[PATCH v20 17/41] usb: dwc3: Specify maximum number of XHCI interrupters

[Wesley Cheng <quic_wcheng@xxxxxxxxxxx>]

Allow for the DWC3 host driver to pass along XHCI property that defines
how many interrupters to allocate.  This is in relation for the number of
event rings that can be potentially used by other processors within the
system.

Acked-by: Thinh Nguyen <Thinh.Nguyen@xxxxxxxxxxxx>
Signed-off-by: Wesley Cheng <quic_wcheng@xxxxxxxxxxx>
---
 drivers/usb/dwc3/core.c | 12 ++++++++++++
 drivers/usb/dwc3/core.h |  2 ++
 drivers/usb/dwc3/host.c |  3 +++
 3 files changed, 17 insertions(+)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 637194af506f..5e31946a1831 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -1488,6 +1488,7 @@ static void dwc3_get_properties(struct dwc3 *dwc)
 	u8			tx_thr_num_pkt_prd = 0;
 	u8			tx_max_burst_prd = 0;
 	u8			tx_fifo_resize_max_num;
+	u16			num_hc_interrupters;
 	const char		*usb_psy_name;
 	int			ret;
 
@@ -1510,6 +1511,9 @@ static void dwc3_get_properties(struct dwc3 *dwc)
 	 */
 	tx_fifo_resize_max_num = 6;
 
+	/* default to a single XHCI interrupter */
+	num_hc_interrupters = 1;
+
 	dwc->maximum_speed = usb_get_maximum_speed(dev);
 	dwc->max_ssp_rate = usb_get_maximum_ssp_rate(dev);
 	dwc->dr_mode = usb_get_dr_mode(dev);
@@ -1563,6 +1567,12 @@ static void dwc3_get_properties(struct dwc3 *dwc)
 				&tx_thr_num_pkt_prd);
 	device_property_read_u8(dev, "snps,tx-max-burst-prd",
 				&tx_max_burst_prd);
+	device_property_read_u16(dev, "num-hc-interrupters",
+				&num_hc_interrupters);
+	/* DWC3 core allowed to have a max of 8 interrupters */
+	if (num_hc_interrupters > 8)
+		num_hc_interrupters = 8;
+
 	dwc->do_fifo_resize = device_property_read_bool(dev,
 							"tx-fifo-resize");
 	if (dwc->do_fifo_resize)
@@ -1651,6 +1661,8 @@ static void dwc3_get_properties(struct dwc3 *dwc)
 	dwc->imod_interval = 0;
 
 	dwc->tx_fifo_resize_max_num = tx_fifo_resize_max_num;
+
+	dwc->num_hc_interrupters = num_hc_interrupters;
 }
 
 /* check whether the core supports IMOD */
diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index 7e80dd3d466b..57c2735925c4 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -1068,6 +1068,7 @@ struct dwc3_scratchpad_array {
  * @tx_max_burst_prd: max periodic ESS transmit burst size
  * @tx_fifo_resize_max_num: max number of fifos allocated during txfifo resize
  * @clear_stall_protocol: endpoint number that requires a delayed status phase
+ * @num_hc_interrupters: number of host controller interrupters
  * @hsphy_interface: "utmi" or "ulpi"
  * @connected: true when we're connected to a host, false otherwise
  * @softconnect: true when gadget connect is called, false when disconnect runs
@@ -1306,6 +1307,7 @@ struct dwc3 {
 	u8			tx_max_burst_prd;
 	u8			tx_fifo_resize_max_num;
 	u8			clear_stall_protocol;
+	u16			num_hc_interrupters;
 
 	const char		*hsphy_interface;
 
diff --git a/drivers/usb/dwc3/host.c b/drivers/usb/dwc3/host.c
index 0204787df81d..f774b843aabb 100644
--- a/drivers/usb/dwc3/host.c
+++ b/drivers/usb/dwc3/host.c
@@ -159,6 +159,9 @@ int dwc3_host_init(struct dwc3 *dwc)
 	if (DWC3_VER_IS_WITHIN(DWC3, ANY, 300A))
 		props[prop_idx++] = PROPERTY_ENTRY_BOOL("quirk-broken-port-ped");
 
+	props[prop_idx++] = PROPERTY_ENTRY_U16("num-hc-interrupters",
+						dwc->num_hc_interrupters);
+
 	if (prop_idx) {
 		ret = device_create_managed_software_node(&xhci->dev, props, NULL);
 		if (ret) {