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Subject[char-misc-next 02/12] mei: hbm: define dma ring setup protocol
Date
The protocol defines how to setup an I/O ring on top of host
memory to utilize the device DMA engine for faster transport.

Three memory buffers are allocated.
A Host circular buffer for from the Host to Device communication.
A Device circular buffer for from Device to the Host communication.
And finally a Control block where the pointers for the both
circular buffers are managed.

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
---
drivers/misc/mei/hw.h | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 49 insertions(+)

diff --git a/drivers/misc/mei/hw.h b/drivers/misc/mei/hw.h
index 3b325d955fbe..76fb502e6f71 100644
--- a/drivers/misc/mei/hw.h
+++ b/drivers/misc/mei/hw.h
@@ -122,6 +122,9 @@
#define MEI_HBM_NOTIFY_RES_CMD 0x90
#define MEI_HBM_NOTIFICATION_CMD 0x11

+#define MEI_HBM_DMA_SETUP_REQ_CMD 0x12
+#define MEI_HBM_DMA_SETUP_RES_CMD 0x92
+
/*
* MEI Stop Reason
* used by hbm_host_stop_request.reason
@@ -449,4 +452,50 @@ struct hbm_notification {
u8 reserved[1];
} __packed;

+/**
+ * struct hbm_dma_mem_dscr - dma ring
+ *
+ * @addr_hi: the high 32bits of 64 bit address
+ * @addr_lo: the low 32bits of 64 bit address
+ * @size : size in bytes (must be power of 2)
+ */
+struct hbm_dma_mem_dscr {
+ u32 addr_hi;
+ u32 addr_lo;
+ u32 size;
+} __packed;
+
+enum {
+ DMA_DSCR_HOST = 0,
+ DMA_DSCR_DEVICE = 1,
+ DMA_DSCR_CTRL = 2,
+ DMA_DSCR_NUM,
+};
+
+/**
+ * struct hbm_dma_setup_request - dma setup request
+ *
+ * @hbm_cmd: bus message command header
+ * @reserved: reserved for alignment
+ * @dma_dscr: dma descriptor for HOST, DEVICE, and CTRL
+ */
+struct hbm_dma_setup_request {
+ u8 hbm_cmd;
+ u8 reserved[3];
+ struct hbm_dma_mem_dscr dma_dscr[DMA_DSCR_NUM];
+} __packed;
+
+/**
+ * struct hbm_dma_setup_response - dma setup response
+ *
+ * @hbm_cmd: bus message command header
+ * @status: 0 on success; otherwise DMA setup failed.
+ * @reserved: reserved for alignment
+ */
+struct hbm_dma_setup_response {
+ u8 hbm_cmd;
+ u8 status;
+ u8 reserved[2];
+} __packed;
+
#endif
--
2.14.4
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