[Xenomai-git] Fabrice Gasnier : fix mscan init on mpc5121

[GIT version control]

Module: xenomai-2.6
Branch: master
Commit: 168da46deab56f617d9d2744554a29fefd13bc23
URL:    
http://git.xenomai.org/?p=xenomai-2.6.git;a=commit;h=168da46deab56f617d9d2744554a29fefd13bc23

Author: Fabrice Gasnier <fabrice.gasn...@cenosys.com>
Date:   Thu Jan  5 10:31:58 2012 +0100

fix mscan init on mpc5121

insmod xeno_rtcan_mscan gets stuck on MPC5121.
driver enters an endless loop at init.
Adapt it using linux driver behavior.

Signed-off-by: Fabrice Gasnier <fabrice.gasn...@cenosys.com>

---

 ksrc/drivers/can/mscan/rtcan_mscan.c |   38 ++++++++++++++++++++++++++++++++-
 1 files changed, 36 insertions(+), 2 deletions(-)

diff --git a/ksrc/drivers/can/mscan/rtcan_mscan.c 
b/ksrc/drivers/can/mscan/rtcan_mscan.c
index d25fc5a..edd590e 100644
--- a/ksrc/drivers/can/mscan/rtcan_mscan.c
+++ b/ksrc/drivers/can/mscan/rtcan_mscan.c
@@ -40,6 +40,8 @@
 #include "rtcan_mscan_regs.h"
 #include "rtcan_mscan.h"
 
+#define MSCAN_SET_MODE_RETRIES 255
+
 /**
  *  Reception Interrupt handler
  *
@@ -306,11 +308,41 @@ static int rtcan_mscan_mode_stop(struct rtcan_device *dev,
 
        /* Switch to sleep mode */
        setbits8(&regs->canctl0, MSCAN_SLPRQ);
+       reg = in_8(&regs->canctl1);
+       while (!(reg & MSCAN_SLPAK) &&
+               (rinit < MSCAN_SET_MODE_RETRIES)) {
+               if (likely(lock_ctx != NULL))
+                       rtdm_lock_put_irqrestore(&dev->device_lock, *lock_ctx);
+               /* Busy sleep 1 microsecond */
+               rtdm_task_busy_sleep(1000);
+               if (likely(lock_ctx != NULL))
+                       rtdm_lock_get_irqsave(&dev->device_lock, *lock_ctx);
+               rinit++;
+               reg = in_8(&regs->canctl1);
+       }
+       /*
+        * The mscan controller will fail to enter sleep mode,
+        * while there are irregular activities on bus, like
+        * somebody keeps retransmitting. This behavior is
+        * undocumented and seems to differ between mscan built
+        * in mpc5200b and mpc5200. We proceed in that case,
+        * since otherwise the slprq will be kept set and the
+        * controller will get stuck. NOTE: INITRQ or CSWAI
+        * will abort all active transmit actions, if still
+        * any, at once.
+        */
+       if (rinit >= MSCAN_SET_MODE_RETRIES)
+               rtdm_printk("rtcan_mscan: device failed to enter sleep mode. "
+                               "We proceed anyhow.\n");
+       else
+               dev->state = CAN_STATE_SLEEPING;
+
+       rinit = 0;
        setbits8(&regs->canctl0, MSCAN_INITRQ);
 
        reg = in_8(&regs->canctl1);
-       while (!(reg & MSCAN_SLPAK) ||
-              !(reg & MSCAN_INITAK)) {
+       while (!(reg & MSCAN_INITAK) &&
+               (rinit < MSCAN_SET_MODE_RETRIES)) {
                if (likely(lock_ctx != NULL))
                        rtdm_lock_put_irqrestore(&dev->device_lock, *lock_ctx);
                /* Busy sleep 1 microsecond */
@@ -320,6 +352,8 @@ static int rtcan_mscan_mode_stop(struct rtcan_device *dev,
                rinit++;
                reg = in_8(&regs->canctl1);
        }
+       if (rinit >= MSCAN_SET_MODE_RETRIES)
+               ret = -ENODEV;
 
        /* Volatile state could have changed while we slept busy. */
        dev->state = CAN_STATE_STOPPED;


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