If TXFIFO resizing is enabled, then based on if endpoint bursting is
required or not, a larger amount of FIFO space is benefical.  Sometimes
a particular interface can take all the available FIFO space, leading
to other interfaces not functioning properly.  This callback ensures that
the minimum fifo requirements, a single fifo per endpoint, can be met,
otherwise the configuration binding will fail.  This will be based on the
maximum number of eps existing in all configurations.

Signed-off-by: Wesley Cheng <wch...@codeaurora.org>
---
 drivers/usb/dwc3/core.h   |  1 +
 drivers/usb/dwc3/gadget.c | 35 +++++++++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+)

diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index e85c1ec70cc3..0559b0a82c4d 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -1249,6 +1249,7 @@ struct dwc3 {
        u16                     imod_interval;
        int                     last_fifo_depth;
        int                     num_ep_resized;
+       int                     max_cfg_eps;
 };
 
 #define INCRX_BURST_MODE 0
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 53e5220f9893..e8f7ea560920 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -2411,6 +2411,7 @@ static int dwc3_gadget_stop(struct usb_gadget *g)
 
 out:
        dwc->gadget_driver      = NULL;
+       dwc->max_cfg_eps = 0;
        spin_unlock_irqrestore(&dwc->lock, flags);
 
        free_irq(dwc->irq_gadget, dwc->ev_buf);
@@ -2518,6 +2519,39 @@ static void dwc3_gadget_set_speed(struct usb_gadget *g,
        spin_unlock_irqrestore(&dwc->lock, flags);
 }
 
+static int dwc3_gadget_check_config(struct usb_gadget *g, unsigned long ep_map)
+{
+       struct dwc3 *dwc = gadget_to_dwc(g);
+       unsigned long in_ep_map;
+       int fifo_size = 0;
+       int ram1_depth;
+       int ep_num;
+
+       if (!dwc->needs_fifo_resize)
+               return 0;
+
+       /* Only interested in the IN endpoints */
+       in_ep_map = ep_map >> 16;
+       ep_num = hweight_long(in_ep_map);
+
+       if (ep_num <= dwc->max_cfg_eps)
+               return 0;
+
+       /* Update the max number of eps in the composition */
+       dwc->max_cfg_eps = ep_num;
+
+       fifo_size = dwc3_gadget_calc_tx_fifo_size(dwc, dwc->max_cfg_eps);
+       /* Based on the equation, increment by one for every ep */
+       fifo_size += dwc->max_cfg_eps;
+
+       /* Check if we can fit a single fifo per endpoint */
+       ram1_depth = DWC3_RAM1_DEPTH(dwc->hwparams.hwparams7);
+       if (fifo_size > ram1_depth)
+               return -ENOMEM;
+
+       return 0;
+}
+
 static const struct usb_gadget_ops dwc3_gadget_ops = {
        .get_frame              = dwc3_gadget_get_frame,
        .wakeup                 = dwc3_gadget_wakeup,
@@ -2527,6 +2561,7 @@ static const struct usb_gadget_ops dwc3_gadget_ops = {
        .udc_stop               = dwc3_gadget_stop,
        .udc_set_speed          = dwc3_gadget_set_speed,
        .get_config_params      = dwc3_gadget_config_params,
+       .check_config           = dwc3_gadget_check_config,
 };
 
 /* -------------------------------------------------------------------------- 
*/
-- 
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a Linux Foundation Collaborative Project

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