[dpdk-dev] [PATCH 1/4] pci: allow access to PCI config space

[Stephen Hemminger]

From: Stephen Hemminger <shemming at 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 at 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(+)

diff --git a/lib/librte_eal/common/include/rte_pci.h b/lib/librte_eal/common/include/rte_pci.h
index 66ed793..a78081f 100644
--- a/lib/librte_eal/common/include/rte_pci.h
+++ b/lib/librte_eal/common/include/rte_pci.h
@@ -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
diff --git a/lib/librte_eal/linuxapp/eal/eal_pci.c b/lib/librte_eal/linuxapp/eal/eal_pci.c
index b5f5410..5bcfffa 100644
--- a/lib/librte_eal/linuxapp/eal/eal_pci.c
+++ b/lib/librte_eal/linuxapp/eal/eal_pci.c
@@ -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)
diff --git a/lib/librte_eal/linuxapp/eal/eal_pci_uio.c b/lib/librte_eal/linuxapp/eal/eal_pci_uio.c
index e53f06b..0396eaa 100644
--- a/lib/librte_eal/linuxapp/eal/eal_pci_uio.c
+++ b/lib/librte_eal/linuxapp/eal/eal_pci_uio.c
@@ -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)
diff --git a/lib/librte_eal/linuxapp/eal/rte_eal_version.map b/lib/librte_eal/linuxapp/eal/rte_eal_version.map
index d36286e..626689c 100644
--- a/lib/librte_eal/linuxapp/eal/rte_eal_version.map
+++ b/lib/librte_eal/linuxapp/eal/rte_eal_version.map
@@ -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;
-- 
2.1.4