dmaengine: sf-pdma: add platform DMA support for HiFive Unleashed A00

Add PDMA driver, sf-pdma, to enable DMA engine on HiFive Unleashed
Rev A00 board.

 - Implement dmaengine APIs, support MEM_TO_MEM async copy.
 - Tested by DMA Test client
 - Supports 4 channels DMA, each channel has 1 done and 1 err
   interrupt connected to platform-level interrupt controller (PLIC).
 - Depends on DMA_ENGINE and DMA_VIRTUAL_CHANNELS

The datasheet is here:

  https://static.dev.sifive.com/FU540-C000-v1.0.pdf

Follow the DMAengine controller doc,
"./Documentation/driver-api/dmaengine/provider.rst" to implement DMA
engine. And use the dma test client in doc,
"./Documentation/driver-api/dmaengine/dmatest.rst", to test.

Each DMA channel has separate HW regs and support done and error ISRs.
4 channels share 1 done and 1 err ISRs. There's no expander/arbitrator
in DMA HW.

   ------               ------
   |    |--< done 23 >--|ch 0|
   |    |--< err  24 >--|    |     (dma0chan0)
   |    |               ------
   |    |               ------
   |    |--< done 25 >--|ch 1|
   |    |--< err  26 >--|    |     (dma0chan1)
   |PLIC|               ------
   |    |               ------
   |    |--< done 27 >--|ch 2|
   |    |--< err  28 >--|    |     (dma0chan2)
   |    |               ------
   |    |               ------
   |    |--< done 29 >--|ch 3|
   |    |--< err  30 >--|    |     (dma0chan3)
   ------               ------

Signed-off-by: Green Wan <green.wan@sifive.com>
Link: https://lore.kernel.org/r/20191107084955.7580-4-green.wan@sifive.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/Kconfig

@@ -689,6 +689,8 @@ source "drivers/dma/dw-edma/Kconfig"
 
 source "drivers/dma/hsu/Kconfig"
 
+source "drivers/dma/sf-pdma/Kconfig"
+
 source "drivers/dma/sh/Kconfig"
 
 source "drivers/dma/ti/Kconfig"

drivers/dma/Makefile

@@ -62,6 +62,7 @@ obj-$(CONFIG_PL330_DMA) += pl330.o
 obj-$(CONFIG_PPC_BESTCOMM) += bestcomm/
 obj-$(CONFIG_PXA_DMA) += pxa_dma.o
 obj-$(CONFIG_RENESAS_DMA) += sh/
+obj-$(CONFIG_SF_PDMA) += sf-pdma/
 obj-$(CONFIG_SIRF_DMA) += sirf-dma.o
 obj-$(CONFIG_STE_DMA40) += ste_dma40.o ste_dma40_ll.o
 obj-$(CONFIG_STM32_DMA) += stm32-dma.o

drivers/dma/sf-pdma/Kconfig

@@ -0,0 +1,6 @@
+config SF_PDMA
+	tristate "Sifive PDMA controller driver"
+	select DMA_ENGINE
+	select DMA_VIRTUAL_CHANNELS
+	help
+	  Support the SiFive PDMA controller.

drivers/dma/sf-pdma/Makefile

@@ -0,0 +1 @@
+obj-$(CONFIG_SF_PDMA)   += sf-pdma.o

drivers/dma/sf-pdma/sf-pdma.h

@@ -0,0 +1,122 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/**
+ * SiFive FU540 Platform DMA driver
+ * Copyright (C) 2019 SiFive
+ *
+ * Based partially on:
+ * - drivers/dma/fsl-edma.c
+ * - drivers/dma/dw-edma/
+ * - drivers/dma/pxa-dma.c
+ *
+ * See the following sources for further documentation:
+ * - Chapter 12 "Platform DMA Engine (PDMA)" of
+ *   SiFive FU540-C000 v1.0
+ *   https://static.dev.sifive.com/FU540-C000-v1.0.pdf
+ */
+#ifndef _SF_PDMA_H
+#define _SF_PDMA_H
+
+#include <linux/dmaengine.h>
+#include <linux/dma-direction.h>
+
+#include "../dmaengine.h"
+#include "../virt-dma.h"
+
+#define PDMA_NR_CH					4
+
+#if (PDMA_NR_CH != 4)
+#error "Please define PDMA_NR_CH to 4"
+#endif
+
+#define PDMA_BASE_ADDR					0x3000000
+#define PDMA_CHAN_OFFSET				0x1000
+
+/* Register Offset */
+#define PDMA_CTRL					0x000
+#define PDMA_XFER_TYPE					0x004
+#define PDMA_XFER_SIZE					0x008
+#define PDMA_DST_ADDR					0x010
+#define PDMA_SRC_ADDR					0x018
+#define PDMA_ACT_TYPE					0x104 /* Read-only */
+#define PDMA_REMAINING_BYTE				0x108 /* Read-only */
+#define PDMA_CUR_DST_ADDR				0x110 /* Read-only*/
+#define PDMA_CUR_SRC_ADDR				0x118 /* Read-only*/
+
+/* CTRL */
+#define PDMA_CLEAR_CTRL					0x0
+#define PDMA_CLAIM_MASK					GENMASK(0, 0)
+#define PDMA_RUN_MASK					GENMASK(1, 1)
+#define PDMA_ENABLE_DONE_INT_MASK			GENMASK(14, 14)
+#define PDMA_ENABLE_ERR_INT_MASK			GENMASK(15, 15)
+#define PDMA_DONE_STATUS_MASK				GENMASK(30, 30)
+#define PDMA_ERR_STATUS_MASK				GENMASK(31, 31)
+
+/* Transfer Type */
+#define PDMA_FULL_SPEED					0xFF000008
+
+/* Error Recovery */
+#define MAX_RETRY					1
+
+struct pdma_regs {
+	/* read-write regs */
+	void __iomem *ctrl;		/* 4 bytes */
+
+	void __iomem *xfer_type;	/* 4 bytes */
+	void __iomem *xfer_size;	/* 8 bytes */
+	void __iomem *dst_addr;		/* 8 bytes */
+	void __iomem *src_addr;		/* 8 bytes */
+
+	/* read-only */
+	void __iomem *act_type;		/* 4 bytes */
+	void __iomem *residue;		/* 8 bytes */
+	void __iomem *cur_dst_addr;	/* 8 bytes */
+	void __iomem *cur_src_addr;	/* 8 bytes */
+};
+
+struct sf_pdma_desc {
+	u32				xfer_type;
+	u64				xfer_size;
+	u64				dst_addr;
+	u64				src_addr;
+	struct virt_dma_desc		vdesc;
+	struct sf_pdma_chan		*chan;
+	bool				in_use;
+	enum dma_transfer_direction	dirn;
+	struct dma_async_tx_descriptor *async_tx;
+};
+
+enum sf_pdma_pm_state {
+	RUNNING = 0,
+	SUSPENDED,
+};
+
+struct sf_pdma_chan {
+	struct virt_dma_chan		vchan;
+	enum dma_status			status;
+	enum sf_pdma_pm_state		pm_state;
+	u32				slave_id;
+	struct sf_pdma			*pdma;
+	struct sf_pdma_desc		*desc;
+	struct dma_slave_config		cfg;
+	u32				attr;
+	dma_addr_t			dma_dev_addr;
+	u32				dma_dev_size;
+	struct tasklet_struct		done_tasklet;
+	struct tasklet_struct		err_tasklet;
+	struct pdma_regs		regs;
+	spinlock_t			lock; /* protect chan data */
+	bool				xfer_err;
+	int				txirq;
+	int				errirq;
+	int				retries;
+};
+
+struct sf_pdma {
+	struct dma_device       dma_dev;
+	void __iomem            *membase;
+	void __iomem            *mappedbase;
+	u32			n_chans;
+	struct sf_pdma_chan	chans[PDMA_NR_CH];
+};
+
+#endif /* _SF_PDMA_H */