[U-Boot] [PATCH v4 2/4] USB: host: Add the USB3 host driver

[Sherry Sun]

Hi Marek,

> 
> On 8/19/19 8:10 AM, Sherry Sun wrote:
> > Add the USB3 host driver for NXP imx8 platform, and the cadence IP is
> > in it. The USB3 host driver support DM mode, it will probe USB3 host
> > node in dts.
> >
> > Signed-off-by: Sherry Sun <sherry.sun at nxp.com>
> 
> [...]
> 
> > +static void xhci_imx8_get_reg_addr(struct udevice *dev) {
> > +	imx8_data.usb3_ctrl_base =
> > +			(void __iomem *)devfdt_get_addr_index(dev, 0);
> > +	imx8_data.usb3_core_base =
> > +			(void __iomem *)devfdt_get_addr_index(dev, 4); }
> 
> Inline this.
> 
> Also, look at drivers/mtd/renesas_rpc_hf.c to handle both 32bit and 64bit DTs
> with multiple "reg" entries.
> 

Actually, I don't think it's needed to change the way getting reg in dts.
For two reasons:
1. This xhci-imx8 driver is only target on imx8 platform which all use 64bit dts.
2. devfdt_get_addr_index() can handle both 32/64 bits dts too.

> [...]
> 
> > +static const struct udevice_id xhci_usb_ids[] = {
> > +	{ .compatible = "cdns,usb3-host", },
> 
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.ker
> nel.org%2Fpatchwork%2Fpatch%2F1059917%2F&data=02%7C01%7Cshe
> rry.sun%40nxp.com%7C70e116ce152a4060dbd508d724987b54%7C686ea1d
> 3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C637018109631327748&sd
> ata=GzX5KNQ8m0CCeBa9tPSV%2BOEwwuSsxDdAiJd1T6or8P0%3D&reser
> ved=0 would suggest that
> cdns,usb3-1.0.0 is the compatible. But I might be wrong.

This patch has not been accepted by the kernel, right?
So I think maybe we can do this change to synchronize with kernel after the cdns3 
kernel patch been accepted. And note that in uboot, one dts node can only bind with
one driver, so we keep the cdns3 node for usb gadget driver, then add a usb host node for 
xhci-imx8 driver in *-uboot.dtsi. so here is no need to change the host driver compatible.
But the compatible in gadget driver should be changed later.

> 
> > +	{ }
> > +};
> > +
> > +U_BOOT_DRIVER(xhci_imx8) = {
> > +	.name	= "xhci_imx8",
> > +	.id	= UCLASS_USB,
> > +	.of_match = xhci_usb_ids,
> > +	.probe = xhci_imx8_probe,
> > +	.remove = xhci_imx8_remove,
> > +	.ops	= &xhci_usb_ops,
> > +	.platdata_auto_alloc_size = sizeof(struct usb_platdata),
> > +	.priv_auto_alloc_size = sizeof(struct xhci_ctrl),
> > +	.flags	= DM_FLAG_ALLOC_PRIV_DMA,
> 
> I think you also need DM_FLAG_OS_PREPARE to trigger .remove before booting
> Linux, but I might be wrong. Please check that.

When use usb stop command to stop the usb host driver, 
device_remove(bus, DM_REMOVE_NORMAL) is called by usb_stop(),
so normally we don’t need the DM_FLAG_OS_PREPARE flag.
But considering some special circumstances, maybe add this flag is helpful.

Best regard
Sherry sun