RE: [PATCH 1/1] usb: cdns3: allocate TX FIFO size according to composite EP number

[Pawel Laszczak]

Hi Frank,

>
>Some devices have USB compositions which may require multiple endpoints.
>To get better performance, need bigger CDNS3_EP_BUF_SIZE.
>
>But bigger CDNS3_EP_BUF_SIZE may exceed total hardware FIFO size when
>multiple endpoints.
>
>By introducing the check_config() callback, calculate CDNS3_EP_BUF_SIZE.
>
>Move CDNS3_EP_BUF_SIZE into cnds3_device: ep_buf_size
>Combine CDNS3_EP_ISO_SS_BURST and CDNS3_EP_ISO_HS_MULT into
>ecnds3_device:ep_iso_burst
>
>Using a simple algorithm to calculate ep_buf_size.
>ep_buf_size = ep_iso_burst = (onchip_buffers - 2k) / (number of IN EP +
>1).
>
>Test at 8qxp:
>
>	Gadget			ep_buf_size
>
>	RNDIS:				5
>	RNDIS+ACM:			3
>	Mass Storage + NCM + ACM	2
>
>Previous CDNS3_EP_BUF_SIZE is 4, RNDIS + ACM will be failure because
>exceed FIFO memory.
>
>Signed-off-by: Frank Li <Frank.Li@xxxxxxx>
>---
> drivers/usb/cdns3/cdns3-gadget.c | 46 +++++++++++++++++++++++++++++---
> drivers/usb/cdns3/cdns3-gadget.h |  6 ++---
> 2 files changed, 45 insertions(+), 7 deletions(-)
>
>diff --git a/drivers/usb/cdns3/cdns3-gadget.c b/drivers/usb/cdns3/cdns3-gadget.c
>index 1f3b4a1422126..62ea1bd773386 100644
>--- a/drivers/usb/cdns3/cdns3-gadget.c
>+++ b/drivers/usb/cdns3/cdns3-gadget.c
>@@ -2050,7 +2050,7 @@ int cdns3_ep_config(struct cdns3_endpoint *priv_ep, bool enable)
> 	u8 mult = 0;
> 	int ret;
>
>-	buffering = CDNS3_EP_BUF_SIZE - 1;
>+	buffering = priv_dev->ep_buf_size - 1;
>
> 	cdns3_configure_dmult(priv_dev, priv_ep);
>
>@@ -2069,7 +2069,7 @@ int cdns3_ep_config(struct cdns3_endpoint *priv_ep, bool enable)
> 		break;
> 	default:
> 		ep_cfg = EP_CFG_EPTYPE(USB_ENDPOINT_XFER_ISOC);
>-		mult = CDNS3_EP_ISO_HS_MULT - 1;
>+		mult = priv_dev->ep_iso_burst - 1;
> 		buffering = mult + 1;
> 	}
>
>@@ -2085,14 +2085,14 @@ int cdns3_ep_config(struct cdns3_endpoint *priv_ep, bool enable)
> 		mult = 0;
> 		max_packet_size = 1024;
> 		if (priv_ep->type == USB_ENDPOINT_XFER_ISOC) {
>-			maxburst = CDNS3_EP_ISO_SS_BURST - 1;
>+			maxburst = priv_dev->ep_iso_burst - 1;
> 			buffering = (mult + 1) *
> 				    (maxburst + 1);
>
> 			if (priv_ep->interval > 1)
> 				buffering++;
> 		} else {
>-			maxburst = CDNS3_EP_BUF_SIZE - 1;
>+			maxburst = priv_dev->ep_buf_size - 1;
> 		}
> 		break;
> 	default:
>@@ -2970,6 +2970,43 @@ static int cdns3_gadget_udc_stop(struct usb_gadget *gadget)
> 	return 0;
> }
>
>+/**
>+ * cdns3_gadget_check_config - ensure cdns3 can support the USB configuration
>+ * @gadget: pointer to the USB gadget
>+ *
>+ * Used to record the maximum number of endpoints being used in a USB composite
>+ * device. (across all configurations)  This is to be used in the calculation
>+ * of the TXFIFO sizes when resizing internal memory for individual endpoints.
>+ * It will help ensured that the resizing logic reserves enough space for at
>+ * least one max packet.
>+ */
>+static int cdns3_gadget_check_config(struct usb_gadget *gadget)
>+{
>+	struct cdns3_device *priv_dev = gadget_to_cdns3_device(gadget);
>+	struct usb_ep *ep;
>+	int n_in = 0;
>+	int total;
>+
>+	list_for_each_entry(ep, &gadget->ep_list, ep_list) {
>+		if (ep->claimed && (ep->address & USB_DIR_IN))
>+			n_in++;
>+	}
>+
>+	priv_dev->ep_buf_size = 1;
>+	priv_dev->ep_iso_burst = 1;
>+
>+	/* 2KB are reserved for EP0, 1KB for out*/
>+	total = 2 + n_in + 1;
>+
>+	if (total > priv_dev->onchip_buffers)
>+		return -ENOMEM;
>+
>+	priv_dev->ep_buf_size = priv_dev->ep_iso_burst =
>+			(priv_dev->onchip_buffers - 2) / (n_in + 1);
>+

I think you should put here or in cdns3_ep_config  some 
Limitation for ep_buf_size and ep_iso_burst. 
What in case e.g. UVC (1 OUT + 1 IN)  when onchip_buffers is 52 ?
As I remember you have 18KB onchip memory, so in your case it will
work fine.

Description of  EP_CFG. BUFFERING:
Max number of buffered packets The maximum number of packets the device
can buffer in the on-chip memory for specified endpoint. Valid values are from 0
to 15 ....

Thanks and Regards
Pawel

>+	return 0;
>+}
>+
> static const struct usb_gadget_ops cdns3_gadget_ops = {
> 	.get_frame = cdns3_gadget_get_frame,
> 	.wakeup = cdns3_gadget_wakeup,
>@@ -2978,6 +3015,7 @@ static const struct usb_gadget_ops cdns3_gadget_ops = {
> 	.udc_start = cdns3_gadget_udc_start,
> 	.udc_stop = cdns3_gadget_udc_stop,
> 	.match_ep = cdns3_gadget_match_ep,
>+	.check_config = cdns3_gadget_check_config,
> };
>
> static void cdns3_free_all_eps(struct cdns3_device *priv_dev)
>diff --git a/drivers/usb/cdns3/cdns3-gadget.h b/drivers/usb/cdns3/cdns3-gadget.h
>index c5660f2c4293f..f333c34b93ffb 100644
>--- a/drivers/usb/cdns3/cdns3-gadget.h
>+++ b/drivers/usb/cdns3/cdns3-gadget.h
>@@ -1094,9 +1094,6 @@ struct cdns3_trb {
> #define CDNS3_ENDPOINTS_MAX_COUNT	32
> #define CDNS3_EP_ZLP_BUF_SIZE		1024
>
>-#define CDNS3_EP_BUF_SIZE		4	/* KB */
>-#define CDNS3_EP_ISO_HS_MULT		3
>-#define CDNS3_EP_ISO_SS_BURST		3
> #define CDNS3_MAX_NUM_DESCMISS_BUF	32
> #define CDNS3_DESCMIS_BUF_SIZE		2048	/* Bytes */
> #define CDNS3_WA2_NUM_BUFFERS		128
>@@ -1333,6 +1330,9 @@ struct cdns3_device {
> 	/*in KB */
> 	u16				onchip_buffers;
> 	u16				onchip_used_size;
>+
>+	u16				ep_buf_size;
>+	u16				ep_iso_burst;
> };
>
> void cdns3_set_register_bit(void __iomem *ptr, u32 mask);
>--
>2.35.1