[media] ivtv: prepare ivtv for adding const to s_register

The ivtv_itvc function receives a pointer to v4l2_dbg_register. When we
add const to that pointer in the s_register case we will run into a problem
here since this common function would discard const in that case. So
change this function so it receives the address and a pointer to a value.
In addition we now set the size field in the g_register function which is
where it belongs.
This will simplify the next patch where const will be added to s_register.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/pci/ivtv/ivtv-ioctl.c

@@ -711,28 +711,26 @@ static int ivtv_g_chip_ident(struct file *file, void *fh, struct v4l2_dbg_chip_i
 }
 
 #ifdef CONFIG_VIDEO_ADV_DEBUG
-static int ivtv_itvc(struct ivtv *itv, unsigned int cmd, void *arg)
+static int ivtv_itvc(struct ivtv *itv, bool get, u64 reg, u64 *val)
 {
-	struct v4l2_dbg_register *regs = arg;
 	volatile u8 __iomem *reg_start;
 
 	if (!capable(CAP_SYS_ADMIN))
 		return -EPERM;
-	if (regs->reg >= IVTV_REG_OFFSET && regs->reg < IVTV_REG_OFFSET + IVTV_REG_SIZE)
+	if (reg >= IVTV_REG_OFFSET && reg < IVTV_REG_OFFSET + IVTV_REG_SIZE)
 		reg_start = itv->reg_mem - IVTV_REG_OFFSET;
-	else if (itv->has_cx23415 && regs->reg >= IVTV_DECODER_OFFSET &&
-			regs->reg < IVTV_DECODER_OFFSET + IVTV_DECODER_SIZE)
+	else if (itv->has_cx23415 && reg >= IVTV_DECODER_OFFSET &&
+			reg < IVTV_DECODER_OFFSET + IVTV_DECODER_SIZE)
 		reg_start = itv->dec_mem - IVTV_DECODER_OFFSET;
-	else if (regs->reg < IVTV_ENCODER_SIZE)
+	else if (reg < IVTV_ENCODER_SIZE)
 		reg_start = itv->enc_mem;
 	else
 		return -EINVAL;
 
-	regs->size = 4;
-	if (cmd == VIDIOC_DBG_G_REGISTER)
-		regs->val = readl(regs->reg + reg_start);
+	if (get)
+		*val = readl(reg + reg_start);
 	else
-		writel(regs->val, regs->reg + reg_start);
+		writel(*val, reg + reg_start);
 	return 0;
 }
 
@@ -740,8 +738,10 @@ static int ivtv_g_register(struct file *file, void *fh, struct v4l2_dbg_register
 {
 	struct ivtv *itv = fh2id(fh)->itv;
 
-	if (v4l2_chip_match_host(&reg->match))
-		return ivtv_itvc(itv, VIDIOC_DBG_G_REGISTER, reg);
+	if (v4l2_chip_match_host(&reg->match)) {
+		reg->size = 4;
+		return ivtv_itvc(itv, true, reg->reg, &reg->val);
+	}
 	/* TODO: subdev errors should not be ignored, this should become a
 	   subdev helper function. */
 	ivtv_call_all(itv, core, g_register, reg);
@@ -753,7 +753,7 @@ static int ivtv_s_register(struct file *file, void *fh, struct v4l2_dbg_register
 	struct ivtv *itv = fh2id(fh)->itv;
 
 	if (v4l2_chip_match_host(&reg->match))
-		return ivtv_itvc(itv, VIDIOC_DBG_S_REGISTER, reg);
+		return ivtv_itvc(itv, false, reg->reg, &reg->val);
 	/* TODO: subdev errors should not be ignored, this should become a
 	   subdev helper function. */
 	ivtv_call_all(itv, core, s_register, reg);