rapidio: add enumeration/discovery start from user space

Add RapidIO enumeration/discovery start from user space.  User space
start allows to defer RapidIO fabric scan until the moment when all
participating endpoints are initialized avoiding mandatory synchronized
start of all endpoints (which may be challenging in systems with large
number of RapidIO endpoints).

Signed-off-by: Alexandre Bounine <alexandre.bounine@idt.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Li Yang <leoli@freescale.com>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: Andre van Herk <andre.van.herk@Prodrive.nl>
Cc: Micha Nelissen <micha.nelissen@Prodrive.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 45 insertions, 0 deletions

diff --git a/drivers/rapidio/rio-sysfs.c b/drivers/rapidio/rio-sysfs.c
index 4dbe360989be..66d4acd5e18f 100644
--- a/drivers/rapidio/rio-sysfs.c
+++ b/drivers/rapidio/rio-sysfs.c
@@ -285,3 +285,48 @@ void rio_remove_sysfs_dev_files(struct rio_dev *rdev)
                         rdev->rswitch->sw_sysfs(rdev, RIO_SW_SYSFS_REMOVE);
         }
 }
+
+static ssize_t bus_scan_store(struct bus_type *bus, const char *buf,
+                                size_t count)
+{
+        long val;
+        struct rio_mport *port = NULL;
+        int rc;
+
+        if (kstrtol(buf, 0, &val) < 0)
+                return -EINVAL;
+
+        if (val == RIO_MPORT_ANY) {
+                rc = rio_init_mports();
+                goto exit;
+        }
+
+        if (val < 0 || val >= RIO_MAX_MPORTS)
+                return -EINVAL;
+
+        port = rio_find_mport((int)val);
+
+        if (!port) {
+                pr_debug("RIO: %s: mport_%d not available\n",
+                         __func__, (int)val);
+                return -EINVAL;
+        }
+
+        if (!port->nscan)
+                return -EINVAL;
+
+        if (port->host_deviceid >= 0)
+                rc = port->nscan->enumerate(port, 0);
+        else
+                rc = port->nscan->discover(port, RIO_SCAN_ENUM_NO_WAIT);
+exit:
+        if (!rc)
+                rc = count;
+
+        return rc;
+}
+
+struct bus_attribute rio_bus_attrs[] = {
+        __ATTR(scan, (S_IWUSR|S_IWGRP), NULL, bus_scan_store),
+        __ATTR_NULL
+};