Re: FW: edac driver initialization, interrupt, & debug

[Borislav Petkov <bp@alien8.de>]

+ York.

On Fri, Nov 16, 2018 at 11:07:50AM -0600, Tracy Smith wrote:
> I’m attempting to insmod/modprobe the layerscape_edac_mod.ko driver.
> It seems the driver enters layerscape_edac.c fsl_ddr_mc_init() and
> completes successfully. But there is no EDAC boot messages and no
> /proc/interrupts entry for the EDAC. I’m backporting the EDAC from the
> LSDK to the SDK 2.0.
> 
> I have set CONFIG_EDAC_DEBUG and set edac_debug_level to 4, but I
> don’t see any debug messages other than printk()s that I add to
> fsl_ddr_mc_init() in layerscape_edac.c. No debug messages appear in
> any logs from fsl_ddr_edac.c.
> 
> 1. How can I enable debug information? Is debugfs required to print
> the debug messages for the edac_debug_level and CONFIG_EDAC_DEBUG in
> the 4.1.35-rt41 kernel for drivers/edac?

No, just slap printks before every return statement, like:

        if (!devres_open_group(&op->dev, fsl_mc_err_probe, GFP_KERNEL)) {
		pr_err("%s: Error devres_open_group()\n", __func__);
                return -ENOMEM;
	}

so that you can get closer to the place where it fails.

> 2. The default EDAC_OPSTATE_INT in fsl_ddr_mc_init() and the
> platform_driver_register() is successful. But I don’t see any printk()
> messages in fsl_mc_err_probe() within fsl_ddr_edac.c. No errors appear
> in any /var/log/*.

Yeah, see if it even gets called at all:

int fsl_mc_err_probe(struct platform_device *op)
{
        struct mem_ctl_info *mci;
        struct edac_mc_layer layers[2];
        struct fsl_mc_pdata *pdata;
        struct resource r;
        u32 sdram_ctl;
        int res;

	pr_err("%s: entry\n", __func__);


> 3. I don’t see any interrupts, so why would there not be an edac
> interrupt in /proc/inturrupts?

Probably because it doesn't reach the point where it registers an IRQ
handler...

> Do I need to inject an error before seeing an edac interrupt in
> /proc/interrupts?

You should, AFAICT, if it loads and registers stuff properly.

> lsmod
> module: layerscape_edac_mod    12594  0
> 
> 4. To inject an error I can use the fsl_mc_inject …. routines in
> fsl_ddr_edac.c and write to the registers. But is there a utility that
> already uses these routines that can be used to inject an error
> (FSL_MC_ECC_ERR_INJECT, FSL_MC_DATA_ERR_INJECT_LO,

You should be able to simply write to *sysfs*. Somewhere under
/sys/devices/system/edac/...

fsl_mc_inject_data_{lo,hi}_store simply writes the low and high inject
register.

Btw, looking at it, York, this whole injection functionality needs to
be behind CONFIG_EDAC_DEBUG because a production driver shouldn't have
injection capability.

Hmmm.

-- 
Regards/Gruss,
    Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.
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