> The "chunk >= 0" condition does not work because count is a u32.
> Also, really we shouldn't enter the loop when "chunk" is zero.
>
> Once that condition is fixed then there is no need for the "last"
> variable. I reversed the "if (chunk <= ep->chunk_max)" as well.
> The new loop is much simpler.
>
> Fixes: 055276c13205 ("usb: gadget: add Aspeed ast2600 udc driver")
> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> ---
> drivers/usb/gadget/udc/aspeed_udc.c | 24 +++++++++++-------------
> 1 file changed, 11 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/usb/gadget/udc/aspeed_udc.c
> b/drivers/usb/gadget/udc/aspeed_udc.c
> index 1fc15228ff15..77376ae04224 100644
> --- a/drivers/usb/gadget/udc/aspeed_udc.c
> +++ b/drivers/usb/gadget/udc/aspeed_udc.c
> @@ -476,8 +476,8 @@ static int ast_dma_descriptor_setup(struct ast_udc_ep
> *ep, u32 dma_buf, {
> struct ast_udc_dev *udc = ep->udc;
> struct device *dev = &udc->pdev->dev;
> - u32 offset, chunk;
> - int count, last;
> + int chunk, count;
> + u32 offset;
>
> if (!ep->descs) {
> dev_warn(dev, "%s: Empty DMA descs list failure\n", @@ -486,30
> +486,28 @@ static int ast_dma_descriptor_setup(struct ast_udc_ep *ep, u32
> dma_buf,
> }
>
> chunk = tx_len;
> - offset = count = last = 0;
> + offset = count = 0;
>
> EP_DBG(ep, "req @%p, %s:%d, %s:0x%x, %s:0x%x\n", req,
> "wptr", ep->descs_wptr, "dma_buf", dma_buf,
> "tx_len", tx_len);
>
> /* Create Descriptor Lists */
> - while (chunk >= 0 && !last && count < AST_UDC_DESCS_COUNT) {
> + while (chunk > 0 && count < AST_UDC_DESCS_COUNT) {
>
Simpler loop looks good to me. But short packet need to be considered also. (chunk == 0)
> ep->descs[ep->descs_wptr].des_0 = dma_buf + offset;
>
> - if (chunk <= ep->chunk_max) {
> - ep->descs[ep->descs_wptr].des_1 = chunk;
> - last = 1;
> - } else {
> + if (chunk > ep->chunk_max)
> ep->descs[ep->descs_wptr].des_1 = ep->chunk_max;
> - chunk -= ep->chunk_max;
> - }
> + else
> + ep->descs[ep->descs_wptr].des_1 = chunk;
> +
> + chunk -= ep->chunk_max;
>
> - EP_DBG(ep, "descs[%d]: 0x%x 0x%x, last:%d\n",
> + EP_DBG(ep, "descs[%d]: 0x%x 0x%x\n",
> ep->descs_wptr,
> ep->descs[ep->descs_wptr].des_0,
> - ep->descs[ep->descs_wptr].des_1,
> - last);
> + ep->descs[ep->descs_wptr].des_1);
>
> if (count == 0)
> req->saved_dma_wptr = ep->descs_wptr;
> --
> 2.35.1
