Change in flashrom[master]: pci2: add mmio bar map/unmap

[Luc Verhaegen (Code Review)]

Luc Verhaegen has uploaded this change for review. ( https://review.coreboot.org/29079

Change subject: pci2: add mmio bar map/unmap
......................................................................

pci2: add mmio bar map/unmap

This works through linux sysfs and opens /sys/bus/pci/devices/.../resource%d
and maps that to neatly circumvent /dev/mem security limitations and
we do not need to figure out BAR address and size ourselves.

Change-Id: I1c67d51d853f751d13271bf83316ee2118c1c476
Signed-off-by: Luc Verhaegen 
---
M pcidev.c
M programmer.h
2 files changed, 75 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/flashrom refs/changes/79/29079/1

diff --git a/pcidev.c b/pcidev.c
index 837b028..8503e78 100644
--- a/pcidev.c
+++ b/pcidev.c
@@ -18,6 +18,11 @@

#include <stdlib.h>
 #include <string.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <unistd.h>
+
 #include "flash.h"
 #include "programmer.h"
 #include "hwaccess.h"
@@ -352,6 +357,69 @@
 /*
  *
  */
+int
+flashrom_pci_mmio_map(struct flashrom_pci_device *device, int bar)
+{
+	char filename[1024];
+	int fd;
+
+	if ((bar < 0) || (bar > 5)) {
+		msg_perr("%s: Invalid BAR provided: %d\n", __func__, bar);
+		return EINVAL;
+	}
+
+	if (device->mmio) {
+		if (device->pci->size[bar] != device->mmio_size) {
+			msg_perr("%s: already mapped bar: 0x%lXbytes @ %p)\n",
+				 __func__, device->mmio_size, device->mmio);
+			return EALREADY;
+		} else
+			return 0;
+	}
+
+	snprintf(filename, sizeof(filename) - 1,
+		 "%sresource%d", device->sysfs_path, bar);
+
+	fd = open(filename, O_RDWR);
+	if (fd == -1) {
+		msg_perr("%s: failed to open %s: %s\n",
+			 __func__, filename, strerror(errno));
+		return errno;
+	}
+
+	device->mmio_size = device->pci->size[bar];
+
+	device->mmio = mmap(NULL, device->mmio_size, PROT_WRITE | PROT_READ,
+			    MAP_SHARED, fd, 0);
+	if (device->mmio == MAP_FAILED) {
+		msg_perr("%s: mapping %s failed: %s\n",
+			 __func__, filename, strerror(errno));
+		close(fd);
+		device->mmio_size = 0;
+		return errno;
+	}
+
+	close(fd);
+
+	return 0;
+}
+
+/*
+ *
+ */
+void
+flashrom_pci_mmio_unmap(struct flashrom_pci_device *device)
+{
+	if (device->mmio && device->mmio_size &&
+	    (device->mmio != MAP_FAILED))
+		munmap((void *) device->mmio, device->mmio_size);
+	device->mmio = NULL;
+	device->mmio_size = 0;
+}
+
+/*
+ *
+ */
 static int
 flashrom_pci_device_shutdown(void *data)
 {
@@ -363,6 +431,8 @@
    	return 1;
    }

+	flashrom_pci_mmio_unmap(device);
+
    free(device->sysfs_path);
    device->sysfs_path = NULL;

diff --git a/programmer.h b/programmer.h
index 0a445fa..d553317 100644
--- a/programmer.h
+++ b/programmer.h
@@ -868,10 +868,15 @@

char *sysfs_path; /* linux only, of course */

+	volatile uint8_t *mmio; /* mapped io memory */
+	size_t mmio_size;
+
    const void *private; /* programmer specific hook */
 };

struct flashrom_pci_device *flashrom_pci_init(const struct flashrom_pci_match *matches);
+int flashrom_pci_mmio_map(struct flashrom_pci_device *device, int bar);
+void flashrom_pci_mmio_unmap(struct flashrom_pci_device *device);
 #endif /* NEED_PCI */

#endif				/* !__PROGRAMMER_H__ */