[U-Boot] [PATCH 3/3] usb: tegra: support device mode

Stephen Warren
2014-04-30T21:09:57Z

From: Stephen Warren <swarren@nvidia.com>

A few changes are made to the Tegra EHCI driver so that it can set
everything up for device-mode operation on the first USB controller.
This can be used in conjunction with ci_udc.c to operate as a USB
device.

Detailed changes are:

* Rename set_host_mode() to set_up_vbus() since that's really what it
does.

* Modify set_up_vbus() to know whether it's initializing in host or
device mode, and:

- Skip the external VBUS check in device mode, since external VBUS is
expected in this case.

- Disable VBUS output in device mode.

* Modify init_phy_mux() to know whether it's initializing in host or
device mode, and hence skip setting USBMODE_CM_HC (which enables host
mode) in device mode. See the comments in that function for why this
is safe w.r.t. the ordering requirements of PHY selection.

* Modify init_utmi_usb_controller() to force "b session valid" in device
mode, since the HW requires this. This is done in UTMI-specific code,
since we only support device mode on the first USB controller, and that
controller can only talk to a UTMI PHY.

* Enhance ehci_hcd_init() to error-check the requested host-/device-mode
vs. the dr_mode (dual-role mode) value present in device tree, and the
HW configurations which support device mode.

* Enhance ehci_hcd_init() not to skip HW initialization when switching
between host and device mode on a controller. This requires remembering
which mode the last initialization used.

Cc: Jim Lin <jilin@nvidia.com>
Cc: Stefan Agner <stefan@agner.ch>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
---
arch/arm/include/asm/arch-tegra/usb.h | 2 +
drivers/usb/host/ehci-tegra.c | 114 +++++++++++++++++++++++++---------
2 files changed, 86 insertions(+), 30 deletions(-)

diff --git a/arch/arm/include/asm/arch-tegra/usb.h b/arch/arm/include/asm/arch-tegra/usb.h
index ceb7bcd9cfb9..c817088fa57e 100644
--- a/arch/arm/include/asm/arch-tegra/usb.h
+++ b/arch/arm/include/asm/arch-tegra/usb.h
@@ -349,6 +349,8 @@ struct usb_ctlr {

/* USB3_IF_USB_PHY_VBUS_SENSORS_0 */
#define VBUS_VLD_STS (1 << 26)
+#define VBUS_B_SESS_VLD_SW_VALUE (1 << 12)
+#define VBUS_B_SESS_VLD_SW_EN (1 << 11)

/* Setup USB on the board */
int usb_process_devicetree(const void *blob);
diff --git a/drivers/usb/host/ehci-tegra.c b/drivers/usb/host/ehci-tegra.c
index 55a546e4d3da..33e5ea9ebdd0 100644
--- a/drivers/usb/host/ehci-tegra.c
+++ b/drivers/usb/host/ehci-tegra.c
@@ -69,6 +69,7 @@ struct fdt_usb {
unsigned enabled:1; /* 1 to enable, 0 to disable */
unsigned has_legacy_mode:1; /* 1 if this port has legacy mode */
unsigned initialized:1; /* has this port already been initialized? */
+ enum usb_init_type init_type;
enum dr_mode dr_mode; /* dual role mode */
enum periph_id periph_id;/* peripheral id */
struct fdt_gpio_state vbus_gpio; /* GPIO for vbus enable */
@@ -237,29 +238,31 @@ int ehci_get_port_speed(struct ehci_hcor *hcor, uint32_t reg)
return PORTSC_PSPD(reg);
}

-/* Put the port into host mode */
-static void set_host_mode(struct fdt_usb *config)
+/* Set up VBUS for host/device mode */
+static void set_up_vbus(struct fdt_usb *config, enum usb_init_type init)
{
/*
- * If we are an OTG port, check if remote host is driving VBus and
- * bail out in this case.
+ * If we are an OTG port initializing in host mode,
+ * check if remote host is driving VBus and bail out in this case.
*/
- if (config->dr_mode == DR_MODE_OTG &&
- (readl(&config->reg->phy_vbus_sensors) & VBUS_VLD_STS))
+ if (init == USB_INIT_HOST &&
+ config->dr_mode == DR_MODE_OTG &&
+ (readl(&config->reg->phy_vbus_sensors) & VBUS_VLD_STS)) {
+ printf("tegrausb: VBUS input active; not enabling as host\n");
return;
+ }

- /*
- * If not driving, we set the GPIO to enable VBUS. We assume
- * that the pinmux is set up correctly for this.
- */
if (fdt_gpio_isvalid(&config->vbus_gpio)) {
+ int vbus_value;
+
fdtdec_setup_gpio(&config->vbus_gpio);
- gpio_direction_output(config->vbus_gpio.gpio,
- (config->vbus_gpio.flags & FDT_GPIO_ACTIVE_LOW) ?
- 0 : 1);
- debug("set_host_mode: GPIO %d %s\n", config->vbus_gpio.gpio,
- (config->vbus_gpio.flags & FDT_GPIO_ACTIVE_LOW) ?
- "low" : "high");
+
+ vbus_value = (init == USB_INIT_HOST) ^
+ !!(config->vbus_gpio.flags & FDT_GPIO_ACTIVE_LOW);
+ gpio_direction_output(config->vbus_gpio.gpio, vbus_value);
+
+ debug("set_up_vbus: GPIO %d %d\n", config->vbus_gpio.gpio,
+ vbus_value);
}
}

@@ -294,7 +297,8 @@ static const unsigned *get_pll_timing(void)
}

/* select the PHY to use with a USB controller */
-static void init_phy_mux(struct fdt_usb *config, uint pts)
+static void init_phy_mux(struct fdt_usb *config, uint pts,
+ enum usb_init_type init)
{
struct usb_ctlr *usbctlr = config->reg;

@@ -309,10 +313,16 @@ static void init_phy_mux(struct fdt_usb *config, uint pts)
clrbits_le32(&usbctlr->port_sc1, STS);
}
#else
- /* Set to Host mode after Controller Reset was done */
+ /* Set to Host mode (if applicable) after Controller Reset was done */
clrsetbits_le32(&usbctlr->usb_mode, USBMODE_CM_HC,
- USBMODE_CM_HC);
- /* Select PHY interface after setting host mode */
+ (init == USB_INIT_HOST) ? USBMODE_CM_HC : 0);
+ /*
+ * Select PHY interface after setting host mode.
+ * For device mode, the ordering requirement is not an issue, since
+ * only the first USB controller supports device mode, and that USB
+ * controller can only talk to a UTMI PHY, so the PHY selection is
+ * already made at reset time, so this write is a no-op.
+ */
clrsetbits_le32(&usbctlr->hostpc1_devlc, PTS_MASK,
pts << PTS_SHIFT);
clrbits_le32(&usbctlr->hostpc1_devlc, STS);
@@ -320,9 +330,10 @@ static void init_phy_mux(struct fdt_usb *config, uint pts)
}

/* set up the UTMI USB controller with the parameters provided */
-static int init_utmi_usb_controller(struct fdt_usb *config)
+static int init_utmi_usb_controller(struct fdt_usb *config,
+ enum usb_init_type init)
{
- u32 val;
+ u32 b_sess_valid_mask, val;
int loop_count;
const unsigned *timing;
struct usb_ctlr *usbctlr = config->reg;
@@ -340,6 +351,10 @@ static int init_utmi_usb_controller(struct fdt_usb *config)
/* Follow the crystal clock disable by >100ns delay */
udelay(1);

+ b_sess_valid_mask = (VBUS_B_SESS_VLD_SW_VALUE | VBUS_B_SESS_VLD_SW_EN);
+ clrsetbits_le32(&usbctlr->phy_vbus_sensors, b_sess_valid_mask,
+ (init == USB_INIT_DEVICE) ? b_sess_valid_mask : 0);
+
/*
* To Use the A Session Valid for cable detection logic, VBUS_WAKEUP
* mux must be switched to actually use a_sess_vld threshold.
@@ -511,7 +526,7 @@ static int init_utmi_usb_controller(struct fdt_usb *config)
clrbits_le32(&usbctlr->icusb_ctrl, IC_ENB1);

/* Select UTMI parallel interface */
- init_phy_mux(config, PTS_UTMI);
+ init_phy_mux(config, PTS_UTMI, init);

/* Deassert power down state */
clrbits_le32(&usbctlr->utmip_xcvr_cfg0, UTMIP_FORCE_PD_POWERDOWN |
@@ -541,7 +556,8 @@ static int init_utmi_usb_controller(struct fdt_usb *config)
#endif

/* set up the ULPI USB controller with the parameters provided */
-static int init_ulpi_usb_controller(struct fdt_usb *config)
+static int init_ulpi_usb_controller(struct fdt_usb *config,
+ enum usb_init_type init)
{
u32 val;
int loop_count;
@@ -569,7 +585,7 @@ static int init_ulpi_usb_controller(struct fdt_usb *config)
ULPI_CLKOUT_PINMUX_BYP | ULPI_OUTPUT_PINMUX_BYP);

/* Select ULPI parallel interface */
- init_phy_mux(config, PTS_ULPI);
+ init_phy_mux(config, PTS_ULPI, init);

/* enable ULPI transceiver */
setbits_le32(&usbctlr->susp_ctrl, ULPI_PHY_ENB);
@@ -618,7 +634,8 @@ static int init_ulpi_usb_controller(struct fdt_usb *config)
return 0;
}
#else
-static int init_ulpi_usb_controller(struct fdt_usb *config)
+static int init_ulpi_usb_controller(struct fdt_usb *config,
+ enum usb_init_type init)
{
printf("No code to set up ULPI controller, please enable"
"CONFIG_USB_ULPI and CONFIG_USB_ULPI_VIEWPORT");
@@ -771,23 +788,60 @@ int ehci_hcd_init(int index, enum usb_init_type init,

config = &port[index];

+ switch (init) {
+ case USB_INIT_HOST:
+ switch (config->dr_mode) {
+ case DR_MODE_HOST:
+ case DR_MODE_OTG:
+ break;
+ default:
+ printf("tegrausb: Invalid dr_mode %d for host mode\n",
+ config->dr_mode);
+ return -1;
+ }
+ break;
+ case USB_INIT_DEVICE:
+ if (config->periph_id != PERIPH_ID_USBD) {
+ printf("tegrausb: Device mode only supported on first USB controller\n");
+ return -1;
+ }
+ if (!config->utmi) {
+ printf("tegrausb: Device mode only supported with UTMI PHY\n");
+ return -1;
+ }
+ switch (config->dr_mode) {
+ case DR_MODE_DEVICE:
+ case DR_MODE_OTG:
+ break;
+ default:
+ printf("tegrausb: Invalid dr_mode %d for device mode\n",
+ config->dr_mode);
+ return -1;
+ }
+ break;
+ default:
+ printf("tegrausb: Unknown USB_INIT_* %d\n", init);
+ return -1;
+ }
+
/* skip init, if the port is already initialized */
- if (config->initialized)
+ if (config->initialized && config->init_type == init)
goto success;

- if (config->utmi && init_utmi_usb_controller(config)) {
+ if (config->utmi && init_utmi_usb_controller(config, init)) {
printf("tegrausb: Cannot init port %d\n", index);
return -1;
}

- if (config->ulpi && init_ulpi_usb_controller(config)) {
+ if (config->ulpi && init_ulpi_usb_controller(config, init)) {
printf("tegrausb: Cannot init port %d\n", index);
return -1;
}

- set_host_mode(config);
+ set_up_vbus(config, init);

config->initialized = 1;
+ config->init_type = init;

success:
usbctlr = config->reg;
--
1.8.1.5