[RFC PATCH v2 15/22] usb: dwc3: Add DT parameter to specify maximum number of interrupters

[Wesley Cheng]

Allow for the DWC3 host driver to pass along a 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.

Signed-off-by: Wesley Cheng <quic_wcheng at quicinc.com>
---
 drivers/usb/dwc3/core.c | 12 ++++++++++++
 drivers/usb/dwc3/core.h |  2 ++
 drivers/usb/dwc3/host.c |  5 ++++-
 3 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 476b63618511..67d6f0ae81d2 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -1446,6 +1446,7 @@ 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;
+	u8			num_hc_interrupters;
 	const char		*usb_psy_name;
 	int			ret;
 
@@ -1468,6 +1469,9 @@ 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);
@@ -1511,6 +1515,12 @@ 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_u8(dev, "snps,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)
@@ -1589,6 +1599,8 @@ 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 8f9959ba9fd4..09037299da53 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -1050,6 +1050,7 @@ 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
@@ -1275,6 +1276,7 @@ struct dwc3 {
 	u8			tx_max_burst_prd;
 	u8			tx_fifo_resize_max_num;
 	u8			clear_stall_protocol;
+	u8			num_hc_interrupters;
 
 	const char		*hsphy_interface;
 
diff --git a/drivers/usb/dwc3/host.c b/drivers/usb/dwc3/host.c
index f6f13e7f1ba1..52a284fdd704 100644
--- a/drivers/usb/dwc3/host.c
+++ b/drivers/usb/dwc3/host.c
@@ -66,7 +66,7 @@ static int dwc3_host_get_irq(struct dwc3 *dwc)
 
 int dwc3_host_init(struct dwc3 *dwc)
 {
-	struct property_entry	props[4];
+	struct property_entry	props[5];
 	struct platform_device	*xhci;
 	int			ret, irq;
 	int			prop_idx = 0;
@@ -112,6 +112,9 @@ 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_U8("num-hc-interrupters",
+								dwc->num_hc_interrupters);
+
 	if (prop_idx) {
 		ret = device_create_managed_software_node(&xhci->dev, props, NULL);
 		if (ret) {