[dpdk-dev] [PATCH v4 11/17] eal/soc: add default scan for Soc devices

Shreyansh Jain shreyansh.jain at nxp.com
Sat Oct 15 15:45:02 CEST 2016


From: Jan Viktorin <viktorin at rehivetech.com>

Default implementation which scans the sysfs platform devices hierarchy.
For each device, extract the ueven and convert into rte_soc_device.

The information populated can then be used in probe to match against
the drivers registered.

Signed-off-by: Jan Viktorin <viktorin at rehivetech.com>
[Shreyansh: restructure commit to be an optional implementation]
Signed-off-by: Shreyansh Jain <shreyansh.jain at nxp.com>
---
 lib/librte_eal/common/include/rte_soc.h |  10 +-
 lib/librte_eal/linuxapp/eal/eal_soc.c   | 315 ++++++++++++++++++++++++++++++++
 2 files changed, 324 insertions(+), 1 deletion(-)

diff --git a/lib/librte_eal/common/include/rte_soc.h b/lib/librte_eal/common/include/rte_soc.h
index 1f5f81b..1865be5 100644
--- a/lib/librte_eal/common/include/rte_soc.h
+++ b/lib/librte_eal/common/include/rte_soc.h
@@ -64,7 +64,10 @@ TAILQ_HEAD(soc_driver_list, rte_soc_driver); /**< SoC drivers in D-linked Q. */
 TAILQ_HEAD(soc_device_list, rte_soc_device); /**< SoC devices in D-linked Q. */
 
 struct rte_soc_id {
-	const char *compatible; /**< OF compatible specification */
+	union {
+		const char *compatible; /**< OF compatible specification */
+		char *_compatible;
+	};
 	uint64_t priv_data;     /**< SoC Driver specific data */
 };
 
@@ -200,6 +203,11 @@ rte_eal_parse_soc_spec(const char *spec, struct rte_soc_addr *addr)
 }
 
 /**
+ * Scan for new SoC devices.
+ */
+int rte_eal_soc_scan(void);
+
+/**
  * Default function for matching the Soc driver with device. Each driver can
  * either use this function or define their own soc matching function.
  * This function relies on the compatible string extracted from sysfs. But,
diff --git a/lib/librte_eal/linuxapp/eal/eal_soc.c b/lib/librte_eal/linuxapp/eal/eal_soc.c
index 3929a76..d8286bb 100644
--- a/lib/librte_eal/linuxapp/eal/eal_soc.c
+++ b/lib/librte_eal/linuxapp/eal/eal_soc.c
@@ -48,6 +48,321 @@
 #include <eal_filesystem.h>
 #include <eal_private.h>
 
+/** Pathname of SoC devices directory. */
+#define SYSFS_SOC_DEVICES "/sys/bus/platform/devices"
+
+static const char *
+soc_get_sysfs_path(void)
+{
+	const char *path = NULL;
+
+	path = getenv("SYSFS_SOC_DEVICES");
+	if (path == NULL)
+		return SYSFS_SOC_DEVICES;
+
+	return path;
+}
+
+static char *
+dev_read_uevent(const char *dirname)
+{
+	char filename[PATH_MAX];
+	struct stat st;
+	char *buf;
+	ssize_t total = 0;
+	int fd;
+
+	snprintf(filename, sizeof(filename), "%s/uevent", dirname);
+	fd = open(filename, O_RDONLY);
+	if (fd < 0) {
+		RTE_LOG(WARNING, EAL, "Failed to open file %s\n", filename);
+		return strdup("");
+	}
+
+	if (fstat(fd, &st) < 0) {
+		RTE_LOG(ERR, EAL, "Failed to stat file %s\n", filename);
+		close(fd);
+		return NULL;
+	}
+
+	if (st.st_size == 0) {
+		close(fd);
+		return strdup("");
+	}
+
+	buf = malloc(st.st_size + 1);
+	if (buf == NULL) {
+		RTE_LOG(ERR, EAL, "Failed to alloc memory to read %s\n",
+			filename);
+		close(fd);
+		return NULL;
+	}
+
+	while (total < st.st_size) {
+		ssize_t rlen = read(fd, buf + total, st.st_size - total);
+		if (rlen < 0) {
+			if (errno == EINTR)
+				continue;
+
+			RTE_LOG(ERR, EAL, "Failed to read file %s\n", filename);
+
+			free(buf);
+			close(fd);
+			return NULL;
+		}
+		if (rlen == 0) /* EOF */
+			break;
+
+		total += rlen;
+	}
+
+	buf[total] = '\0';
+	close(fd);
+
+	return buf;
+}
+
+static const char *
+dev_uevent_find(const char *uevent, const char *key)
+{
+	const size_t keylen = strlen(key);
+	const size_t total = strlen(uevent);
+	const char *p = uevent;
+
+	/* check whether it is the first key */
+	if (!strncmp(uevent, key, keylen))
+		return uevent + keylen;
+
+	/* check 2nd key or further... */
+	do {
+		p = strstr(p, key);
+		if (p == NULL)
+			break;
+
+		if (p[-1] == '\n') /* check we are at a new line */
+			return p + keylen;
+
+		p += keylen; /* skip this one */
+	} while (p - uevent < (ptrdiff_t) total);
+
+	return NULL;
+}
+
+static char *
+strdup_until_nl(const char *p)
+{
+	const char *nl = strchr(p, '\n');
+	if (nl == NULL)
+		return strdup(p); /* no newline, copy until '\0' */
+
+	return strndup(p, nl - p);
+}
+
+static int
+dev_parse_uevent(struct rte_soc_device *dev, const char *uevent)
+{
+	const char *of;
+	const char *compat_n;
+	char *err;
+	long n;
+	char compat[strlen("OF_COMPATIBLE_NNNN=")];
+	long i;
+
+	of = dev_uevent_find(uevent, "OF_FULLNAME=");
+	if (of == NULL)
+		return 1; /* don't care about this device */
+
+	dev->addr.fdt_path = strdup_until_nl(of);
+	if (dev->addr.fdt_path == NULL) {
+		RTE_LOG(ERR, PMD,
+			"Failed to alloc memory for fdt_path\n");
+		return -1;
+	}
+
+	RTE_LOG(DEBUG, EAL, "Detected device %s (%s)\n",
+			dev->addr.name, dev->addr.fdt_path);
+
+	compat_n = dev_uevent_find(uevent, "OF_COMPATIBLE_N=");
+	if (compat_n == NULL) {
+		RTE_LOG(ERR, EAL, "No OF_COMPATIBLE_N found\n");
+		return -1;
+	}
+
+	n = strtoul(compat_n, &err, 0);
+	if (*err != '\n' && err != NULL) {
+		RTE_LOG(ERR, EAL, "Failed to parse OF_COMPATIBLE_N: %.10s\n",
+			err);
+		goto fail_fdt_path;
+	}
+
+	if (n == 0)
+		return 1; /* cannot match anything */
+	if (n > 9999) { /* match NNNN */
+		RTE_LOG(ERR, EAL, "OF_COMPATIBLE_N is invalid: %ld\n", n);
+		goto fail_fdt_path;
+	}
+
+	dev->id = calloc(n + 1, sizeof(*dev->id));
+	if (dev->id == NULL) {
+		RTE_LOG(ERR, PMD, "Failed to alloc memory for ID\n");
+		free(dev->addr.fdt_path);
+		return -1;
+	}
+
+	for (i = 0; i < n; ++i) {
+		snprintf(compat, sizeof(compat), "OF_COMPATIBLE_%lu=", i);
+		const char *val;
+
+		val = dev_uevent_find(uevent, compat);
+		if (val == NULL) {
+			RTE_LOG(ERR, EAL, "%s was not found\n", compat);
+			goto fail_id;
+		}
+
+		dev->id[i]._compatible = strdup_until_nl(val);
+		if (dev->id[i]._compatible == NULL) {
+			RTE_LOG(ERR, PMD,
+				"Failed to alloc memory for compatible\n");
+			goto fail_id;
+		}
+
+		RTE_LOG(DEBUG, EAL, "  compatible: %s\n",
+				dev->id[i].compatible);
+	}
+
+	dev->id[n]._compatible = NULL; /* mark last one */
+
+	return 0;
+
+fail_id:
+	while (i-- >= 0)
+		free(dev->id[i]._compatible);
+	free(dev->id);
+fail_fdt_path:
+	free(dev->addr.fdt_path);
+	return -1;
+}
+
+static void
+dev_content_free(struct rte_soc_device *dev)
+{
+	int i;
+
+	if (dev->addr.fdt_path)
+		free(dev->addr.fdt_path);
+
+	if (dev->id != NULL) {
+		for (i = 0; dev->id[i]._compatible; ++i)
+			free(dev->id[i]._compatible);
+
+		free(dev->id);
+		dev->id = NULL;
+	}
+}
+
+/**
+ * Scan one SoC sysfs entry, and fill the devices list from it.
+ * We require to have the uevent file with records: OF_FULLNAME and
+ * OF_COMPATIBLE array (with at least one entry). Otherwise, such device
+ * is skipped.
+ */
+static int
+soc_scan_one(const char *dirname, const char *name)
+{
+	struct rte_soc_device *dev;
+	char *uevent;
+	int ret;
+
+	uevent = dev_read_uevent(dirname);
+	if (uevent == NULL)
+		return -1;
+
+	if (uevent[0] == '\0') {
+		/* ignore directory without uevent file */
+		free(uevent);
+		return 1;
+	}
+
+	dev = malloc(sizeof(*dev) + strlen(name) + 1);
+	if (dev == NULL) {
+		RTE_LOG(ERR, PMD, "Failed to alloc memory for %s\n", name);
+		free(uevent);
+		return -1;
+	}
+
+	memset(dev, 0, sizeof(*dev));
+	dev->addr.name = (char *) (dev + 1);
+	strcpy(dev->addr.name, name);
+
+	ret = dev_parse_uevent(dev, uevent);
+	if (ret)
+		goto fail;
+	free(uevent); /* not needed anymore */
+
+	/* device is valid, add in list (sorted) */
+	if (TAILQ_EMPTY(&soc_device_list)) {
+		TAILQ_INSERT_TAIL(&soc_device_list, dev, next);
+	} else {
+		struct rte_soc_device *dev2;
+
+		TAILQ_FOREACH(dev2, &soc_device_list, next) {
+			ret = rte_eal_compare_soc_addr(&dev->addr, &dev2->addr);
+			if (ret > 0)
+				continue;
+
+			if (ret < 0) {
+				TAILQ_INSERT_BEFORE(dev2, dev, next);
+			} else { /* already registered */
+				dev_content_free(dev2);
+				dev2->addr.fdt_path = dev->addr.fdt_path;
+				dev2->id = dev->id;
+				free(dev);
+			}
+			return 0;
+		}
+		TAILQ_INSERT_TAIL(&soc_device_list, dev, next);
+	}
+
+	return 0;
+
+fail:
+	free(uevent);
+	dev_content_free(dev);
+	free(dev);
+	return ret;
+}
+
+int
+rte_eal_soc_scan(void)
+{
+	struct dirent *e;
+	DIR *dir;
+	char dirname[PATH_MAX];
+
+	dir = opendir(soc_get_sysfs_path());
+	if (dir == NULL) {
+		RTE_LOG(ERR, EAL, "%s(): opendir failed: %s\n",
+			__func__, strerror(errno));
+		return -1;
+	}
+
+	while ((e = readdir(dir)) != NULL) {
+		if (e->d_name[0] == '.')
+			continue;
+
+		snprintf(dirname, sizeof(dirname), "%s/%s",
+				soc_get_sysfs_path(), e->d_name);
+		if (soc_scan_one(dirname, e->d_name) < 0)
+			goto error;
+	}
+	closedir(dir);
+	return 0;
+
+error:
+	closedir(dir);
+	return -1;
+}
+
 /* Init the SoC EAL subsystem */
 int
 rte_eal_soc_init(void)
-- 
2.7.4



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