The cdns3_bind() function is responsible for identifying the appropriate driver to bind to the USB Controller's device-tree node. If the device-tree node has the 'dr_mode' property set to 'otg', the existing approach fails to bind a driver, leading to loss of functionality.
To address this, use the VBUS Valid field of the OTG Status register to determine the role as follows: - If VBUS Valid field is set, it indicates that a USB Host is supplying power and the Controller should assume the Peripheral role. - If VBUS Valid field is clear, it indicates the absence of a USB Host and the Controller should assume the Host role. Additionally, when 'dr_mode' happens to be 'otg' and the STRAP settings are not specified, use VBUS Valid to determine the role in cdns3_drd_init() and assign it to cdns->dr_mode. Signed-off-by: Siddharth Vadapalli <[email protected]> --- Hello, This patch is based on commit f9ffeec4bdc board: toradex: Make A53 get RAM size from DT in K3 boards of the master branch of U-Boot. v1 of this patch is at: https://patchwork.ozlabs.org/project/uboot/patch/[email protected]/ Changes since v1: - Addressed feedback from Marek by updating cdns3_get_otg_mode() to: i) Return an error code (or zero in case of success) instead of returning dr_mode ii) Fill in the mode in a parameter passed to the function and updating cdns3_bind() to return an error when cdns3_get_otg_mode() fails, instead of continuing. Patch has been tested on the J784S4 EVM in the context of USB DFU Boot with dr_mode set to 'otg' in the device-tree. Logs: https://gist.github.com/Siddharth-Vadapalli-at-TI/7a696ba0a4871317361c54003ab75360 Regards, Siddharth. drivers/usb/cdns3/core.c | 64 ++++++++++++++++++++++++++++++++++++++++ drivers/usb/cdns3/drd.c | 11 +++++++ 2 files changed, 75 insertions(+) diff --git a/drivers/usb/cdns3/core.c b/drivers/usb/cdns3/core.c index 4434dc15bec..801c4f1091f 100644 --- a/drivers/usb/cdns3/core.c +++ b/drivers/usb/cdns3/core.c @@ -392,6 +392,63 @@ static const struct udevice_id cdns3_ids[] = { { }, }; +/* + * The VBUS Valid Bit in the OTG Status register can be used to determine + * the role. When VBUS Valid is set, it indicates that a USB Host is supplying + * power, so the Controller should assume the PERIPHERAL role. If it isn't set, + * it indicates the absence of a USB Host, so the Controller should assume the + * HOST role. If the OTG Status register is inaccessible, return an error. + */ +static int cdns3_get_otg_mode(ofnode node, enum usb_dr_mode *mode) +{ + struct cdns3 cdns, *cdnsp; + void __iomem *otg_regs; + fdt_addr_t otg_addr; + int otg_reg_index; + int vbus; + + otg_reg_index = ofnode_stringlist_search(node, "reg-names", "otg"); + if (otg_reg_index < 0) { + printf("%s: dr_mode is otg but otg register name is missing\n", __func__); + return -ENOENT; + } + + otg_addr = ofnode_get_addr_index(node, otg_reg_index); + if (otg_addr == FDT_ADDR_T_NONE) { + printf("%s: address of otg registers is unspecified\n", __func__); + return -ENOENT; + } + + otg_regs = map_physmem(otg_addr, 0, MAP_NOCACHE); + if (!otg_regs) { + printf("%s: failed to map otg registers\n", __func__); + return -EINVAL; + } + + /* + * As mentioned in drivers/usb/cdns3/drd.c, there are two versions + * of the Controller. The following logic detects the version of the + * Controller and interprets the register layout accordingly. + */ + cdnsp = &cdns; + cdnsp->otg_v0_regs = otg_regs; + if (!readl(&cdnsp->otg_v0_regs->cmd)) { + cdnsp->otg_regs = otg_regs; + } else { + cdnsp->otg_v1_regs = otg_regs; + cdnsp->otg_regs = (void *)&cdnsp->otg_v1_regs->cmd; + } + + /* Use VBUS Valid to determine role */ + vbus = !!(readl(&cdnsp->otg_regs->sts) & OTGSTS_VBUS_VALID); + if (vbus) + *mode = USB_DR_MODE_PERIPHERAL; + else + *mode = USB_DR_MODE_HOST; + + return 0; +} + int cdns3_bind(struct udevice *parent) { enum usb_dr_mode dr_mode; @@ -413,6 +470,13 @@ int cdns3_bind(struct udevice *parent) if (dr_mode == USB_DR_MODE_UNKNOWN) dr_mode = usb_get_dr_mode(dev_ofnode(parent)); + /* Use VBUS Valid to determine role */ + if (dr_mode == USB_DR_MODE_OTG) { + ret = cdns3_get_otg_mode(node, &dr_mode); + if (ret < 0) + return ret; + } + switch (dr_mode) { #if defined(CONFIG_SPL_USB_HOST) || \ (!defined(CONFIG_XPL_BUILD) && defined(CONFIG_USB_HOST)) diff --git a/drivers/usb/cdns3/drd.c b/drivers/usb/cdns3/drd.c index cbb13342343..0ca40a5cc8d 100644 --- a/drivers/usb/cdns3/drd.c +++ b/drivers/usb/cdns3/drd.c @@ -301,6 +301,17 @@ int cdns3_drd_init(struct cdns3 *cdns) cdns->dr_mode = USB_DR_MODE_PERIPHERAL; } + /* + * In the absence of STRAP configuration, use VBUS Valid to + * determine the appropriate role to be assigned to dr_mode. + */ + if (cdns->dr_mode == USB_DR_MODE_OTG) { + if (cdns3_get_vbus(cdns)) + cdns->dr_mode = USB_DR_MODE_PERIPHERAL; + else + cdns->dr_mode = USB_DR_MODE_HOST; + } + state = readl(&cdns->otg_regs->sts); if (OTGSTS_OTG_NRDY(state) != 0) { dev_err(cdns->dev, "Cadence USB3 OTG device not ready\n"); -- 2.51.1
