xhci: mediatek: support MTK xHCI host controller

There some vendor quirks for MTK xhci host controller:
1. It defines some extra SW scheduling parameters for HW
  to minimize the scheduling effort for synchronous and
  interrupt endpoints. The parameters are put into reseved
  DWs of slot context and endpoint context.
2. Its IMODI unit for Interrupter Moderation register is
  8 times as much as that defined in xHCI spec.
3. Its TDS in  Normal TRB defines a number of packets that
  remains to be transferred for a TD after processing all
  Max packets in all previous TRBs.

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Tested-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 415 insertions, 0 deletions

diff --git a/drivers/usb/host/xhci-mtk-sch.c b/drivers/usb/host/xhci-mtk-sch.c
new file mode 100644
index 000000000000..c30de7c39f44
--- /dev/null
+++ b/drivers/usb/host/xhci-mtk-sch.c
@@ -0,0 +1,415 @@
+/*
+ * Copyright (c) 2015 MediaTek Inc.
+ * Author:
+ *  Zhigang.Wei <zhigang.wei@mediatek.com>
+ *  Chunfeng.Yun <chunfeng.yun@mediatek.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+#include "xhci.h"
+#include "xhci-mtk.h"
+
+#define SS_BW_BOUNDARY	51000
+/* table 5-5. High-speed Isoc Transaction Limits in usb_20 spec */
+#define HS_BW_BOUNDARY	6144
+/* usb2 spec section11.18.1: at most 188 FS bytes per microframe */
+#define FS_PAYLOAD_MAX 188
+
+/* mtk scheduler bitmasks */
+#define EP_BPKTS(p)	((p) & 0x3f)
+#define EP_BCSCOUNT(p)	(((p) & 0x7) << 8)
+#define EP_BBM(p)	((p) << 11)
+#define EP_BOFFSET(p)	((p) & 0x3fff)
+#define EP_BREPEAT(p)	(((p) & 0x7fff) << 16)
+
+static int is_fs_or_ls(enum usb_device_speed speed)
+{
+	return speed == USB_SPEED_FULL || speed == USB_SPEED_LOW;
+}
+
+/*
+* get the index of bandwidth domains array which @ep belongs to.
+*
+* the bandwidth domain array is saved to @sch_array of struct xhci_hcd_mtk,
+* each HS root port is treated as a single bandwidth domain,
+* but each SS root port is treated as two bandwidth domains, one for IN eps,
+* one for OUT eps.
+* @real_port value is defined as follow according to xHCI spec:
+* 1 for SSport0, ..., N+1 for SSportN, N+2 for HSport0, N+3 for HSport1, etc
+* so the bandwidth domain array is organized as follow for simplification:
+* SSport0-OUT, SSport0-IN, ..., SSportX-OUT, SSportX-IN, HSport0, ..., HSportY
+*/
+static int get_bw_index(struct xhci_hcd *xhci, struct usb_device *udev,
+	struct usb_host_endpoint *ep)
+{
+	struct xhci_virt_device *virt_dev;
+	int bw_index;
+
+	virt_dev = xhci->devs[udev->slot_id];
+
+	if (udev->speed == USB_SPEED_SUPER) {
+		if (usb_endpoint_dir_out(&ep->desc))
+			bw_index = (virt_dev->real_port - 1) * 2;
+		else
+			bw_index = (virt_dev->real_port - 1) * 2 + 1;
+	} else {
+		/* add one more for each SS port */
+		bw_index = virt_dev->real_port + xhci->num_usb3_ports - 1;
+	}
+
+	return bw_index;
+}
+
+static void setup_sch_info(struct usb_device *udev,
+		struct xhci_ep_ctx *ep_ctx, struct mu3h_sch_ep_info *sch_ep)
+{
+	u32 ep_type;
+	u32 ep_interval;
+	u32 max_packet_size;
+	u32 max_burst;
+	u32 mult;
+	u32 esit_pkts;
+
+	ep_type = CTX_TO_EP_TYPE(le32_to_cpu(ep_ctx->ep_info2));
+	ep_interval = CTX_TO_EP_INTERVAL(le32_to_cpu(ep_ctx->ep_info));
+	max_packet_size = MAX_PACKET_DECODED(le32_to_cpu(ep_ctx->ep_info2));
+	max_burst = CTX_TO_MAX_BURST(le32_to_cpu(ep_ctx->ep_info2));
+	mult = CTX_TO_EP_MULT(le32_to_cpu(ep_ctx->ep_info));
+
+	sch_ep->esit = 1 << ep_interval;
+	sch_ep->offset = 0;
+	sch_ep->burst_mode = 0;
+
+	if (udev->speed == USB_SPEED_HIGH) {
+		sch_ep->cs_count = 0;
+
+		/*
+		 * usb_20 spec section5.9
+		 * a single microframe is enough for HS synchromous endpoints
+		 * in a interval
+		 */
+		sch_ep->num_budget_microframes = 1;
+		sch_ep->repeat = 0;
+
+		/*
+		 * xHCI spec section6.2.3.4
+		 * @max_burst is the number of additional transactions
+		 * opportunities per microframe
+		 */
+		sch_ep->pkts = max_burst + 1;
+		sch_ep->bw_cost_per_microframe = max_packet_size * sch_ep->pkts;
+	} else if (udev->speed == USB_SPEED_SUPER) {
+		/* usb3_r1 spec section4.4.7 & 4.4.8 */
+		sch_ep->cs_count = 0;
+		esit_pkts = (mult + 1) * (max_burst + 1);
+		if (ep_type == INT_IN_EP || ep_type == INT_OUT_EP) {
+			sch_ep->pkts = esit_pkts;
+			sch_ep->num_budget_microframes = 1;
+			sch_ep->repeat = 0;
+		}
+
+		if (ep_type == ISOC_IN_EP || ep_type == ISOC_OUT_EP) {
+			if (esit_pkts <= sch_ep->esit)
+				sch_ep->pkts = 1;
+			else
+				sch_ep->pkts = roundup_pow_of_two(esit_pkts)
+					/ sch_ep->esit;
+
+			sch_ep->num_budget_microframes =
+				DIV_ROUND_UP(esit_pkts, sch_ep->pkts);
+
+			if (sch_ep->num_budget_microframes > 1)
+				sch_ep->repeat = 1;
+			else
+				sch_ep->repeat = 0;
+		}
+		sch_ep->bw_cost_per_microframe = max_packet_size * sch_ep->pkts;
+	} else if (is_fs_or_ls(udev->speed)) {
+
+		/*
+		 * usb_20 spec section11.18.4
+		 * assume worst cases
+		 */
+		sch_ep->repeat = 0;
+		sch_ep->pkts = 1; /* at most one packet for each microframe */
+		if (ep_type == INT_IN_EP || ep_type == INT_OUT_EP) {
+			sch_ep->cs_count = 3; /* at most need 3 CS*/
+			/* one for SS and one for budgeted transaction */
+			sch_ep->num_budget_microframes = sch_ep->cs_count + 2;
+			sch_ep->bw_cost_per_microframe = max_packet_size;
+		}
+		if (ep_type == ISOC_OUT_EP) {
+
+			/*
+			 * the best case FS budget assumes that 188 FS bytes
+			 * occur in each microframe
+			 */
+			sch_ep->num_budget_microframes = DIV_ROUND_UP(
+				max_packet_size, FS_PAYLOAD_MAX);
+			sch_ep->bw_cost_per_microframe = FS_PAYLOAD_MAX;
+			sch_ep->cs_count = sch_ep->num_budget_microframes;
+		}
+		if (ep_type == ISOC_IN_EP) {
+			/* at most need additional two CS. */
+			sch_ep->cs_count = DIV_ROUND_UP(
+				max_packet_size, FS_PAYLOAD_MAX) + 2;
+			sch_ep->num_budget_microframes = sch_ep->cs_count + 2;
+			sch_ep->bw_cost_per_microframe = FS_PAYLOAD_MAX;
+		}
+	}
+}
+
+/* Get maximum bandwidth when we schedule at offset slot. */
+static u32 get_max_bw(struct mu3h_sch_bw_info *sch_bw,
+	struct mu3h_sch_ep_info *sch_ep, u32 offset)
+{
+	u32 num_esit;
+	u32 max_bw = 0;
+	int i;
+	int j;
+
+	num_esit = XHCI_MTK_MAX_ESIT / sch_ep->esit;
+	for (i = 0; i < num_esit; i++) {
+		u32 base = offset + i * sch_ep->esit;
+
+		for (j = 0; j < sch_ep->num_budget_microframes; j++) {
+			if (sch_bw->bus_bw[base + j] > max_bw)
+				max_bw = sch_bw->bus_bw[base + j];
+		}
+	}
+	return max_bw;
+}
+
+static void update_bus_bw(struct mu3h_sch_bw_info *sch_bw,
+	struct mu3h_sch_ep_info *sch_ep, int bw_cost)
+{
+	u32 num_esit;
+	u32 base;
+	int i;
+	int j;
+
+	num_esit = XHCI_MTK_MAX_ESIT / sch_ep->esit;
+	for (i = 0; i < num_esit; i++) {
+		base = sch_ep->offset + i * sch_ep->esit;
+		for (j = 0; j < sch_ep->num_budget_microframes; j++)
+			sch_bw->bus_bw[base + j] += bw_cost;
+	}
+}
+
+static int check_sch_bw(struct usb_device *udev,
+	struct mu3h_sch_bw_info *sch_bw, struct mu3h_sch_ep_info *sch_ep)
+{
+	u32 offset;
+	u32 esit;
+	u32 num_budget_microframes;
+	u32 min_bw;
+	u32 min_index;
+	u32 worst_bw;
+	u32 bw_boundary;
+
+	if (sch_ep->esit > XHCI_MTK_MAX_ESIT)
+		sch_ep->esit = XHCI_MTK_MAX_ESIT;
+
+	esit = sch_ep->esit;
+	num_budget_microframes = sch_ep->num_budget_microframes;
+
+	/*
+	 * Search through all possible schedule microframes.
+	 * and find a microframe where its worst bandwidth is minimum.
+	 */
+	min_bw = ~0;
+	min_index = 0;
+	for (offset = 0; offset < esit; offset++) {
+		if ((offset + num_budget_microframes) > sch_ep->esit)
+			break;
+
+		/*
+		 * usb_20 spec section11.18:
+		 * must never schedule Start-Split in Y6
+		 */
+		if (is_fs_or_ls(udev->speed) && (offset % 8 == 6))
+			continue;
+
+		worst_bw = get_max_bw(sch_bw, sch_ep, offset);
+		if (min_bw > worst_bw) {
+			min_bw = worst_bw;
+			min_index = offset;
+		}
+		if (min_bw == 0)
+			break;
+	}
+	sch_ep->offset = min_index;
+
+	bw_boundary = (udev->speed == USB_SPEED_SUPER)
+				? SS_BW_BOUNDARY : HS_BW_BOUNDARY;
+
+	/* check bandwidth */
+	if (min_bw + sch_ep->bw_cost_per_microframe > bw_boundary)
+		return -ERANGE;
+
+	/* update bus bandwidth info */
+	update_bus_bw(sch_bw, sch_ep, sch_ep->bw_cost_per_microframe);
+
+	return 0;
+}
+
+static bool need_bw_sch(struct usb_host_endpoint *ep,
+	enum usb_device_speed speed, int has_tt)
+{
+	/* only for periodic endpoints */
+	if (usb_endpoint_xfer_control(&ep->desc)
+		|| usb_endpoint_xfer_bulk(&ep->desc))
+		return false;
+
+	/*
+	 * for LS & FS periodic endpoints which its device don't attach
+	 * to TT are also ignored, root-hub will schedule them directly
+	 */
+	if (is_fs_or_ls(speed) && !has_tt)
+		return false;
+
+	return true;
+}
+
+int xhci_mtk_sch_init(struct xhci_hcd_mtk *mtk)
+{
+	struct mu3h_sch_bw_info *sch_array;
+	int num_usb_bus;
+	int i;
+
+	/* ss IN and OUT are separated */
+	num_usb_bus = mtk->num_u3_ports * 2 + mtk->num_u2_ports;
+
+	sch_array = kcalloc(num_usb_bus, sizeof(*sch_array), GFP_KERNEL);
+	if (sch_array == NULL)
+		return -ENOMEM;
+
+	for (i = 0; i < num_usb_bus; i++)
+		INIT_LIST_HEAD(&sch_array[i].bw_ep_list);
+
+	mtk->sch_array = sch_array;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(xhci_mtk_sch_init);
+
+void xhci_mtk_sch_exit(struct xhci_hcd_mtk *mtk)
+{
+	kfree(mtk->sch_array);
+}
+EXPORT_SYMBOL_GPL(xhci_mtk_sch_exit);
+
+int xhci_mtk_add_ep_quirk(struct usb_hcd *hcd, struct usb_device *udev,
+		struct usb_host_endpoint *ep)
+{
+	struct xhci_hcd_mtk *mtk = hcd_to_mtk(hcd);
+	struct xhci_hcd *xhci;
+	struct xhci_ep_ctx *ep_ctx;
+	struct xhci_slot_ctx *slot_ctx;
+	struct xhci_virt_device *virt_dev;
+	struct mu3h_sch_bw_info *sch_bw;
+	struct mu3h_sch_ep_info *sch_ep;
+	struct mu3h_sch_bw_info *sch_array;
+	unsigned int ep_index;
+	int bw_index;
+	int ret = 0;
+
+	xhci = hcd_to_xhci(hcd);
+	virt_dev = xhci->devs[udev->slot_id];
+	ep_index = xhci_get_endpoint_index(&ep->desc);
+	slot_ctx = xhci_get_slot_ctx(xhci, virt_dev->in_ctx);
+	ep_ctx = xhci_get_ep_ctx(xhci, virt_dev->in_ctx, ep_index);
+	sch_array = mtk->sch_array;
+
+	xhci_dbg(xhci, "%s() type:%d, speed:%d, mpkt:%d, dir:%d, ep:%p\n",
+		__func__, usb_endpoint_type(&ep->desc), udev->speed,
+		GET_MAX_PACKET(usb_endpoint_maxp(&ep->desc)),
+		usb_endpoint_dir_in(&ep->desc), ep);
+
+	if (!need_bw_sch(ep, udev->speed, slot_ctx->tt_info & TT_SLOT))
+		return 0;
+
+	bw_index = get_bw_index(xhci, udev, ep);
+	sch_bw = &sch_array[bw_index];
+
+	sch_ep = kzalloc(sizeof(struct mu3h_sch_ep_info), GFP_NOIO);
+	if (!sch_ep)
+		return -ENOMEM;
+
+	setup_sch_info(udev, ep_ctx, sch_ep);
+
+	ret = check_sch_bw(udev, sch_bw, sch_ep);
+	if (ret) {
+		xhci_err(xhci, "Not enough bandwidth!\n");
+		kfree(sch_ep);
+		return -ENOSPC;
+	}
+
+	list_add_tail(&sch_ep->endpoint, &sch_bw->bw_ep_list);
+	sch_ep->ep = ep;
+
+	ep_ctx->reserved[0] |= cpu_to_le32(EP_BPKTS(sch_ep->pkts)
+		| EP_BCSCOUNT(sch_ep->cs_count) | EP_BBM(sch_ep->burst_mode));
+	ep_ctx->reserved[1] |= cpu_to_le32(EP_BOFFSET(sch_ep->offset)
+		| EP_BREPEAT(sch_ep->repeat));
+
+	xhci_dbg(xhci, " PKTS:%x, CSCOUNT:%x, BM:%x, OFFSET:%x, REPEAT:%x\n",
+			sch_ep->pkts, sch_ep->cs_count, sch_ep->burst_mode,
+			sch_ep->offset, sch_ep->repeat);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(xhci_mtk_add_ep_quirk);
+
+void xhci_mtk_drop_ep_quirk(struct usb_hcd *hcd, struct usb_device *udev,
+		struct usb_host_endpoint *ep)
+{
+	struct xhci_hcd_mtk *mtk = hcd_to_mtk(hcd);
+	struct xhci_hcd *xhci;
+	struct xhci_slot_ctx *slot_ctx;
+	struct xhci_virt_device *virt_dev;
+	struct mu3h_sch_bw_info *sch_array;
+	struct mu3h_sch_bw_info *sch_bw;
+	struct mu3h_sch_ep_info *sch_ep;
+	int bw_index;
+
+	xhci = hcd_to_xhci(hcd);
+	virt_dev = xhci->devs[udev->slot_id];
+	slot_ctx = xhci_get_slot_ctx(xhci, virt_dev->in_ctx);
+	sch_array = mtk->sch_array;
+
+	xhci_dbg(xhci, "%s() type:%d, speed:%d, mpks:%d, dir:%d, ep:%p\n",
+		__func__, usb_endpoint_type(&ep->desc), udev->speed,
+		GET_MAX_PACKET(usb_endpoint_maxp(&ep->desc)),
+		usb_endpoint_dir_in(&ep->desc), ep);
+
+	if (!need_bw_sch(ep, udev->speed, slot_ctx->tt_info & TT_SLOT))
+		return;
+
+	bw_index = get_bw_index(xhci, udev, ep);
+	sch_bw = &sch_array[bw_index];
+
+	list_for_each_entry(sch_ep, &sch_bw->bw_ep_list, endpoint) {
+		if (sch_ep->ep == ep) {
+			update_bus_bw(sch_bw, sch_ep,
+				-sch_ep->bw_cost_per_microframe);
+			list_del(&sch_ep->endpoint);
+			kfree(sch_ep);
+			break;
+		}
+	}
+}
+EXPORT_SYMBOL_GPL(xhci_mtk_drop_ep_quirk);