* Re: [PATCH 2/2] [media] dvb-usb-firmware: don't do DMA on stack
2017-02-05 14:58 ` [PATCH 2/2] [media] dvb-usb-firmware: don't do DMA on stack Stefan Brüns
@ 2017-02-08 13:57 ` Mauro Carvalho Chehab
0 siblings, 0 replies; 2+ messages in thread
From: Mauro Carvalho Chehab @ 2017-02-08 13:57 UTC (permalink / raw)
To: Stefan Brüns
Cc: linux-media, linux-kernel, Mauro Carvalho Chehab, Michael Krufky
Hi Stefan,
Em Sun, 5 Feb 2017 15:58:00 +0100
Stefan Brüns <stefan.bruens@rwth-aachen.de> escreveu:
The first patch in this series looked ok. Applied, thanks!
> The USB control messages require DMA to work. We cannot pass
> a stack-allocated buffer, as it is not warranted that the
> stack would be into a DMA enabled area.
I applied a similar patch to this one sometime ago at the linux media
tree:
https://git.linuxtv.org/media_tree.git/
Could you please check if the issues you're noticing were already
fixed, and, if not, send me a patch rebased against it?
Thanks!
Mauro
>
> Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de>
> ---
> drivers/media/usb/dvb-usb/dvb-usb-firmware.c | 30 ++++++++++++++++------------
> 1 file changed, 17 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/media/usb/dvb-usb/dvb-usb-firmware.c b/drivers/media/usb/dvb-usb/dvb-usb-firmware.c
> index dd048a7c461c..189b6725edd0 100644
> --- a/drivers/media/usb/dvb-usb/dvb-usb-firmware.c
> +++ b/drivers/media/usb/dvb-usb/dvb-usb-firmware.c
> @@ -35,41 +35,45 @@ static int usb_cypress_writemem(struct usb_device *udev,u16 addr,u8 *data, u8 le
>
> int usb_cypress_load_firmware(struct usb_device *udev, const struct firmware *fw, int type)
> {
> - struct hexline hx;
> - u8 reset;
> - int ret,pos=0;
> + u8 *buf = kmalloc(sizeof(struct hexline), GFP_KERNEL);
> + struct hexline *hx = (struct hexline *)buf;
> + int ret, pos = 0;
> + u16 cpu_cs_register = cypress[type].cpu_cs_register;
>
> /* stop the CPU */
> - reset = 1;
> - if ((ret = usb_cypress_writemem(udev,cypress[type].cpu_cs_register,&reset,1)) != 1)
> + buf[0] = 1;
> + if (usb_cypress_writemem(udev, cpu_cs_register, buf, 1) != 1)
> err("could not stop the USB controller CPU.");
>
> - while ((ret = dvb_usb_get_hexline(fw,&hx,&pos)) > 0) {
> - deb_fw("writing to address 0x%04x (buffer: 0x%02x %02x)\n",hx.addr,hx.len,hx.chk);
> - ret = usb_cypress_writemem(udev,hx.addr,hx.data,hx.len);
> + while ((ret = dvb_usb_get_hexline(fw, hx, &pos)) > 0) {
> + deb_fw("writing to address 0x%04x (buffer: 0x%02x %02x)\n",
> + hx->addr, hx->len, hx->chk);
> + ret = usb_cypress_writemem(udev, hx->addr, hx->data, hx->len);
>
> - if (ret != hx.len) {
> + if (ret != hx->len) {
> err("error while transferring firmware "
> "(transferred size: %d, block size: %d)",
> - ret,hx.len);
> + ret, hx->len);
> ret = -EINVAL;
> break;
> }
> }
> if (ret < 0) {
> - err("firmware download failed at %d with %d",pos,ret);
> + err("firmware download failed at %d with %d", pos, ret);
> + kfree(buf);
> return ret;
> }
>
> if (ret == 0) {
> /* restart the CPU */
> - reset = 0;
> - if (ret || usb_cypress_writemem(udev,cypress[type].cpu_cs_register,&reset,1) != 1) {
> + buf[0] = 0;
> + if (usb_cypress_writemem(udev, cpu_cs_register, buf, 1) != 1) {
> err("could not restart the USB controller CPU.");
> ret = -EINVAL;
> }
> } else
> ret = -EIO;
> + kfree(buf);
>
> return ret;
> }
Thanks,
Mauro
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