diff options
Diffstat (limited to 'usb/usb-s3c-hsotg-avoid-overwriting-contents-of-perodic-in-fifo.patch')
| -rw-r--r-- | usb/usb-s3c-hsotg-avoid-overwriting-contents-of-perodic-in-fifo.patch | 51 |
1 files changed, 51 insertions, 0 deletions
diff --git a/usb/usb-s3c-hsotg-avoid-overwriting-contents-of-perodic-in-fifo.patch b/usb/usb-s3c-hsotg-avoid-overwriting-contents-of-perodic-in-fifo.patch new file mode 100644 index 00000000000000..699fd2f9f8df31 --- /dev/null +++ b/usb/usb-s3c-hsotg-avoid-overwriting-contents-of-perodic-in-fifo.patch @@ -0,0 +1,51 @@ +From ben@ben-laptop.fluff.org Thu Jul 22 16:49:05 2010 +From: Ben Dooks <ben-linux@fluff.org> +To: linux-samsung-soc@vger.kernel.org, linux-usb@vger.kernel.org +Cc: gregkh@suse.de, Ben Dooks <ben-linux@fluff.org> +Subject: USB: s3c-hsotg: Avoid overwriting contents of perodic in 'fifo' +Date: Mon, 19 Jul 2010 09:40:42 +0100 +Message-Id: <1279528850-28245-4-git-send-email-ben-linux@fluff.org> + +In shared fifo mode (used on older SoCs) the periodic in fifo beahves +much more like a packet buffer, discarding old data when writing new +data. Avoid this by ensuring that we do not load new transactions in +when there is data sitting already in the FIFO. + +Note, this may not be an observed bug, we are fixing the case that this +may happen. + +Signed-off-by: Ben Dooks <ben-linux@fluff.org> +Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> + +--- + drivers/usb/gadget/s3c-hsotg.c | 12 +++++++++++- + 1 file changed, 11 insertions(+), 1 deletion(-) + +--- a/drivers/usb/gadget/s3c-hsotg.c ++++ b/drivers/usb/gadget/s3c-hsotg.c +@@ -91,7 +91,9 @@ struct s3c_hsotg_req; + * For periodic IN endpoints, we have fifo_size and fifo_load to try + * and keep track of the amount of data in the periodic FIFO for each + * of these as we don't have a status register that tells us how much +- * is in each of them. ++ * is in each of them. (note, this may actually be useless information ++ * as in shared-fifo mode periodic in acts like a single-frame packet ++ * buffer than a fifo) + */ + struct s3c_hsotg_ep { + struct usb_ep ep; +@@ -474,6 +476,14 @@ static int s3c_hsotg_write_fifo(struct s + + size_left = S3C_DxEPTSIZ_XferSize_GET(epsize); + ++ /* if shared fifo, we cannot write anything until the ++ * previous data has been completely sent. ++ */ ++ if (hs_ep->fifo_load != 0) { ++ s3c_hsotg_en_gsint(hsotg, S3C_GINTSTS_PTxFEmp); ++ return -ENOSPC; ++ } ++ + dev_dbg(hsotg->dev, "%s: left=%d, load=%d, fifo=%d, size %d\n", + __func__, size_left, + hs_ep->size_loaded, hs_ep->fifo_load, hs_ep->fifo_size); |