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authorMauro Carvalho Chehab <mchehab@redhat.com>2008-11-18 14:51:08 -0300
committerMauro Carvalho Chehab <mchehab@redhat.com>2008-11-20 17:19:31 -0200
commitc4a98793a63c423c9e1af51822325969e23c16d4 (patch)
tree9711b371b6eb6ba1ffa9a8201f3528308526cd00 /drivers/media
parent625ff1679456d8adb9af0c980394ea3954e727a8 (diff)
V4L/DVB (9646): em28xx: avoid allocating/dealocating memory on every control urb
Before this patch, every register setup on em28xx were dynamically allocating a temporary buffer for control URB's to be handled. To avoid this ping-pong, use, instead a pre-allocated buffer. Also, be sure that read control URB's also use the buffer, instead of relying on a stack buffer. Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'drivers/media')
-rw-r--r--drivers/media/video/em28xx/em28xx-core.c48
-rw-r--r--drivers/media/video/em28xx/em28xx.h5
2 files changed, 31 insertions, 22 deletions
diff --git a/drivers/media/video/em28xx/em28xx-core.c b/drivers/media/video/em28xx/em28xx-core.c
index 038da614a73..9551b8ab8c4 100644
--- a/drivers/media/video/em28xx/em28xx-core.c
+++ b/drivers/media/video/em28xx/em28xx-core.c
@@ -69,19 +69,29 @@ int em28xx_read_reg_req_len(struct em28xx *dev, u8 req, u16 reg,
int ret, byte;
if (dev->state & DEV_DISCONNECTED)
- return(-ENODEV);
+ return -ENODEV;
+
+ if (len > URB_MAX_CTRL_SIZE)
+ return -EINVAL;
em28xx_regdbg("req=%02x, reg=%02x ", req, reg);
ret = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0), req,
USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
- 0x0000, reg, buf, len, HZ);
+ 0x0000, reg, dev->urb_buf, len, HZ);
+ if (ret < 0) {
+ if (reg_debug)
+ printk(" failed!\n");
+ return ret;
+ }
+
+ if (len)
+ memcpy(buf, dev->urb_buf, len);
if (reg_debug) {
- printk(ret < 0 ? " failed!\n" : "%02x values: ", ret);
+ printk("%02x values: ", ret);
for (byte = 0; byte < len; byte++)
printk(" %02x", (unsigned char)buf[byte]);
-
printk("\n");
}
@@ -104,14 +114,16 @@ int em28xx_read_reg_req(struct em28xx *dev, u8 req, u16 reg)
ret = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0), req,
USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
- 0x0000, reg, &val, 1, HZ);
+ 0x0000, reg, dev->urb_buf, 1, HZ);
+ if (ret < 0) {
+ printk(" failed!\n");
+ return ret;
+ }
- if (reg_debug)
- printk(ret < 0 ? " failed!\n" :
- "%02x\n", (unsigned char) val);
+ val = dev->urb_buf[0];
- if (ret < 0)
- return ret;
+ if (reg_debug)
+ printk("%02x\n", (unsigned char) val);
return val;
}
@@ -130,19 +142,13 @@ int em28xx_write_regs_req(struct em28xx *dev, u8 req, u16 reg, char *buf,
{
int ret;
- /*usb_control_msg seems to expect a kmalloced buffer */
- unsigned char *bufs;
-
if (dev->state & DEV_DISCONNECTED)
return -ENODEV;
- if (len < 1)
+ if ((len < 1) || (len > URB_MAX_CTRL_SIZE))
return -EINVAL;
- bufs = kmalloc(len, GFP_KERNEL);
-
em28xx_regdbg("req=%02x reg=%02x:", req, reg);
-
if (reg_debug) {
int i;
for (i = 0; i < len; ++i)
@@ -150,16 +156,14 @@ int em28xx_write_regs_req(struct em28xx *dev, u8 req, u16 reg, char *buf,
printk("\n");
}
- if (!bufs)
- return -ENOMEM;
- memcpy(bufs, buf, len);
+ memcpy(dev->urb_buf, buf, len);
ret = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0), req,
USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
- 0x0000, reg, bufs, len, HZ);
+ 0x0000, reg, dev->urb_buf, len, HZ);
+
if (dev->wait_after_write)
msleep(dev->wait_after_write);
- kfree(bufs);
return ret;
}
diff --git a/drivers/media/video/em28xx/em28xx.h b/drivers/media/video/em28xx/em28xx.h
index 82781178e0a..1adf3d9d9bf 100644
--- a/drivers/media/video/em28xx/em28xx.h
+++ b/drivers/media/video/em28xx/em28xx.h
@@ -102,6 +102,9 @@
#define EM28XX_MIN_BUF 4
#define EM28XX_DEF_BUF 8
+/*Limits the max URB message size */
+#define URB_MAX_CTRL_SIZE 80
+
/* Params for validated field */
#define EM28XX_BOARD_NOT_VALIDATED 1
#define EM28XX_BOARD_VALIDATED 0
@@ -451,6 +454,8 @@ struct em28xx {
unsigned int *alt_max_pkt_size; /* array of wMaxPacketSize */
struct urb *urb[EM28XX_NUM_BUFS]; /* urb for isoc transfers */
char *transfer_buffer[EM28XX_NUM_BUFS]; /* transfer buffers for isoc transfer */
+ char urb_buf[URB_MAX_CTRL_SIZE]; /* urb control msg buffer */
+
/* helper funcs that call usb_control_msg */
int (*em28xx_write_regs) (struct em28xx *dev, u16 reg,
char *buf, int len);