Hi Mugunthan, On Jan 30, 2013, at 12:55 PM, Mugunthan V N wrote: > On 1/30/2013 3:06 PM, Pantelis Antoniou wrote: >> Hi, >> >> On Jan 30, 2013, at 11:03 AM, Mugunthan V N wrote: >> >>> On 1/30/2013 2:06 PM, Pantelis Antoniou wrote: >>>> Hi Mugunthan, >>>> >>>> On Jan 29, 2013, at 1:45 PM, Mugunthan V N wrote: >>>> >>>>> On 1/28/2013 6:41 PM, Pantelis Antoniou wrote: >>>>>> Fix interrupt storm on bone A4 cause by non-by-the-book interrupt handling. >>>>>> While at it, added a non-NAPI mode (which is easier to debug), plus >>>>>> some general fixes. >>>>>> >>>>>> Signed-off-by: Pantelis Antoniou <panto@xxxxxxxxxxxxxxxxxxxxxxx> >>>>>> --- >>>>>> Documentation/devicetree/bindings/net/cpsw.txt | 1 + >>>>>> drivers/net/ethernet/ti/cpsw.c | 222 +++++++++++++++++++++---- >>>>>> drivers/net/ethernet/ti/davinci_cpdma.c | 4 +- >>>>>> drivers/net/ethernet/ti/davinci_cpdma.h | 2 +- >>>>>> include/linux/platform_data/cpsw.h | 1 + >>>>>> 5 files changed, 194 insertions(+), 36 deletions(-) >>>>> I have tested CPSW on AM335x EVM 1.5A with flood ping and i am not >>>>> seeing any interrupt storm. >>>>> Can you provide more details on how to reproduce the issue. >>>>> >>>> A beaglebone prototype with the new silicon version, with the ethernet errata >>>> fixed displays this. You can't trigger it on old silicon. >>>> >>>> The TI people on the CC list can confirm. >>> But i have the same silicon revision (PG2.0) in my EVM and I am not seeing any issues. Can you >>> point me to the ethernet errata which you are mentioning? >>> >>> Regards >>> Mugunthan V N >> What kernel version are you using? This is only triggered on the mainline driver. >> >> The advisory in question: From http://www.ti.com/lit/er/sprz360c/sprz360c.pdf >> >> Advisory 1.0.9: "Ethernet Media Access Controller and Switch Subsystem: C0_TX_PEND >> and C0_RX_PEND Interrupts Not Connected to ARM Cortex-A8" >> >> I bet you're using an old kernel driver with the workarounds with the timers. >> >> If I had to guess (although I didn't use a probe or anything) is that the >> interrupts are now proper level interrupts, instead of working in edge >> triggered mode due to the workaround. >> >> Apparently the interrupt was never acked properly in the original driver >> (the sequence described in the TRM is not followed). >> >> Looking at the TRM (spruh73g.pdf) 14.3.1.3 Interrupts in particular, the >> the status registers are not read, and more damning the proper values to the >> CPDMA_EOI_VECTOR register are not written. >> >> The original driver blindly wrote zero (cpdma_ctlr_eoi), while you have to >> write different values according to the interrupt you ack. >> >> What happened was that on the first interrupt, the interrupt was never acked, >> and we had an irq storm... >> >> Regards >> >> -- Pantelis > The above mentioned advisory is for PG1.0 and not for PG2.0 > I am booting net-next kernel. > > [ 0.000000] Booting Linux on physical CPU 0x0 > [ 0.000000] Linux version 3.8.0-rc5-01248-gd2ed273 (a0131834@a0131834-linux) (gcc version 4.5.3 20110311 (prerelease) (GCC) ) #21 SMP Wed Jan 30 163 > [ 0.000000] CPU: ARMv7 Processor [413fc082] revision 2 (ARMv7), cr=10c53c7d > [ 0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache > > [root@arago /]# uname -a > Linux arago 3.8.0-rc5-01248-gd2ed273 #21 SMP Wed Jan 30 16:13:26 IST 2013 armv7l GNU/Linux > > In theory what you are mentioning is correct. I have a beagle bone black and yet to try it. > I don't know what kind of silicon revision you have there. FWIW both the original bone and the black show the exact same CPU: ARMv7 lines: bone-original: [ 0.000000] CPU: ARMv7 Processor [413fc082] revision 2 (ARMv7), cr=10c5387d bone-black: (with the known silicon version that has the fix) [ 0.000000] CPU: ARMv7 Processor [413fc082] revision 2 (ARMv7), cr=10c5387d TBH I haven't found a simple way to print out the silicon revision number. Anyone on the list know a quick and dirty method? > Regards > Mugunthan V N Regards -- Pantelis -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
