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Subject[PATCH v2 07/10] RapidIO: Add handling of orphan port-write message
Date
Add check for access to port-write (PW) message source device before processing
the PW message. If source RIO device is not available (power down or RIO link
failure) trace back to a last available switch/port on the PW message route
and service failure at that point.

Signed-off-by: Alexandre Bounine <alexandre.bounine@idt.com>
Cc: Thomas Moll <thomas.moll@sysgo.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Li Yang <leoli@freescale.com>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: Micha Nelissen <micha@neli.hopto.org>
---
drivers/rapidio/rio.c | 113 ++++++++++++++++++++++++++++++++++++++++++++++--
drivers/rapidio/rio.h | 2 +
2 files changed, 110 insertions(+), 5 deletions(-)
diff --git a/drivers/rapidio/rio.c b/drivers/rapidio/rio.c
index 77bd416..aefc2a0 100644
--- a/drivers/rapidio/rio.c
+++ b/drivers/rapidio/rio.c
@@ -495,6 +495,92 @@ int rio_set_port_lockout(struct rio_dev *rdev, u32 pnum, int lock)
}

/**
+ * rio_chk_dev_route - Validate route to the specified device.
+ * @rdev: RIO device failed to respond
+ * @nrdev: Last active device on the route to rdev
+ * @npnum: nrdev's port number on the route to rdev
+ *
+ * Follows a route to the specified RIO device to determine the last available
+ * device (and corresponding RIO port) on the route.
+ */
+static int
+rio_chk_dev_route(struct rio_dev *rdev, struct rio_dev **nrdev, int *npnum)
+{
+ u32 result;
+ int p_port, rc = -EIO;
+ struct rio_dev *prev = NULL;
+
+ /* Find switch with failed RIO link */
+ while (rdev->prev && (rdev->prev->pef & RIO_PEF_SWITCH)) {
+ if (!rio_read_config_32(rdev->prev, RIO_DEV_ID_CAR, &result)) {
+ prev = rdev->prev;
+ break;
+ }
+ rdev = rdev->prev;
+ }
+
+ if (prev == NULL)
+ goto err_out;
+
+ /* Find port with failed RIO link */
+ for (p_port = 0;
+ p_port < RIO_GET_TOTAL_PORTS(prev->swpinfo); p_port++)
+ if (prev->rswitch->nextdev[p_port] == rdev)
+ break;
+
+ if (p_port < RIO_GET_TOTAL_PORTS(prev->swpinfo)) {
+ pr_debug("RIO: link failed on [%s]-P%d\n",
+ rio_name(prev), p_port);
+ *nrdev = prev;
+ *npnum = p_port;
+ rc = 0;
+ } else
+ pr_debug("RIO: failed to trace route to %s\n", rio_name(prev));
+err_out:
+ return rc;
+}
+
+/**
+ * rio_mport_chk_dev_access - Validate access to the specified device.
+ * @mport: Master port to send transactions
+ * @destid: Device destination ID in network
+ * @hopcount: Number of hops into the network
+ */
+static int
+rio_mport_chk_dev_access(struct rio_mport *mport, u16 destid, u8 hopcount)
+{
+ int i = 0;
+ u32 tmp;
+
+ while (rio_mport_read_config_32(mport, destid, hopcount,
+ RIO_DEV_ID_CAR, &tmp)) {
+ i++;
+ if (i == RIO_MAX_CHK_RETRY)
+ return -EIO;
+ mdelay(1);
+ }
+
+ return 0;
+}
+
+/**
+ * rio_chk_dev_access - Validate access to the specified device.
+ * @rdev: Pointer to RIO device control structure
+ */
+static int rio_chk_dev_access(struct rio_dev *rdev)
+{
+ u8 hopcount = 0xff;
+ u16 destid = rdev->destid;
+
+ if (rdev->rswitch) {
+ destid = rdev->rswitch->destid;
+ hopcount = rdev->rswitch->hopcount;
+ }
+
+ return rio_mport_chk_dev_access(rdev->net->hport, destid, hopcount);
+}
+
+/**
* rio_get_input_status - Sends a Link-Request/Input-Status control symbol and
* returns link-response (if requested).
* @rdev: RIO devive to issue Input-status command
@@ -654,8 +740,8 @@ int rio_inb_pwrite_handler(union rio_pw_msg *pw_msg)

rdev = rio_get_comptag(pw_msg->em.comptag, NULL);
if (rdev == NULL) {
- /* Someting bad here (probably enumeration error) */
- pr_err("RIO: %s No matching device for CTag 0x%08x\n",
+ /* Device removed or enumeration error */
+ pr_debug("RIO: %s No matching device for CTag 0x%08x\n",
__func__, pw_msg->em.comptag);
return -EIO;
}
@@ -686,6 +772,26 @@ int rio_inb_pwrite_handler(union rio_pw_msg *pw_msg)
return 0;
}

+ portnum = pw_msg->em.is_port & 0xFF;
+
+ /* Check if device and route to it are functional:
+ * Sometimes devices may send PW message(s) just before being
+ * powered down (or link being lost).
+ */
+ if (rio_chk_dev_access(rdev)) {
+ pr_debug("RIO: device access failed - get link partner\n");
+ /* Scan route to the device and identify failed link.
+ * This will replace device and port reported in PW message.
+ * PW message should not be used after this point.
+ */
+ if (rio_chk_dev_route(rdev, &rdev, &portnum)) {
+ pr_err("RIO: Route trace for %s failed\n",
+ rio_name(rdev));
+ return -EIO;
+ }
+ pw_msg = NULL;
+ }
+
/* For End-point devices processing stops here */
if (!(rdev->pef & RIO_PEF_SWITCH))
return 0;
@@ -703,9 +809,6 @@ int rio_inb_pwrite_handler(union rio_pw_msg *pw_msg)
/*
* Process the port-write notification from switch
*/
-
- portnum = pw_msg->em.is_port & 0xFF;
-
if (rdev->rswitch->em_handle)
rdev->rswitch->em_handle(rdev, portnum);

diff --git a/drivers/rapidio/rio.h b/drivers/rapidio/rio.h
index f27b7a9..bc71ba1 100644
--- a/drivers/rapidio/rio.h
+++ b/drivers/rapidio/rio.h
@@ -14,6 +14,8 @@
#include <linux/list.h>
#include <linux/rio.h>

+#define RIO_MAX_CHK_RETRY 3
+
/* Functions internal to the RIO core code */

extern u32 rio_mport_get_feature(struct rio_mport *mport, int local, u16 destid,
--
1.7.0.5


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