mmap file operation. Below interfaces are exposed to user:

Sysfs interface:
* /sys/class/fpga_region/<regionX>/<dfl-port.x>/afu_id
  Read-only. Indicate which PR bitstream is programmed to this AFU.

Ioctl interfaces:
* DFL_FPGA_PORT_GET_INFO
  Provide info to userspace on the number of supported region.
  Only UAFU region is supported now.

* DFL_FPGA_PORT_GET_REGION_INFO
  Provide region information, including access permission, region size,
  offset from the start of device fd.

Signed-off-by: Tim Whisonant <[email protected]>
Signed-off-by: Enno Luebbers <[email protected]>
Signed-off-by: Shiva Rao <[email protected]>
Signed-off-by: Christopher Rauer <[email protected]>
Signed-off-by: Xiao Guangrong <[email protected]>
Signed-off-by: Wu Hao <[email protected]>
Acked-by: Alan Tull <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: Xiao Guangrong

Documentation/ABI/testing/sysfs-platform-dfl-port

@@ -5,3 +5,12 @@ Contact:	Wu Hao <[email protected]>
 Description:	Read-only. It returns id of this port. One DFL FPGA device
 		may have more than one port. Userspace could use this id to
 		distinguish different ports under same FPGA device.
+
+What:		/sys/bus/platform/devices/dfl-port.0/afu_id
+Date:		June 2018
+KernelVersion:	4.19
+Contact:	Wu Hao <[email protected]>
+Description:	Read-only. User can program different PR bitstreams to FPGA
+		Accelerator Function Unit (AFU) for different functions. It
+		returns uuid which could be used to identify which PR bitstream
+		is programmed in this AFU.

drivers/fpga/Makefile

@@ -38,7 +38,7 @@ obj-$(CONFIG_FPGA_DFL_FME_REGION)	+= dfl-fme-region.o
 obj-$(CONFIG_FPGA_DFL_AFU)		+= dfl-afu.o
 
 dfl-fme-objs := dfl-fme-main.o dfl-fme-pr.o
-dfl-afu-objs := dfl-afu-main.o
+dfl-afu-objs := dfl-afu-main.o dfl-afu-region.o
 
 # Drivers for FPGAs which implement DFL
 obj-$(CONFIG_FPGA_DFL_PCI)		+= dfl-pci.o

drivers/fpga/dfl-afu-main.c

@@ -16,18 +16,18 @@
 
 #include <linux/kernel.h>
 #include <linux/module.h>
+#include <linux/uaccess.h>
 #include <linux/fpga-dfl.h>
 
-#include "dfl.h"
+#include "dfl-afu.h"
 
 /**
  * port_enable - enable a port
  * @pdev: port platform device.
  *
  * Enable Port by clear the port soft reset bit, which is set by default.
- * The User AFU is unable to respond to any MMIO access while in reset.
- * port_enable function should only be used after port_disable
- * function.
+ * The AFU is unable to respond to any MMIO access while in reset.
+ * port_enable function should only be used after port_disable function.
  */
 static void port_enable(struct platform_device *pdev)
 {
@@ -191,11 +191,74 @@ static const struct dfl_feature_ops port_hdr_ops = {
 	.ioctl = port_hdr_ioctl,
 };
 
+static ssize_t
+afu_id_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct dfl_feature_platform_data *pdata = dev_get_platdata(dev);
+	void __iomem *base;
+	u64 guidl, guidh;
+
+	base = dfl_get_feature_ioaddr_by_id(dev, PORT_FEATURE_ID_AFU);
+
+	mutex_lock(&pdata->lock);
+	if (pdata->disable_count) {
+		mutex_unlock(&pdata->lock);
+		return -EBUSY;
+	}
+
+	guidl = readq(base + GUID_L);
+	guidh = readq(base + GUID_H);
+	mutex_unlock(&pdata->lock);
+
+	return scnprintf(buf, PAGE_SIZE, "%016llx%016llx\n", guidh, guidl);
+}
+static DEVICE_ATTR_RO(afu_id);
+
+static const struct attribute *port_afu_attrs[] = {
+	&dev_attr_afu_id.attr,
+	NULL
+};
+
+static int port_afu_init(struct platform_device *pdev,
+			 struct dfl_feature *feature)
+{
+	struct resource *res = &pdev->resource[feature->resource_index];
+	int ret;
+
+	dev_dbg(&pdev->dev, "PORT AFU Init.\n");
+
+	ret = afu_mmio_region_add(dev_get_platdata(&pdev->dev),
+				  DFL_PORT_REGION_INDEX_AFU, resource_size(res),
+				  res->start, DFL_PORT_REGION_READ |
+				  DFL_PORT_REGION_WRITE | DFL_PORT_REGION_MMAP);
+	if (ret)
+		return ret;
+
+	return sysfs_create_files(&pdev->dev.kobj, port_afu_attrs);
+}
+
+static void port_afu_uinit(struct platform_device *pdev,
+			   struct dfl_feature *feature)
+{
+	dev_dbg(&pdev->dev, "PORT AFU UInit.\n");
+
+	sysfs_remove_files(&pdev->dev.kobj, port_afu_attrs);
+}
+
+static const struct dfl_feature_ops port_afu_ops = {
+	.init = port_afu_init,
+	.uinit = port_afu_uinit,
+};
+
 static struct dfl_feature_driver port_feature_drvs[] = {
 	{
 		.id = PORT_FEATURE_ID_HEADER,
 		.ops = &port_hdr_ops,
 	},
+	{
+		.id = PORT_FEATURE_ID_AFU,
+		.ops = &port_afu_ops,
+	},
 	{
 		.ops = NULL,
 	}
@@ -243,6 +306,64 @@ static long afu_ioctl_check_extension(struct dfl_feature_platform_data *pdata,
 	return 0;
 }
 
+static long
+afu_ioctl_get_info(struct dfl_feature_platform_data *pdata, void __user *arg)
+{
+	struct dfl_fpga_port_info info;
+	struct dfl_afu *afu;
+	unsigned long minsz;
+
+	minsz = offsetofend(struct dfl_fpga_port_info, num_umsgs);
+
+	if (copy_from_user(&info, arg, minsz))
+		return -EFAULT;
+
+	if (info.argsz < minsz)
+		return -EINVAL;
+
+	mutex_lock(&pdata->lock);
+	afu = dfl_fpga_pdata_get_private(pdata);
+	info.flags = 0;
+	info.num_regions = afu->num_regions;
+	info.num_umsgs = afu->num_umsgs;
+	mutex_unlock(&pdata->lock);
+
+	if (copy_to_user(arg, &info, sizeof(info)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static long afu_ioctl_get_region_info(struct dfl_feature_platform_data *pdata,
+				      void __user *arg)
+{
+	struct dfl_fpga_port_region_info rinfo;
+	struct dfl_afu_mmio_region region;
+	unsigned long minsz;
+	long ret;
+
+	minsz = offsetofend(struct dfl_fpga_port_region_info, offset);
+
+	if (copy_from_user(&rinfo, arg, minsz))
+		return -EFAULT;
+
+	if (rinfo.argsz < minsz || rinfo.padding)
+		return -EINVAL;
+
+	ret = afu_mmio_region_get_by_index(pdata, rinfo.index, &region);
+	if (ret)
+		return ret;
+
+	rinfo.flags = region.flags;
+	rinfo.size = region.size;
+	rinfo.offset = region.offset;
+
+	if (copy_to_user(arg, &rinfo, sizeof(rinfo)))
+		return -EFAULT;
+
+	return 0;
+}
+
 static long afu_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
 	struct platform_device *pdev = filp->private_data;
@@ -259,6 +380,10 @@ static long afu_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		return DFL_FPGA_API_VERSION;
 	case DFL_FPGA_CHECK_EXTENSION:
 		return afu_ioctl_check_extension(pdata, arg);
+	case DFL_FPGA_PORT_GET_INFO:
+		return afu_ioctl_get_info(pdata, (void __user *)arg);
+	case DFL_FPGA_PORT_GET_REGION_INFO:
+		return afu_ioctl_get_region_info(pdata, (void __user *)arg);
 	default:
 		/*
 		 * Let sub-feature's ioctl function to handle the cmd
@@ -277,13 +402,83 @@ static long afu_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 	return -EINVAL;
 }
 
+static int afu_mmap(struct file *filp, struct vm_area_struct *vma)
+{
+	struct platform_device *pdev = filp->private_data;
+	struct dfl_feature_platform_data *pdata;
+	u64 size = vma->vm_end - vma->vm_start;
+	struct dfl_afu_mmio_region region;
+	u64 offset;
+	int ret;
+
+	if (!(vma->vm_flags & VM_SHARED))
+		return -EINVAL;
+
+	pdata = dev_get_platdata(&pdev->dev);
+
+	offset = vma->vm_pgoff << PAGE_SHIFT;
+	ret = afu_mmio_region_get_by_offset(pdata, offset, size, &region);
+	if (ret)
+		return ret;
+
+	if (!(region.flags & DFL_PORT_REGION_MMAP))
+		return -EINVAL;
+
+	if ((vma->vm_flags & VM_READ) && !(region.flags & DFL_PORT_REGION_READ))
+		return -EPERM;
+
+	if ((vma->vm_flags & VM_WRITE) &&
+	    !(region.flags & DFL_PORT_REGION_WRITE))
+		return -EPERM;
+
+	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+
+	return remap_pfn_range(vma, vma->vm_start,
+			(region.phys + (offset - region.offset)) >> PAGE_SHIFT,
+			size, vma->vm_page_prot);
+}
+
 static const struct file_operations afu_fops = {
 	.owner = THIS_MODULE,
 	.open = afu_open,
 	.release = afu_release,
 	.unlocked_ioctl = afu_ioctl,
+	.mmap = afu_mmap,
 };
 
+static int afu_dev_init(struct platform_device *pdev)
+{
+	struct dfl_feature_platform_data *pdata = dev_get_platdata(&pdev->dev);
+	struct dfl_afu *afu;
+
+	afu = devm_kzalloc(&pdev->dev, sizeof(*afu), GFP_KERNEL);
+	if (!afu)
+		return -ENOMEM;
+
+	afu->pdata = pdata;
+
+	mutex_lock(&pdata->lock);
+	dfl_fpga_pdata_set_private(pdata, afu);
+	afu_mmio_region_init(pdata);
+	mutex_unlock(&pdata->lock);
+
+	return 0;
+}
+
+static int afu_dev_destroy(struct platform_device *pdev)
+{
+	struct dfl_feature_platform_data *pdata = dev_get_platdata(&pdev->dev);
+	struct dfl_afu *afu;
+
+	mutex_lock(&pdata->lock);
+	afu = dfl_fpga_pdata_get_private(pdata);
+	afu_mmio_region_destroy(pdata);
+	dfl_fpga_pdata_set_private(pdata, NULL);
+	mutex_unlock(&pdata->lock);
+
+	return 0;
+}
+
 static int port_enable_set(struct platform_device *pdev, bool enable)
 {
 	struct dfl_feature_platform_data *pdata = dev_get_platdata(&pdev->dev);
@@ -312,14 +507,25 @@ static int afu_probe(struct platform_device *pdev)
 
 	dev_dbg(&pdev->dev, "%s\n", __func__);
 
+	ret = afu_dev_init(pdev);
+	if (ret)
+		goto exit;
+
 	ret = dfl_fpga_dev_feature_init(pdev, port_feature_drvs);
 	if (ret)
-		return ret;
+		goto dev_destroy;
 
 	ret = dfl_fpga_dev_ops_register(pdev, &afu_fops, THIS_MODULE);
-	if (ret)
+	if (ret) {
 		dfl_fpga_dev_feature_uinit(pdev);
+		goto dev_destroy;
+	}
+
+	return 0;
 
+dev_destroy:
+	afu_dev_destroy(pdev);
+exit:
 	return ret;
 }
 
@@ -329,6 +535,7 @@ static int afu_remove(struct platform_device *pdev)
 
 	dfl_fpga_dev_ops_unregister(pdev);
 	dfl_fpga_dev_feature_uinit(pdev);
+	afu_dev_destroy(pdev);
 
 	return 0;
 }