mei: hw: add dma ring control block

The DMA ring control block contains write and read
indices for host and device circular buffers.
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/mei/dma-ring.c

@@ -97,3 +97,23 @@ bool mei_dma_ring_is_allocated(struct mei_device *dev)
 {
 	return !!dev->dr_dscr[DMA_DSCR_HOST].vaddr;
 }
+
+static inline
+struct hbm_dma_ring_ctrl *mei_dma_ring_ctrl(struct mei_device *dev)
+{
+	return (struct hbm_dma_ring_ctrl *)dev->dr_dscr[DMA_DSCR_CTRL].vaddr;
+}
+
+/**
+ * mei_dma_ring_reset() - reset the dma control block
+ * @dev: mei device
+ */
+void mei_dma_ring_reset(struct mei_device *dev)
+{
+	struct hbm_dma_ring_ctrl *ctrl = mei_dma_ring_ctrl(dev);
+
+	if (!ctrl)
+		return;
+
+	memset(ctrl, 0, sizeof(*ctrl));
+}

drivers/misc/mei/hbm.c

@@ -323,6 +323,8 @@ static int mei_hbm_dma_setup_req(struct mei_device *dev)
 		req.dma_dscr[i].size = dev->dr_dscr[i].size;
 	}
 
+	mei_dma_ring_reset(dev);
+
 	ret = mei_hbm_write_message(dev, &mei_hdr, &req);
 	if (ret) {
 		dev_err(dev->dev, "dma setup request write failed: ret = %d.\n",

drivers/misc/mei/hw.h

@@ -512,4 +512,27 @@ struct hbm_dma_setup_response {
 	u8 reserved[2];
 } __packed;
 
+/**
+ * struct mei_dma_ring_ctrl - dma ring control block
+ *
+ * @hbuf_wr_idx: host circular buffer write index in slots
+ * @reserved1: reserved for alignment
+ * @hbuf_rd_idx: host circular buffer read index in slots
+ * @reserved2: reserved for alignment
+ * @dbuf_wr_idx: device circular buffer write index in slots
+ * @reserved3: reserved for alignment
+ * @dbuf_rd_idx: device circular buffer read index in slots
+ * @reserved4: reserved for alignment
+ */
+struct hbm_dma_ring_ctrl {
+	u32 hbuf_wr_idx;
+	u32 reserved1;
+	u32 hbuf_rd_idx;
+	u32 reserved2;
+	u32 dbuf_wr_idx;
+	u32 reserved3;
+	u32 dbuf_rd_idx;
+	u32 reserved4;
+} __packed;
+
 #endif

drivers/misc/mei/mei_dev.h

@@ -597,6 +597,7 @@ void mei_cancel_work(struct mei_device *dev);
 int mei_dmam_ring_alloc(struct mei_device *dev);
 void mei_dmam_ring_free(struct mei_device *dev);
 bool mei_dma_ring_is_allocated(struct mei_device *dev);
+void mei_dma_ring_reset(struct mei_device *dev);
 
 /*
  *  MEI interrupt functions prototype