media: ti-vpe: cal: allocate pix proc dynamically

CAL has 4 pixel processing units but the units are not needed e.g. for
metadata. As we could be capturing 4 pixel streams and 4 metadata
streams, i.e. using 8 DMA contexts, we cannot assign a pixel processing
unit to every DMA context. Instead we need to reserve a pixel processing
unit only when needed.

Add functions to reserve and release a pix proc unit, and use them in
cal_ctx_prepare/unprepare. Note that for the time being we still always
reserve a pix proc unit.
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/platform/ti-vpe/cal.c

@@ -290,6 +290,37 @@ void cal_quickdump_regs(struct cal_dev *cal)
  * ------------------------------------------------------------------
  */
 
+#define CAL_MAX_PIX_PROC 4
+
+static int cal_reserve_pix_proc(struct cal_dev *cal)
+{
+	unsigned long ret;
+
+	spin_lock(&cal->v4l2_dev.lock);
+
+	ret = find_first_zero_bit(&cal->reserved_pix_proc_mask, CAL_MAX_PIX_PROC);
+
+	if (ret == CAL_MAX_PIX_PROC) {
+		spin_unlock(&cal->v4l2_dev.lock);
+		return -ENOSPC;
+	}
+
+	cal->reserved_pix_proc_mask |= BIT(ret);
+
+	spin_unlock(&cal->v4l2_dev.lock);
+
+	return ret;
+}
+
+static void cal_release_pix_proc(struct cal_dev *cal, unsigned int pix_proc_num)
+{
+	spin_lock(&cal->v4l2_dev.lock);
+
+	cal->reserved_pix_proc_mask &= ~BIT(pix_proc_num);
+
+	spin_unlock(&cal->v4l2_dev.lock);
+}
+
 static void cal_ctx_csi2_config(struct cal_ctx *ctx)
 {
 	u32 val;
@@ -433,11 +464,22 @@ static bool cal_ctx_wr_dma_stopped(struct cal_ctx *ctx)
 
 int cal_ctx_prepare(struct cal_ctx *ctx)
 {
+	int ret;
+
+	ret = cal_reserve_pix_proc(ctx->cal);
+	if (ret < 0) {
+		ctx_err(ctx, "Failed to reserve pix proc: %d\n", ret);
+		return ret;
+	}
+
+	ctx->pix_proc = ret;
+
 	return 0;
 }
 
 void cal_ctx_unprepare(struct cal_ctx *ctx)
 {
+	cal_release_pix_proc(ctx->cal, ctx->pix_proc);
 }
 
 void cal_ctx_start(struct cal_ctx *ctx)
@@ -872,7 +914,6 @@ static struct cal_ctx *cal_ctx_create(struct cal_dev *cal, int inst)
 	ctx->dma_ctx = inst;
 	ctx->csi2_ctx = inst;
 	ctx->cport = inst;
-	ctx->pix_proc = inst;
 
 	ret = cal_ctx_v4l2_init(ctx);
 	if (ret)

drivers/media/platform/ti-vpe/cal.h

@@ -188,6 +188,8 @@ struct cal_dev {
 	struct media_device	mdev;
 	struct v4l2_device	v4l2_dev;
 	struct v4l2_async_notifier notifier;
+
+	unsigned long		reserved_pix_proc_mask;
 };
 
 /*