Re: [PATCH v20 2/9] usb: dwc3: core: Access XHCI address space temporarily to read port info

Thinh Nguyen
2024-04-09T00:29:01Z

On Mon, Apr 08, 2024, Krishna Kurapati wrote:
> All DWC3 Multi Port controllers that exist today only support host mode.
> Temporarily map XHCI address space for host-only controllers and parse
> XHCI Extended Capabilities registers to read number of usb2 ports and
> usb3 ports present on multiport controller. Each USB Port is at least HS
> capable.
>
> The port info for usb2 and usb3 phy are identified as num_usb2_ports
> and num_usb3_ports. The intention is as follows:
>
> Wherever we need to perform phy operations like:
>
> LOOP_OVER_NUMBER_OF_AVAILABLE_PORTS()
> {
> phy_set_mode(dwc->usb2_generic_phy[i], PHY_MODE_USB_HOST);
> phy_set_mode(dwc->usb3_generic_phy[i], PHY_MODE_USB_HOST);
> }
>
> If number of usb2 ports is 3, loop can go from index 0-2 for
> usb2_generic_phy. If number of usb3-ports is 2, we don't know for sure,
> if the first 2 ports are SS capable or some other ports like (2 and 3)
> are SS capable. So instead, num_usb2_ports is used to loop around all
> phy's (both hs and ss) for performing phy operations. If any
> usb3_generic_phy turns out to be NULL, phy operation just bails out.
> num_usb3_ports is used to modify GUSB3PIPECTL registers while setting up
> phy's as we need to know how many SS capable ports are there for this.
>
> Signed-off-by: Krishna Kurapati <quic_kriskura@quicinc.com>
> Reviewed-by: Bjorn Andersson <quic_bjorande@quicinc.com>
> ---
> drivers/usb/dwc3/core.c | 61 +++++++++++++++++++++++++++++++++++++++++
> drivers/usb/dwc3/core.h | 5 ++++
> 2 files changed, 66 insertions(+)
>
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index 31684cdaaae3..ddab30531f8a 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -39,6 +39,7 @@
> #include "io.h"
>
> #include "debug.h"
> +#include "../host/xhci-ext-caps.h"
>
> #define DWC3_DEFAULT_AUTOSUSPEND_DELAY 5000 /* ms */
>
> @@ -1881,10 +1882,56 @@ static int dwc3_get_clocks(struct dwc3 *dwc)
> return 0;
> }
>
> +static int dwc3_get_num_ports(struct dwc3 *dwc)
> +{
> + void __iomem *base;
> + u8 major_revision;
> + u32 offset;
> + u32 val;
> +
> + /*
> + * Remap xHCI address space to access XHCI ext cap regs since it is
> + * needed to get information on number of ports present.
> + */
> + base = ioremap(dwc->xhci_resources[0].start,
> + resource_size(&dwc->xhci_resources[0]));
> + if (!base)
> + return -ENOMEM;
> +
> + offset = 0;
> + do {
> + offset = xhci_find_next_ext_cap(base, offset,
> + XHCI_EXT_CAPS_PROTOCOL);
> + if (!offset)
> + break;
> +
> + val = readl(base + offset);
> + major_revision = XHCI_EXT_PORT_MAJOR(val);
> +
> + val = readl(base + offset + 0x08);
> + if (major_revision == 0x03) {
> + dwc->num_usb3_ports += XHCI_EXT_PORT_COUNT(val);
> + } else if (major_revision <= 0x02) {
> + dwc->num_usb2_ports += XHCI_EXT_PORT_COUNT(val);
> + } else {
> + dev_warn(dwc->dev, "unrecognized port major revision %d\n",
> + major_revision);
> + }
> + } while (1);
> +
> + dev_dbg(dwc->dev, "hs-ports: %u ss-ports: %u\n",
> + dwc->num_usb2_ports, dwc->num_usb3_ports);
> +
> + iounmap(base);
> +
> + return 0;
> +}
> +
> static int dwc3_probe(struct platform_device *pdev)
> {
> struct device *dev = &pdev->dev;
> struct resource *res, dwc_res;
> + unsigned int hw_mode;
> void __iomem *regs;
> struct dwc3 *dwc;
> int ret;
> @@ -1968,6 +2015,20 @@ static int dwc3_probe(struct platform_device *pdev)
> goto err_disable_clks;
> }
>
> + /*
> + * Currently only DWC3 controllers that are host-only capable
> + * can have more than one port.
> + */
> + hw_mode = DWC3_GHWPARAMS0_MODE(dwc->hwparams.hwparams0);
> + if (hw_mode == DWC3_GHWPARAMS0_MODE_HOST) {
> + ret = dwc3_get_num_ports(dwc);
> + if (ret)
> + goto err_disable_clks;
> + } else {
> + dwc->num_usb2_ports = 1;
> + dwc->num_usb3_ports = 1;
> + }
> +
> spin_lock_init(&dwc->lock);
> mutex_init(&dwc->mutex);
>
> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
> index 7e80dd3d466b..341e4c73cb2e 100644
> --- a/drivers/usb/dwc3/core.h
> +++ b/drivers/usb/dwc3/core.h
> @@ -1039,6 +1039,8 @@ struct dwc3_scratchpad_array {
> * @usb3_phy: pointer to USB3 PHY
> * @usb2_generic_phy: pointer to USB2 PHY
> * @usb3_generic_phy: pointer to USB3 PHY
> + * @num_usb2_ports: number of USB2 ports
> + * @num_usb3_ports: number of USB3 ports
> * @phys_ready: flag to indicate that PHYs are ready
> * @ulpi: pointer to ulpi interface
> * @ulpi_ready: flag to indicate that ULPI is initialized
> @@ -1187,6 +1189,9 @@ struct dwc3 {
> struct phy *usb2_generic_phy;
> struct phy *usb3_generic_phy;
>
> + u8 num_usb2_ports;
> + u8 num_usb3_ports;
> +
> bool phys_ready;
>
> struct ulpi *ulpi;
> --
> 2.34.1
>

Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>

Thanks,
Thinh