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Subject[PATCH v2 1/1] xhci: add USB2 test mode support
Date
This patch adds support for USB2 test mode (Test_J, Test_K,
Test_SE0_NAK and Test_Packet) per XHCI spec 4.19.6.

USB2 test mode is a required hardware feature for system integrators
validating their hardware according to USB spec, regarding signal
strength and stuff. It is purely a hardware test feature.

Usually you need an oscilloscope and have to enable those test modes on
the hardware. This will send some specific test patterns on D+/D-. There
is no report available (in Linux itself) as it is purely externally
visible. Regular USB usage is not possible at that time.
Anyone (well access to e.g. /dev/bus/usb/001/001 provided) can use it by
sending appropriate USB_PORT_FEAT_TEST requests to the hub.
The same feature for ehci based hosts is already available at
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/usb/host/ehci-hub.c#n1267

Signed-off-by: "Wang, Yu" <yu.y.wang@intel.com>
Signed-off-by: "Li, Guanglei" <guangleix.li@intel.com>
Signed-off-by: "Wu, Hao" <hao.wu@intel.com>
Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
---
Changes in v2:
* Added additional info about USB2 test modes itself into commit message
* Add URL for same test mode feature on ehci hosts.

drivers/usb/host/xhci-hub.c | 63 ++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 62 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c
index 0ef1690..cd561f1 100644
--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -879,13 +879,14 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
int max_ports;
unsigned long flags;
u32 temp, status;
- int retval = 0;
+ int i, retval = 0;
__le32 __iomem **port_array;
int slot_id;
struct xhci_bus_state *bus_state;
u16 link_state = 0;
u16 wake_mask = 0;
u16 timeout = 0;
+ u16 selector = 0;

max_ports = xhci_get_ports(hcd, &port_array);
bus_state = &xhci->bus_state[hcd_index(hcd)];
@@ -959,6 +960,8 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
link_state = (wIndex & 0xff00) >> 3;
if (wValue == USB_PORT_FEAT_REMOTE_WAKE_MASK)
wake_mask = wIndex & 0xff00;
+ if (wValue == USB_PORT_FEAT_TEST)
+ selector = (wIndex & 0xff00) >> 8;
/* The MSB of wIndex is the U1/U2 timeout */
timeout = (wIndex & 0xff00) >> 8;
wIndex &= 0xff;
@@ -1134,6 +1137,64 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
temp |= PORT_U2_TIMEOUT(timeout);
writel(temp, port_array[wIndex] + PORTPMSC);
break;
+ case USB_PORT_FEAT_TEST:
+ /* 4.19.6 Port Test Modes (USB2 Test Mode) */
+ if (hcd->speed != HCD_USB2)
+ goto error;
+
+ /* FIXME: Test_Force_Enable case to be implemented */
+ if (selector < TEST_J || selector > TEST_PACKET)
+ goto error;
+
+ /* Disable all Device Slots */
+ for (i = 0; i < MAX_HC_SLOTS; i++) {
+ struct xhci_command *command;
+
+ if (!xhci->dcbaa->dev_context_ptrs[i])
+ continue;
+ command = xhci_alloc_command(xhci, false,
+ false, GFP_ATOMIC);
+ if (!command)
+ return -ENOMEM;
+ if (xhci_queue_slot_control(xhci, command,
+ TRB_DISABLE_SLOT, i)) {
+ xhci_err(xhci,
+ "Disable slot[%d] fail!\n", i);
+ goto error;
+ }
+ xhci_dbg(xhci, "Disable Slot[%d].\n", i);
+ }
+
+ /* Put all ports to the Disable state by clear PP */
+ xhci_dbg(xhci, "Disable all port (PP = 0)\n");
+ for (i = 0; i < max_ports; i++) {
+ temp = readl(port_array[i]);
+ temp &= ~PORT_POWER;
+ writel(temp, port_array[i]);
+ }
+
+ /* Stop the controller */
+ xhci_dbg(xhci, "Stop controller\n");
+ temp = readl(&xhci->op_regs->command);
+ temp &= ~CMD_RUN;
+ writel(temp, &xhci->op_regs->command);
+
+ if (xhci_handshake(&xhci->op_regs->status,
+ STS_HALT, STS_HALT, XHCI_MAX_HALT_USEC)) {
+ xhci_warn(xhci, "Stop controller timeout\n");
+ return -ETIMEDOUT;
+ }
+
+ /* Disable runtime PM for test mode */
+ pm_runtime_forbid(hcd->self.controller);
+
+ /* Set PORTPMSC.PTC field for selected test mode */
+ xhci_dbg(xhci, "Enter Test Mode: %d\n", selector);
+ temp = readl(port_array[wIndex] + PORTPMSC);
+ temp |= selector << 28;
+ writel(temp, port_array[wIndex] + PORTPMSC);
+
+ break;
default:
goto error;
}
--
2.10.2
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