usb: xhci: Initialize scratchpad buffer array and scratchpad buffers

The scratchpad buffer array is used to define the locations of
statically allocated memory pages that are available for the
private use of the xHC. The xHCI spec explicitly mentions that
system software shall allocate the scratchpad buffers before
placing the xHC in to Run mode (Run/Stop (R/S) = ‘1’), however
U-Boot is missing this part.

This causes xHC on Intel platform does not respond the very first
'enable slot' command that is given to xHC and the 'enable slot'
command completion event TRB is never generated and xHC seems to
hang forever.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Stefan Roese <sr@denx.de>
Tested-by: Stefan Roese <sr@denx.de>

1 files changed, 87 insertions, 0 deletions

diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index 62db51d0185..12e277a26d9 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -96,6 +96,25 @@ static void xhci_ring_free(struct xhci_ring *ring)
 }
 
 /**
+ * Free the scratchpad buffer array and scratchpad buffers
+ *
+ * @ctrl	host controller data structure
+ * @return	none
+ */
+static void xhci_scratchpad_free(struct xhci_ctrl *ctrl)
+{
+	if (!ctrl->scratchpad)
+		return;
+
+	ctrl->dcbaa->dev_context_ptrs[0] = 0;
+
+	free((void *)(uintptr_t)ctrl->scratchpad->sp_array[0]);
+	free(ctrl->scratchpad->sp_array);
+	free(ctrl->scratchpad);
+	ctrl->scratchpad = NULL;
+}
+
+/**
  * frees the "xhci_container_ctx" pointer passed
  *
  * @param ptr	pointer to "xhci_container_ctx" to be freed
@@ -155,6 +174,7 @@ void xhci_cleanup(struct xhci_ctrl *ctrl)
 {
 	xhci_ring_free(ctrl->event_ring);
 	xhci_ring_free(ctrl->cmd_ring);
+	xhci_scratchpad_free(ctrl);
 	xhci_free_virt_devices(ctrl);
 	free(ctrl->erst.entries);
 	free(ctrl->dcbaa);
@@ -320,6 +340,70 @@ struct xhci_ring *xhci_ring_alloc(unsigned int num_segs, bool link_trbs)
 }
 
 /**
+ * Set up the scratchpad buffer array and scratchpad buffers
+ *
+ * @ctrl	host controller data structure
+ * @return	-ENOMEM if buffer allocation fails, 0 on success
+ */
+static int xhci_scratchpad_alloc(struct xhci_ctrl *ctrl)
+{
+	struct xhci_hccr *hccr = ctrl->hccr;
+	struct xhci_hcor *hcor = ctrl->hcor;
+	struct xhci_scratchpad *scratchpad;
+	int num_sp;
+	uint32_t page_size;
+	void *buf;
+	int i;
+
+	num_sp = HCS_MAX_SCRATCHPAD(xhci_readl(&hccr->cr_hcsparams2));
+	if (!num_sp)
+		return 0;
+
+	scratchpad = malloc(sizeof(*scratchpad));
+	if (!scratchpad)
+		goto fail_sp;
+	ctrl->scratchpad = scratchpad;
+
+	scratchpad->sp_array = xhci_malloc(num_sp * sizeof(u64));
+	if (!scratchpad->sp_array)
+		goto fail_sp2;
+	ctrl->dcbaa->dev_context_ptrs[0] =
+		cpu_to_le64((uintptr_t)scratchpad->sp_array);
+
+	page_size = xhci_readl(&hcor->or_pagesize) & 0xffff;
+	for (i = 0; i < 16; i++) {
+		if ((0x1 & page_size) != 0)
+			break;
+		page_size = page_size >> 1;
+	}
+	BUG_ON(i == 16);
+
+	page_size = 1 << (i + 12);
+	buf = memalign(page_size, num_sp * page_size);
+	if (!buf)
+		goto fail_sp3;
+	memset(buf, '\0', num_sp * page_size);
+	xhci_flush_cache((uintptr_t)buf, num_sp * page_size);
+
+	for (i = 0; i < num_sp; i++) {
+		uintptr_t ptr = (uintptr_t)buf + i * page_size;
+		scratchpad->sp_array[i] = cpu_to_le64(ptr);
+	}
+
+	return 0;
+
+fail_sp3:
+	free(scratchpad->sp_array);
+
+fail_sp2:
+	free(scratchpad);
+	ctrl->scratchpad = NULL;
+
+fail_sp:
+	return -ENOMEM;
+}
+
+/**
  * Allocates the Container context
  *
  * @param ctrl	Host controller data structure
@@ -499,6 +583,9 @@ int xhci_mem_init(struct xhci_ctrl *ctrl, struct xhci_hccr *hccr,
 
 	xhci_writeq(&ctrl->ir_set->erst_base, val_64);
 
+	/* set up the scratchpad buffer array and scratchpad buffers */
+	xhci_scratchpad_alloc(ctrl);
+
 	/* initializing the virtual devices to NULL */
 	for (i = 0; i < MAX_HC_SLOTS; ++i)
 		ctrl->devs[i] = NULL;