Mathias Nyman wrote:

Hi

On 2.2.2021 5.42, Thinh Nguyen wrote:

quoted

The current xhci_create_usb3_bos_desc() uses a static bos structure and
various magic numbers and offset making it difficult to extend support
for USB 3.2. Let's rewrite this entire function to support dual-lane in
USB 3.2.

Agree, it's time to get rid of the static u8 array used for bos.
 

quoted

The hub driver matches the port speed ID from the extended port status
to the SSID of the sublink speed attributes to detect if the device
supports SuperSpeed Plus. Currently we don't provide the default gen1x2
and gen2x2 sublink speed capability descriptor for USB 3.2 roothub. The
USB stack depends on this to detect and match the correct speed.
In addition, if the xHCI host provides Protocol Speed ID (PSI)
capability, then make sure to convert Protocol Speed ID Mantissa and
Exponent (PSIM & PSIE) to lane speed for gen1x2 and gen2x2.

Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
---
 drivers/usb/host/xhci-hub.c | 279 +++++++++++++++++++++++++++++++++++-
 1 file changed, 277 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c
index 74c497fd3476..c095c30212e5 100644
--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c

@@ -11,6 +11,7 @@
 
 #include <linux/slab.h>
 #include <asm/unaligned.h>
+#include <linux/bitfield.h>
 
 #include "xhci.ch"
 #include "xhci-trace.h"

@@ -52,7 +53,281 @@ static u8 usb_bos_descriptor [] = {
 	0xb5, 0x40, 0x0a, 0x00,		/* 10Gbps, SSP, symmetric, tx, ID = 5 */
 };
 
-static int xhci_create_usb3_bos_desc(struct xhci_hcd *xhci, char *buf,
+static int xhci_fill_default_ssp_attr(struct xhci_hcd *xhci,
+		struct usb_ssp_cap_descriptor *ssp_cap)
+{
+	u32 attr;
+	u8 ssac;
+	int i;
+
+	attr = le32_to_cpu(ssp_cap->bmAttributes);
+	ssac = FIELD_GET(USB_SSP_SUBLINK_SPEED_ATTRIBS, attr);
+
+	/* Currently we only support USB 3.1 and 3.2 */
+	if (ssac != 3 && ssac != 7)
+		return -EINVAL;
+
+	/*
+	 * Map default xHCI port speed ID to SSID:
+	 *  SSID 4 = Symmetric SSP Gen1x1
+	 *  SSID 5 = Symmetric SSP Gen2x1
+	 *  SSID 6 = Symmetric SSP Gen1x2
+	 *  SSID 7 = Symmetric SSP Gen2x2
+	 */
+	for (i = 0; i < ssac + 1; i++) {
+		u8 ssid;
+		u8 type;
+		u8 lp;
+		u16 mantissa;
+
+		ssid = (i >> 1) + 4;
+
+		if (ssid > 4)
+			lp = USB_SSP_SUBLINK_SPEED_LP_SSP;
+		else
+			lp = USB_SSP_SUBLINK_SPEED_LP_SS;
+
+		if (ssid == 5 || ssid == 7)
+			mantissa = 10;
+		else
+			mantissa = 5;
+
+		if (i % 2)
+			type = USB_SSP_SUBLINK_SPEED_ST_SYM_TX;
+		else
+			type = USB_SSP_SUBLINK_SPEED_ST_SYM_RX;
+
+		ssp_cap->bmSublinkSpeedAttr[i] =
+			cpu_to_le32(FIELD_PREP(USB_SSP_SUBLINK_SPEED_SSID,
+					       ssid) |
+				    FIELD_PREP(USB_SSP_SUBLINK_SPEED_LSE,
+					       USB_SSP_SUBLINK_SPEED_LSE_GBPS) |
+				    FIELD_PREP(USB_SSP_SUBLINK_SPEED_ST, type) |
+				    FIELD_PREP(USB_SSP_SUBLINK_SPEED_LP, lp) |
+				    FIELD_PREP(USB_SSP_SUBLINK_SPEED_LSM,
+					       mantissa));
+	}
+
+	return 0;
+}

I don't think it makes sense to generates the default sublinkSpeedAttr[] entries like
the function above does.
The content is static and defined in xhci spec.
For these I'd just make a static u32 array. (minding endianness)

static u32 ssp_cap_default_ssa[] = {
	0xaaaaaaaa, /* USB 3.0 SS 5Gbps Id:4, rx */ 
	0xbbbbbbbb, /* USB 3.0 SS 5Gbps Id:4, tx */ 
	0xcccccccc, /* USB 3.1 SSP 10Gbps Id:5  rx */ 
	0xdddddddd, /* USB 3.1 SSP 10Gbps Id:5, tx */ 
	0xeeeeeeee, /* USB 3.2 Gen1x2 10Gbps Id:6, rx */ 
	...
}

Then when creating the ssp cap descriptor set the attribute count (ssac) based on
bcdUSB as you do, and assign the default values if custom ones aren't given (!psi_count).

for (i = 0; i < ssac + 1; i++)
	ssp_cap->mbSublinkSpeedAttr[i] = ssp_capdefault_ssa[i]; 

That looks good. I'll revise it.

quoted

+
+static int xhci_create_usb3x_bos_desc(struct xhci_hcd *xhci, char *buf,
+				      u16 wLength)
+{
+	struct usb_bos_descriptor	*bos;
+	struct usb_ss_cap_descriptor	*ss_cap;
+	struct usb_ssp_cap_descriptor	*ssp_cap;
+	struct xhci_port_cap		*port_cap = NULL;
+	u16				bcdUSB;
+	u32				reg;
+	u32				min_rate = 0;
+	u8				min_ssid;
+	u8				ssac;
+	u8				ssic;
+	int				offset;
+	int				i;
+
+	/* BOS descriptor */
+	bos = (struct usb_bos_descriptor *)buf;
+	bos->bLength = USB_DT_BOS_SIZE;
+	bos->bDescriptorType = USB_DT_BOS;
+	bos->wTotalLength = cpu_to_le16(USB_DT_BOS_SIZE +
+					USB_DT_USB_SS_CAP_SIZE);
+	bos->bNumDeviceCaps = 1;

This is much better than the current way we fill the descriptor, much more readable.

quoted

+
+	/* Create the descriptor for port with the highest revision */
+	for (i = 0; i < xhci->num_port_caps; i++) {
+		u8 major = xhci->port_caps[i].maj_rev;
+		u8 minor = xhci->port_caps[i].min_rev;
+		u16 rev = (major << 8) | minor;
+
+		if (i == 0 || bcdUSB < rev) {
+			bcdUSB = rev;
+			port_cap = &xhci->port_caps[i];
+		}
+	}
+
+	if (bcdUSB >= 0x0310) {
+		/* Two SSA entries for each unique PSI ID, RX and TX */
+		if (port_cap->psi_count)
+			ssac = port_cap->psi_uid_count * 2 - 1;
+		else if (bcdUSB == 0x0320)

maybe (bcdUSB >= 0x320), allows old driver to handle future hardware.

Ok.

quoted

+			ssac = 7;
+		else
+			ssac = 3;
+
+		if (port_cap->psi_count)
+			ssic = port_cap->psi_count - 1;
+		else
+			ssic = (ssac + 1) / 2 - 1;
+
+		bos->bNumDeviceCaps++;
+		bos->wTotalLength = cpu_to_le16(USB_DT_BOS_SIZE +
+						USB_DT_USB_SS_CAP_SIZE +
+						USB_DT_USB_SSP_CAP_SIZE(ssac));
+	}
+
+	if (wLength < USB_DT_BOS_SIZE + USB_DT_USB_SS_CAP_SIZE)
+		return wLength;
+
+	/* SuperSpeed USB Device Capability */
+	ss_cap = (struct usb_ss_cap_descriptor *)&buf[USB_DT_BOS_SIZE];
+	ss_cap->bLength = USB_DT_USB_SS_CAP_SIZE;
+	ss_cap->bDescriptorType = USB_DT_DEVICE_CAPABILITY;
+	ss_cap->bDevCapabilityType = USB_SS_CAP_TYPE;
+	ss_cap->bmAttributes = 0; /* set later */
+	ss_cap->wSpeedSupported = cpu_to_le16(USB_5GBPS_OPERATION);
+	ss_cap->bFunctionalitySupport = USB_LOW_SPEED_OPERATION;
+	ss_cap->bU1devExitLat = 0; /* set later */
+	ss_cap->bU2DevExitLat = 0; /* set later */
+
+	reg = readl(&xhci->cap_regs->hcc_params);
+	if (HCC_LTC(reg))
+		ss_cap->bmAttributes |= USB_LTM_SUPPORT;
+
+	if ((xhci->quirks & XHCI_LPM_SUPPORT)) {
+		reg = readl(&xhci->cap_regs->hcs_params3);
+		ss_cap->bU1devExitLat = HCS_U1_LATENCY(reg);
+		ss_cap->bU2DevExitLat = cpu_to_le16(HCS_U2_LATENCY(reg));
+	}
+
+	if (wLength < le16_to_cpu(bos->wTotalLength))
+		return wLength;
+
+	if (bcdUSB < 0x0310)
+		return le16_to_cpu(bos->wTotalLength);
+
+	ssp_cap = (struct usb_ssp_cap_descriptor *)&buf[USB_DT_BOS_SIZE +
+		USB_DT_USB_SS_CAP_SIZE];
+	ssp_cap->bLength = USB_DT_USB_SSP_CAP_SIZE(ssac);
+	ssp_cap->bDescriptorType = USB_DT_DEVICE_CAPABILITY;
+	ssp_cap->bDevCapabilityType = USB_SSP_CAP_TYPE;
+	ssp_cap->bReserved = 0;
+	ssp_cap->wReserved = 0;
+	ssp_cap->bmAttributes =
+		cpu_to_le32(FIELD_PREP(USB_SSP_SUBLINK_SPEED_ATTRIBS, ssac) |
+			    FIELD_PREP(USB_SSP_SUBLINK_SPEED_IDS, ssic));
+
+	if (!port_cap->psi_count) {

for (i = 0; i < ssac + 1; i++)
	ssp_cap->mbSublinkSpeedAttr[i] = ssp_cap_default_ssa[i];  //mind endianness

quoted

+		int ret;
+
+		ret = xhci_fill_default_ssp_attr(xhci, ssp_cap);
+		if (ret)
+			return ret;
+
+		min_ssid = 4;
+		goto out;
+	}
+
+	offset = 0;
+	for (i = 0; i < port_cap->psi_count; i++) {

I need to take a better look at this sublinkSpeedAttr[] creation from custom PSIC table a bit later.

Thanks
-Mathias

Thanks for the review!

Thinh