media: mediatek: vcodec: Coverity issues in encoder driver

CERT-C Characters and Strings:
check core id is in valid range:
dev->reg_base[dev->venc_pdata->core_id] evaluates to an address
that could be at negative offset of an array.

CERT-C Expression:
check buf is not NULL before used:
Dereferencing buf, which is known to be NULL.

Signed-off-by: Irui Wang <[e-mail]>
Signed-off-by: Hans Verkuil <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/media/platform/mediatek/vcodec/mtk_vcodec_enc.c

···
 		 * FIXME: This check is not needed as only active buffers
 		 * can be marked as done.
 		 */
-		if (buf->state == VB2_BUF_STATE_ACTIVE) {
+		if (buf && buf->state == VB2_BUF_STATE_ACTIVE) {
 			mtk_v4l2_debug(0, "[%d] id=%d, type=%d, %d -> VB2_BUF_STATE_QUEUED",
 					ctx->id, i, q->type,
 					(int)buf->state);

drivers/media/platform/mediatek/vcodec/mtk_vcodec_enc_drv.c

···
 	struct mtk_vcodec_ctx *ctx;
 	unsigned long flags;
 	void __iomem *addr;
+	int core_id;
 
 	spin_lock_irqsave(&dev->irqlock, flags);
 	ctx = dev->curr_ctx;
 	spin_unlock_irqrestore(&dev->irqlock, flags);
 
-	mtk_v4l2_debug(1, "id=%d coreid:%d", ctx->id, dev->venc_pdata->core_id);
-	addr = dev->reg_base[dev->venc_pdata->core_id] +
-				MTK_VENC_IRQ_ACK_OFFSET;
+	core_id = dev->venc_pdata->core_id;
+	if (core_id < 0 || core_id >= NUM_MAX_VCODEC_REG_BASE) {
+		mtk_v4l2_err("Invalid core id: %d, ctx id: %d",
+			     core_id, ctx->id);
+		return IRQ_HANDLED;
+	}
 
-	ctx->irq_status = readl(dev->reg_base[dev->venc_pdata->core_id] +
+	mtk_v4l2_debug(1, "id: %d, core id: %d", ctx->id, core_id);
+
+	addr = dev->reg_base[core_id] + MTK_VENC_IRQ_ACK_OFFSET;
+
+	ctx->irq_status = readl(dev->reg_base[core_id] +
 				(MTK_VENC_IRQ_STATUS_OFFSET));
 
 	clean_irq_status(ctx->irq_status, addr);