[dpdk-dev,1/4] pci: allow access to PCI config space
Commit Message
From: Stephen Hemminger <shemming@brocade.com>
Some drivers need ability to access PCI config (for example for power
management). This adds an abstraction to do this; only implemented
on Linux, but should be possible on BSD.
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
lib/librte_eal/common/include/rte_pci.h | 29 +++++++++++++++++++++++++
lib/librte_eal/linuxapp/eal/eal_pci.c | 15 +++++++++++++
lib/librte_eal/linuxapp/eal/eal_pci_uio.c | 10 +++++++++
lib/librte_eal/linuxapp/eal/rte_eal_version.map | 2 ++
4 files changed, 56 insertions(+)
Comments
Hello Stephen,
- It looks a bit odd to me, we end up with something asymetric between uio
/ vfio wrt pci config space.
Can we an api consistent between the two ?
Does this mean that your pmd cannot work / has not been used with vfio ?
- Anyway, I suppose we could reuse this api to remove the RTE_PCI_CONFIG
#ifdef / hardcoded stuff from linux eal / igb_uio.
Opinion ?
On Mon, 9 Feb 2015 10:45:01 +0100
David Marchand <david.marchand@6wind.com> wrote:
> Hello Stephen,
>
> - It looks a bit odd to me, we end up with something asymetric between uio / vfio wrt pci config space.
> Can we an api consistent between the two ?
> Does this mean that your pmd cannot work / has not been used with vfio ?
>
> - Anyway, I suppose we could reuse this api to remove the RTE_PCI_CONFIG #ifdef / hardcoded stuff from linux eal / igb_uio.
> Opinion ?
>
>
> --
> David Marchand
Ok, please send patches to VFIO to use this API.
It is not possible to do VFIO style config access through older UIO.
Therefore a wrapper like this is needed.
@@ -152,6 +152,7 @@ struct rte_pci_device {
uint16_t max_vfs; /**< sriov enable if not zero */
int numa_node; /**< NUMA node connection */
struct rte_devargs *devargs; /**< Device user arguments */
+ int config_fd; /**< PCI config access */
};
/** Any PCI device identifier (vendor, device, ...) */
@@ -298,6 +299,34 @@ void rte_eal_pci_register(struct rte_pci_driver *driver);
*/
void rte_eal_pci_unregister(struct rte_pci_driver *driver);
+/**
+ * Read PCI config space.
+ *
+ * @param device
+ * A pointer to a rte_pci_device structure describing the device
+ * to use
+ * @param buf
+ * A data buffer where the bytes should be read into
+ * @param size
+ * The length of the data buffer.
+ */
+int rte_eal_pci_read_config(const struct rte_pci_device *device,
+ void *buf, size_t len, off_t offset);
+
+/**
+ * Write PCI config space.
+ *
+ * @param device
+ * A pointer to a rte_pci_device structure describing the device
+ * to use
+ * @param buf
+ * A data buffer containing the bytes should be written
+ * @param size
+ * The length of the data buffer.
+ */
+int rte_eal_pci_write_config(const struct rte_pci_device *device,
+ const void *buf, size_t len, off_t offset);
+
#ifdef __cplusplus
}
#endif
@@ -233,6 +233,7 @@ pci_scan_one(const char *dirname, uint16_t domain, uint8_t bus,
dev->addr.bus = bus;
dev->addr.devid = devid;
dev->addr.function = function;
+ dev->config_fd = -1;
/* get vendor id */
snprintf(filename, sizeof(filename), "%s/vendor", dirname);
@@ -592,6 +593,20 @@ rte_eal_pci_probe_one_driver(struct rte_pci_driver *dr, struct rte_pci_device *d
return 1;
}
+/* Read PCI config space. */
+int rte_eal_pci_read_config(const struct rte_pci_device *device,
+ void *buf, size_t len, off_t offset)
+{
+ return pread(device->config_fd, buf, len, offset);
+}
+
+/* Write PCI config space. */
+int rte_eal_pci_write_config(const struct rte_pci_device *device,
+ const void *buf, size_t len, off_t offset)
+{
+ return pwrite(device->config_fd, buf, len, offset);
+}
+
/* Init the PCI EAL subsystem */
int
rte_eal_pci_init(void)
@@ -213,6 +213,7 @@ pci_get_uio_dev(struct rte_pci_device *dev, char *dstbuf,
struct dirent *e;
DIR *dir;
char dirname[PATH_MAX];
+ char filename[PATH_MAX];
/* depending on kernel version, uio can be located in uio/uioX
* or uio:uioX */
@@ -268,6 +269,15 @@ pci_get_uio_dev(struct rte_pci_device *dev, char *dstbuf,
if (e == NULL)
return -1;
+ /* Open fd for access to PCI config */
+ snprintf(filename, sizeof(filename), "%s/device/config", dirname);
+ dev->config_fd = open(filename, O_RDWR);
+ if (dev->config_fd < 0) {
+ RTE_LOG(ERR, EAL, "%s(): cannot open %s: %s\n",
+ __func__, filename, strerror(errno));
+ return -1;
+ }
+
/* create uio device if we've been asked to */
if (internal_config.create_uio_dev &&
pci_mknod_uio_dev(dstbuf, uio_num) < 0)
@@ -40,6 +40,8 @@ DPDK_2.0 {
rte_eal_pci_probe;
rte_eal_pci_register;
rte_eal_pci_unregister;
+ rte_eal_pci_read_config;
+ rte_eal_pci_write_config;
rte_eal_process_type;
rte_eal_remote_launch;
rte_eal_tailq_lookup;