Re: [PATCH v7] edac: synps: Added EDAC support for zynq ddr ecc controller

[Borislav Petkov <bp@alien8.de>]

On Fri, Jan 02, 2015 at 09:52:20AM +0530, Punnaiah Choudary Kalluri wrote:
> +/**
> + * synps_edac_handle_error - Handle controller error types CE and UE
> + * @mci:	Pointer to the edac memory controller instance
> + * @p:		Pointer to the synopsys ecc status structure
> + *
> + * Handles the controller ECC correctable and un correctable error.
> + */
> +static void synps_edac_handle_error(struct mem_ctl_info *mci,
> +				    struct synps_ecc_status *p)
> +{
> +	char message[SYNPS_EDAC_MSG_SIZE];

This is still on the stack. My previous comment:

"You could preallocate this on driver init so you don't do relatively
big stack allocations on the error reporting path and remain lean."

> +	struct ecc_error_info *pinf;
> +
> +	if (p->ce_cnt) {
> +		pinf = &p->ceinfo;
> +		snprintf(message, SYNPS_EDAC_MSG_SIZE,
> +			 "DDR ECC error type :%s Row %d Bank %d Col %d ",
> +			 "CE", pinf->row, pinf->bank, pinf->col);
> +		edac_mc_handle_error(HW_EVENT_ERR_CORRECTED, mci,
> +				     p->ce_cnt, 0, 0, 0, 0, 0, -1,
> +				     message, "");
> +	}
> +
> +	if (p->ue_cnt) {
> +		pinf = &p->ueinfo;
> +		snprintf(message, SYNPS_EDAC_MSG_SIZE,
> +			 "DDR ECC error type :%s Row %d Bank %d Col %d ",
> +			 "UE", pinf->row, pinf->bank, pinf->col);
> +		edac_mc_handle_error(HW_EVENT_ERR_UNCORRECTED, mci,
> +				     p->ue_cnt, 0, 0, 0, 0, 0, -1,
> +				     message, "");
> +	}

>From the previous review:

"If you memset(p, 0,...) here, after consumption, you don't need to do
it anywhere else and be sure that *p would be always clean and ready for
the next error."

Looks like you've missed those two points.

> +static int synps_edac_mc_probe(struct platform_device *pdev)
> +{
> +	struct mem_ctl_info *mci;
> +	struct edac_mc_layer layers[2];
> +	struct synps_edac_priv *priv;
> +	int rc;
> +	struct resource *res;
> +	void __iomem *baseaddr;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	baseaddr = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(baseaddr))
> +		return PTR_ERR(baseaddr);
> +
> +	if (!synps_edac_get_eccstate(baseaddr)) {
> +		edac_printk(KERN_INFO, EDAC_MC, "ECC not enabled\n");
> +		return -ENXIO;
> +	}
> +
> +	layers[0].type = EDAC_MC_LAYER_CHIP_SELECT;
> +	layers[0].size = SYNPS_EDAC_NR_CSROWS;
> +	layers[0].is_virt_csrow = true;
> +	layers[1].type = EDAC_MC_LAYER_CHANNEL;
> +	layers[1].size = SYNPS_EDAC_NR_CHANS;
> +	layers[1].is_virt_csrow = false;
> +
> +	mci = edac_mc_alloc(0, ARRAY_SIZE(layers), layers,
> +			    sizeof(struct synps_edac_priv));
> +	if (!mci) {
> +		edac_printk(KERN_ERR, EDAC_MC,
> +			    "Failed memory allocation for mc instance\n");
> +		return -ENOMEM;
> +	}
> +
> +	priv = mci->pvt_info;
> +	priv->baseaddr = baseaddr;
> +	rc = synps_edac_mc_init(mci, pdev);
> +	if (rc) {
> +		edac_printk(KERN_ERR, EDAC_MC,
> +			    "Failed to initialize instance\n");
> +		goto free_edac_mc;
> +	}
> +
> +	rc = edac_mc_add_mc(mci);
> +	if (rc) {
> +		edac_printk(KERN_ERR, EDAC_MC,
> +			    "Failed to register with EDAC core\n");
> +		goto free_edac_mc;
> +	}

With all the more or less redundant commenting in this driver, the *one*
line which definitely needs a comment is without one:

	/*
	 * Start capturing the correctable and uncorrectable errors. A write of
	 * 0 starts the counters.
	 */
> +	writel(0x0, baseaddr + ECC_CTRL_OFST);
> +	return rc;
> +
> +free_edac_mc:
> +	edac_mc_free(mci);
> +
> +	return rc;
> +}

-- 
Regards/Gruss,
    Boris.

Sent from a fat crate under my desk. Formatting is fine.
--