Re: [RFC PATCH v2 2/3] usb: xhci-mtk: modify the SOF/ITP interval for mt8195

From: Chunfeng Yun <chunfeng.yun@mediatek.com>
To: Mathias Nyman <mathias.nyman@intel.com>
Cc: Rob Herring <robh+dt@kernel.org>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	Mathias Nyman <mathias.nyman@intel.com>,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	<linux-usb@vger.kernel.org>, <devicetree@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-mediatek@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>, "Ikjoon Jang" <ikjn@chromium.org>,
	Nicolas Boichat <drinkcat@chromium.org>
Subject: Re: [RFC PATCH v2 2/3] usb: xhci-mtk: modify the SOF/ITP interval for mt8195
Date: Sun, 7 Feb 2021 10:27:13 +0800	[thread overview]
Message-ID: <1612664833.5147.30.camel@mhfsdcap03> (raw)
In-Reply-To: <20210203102642.7353-2-chunfeng.yun@mediatek.com>

Hi Mathias,

On Wed, 2021-02-03 at 18:26 +0800, Chunfeng Yun wrote:
> There are 4 USB controllers on MT8195, the controllers (IP1~IP3,
> exclude IP0) have a wrong default SOF/ITP interval which is
> calculated from the frame counter clock 24Mhz by default, but
> in fact, the frame counter clock is 48Mhz, so we should set
> the accurate interval according to 48Mhz for those controllers.
> Note: the first controller no need set it.
> 
> Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
> ---
> v2: fix typo of comaptible
> ---
>  drivers/usb/host/xhci-mtk.c | 63 +++++++++++++++++++++++++++++++++++++
>  1 file changed, 63 insertions(+)
> 
> diff --git a/drivers/usb/host/xhci-mtk.c b/drivers/usb/host/xhci-mtk.c
> index 8f321f39ab96..0a68c4ac8b48 100644
> --- a/drivers/usb/host/xhci-mtk.c
> +++ b/drivers/usb/host/xhci-mtk.c
> @@ -68,11 +68,71 @@
>  #define SSC_IP_SLEEP_EN	BIT(4)
>  #define SSC_SPM_INT_EN		BIT(1)
>  
Can I Read/Write the following xHCI controller's registers  in
xhci-mtk.c?

Ideally, xhci-mtk.c should not access them, because xhci-mtk is only a
glue driver used to initialize clocks/power and IPPC registers which
don't belong to xHCI controller.

Thanks

> +/* xHCI csr */
> +#define LS_EOF			0x930
> +#define LS_EOF_OFFSET		0x89
> +
> +#define FS_EOF			0x934
> +#define FS_EOF_OFFSET		0x2e
> +
> +#define SS_GEN1_EOF		0x93c
> +#define SS_GEN1_EOF_OFFSET	0x78
> +
> +#define HFCNTR_CFG		0x944
> +#define ITP_DELTA_CLK		(0xa << 1)
> +#define ITP_DELTA_CLK_MASK	GENMASK(5, 1)
> +#define FRMCNT_LEV1_RANG	(0x12b << 8)
> +#define FRMCNT_LEV1_RANG_MASK	GENMASK(19, 8)
> +
> +#define SS_GEN2_EOF		0x990
> +#define SS_GEN2_EOF_OFFSET	0x3c
> +#define EOF_OFFSET_MASK		GENMASK(11, 0)
> +
>  enum ssusb_uwk_vers {
>  	SSUSB_UWK_V1 = 1,
>  	SSUSB_UWK_V2,
>  };
>  
> +/*
> + * MT8195 has 4 controllers, the controller1~3's default SOF/ITP interval
> + * is calculated from the frame counter clock 24M, but in fact, the clock
> + * is 48M, so need change the interval.
> + */
> +static void xhci_mtk_set_frame_interval(struct xhci_hcd_mtk *mtk)
> +{
> +	struct device *dev = mtk->dev;
> +	struct usb_hcd *hcd = mtk->hcd;
> +	u32 value;
> +
> +	if (!of_device_is_compatible(dev->of_node, "mediatek,mt8195-xhci"))
> +		return;
> +
> +	value = readl(hcd->regs + HFCNTR_CFG);
> +	value &= ~(ITP_DELTA_CLK_MASK | FRMCNT_LEV1_RANG_MASK);
> +	value |= (ITP_DELTA_CLK | FRMCNT_LEV1_RANG);
> +	writel(value, hcd->regs + HFCNTR_CFG);
> +
> +	value = readl(hcd->regs + LS_EOF);
> +	value &= ~EOF_OFFSET_MASK;
> +	value |= LS_EOF_OFFSET;
> +	writel(value, hcd->regs + LS_EOF);
> +
> +	value = readl(hcd->regs + FS_EOF);
> +	value &= ~EOF_OFFSET_MASK;
> +	value |= FS_EOF_OFFSET;
> +	writel(value, hcd->regs + FS_EOF);
> +
> +	value = readl(hcd->regs + SS_GEN1_EOF);
> +	value &= ~EOF_OFFSET_MASK;
> +	value |= SS_GEN1_EOF_OFFSET;
> +	writel(value, hcd->regs + SS_GEN1_EOF);
> +
> +	value = readl(hcd->regs + SS_GEN2_EOF);
> +	value &= ~EOF_OFFSET_MASK;
> +	value |= SS_GEN2_EOF_OFFSET;
> +	writel(value, hcd->regs + SS_GEN2_EOF);
> +}
> +
>  static int xhci_mtk_host_enable(struct xhci_hcd_mtk *mtk)
>  {
>  	struct mu3c_ippc_regs __iomem *ippc = mtk->ippc_regs;
> @@ -407,6 +467,8 @@ static int xhci_mtk_setup(struct usb_hcd *hcd)
>  		ret = xhci_mtk_ssusb_config(mtk);
>  		if (ret)
>  			return ret;
> +
> +		xhci_mtk_set_frame_interval(mtk);
>  	}
>  
>  	ret = xhci_gen_setup(hcd, xhci_mtk_quirks);
> @@ -655,6 +717,7 @@ static const struct dev_pm_ops xhci_mtk_pm_ops = {
>  #ifdef CONFIG_OF
>  static const struct of_device_id mtk_xhci_of_match[] = {
>  	{ .compatible = "mediatek,mt8173-xhci"},
> +	{ .compatible = "mediatek,mt8195-xhci"},
>  	{ .compatible = "mediatek,mtk-xhci"},
>  	{ },
>  };