linux-kernel - RE: [patch v3 3/4] EDAC: synopsys: Add edac driver support for i.MX8MP

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Date:   Thu, 2 Apr 2020 13:09:57 +0000
From:   Sherry Sun <sherry.sun@....com>
To:     Robert Richter <rrichter@...vell.com>
CC:     "bp@...en8.de" <bp@...en8.de>,
        "mchehab@...nel.org" <mchehab@...nel.org>,
        "tony.luck@...el.com" <tony.luck@...el.com>,
        "james.morse@....com" <james.morse@....com>,
        "michal.simek@...inx.com" <michal.simek@...inx.com>,
        "manish.narani@...inx.com" <manish.narani@...inx.com>,
        "linux-edac@...r.kernel.org" <linux-edac@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        dl-linux-imx <linux-imx@....com>, Frank Li <frank.li@....com>
Subject: RE: [patch v3 3/4] EDAC: synopsys: Add edac driver support for
 i.MX8MP

Hi Robert,

> -----Original Message-----
> From: Robert Richter <rrichter@...vell.com>
> Sent: 2020年4月2日 19:17
> To: Sherry Sun <sherry.sun@....com>
> Cc: bp@...en8.de; mchehab@...nel.org; tony.luck@...el.com;
> james.morse@....com; michal.simek@...inx.com;
> manish.narani@...inx.com; linux-edac@...r.kernel.org; linux-
> kernel@...r.kernel.org; dl-linux-imx <linux-imx@....com>; Frank Li
> <frank.li@....com>
> Subject: Re: [patch v3 3/4] EDAC: synopsys: Add edac driver support for
> i.MX8MP
> 
> On 02.04.20 09:06:27, Sherry Sun wrote:
> > > From: Robert Richter <rrichter@...vell.com> On 02.04.20 09:20:32,
> > > Sherry Sun wrote:
> 
> > > > +static void enable_intr_imx8mp(struct synps_edac_priv *priv) {
> > > > +	int regval;
> > > > +
> > > > +	regval = readl(priv->baseaddr + ECC_CLR_OFST);
> > > > +	regval |= (DDR_CE_INTR_EN_MASK | DDR_UE_INTR_EN_MASK);
> > > > +	writel(regval, priv->baseaddr + ECC_CLR_OFST); }
> > > > +
> > > > +static void disable_intr_imx8mp(struct synps_edac_priv *priv) {
> > > > +	int regval;
> > > > +
> > > > +	regval = readl(priv->baseaddr + ECC_CLR_OFST);
> > > > +	regval &= ~(DDR_CE_INTR_EN_MASK | DDR_UE_INTR_EN_MASK);
> > > > +	writel(regval, priv->baseaddr + ECC_CLR_OFST); }
> > > > +
> > > > +/* Interrupt Handler for ECC interrupts on imx8mp platform. */
> > > > +static irqreturn_t intr_handler_imx8mp(int irq, void *dev_id) {
> > > > +	const struct synps_platform_data *p_data;
> > > > +	struct mem_ctl_info *mci = dev_id;
> > > > +	struct synps_edac_priv *priv;
> > > > +	int status, regval;
> > > > +
> > > > +	priv = mci->pvt_info;
> > > > +	p_data = priv->p_data;
> > > > +
> > > > +	regval = readl(priv->baseaddr + ECC_STAT_OFST);
> > > > +	if (!(regval & ECC_INTR_MASK))
> > > > +		return IRQ_NONE;
> > > > +
> > > > +	status = p_data->get_error_info(priv);
> > > > +	if (status)
> > > > +		return IRQ_NONE;
> > > > +
> > > > +	priv->ce_cnt += priv->stat.ce_cnt;
> > > > +	priv->ue_cnt += priv->stat.ue_cnt;
> > > > +	handle_error(mci, &priv->stat);
> > > > +
> > > > +	edac_dbg(3, "Total error count CE %d UE %d\n",
> > > > +		 priv->ce_cnt, priv->ue_cnt);
> > > > +	enable_intr_imx8mp(priv);
> > >
> > > Why do you enable interrupts here?
> >
> > Because zynqmp_get_error_info() wrote 0 to ECC_CLR_OFST, so here have
> to re-enable the interrupts.
> 
> This does not seem to be the right place for it.
> 
> > As said in the commit, the main difference between ZynqMP and i.MX8MP
> ddr controller is the interrupt registers.
> > ZynqMP use DDR QOS Interrupt registers,  but i.MX8MP use ECC_CLR_OFST
> Register(bit8 and bit9) to enable/disable the ce/ue interrupts.
> >
> > In zynqmp_get_error_info(), Zynqmp wrote 0 to ECC_CLR_OFST register to
> clear CE/UE error flags and counts, it has no effect on Zynqmp interrupts.
> > But for i.MX8MP, wirte 0 to ECC_CLR_OFST will disable i.MX8MP CE/UE
> interrupt, so need re-enable the interrupts.
> 
> All this shows one more time there should be separate handlers. You should
> get rid most callbacks in struct synps_platform_data and instead have
> separate probe functions for both flavors that share common code.

Do you mean that I should create specific callbacks in struct synps_platform_data for i.MX8MP instead reuse the ZynqMP functions?
But except this operation of write 0 to ECC_CLR_OFST in zynqmp_get_error_info(), 
the other callbacks in struct synps_platform_data are all the same between ZynqMP and i.MX8MP.

Best regards
Sherry Sun