> -----Original Message-----
> From: Damien Le Moal <dlemoal@xxxxxxxxxx>
> Sent: 2024年7月16日 6:01
> To: Hongxing Zhu <hongxing.zhu@xxxxxxx>; tj@xxxxxxxxxx; cassel@xxxxxxxxxx;
> robh@xxxxxxxxxx; krzk+dt@xxxxxxxxxx; conor+dt@xxxxxxxxxx;
> shawnguo@xxxxxxxxxx; s.hauer@xxxxxxxxxxxxxx; festevam@xxxxxxxxx
> Cc: linux-ide@xxxxxxxxxxxxxxx; stable@xxxxxxxxxxxxxxx;
> devicetree@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; imx@xxxxxxxxxxxxxxx;
> kernel@xxxxxxxxxxxxxx
> Subject: Re: [PATCH v2 3/4] ata: ahci_imx: Enlarge RX water mark for i.MX8QM
> SATA
>
> On 7/15/24 10:53, Richard Zhu wrote:
> > The RXWM(RxWaterMark) sets the minimum number of free location within
> > the RX FIFO before the watermark is exceeded which in turn will cause
> > the Transport Layer to instruct the Link Layer to transmit HOLDS to
> > the transmitting end.
> >
> > Based on the default RXWM value 0x20, RX FIFO overflow might be
> > observed on i.MX8QM MEK board, when some Gen3 SATA disks are used.
> >
> > The FIFO overflow will result in CRC error, internal error and
> > protocol error, then the SATA link is not stable anymore.
> >
> > To fix this issue, enlarge RX water mark setting from 0x20 to 0x29.
> >
> > Fixes: 027fa4dee935 ("ahci: imx: add the imx8qm ahci sata support")
> > Cc: stable@xxxxxxxxxxxxxxx
> > Signed-off-by: Richard Zhu <hongxing.zhu@xxxxxxx>
> > ---
> > drivers/ata/ahci_imx.c | 10 ++++++++++
> > 1 file changed, 10 insertions(+)
> >
> > diff --git a/drivers/ata/ahci_imx.c b/drivers/ata/ahci_imx.c index
> > e94c0fdea2260..12d69a6429b6a 100644
> > --- a/drivers/ata/ahci_imx.c
> > +++ b/drivers/ata/ahci_imx.c
> > @@ -45,6 +45,10 @@ enum {
> > /* Clock Reset Register */
> > IMX_CLOCK_RESET = 0x7f3f,
> > IMX_CLOCK_RESET_RESET = 1 << 0,
> > + /* IMX8QM SATA specific control registers */
> > + IMX8QM_SATA_AHCI_VEND_PTC = 0xc8,
> > + IMX8QM_SATA_AHCI_VEND_PTC_RXWM_MASK = 0x7f,
>
> Please use GENMASK() macro to define this.
Thanks for your comments.
Okay.
>
> > + IMX8QM_SATA_AHCI_VEND_PTC_NEWRXWM = 0x29,
>
> Here too. And I do not see the point of the "NEW" in the macro name.
>
Okay, "NEW" would be removed.
> Also, what is "_VEND_" supposed to mean in the macro names ? "Vendor" ?
> If that is the case, remove that too, which will give you shorter macro names.
> If not, then spell it out because that is not clear.
Yes, you're right.
"_VEND_" means "Vendor". I would remove them later.
Best Regards
Richard Zhu
>
> > };
> >
> > enum ahci_imx_type {
> > @@ -466,6 +470,12 @@ static int imx8_sata_enable(struct ahci_host_priv
> *hpriv)
> > phy_power_off(imxpriv->cali_phy0);
> > phy_exit(imxpriv->cali_phy0);
> >
> > + /* RxWaterMark setting */
> > + val = readl(hpriv->mmio + IMX8QM_SATA_AHCI_VEND_PTC);
> > + val &= ~IMX8QM_SATA_AHCI_VEND_PTC_RXWM_MASK;
> > + val |= IMX8QM_SATA_AHCI_VEND_PTC_NEWRXWM;
> > + writel(val, hpriv->mmio + IMX8QM_SATA_AHCI_VEND_PTC);
> > +
> > return 0;
> >
> > err_sata_phy_exit:
>
> --
> Damien Le Moal
> Western Digital Research
