Re: [Socketcan-users] flexcan: Re: Help with CAN_RAW_LOOPBACK

[Mike Brown]

On 07/19/2011 04:40 PM, Oliver Hartkopp wrote:
Sorry Marc, i was probably wrong with my assumption below:
There IS a significant difference in the flexcan_chip_start() function of the
'freescale modified' flexcan driver posted by Mike:

The FLEXCAN_MCR_SRX_DIS bit is set there, which means:

---8<---
This bit defines whether FlexCAN is allowed to receive frames transmitted by
itself. If this bit is set to 1, frames transmitted by the module are not
stored in any message buffer, regardless if the message buffer is programmed
with an ID that matches the transmitted frame, and no interrupt flag or
interrupt signal is generated due to the frame reception.
0 Self reception enabled
1 Self reception disabled
---8<---

See the diff here:

--- flexcan     2011-07-19 23:30:55.411117151 +0200
+++ net-next-2.6/drivers/net/can/flexcan.c      2011-06-21 15:20:23.220000347 
+0200
@@ -540,12 +675,12 @@
          * choose format C
          *
          */
-       reg_mcr = flexcan_cb->read(&regs->mcr);
+       reg_mcr = readl(&regs->mcr);
         reg_mcr |= FLEXCAN_MCR_FRZ | FLEXCAN_MCR_FEN | FLEXCAN_MCR_HALT |
-               FLEXCAN_MCR_SUPV | FLEXCAN_MCR_WRN_EN | FLEXCAN_MCR_IDAM_C |
-               FLEXCAN_MCR_SRX_DIS;
+               FLEXCAN_MCR_SUPV | FLEXCAN_MCR_WRN_EN |
+               FLEXCAN_MCR_IDAM_C;
         dev_dbg(dev->dev.parent, "%s: writing mcr=0x%08x", __func__, reg_mcr);
-       flexcan_cb->write(reg_mcr,&regs->mcr);
+       writel(reg_mcr,&regs->mcr);

         /*
          * CTRL


Mike, please check if removing the FLEXCAN_MCR_SRX_DIS bit in reg_mcr fixes the
problem, when 'dev->flags |= IFF_ECHO' is enabled again.
All of my test cases appear to work with IFF_ECHO set, and 
FLEXCAN_MCR_SRC_DIS clear.



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