[PATCH v2] dwc2: gadget: Fix ISOC IN DDMA PID bitfield value calculation

[Minas Harutyunyan]

PID bitfield in descriptor should be set based on particular request
length, not based on EP's mc value. PID value can't be set to 0 even
request length is 0.

If request length is 0 then SP bit should be set along PID.

Signed-off-by: Minas Harutyunyan <hmi...@synopsys.com>
---
 drivers/usb/dwc2/gadget.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c
index f0d9ccf1d665..20b04c00e626 100644
--- a/drivers/usb/dwc2/gadget.c
+++ b/drivers/usb/dwc2/gadget.c
@@ -812,6 +812,8 @@ static int dwc2_gadget_fill_isoc_desc(struct dwc2_hsotg_ep 
*hs_ep,
        u32 index;
        u32 maxsize = 0;
        u32 mask = 0;
+       u32 sp = 0;
+       u8 pid = 0;
 
        maxsize = dwc2_gadget_get_desc_params(hs_ep, &mask);
 
@@ -840,10 +842,15 @@ static int dwc2_gadget_fill_isoc_desc(struct 
dwc2_hsotg_ep *hs_ep,
                         ((len << DEV_DMA_NBYTES_SHIFT) & mask));
 
        if (hs_ep->dir_in) {
-               desc->status |= ((hs_ep->mc << DEV_DMA_ISOC_PID_SHIFT) &
-                                DEV_DMA_ISOC_PID_MASK) |
-                               ((len % hs_ep->ep.maxpacket) ?
-                                DEV_DMA_SHORT : 0) |
+               if (len) {
+                       pid = DIV_ROUND_UP(len, hs_ep->ep.maxpacket);
+                       sp = (len % hs_ep->ep.maxpacket) ? DEV_DMA_SHORT : 0;
+               } else {
+                       pid = 1;
+                       sp = DEV_DMA_SHORT;
+               }
+               desc->status |= ((pid << DEV_DMA_ISOC_PID_SHIFT) &
+                                DEV_DMA_ISOC_PID_MASK) | sp |
                                ((hs_ep->target_frame <<
                                  DEV_DMA_ISOC_FRNUM_SHIFT) &
                                 DEV_DMA_ISOC_FRNUM_MASK);
-- 
2.11.0

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