HID: intel-thc-hid: intel-thc: Add THC DMA interfaces

As THC PIO only has 64 bytes FIFO length, THC DMAs are introduced to
send/receive large data packets.

THC has three types of DMA channels: Read DMA channel (RxDMA), Write DMA
channel (TxDMA) and Software DMA (SWDMA).

In addition to basic DMA functions, THC RxDMA also includes an auto
hardware sequence which can handle external touch device's interrupt
automatically without software involved. THC RxDMA channel usually is
used for handling touch input reports.

THC TxDMA is very similar with general IO TxDMA, and usually is used
for sending command/request to exteranl touch device.

THC SWDMA can perform read, write followed by read operation
according to different configurations. Unlike RxDMA triggered by bus
activity, SWDMA can be triggered by SW driver at any time, for example:
- Retrieving an input report without interrupt
- Sending command followed by reading response

THC DMA operation flow includes 4 steps:
1. Allocate DMA buffers
2. Configure opcode, fill PRD table with DMA buffers, enable DMA channel
3. Wait for completion, read out DMA buffers and update buffer pointers
4. Stop DMA and release DMA buffers

THC Hardware layer driver provides APIs for all above DMA Steps.

Co-developed-by: Xinpeng Sun <[email protected]>
Signed-off-by: Xinpeng Sun <[email protected]>
Signed-off-by: Even Xu <[email protected]>
Tested-by: Rui Zhang <[email protected]>
Tested-by: Mark Pearson <[email protected]>
Reviewed-by: Srinivas Pandruvada <[email protected]>
Reviewed-by: Mark Pearson <[email protected]>
Tested-by: Aaron Ma <[email protected]>
Signed-off-by: Jiri Kosina <[email protected]>

Author: Evenxf

drivers/hid/intel-thc-hid/Makefile

@@ -7,5 +7,6 @@
 
 obj-$(CONFIG_INTEL_THC_HID) += intel-thc.o
 intel-thc-objs += intel-thc/intel-thc-dev.o
+intel-thc-objs += intel-thc/intel-thc-dma.o
 
 ccflags-y += -I $(src)/intel-thc

drivers/hid/intel-thc-hid/intel-thc/intel-thc-dev.c

@@ -211,6 +211,14 @@ struct thc_device *thc_dev_init(struct device *device, void __iomem *mem_addr)
 	thc_clear_state(thc_dev);
 
 	mutex_init(&thc_dev->thc_bus_lock);
+	init_waitqueue_head(&thc_dev->write_complete_wait);
+	init_waitqueue_head(&thc_dev->swdma_complete_wait);
+
+	thc_dev->dma_ctx = thc_dma_init(thc_dev);
+	if (!thc_dev->dma_ctx) {
+		dev_err_once(device, "DMA context init failed\n");
+		return ERR_PTR(-ENOMEM);
+	}
 
 	return thc_dev;
 }

drivers/hid/intel-thc-hid/intel-thc/intel-thc-dev.h

@@ -6,6 +6,9 @@
 
 #include <linux/cdev.h>
 #include <linux/mutex.h>
+#include <linux/workqueue.h>
+
+#include "intel-thc-dma.h"
 
 #define THC_REGMAP_COMMON_OFFSET  0x10
 #define THC_REGMAP_MMIO_OFFSET    0x1000
@@ -27,6 +30,12 @@ enum thc_port_type {
  * @thc_bus_lock: mutex locker for THC config
  * @port_type: port type of THC port instance
  * @pio_int_supported: PIO interrupt supported flag
+ * @dma_ctx: DMA specific data
+ * @write_complete_wait: signal event for DMA write complete
+ * @swdma_complete_wait: signal event for SWDMA sequence complete
+ * @write_done: bool value that indicates if DMA write is done
+ * @swdma_done: bool value that indicates if SWDMA swquence is done
+ * @perf_limit: the delay between read operation and write operation
  */
 struct thc_device {
 	struct device *dev;
@@ -35,6 +44,15 @@ struct thc_device {
 	struct mutex thc_bus_lock;
 	enum thc_port_type port_type;
 	bool pio_int_supported;
+
+	struct thc_dma_context *dma_ctx;
+
+	wait_queue_head_t write_complete_wait;
+	wait_queue_head_t swdma_complete_wait;
+	bool write_done;
+	bool swdma_done;
+
+	u32 perf_limit;
 };
 
 struct thc_device *thc_dev_init(struct device *device, void __iomem *mem_addr);