[PATCH v2] uio: uio_pci_generic: add memory resource mappings

[Firas Ashkar]

import memory resources from underlying pci device, thus allowing
userspace applications to memory map those resources.

without this change, current implementation, does not populate the
memory maps and are not shown under the corresponding sysfs uio entry:

root@apalis-imx8:~# echo "ad00 0122" > \
			/sys/bus/pci/drivers/uio_pci_generic/new_id
[   55.736433] uio_pci_generic 0000:01:00.0: enabling device (0000 -> 0002)
root@apalis-imx8:~# ls -lsrt /sys/class/uio/uio0/
     0 -rw-r--r--    1 root     root          4096 Apr 27 18:52 uevent
     0 -r--r--r--    1 root     root          4096 Apr 27 18:52 version
     0 -r--r--r--    1 root     root          4096 Apr 27 18:52 suppliers
     0 lrwxrwxrwx    1 root     root             0 Apr 27 18:52 subsystem
-> ../../../../../../../../../class/uio
     0 drwxr-xr-x    2 root     root             0 Apr 27 18:52 power
     0 -r--r--r--    1 root     root          4096 Apr 27 18:52 name
     0 -r--r--r--    1 root     root          4096 Apr 27 18:52 event
     0 lrwxrwxrwx    1 root     root             0 Apr 27 18:52 device
-> ../../../0000:01:00.0
     0 -r--r--r--    1 root     root          4096 Apr 27 18:52 dev
     0 -r--r--r--    1 root     root          4096 Apr 27 18:52 consumers
root@apalis-imx8:~#

with the proposed changed, have following instead:
root@apalis-imx8:~# ls -lsrt /sys/class/uio/uio0/
     0 -rw-r--r--    1 root     root          4096 Apr 27 19:06 uevent
     0 -r--r--r--    1 root     root          4096 Apr 27 19:06 version
     0 -r--r--r--    1 root     root          4096 Apr 27 19:06 suppliers
     0 lrwxrwxrwx    1 root     root             0 Apr 27 19:06 subsystem
-> ../../../../../../../../../class/uio
     0 drwxr-xr-x    2 root     root             0 Apr 27 19:06 power
     0 -r--r--r--    1 root     root          4096 Apr 27 19:06 name
     0 drwxr-xr-x    4 root     root             0 Apr 27 19:06 maps
     0 -r--r--r--    1 root     root          4096 Apr 27 19:06 event
     0 lrwxrwxrwx    1 root     root             0 Apr 27 19:06 device
-> ../../../0000:01:00.0
     0 -r--r--r--    1 root     root          4096 Apr 27 19:06 dev
     0 -r--r--r--    1 root     root          4096 Apr 27 19:06 consumers
root@apalis-imx8:~#

root@apalis-imx8:~# ls -lsrt /sys/class/uio/uio0/maps/
     0 drwxr-xr-x    2 root     root             0 Apr 27 19:07 map1
     0 drwxr-xr-x    2 root     root             0 Apr 27 19:07 map0
root@apalis-imx8:~#

root@apalis-imx8:~# cat /sys/class/uio/uio0/maps/map1/addr
0x0000000062000000
root@apalis-imx8:~#

root@apalis-imx8:~# cat /sys/class/uio/uio0/maps/map1/size
0x0000000000200000
root@apalis-imx8:~#

tested on AltaData ARINC 429 MiniPCIE module on imx8qm-apalis-ixora-v1.2

Signed-off-by: Firas Ashkar <firas.ashkar@xxxxxxxxxxxxxxxxxxxx>
---

Notes:
    Changes in V2
    * add detailed description why this change is needed
    * add test hardware name and version

:100644 100644 c7d681fef198 efc43869131d M	drivers/uio/uio_pci_generic.c
 drivers/uio/uio_pci_generic.c | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/drivers/uio/uio_pci_generic.c b/drivers/uio/uio_pci_generic.c
index c7d681fef198..efc43869131d 100644
--- a/drivers/uio/uio_pci_generic.c
+++ b/drivers/uio/uio_pci_generic.c
@@ -72,7 +72,9 @@ static int probe(struct pci_dev *pdev,
 			   const struct pci_device_id *id)
 {
 	struct uio_pci_generic_dev *gdev;
+	struct uio_mem *uiomem;
 	int err;
+	int i;
 
 	err = pcim_enable_device(pdev);
 	if (err) {
@@ -101,6 +103,36 @@ static int probe(struct pci_dev *pdev,
 			 "no support for interrupts?\n");
 	}
 
+	uiomem = &gdev->info.mem[0];
+	for (i = 0; i < MAX_UIO_MAPS; ++i) {
+		struct resource *r = &pdev->resource[i];
+
+		if (r->flags != (IORESOURCE_SIZEALIGN | IORESOURCE_MEM))
+			continue;
+
+		if (uiomem >= &gdev->info.mem[MAX_UIO_MAPS]) {
+			dev_warn(
+				&pdev->dev,
+				"device has more than " __stringify(
+					MAX_UIO_MAPS) " I/O memory resources.\n");
+			break;
+		}
+
+		uiomem->memtype = UIO_MEM_PHYS;
+		uiomem->addr = r->start & PAGE_MASK;
+		uiomem->offs = r->start & ~PAGE_MASK;
+		uiomem->size =
+			(uiomem->offs + resource_size(r) + PAGE_SIZE - 1) &
+			PAGE_MASK;
+		uiomem->name = r->name;
+		++uiomem;
+	}
+
+	while (uiomem < &gdev->info.mem[MAX_UIO_MAPS]) {
+		uiomem->size = 0;
+		++uiomem;
+	}
+
 	return devm_uio_register_device(&pdev->dev, &gdev->info);
 }
 
-- 
2.25.1