netdev - RE: [PATCH linux-can-next/flexcan 1/4] can: flexcan: initialize all flexcan memory for ECC function

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Message-ID: <DB8PR04MB679575A5E8EE9C7534A446BAE6350@DB8PR04MB6795.eurprd04.prod.outlook.com>
Date:   Mon, 28 Sep 2020 07:58:41 +0000
From:   Joakim Zhang <qiangqing.zhang@....com>
To:     Marc Kleine-Budde <mkl@...gutronix.de>,
        "linux-can@...r.kernel.org" <linux-can@...r.kernel.org>,
        Pankaj Bansal <pankaj.bansal@....com>
CC:     dl-linux-imx <linux-imx@....com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: RE: [PATCH linux-can-next/flexcan 1/4] can: flexcan: initialize all
 flexcan memory for ECC function


> -----Original Message-----
> From: Marc Kleine-Budde <mkl@...gutronix.de>
> Sent: 2020年9月28日 15:01
> To: Joakim Zhang <qiangqing.zhang@....com>; linux-can@...r.kernel.org;
> Pankaj Bansal <pankaj.bansal@....com>
> Cc: dl-linux-imx <linux-imx@....com>; netdev@...r.kernel.org
> Subject: Re: [PATCH linux-can-next/flexcan 1/4] can: flexcan: initialize all flexcan
> memory for ECC function
> 
> On 9/28/20 4:27 AM, Joakim Zhang wrote:
> >> If it's OK on all SoCs to initialize the complete RAM area, just do
> >> it. Then we can get rid of the proposed struct at all.
> >
> > Should be OK according to IP guys feedbacks.
> 
> Good!
> 
> > static const struct flexcan_devtype_data fsl_vf610_devtype_data = {
> > 	.quirks = FLEXCAN_QUIRK_DISABLE_RXFG |
> FLEXCAN_QUIRK_ENABLE_EACEN_RRS |
> > 		FLEXCAN_QUIRK_DISABLE_MECR |
> FLEXCAN_QUIRK_USE_OFF_TIMESTAMP |
> > 		FLEXCAN_QUIRK_BROKEN_PERR_STATE,
> > };
> >
> > static const struct flexcan_devtype_data fsl_ls1021a_r2_devtype_data = {
> > 	.quirks = FLEXCAN_QUIRK_DISABLE_RXFG |
> FLEXCAN_QUIRK_ENABLE_EACEN_RRS |
> > 		FLEXCAN_QUIRK_DISABLE_MECR |
> FLEXCAN_QUIRK_BROKEN_PERR_STATE |
> > 		FLEXCAN_QUIRK_USE_OFF_TIMESTAMP,
> > };
> >
> > static const struct flexcan_devtype_data fsl_lx2160a_r1_devtype_data = {
> > 	.quirks = FLEXCAN_QUIRK_DISABLE_RXFG |
> FLEXCAN_QUIRK_ENABLE_EACEN_RRS |
> > 		FLEXCAN_QUIRK_DISABLE_MECR |
> FLEXCAN_QUIRK_BROKEN_PERR_STATE |
> > 		FLEXCAN_QUIRK_USE_OFF_TIMESTAMP |
> FLEXCAN_QUIRK_SUPPORT_FD, };
> 
> > I am checking layerscape's CAN section:
> >
> > There is no ECC section in LS1021A
> > https://www.nxp.com/products/processors-and-microcontrollers/arm-proce
> > ssors/layerscape-multicore-processors/layerscape-1021a-dual-core-commu
> > nications-processor-with-lcd-controller:LS1021A?tab=Documentation_Tab
> 
> Hmmm, why does the LS1021A have "FLEXCAN_QUIRK_DISABLE_MECR"? The
> bits in the
> ctrl2 and the mecr register itself used in the quirk are marked as reserved in
> this datasheet....
> 
> Can @Pankaj Bansal clarify this?
> 
> > ECC section in LX2160A, also contains the same NOTE as i.MX8MP.
> > https://www.nxp.com/products/processors-and-microcontrollers/arm-proce
> > ssors/layerscape-multicore-processors/layerscape-lx2160a-multicore-com
> > munications-processor:LX2160A?tab=Documentation_Tab
> 
> > Hi @Pankaj Bansal, could you please also have a check?
> Can someone check the vf610, too?

I check the VF610 RM just now, indeed it has ECC feature, there is also a NOTE in "12.1.4.13 Detection and Correction of Memory Errors" section:

All FlexCAN memory must be initialized before starting its
operation in order to have the parity bits in memory properly
updated. The WRMFRZ bit in Control 2 Register (CTRL2)
grants write access to all memory positions from 0x080 to
0xADF.

Best Regards,
Joakim Zhang
> regards,
> Marc
> 
> --
> Pengutronix e.K.                 | Marc Kleine-Budde           |
> Embedded Linux                   | https://www.pengutronix.de  |
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