Re: [RESEND PATCH V11 XDMA 1/2] dmaengine: xilinx: xdma: Add xilinx xdma driver
From: Vinod Koul
Date: Wed Jan 18 2023 - 01:55:42 EST
On 17-01-23, 12:54, Lizhi Hou wrote:
> Add driver to enable PCIe board which uses XDMA (the DMA/Bridge Subsystem
> for PCI Express). For example, Xilinx Alveo PCIe devices.
> https://www.xilinx.com/products/boards-and-kits/alveo.html
>
> The XDMA engine support up to 4 Host to Card (H2C) and 4 Card to Host (C2H)
> channels. Memory transfers are specified on a per-channel basis in
> descriptor linked lists, which the DMA fetches from host memory and
> processes. Events such as descriptor completion and errors are signaled
> using interrupts. The hardware detail is provided by
> https://docs.xilinx.com/r/en-US/pg195-pcie-dma/Introduction
>
> This driver implements dmaengine APIs.
> - probe the available DMA channels
> - use dma_slave_map for channel lookup
> - use virtual channel to manage dmaengine tx descriptors
> - implement device_prep_slave_sg callback to handle host scatter gather
> list
> - implement device_config to config device address for DMA transfer
>
> Signed-off-by: Lizhi Hou <lizhi.hou@xxxxxxx>
> Signed-off-by: Sonal Santan <sonal.santan@xxxxxxx>
> Signed-off-by: Max Zhen <max.zhen@xxxxxxx>
> Signed-off-by: Brian Xu <brian.xu@xxxxxxx>
> Tested-by: Martin Tuma <tumic@xxxxxxxxxx>
> ---
> MAINTAINERS | 10 +
> drivers/dma/Kconfig | 14 +
> drivers/dma/xilinx/Makefile | 1 +
> drivers/dma/xilinx/xdma-regs.h | 173 +++++
> drivers/dma/xilinx/xdma.c | 919 +++++++++++++++++++++++++
> include/linux/platform_data/amd_xdma.h | 34 +
> 6 files changed, 1151 insertions(+)
> create mode 100644 drivers/dma/xilinx/xdma-regs.h
> create mode 100644 drivers/dma/xilinx/xdma.c
> create mode 100644 include/linux/platform_data/amd_xdma.h
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index e68a0804394d..d598c4e23901 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -22575,6 +22575,16 @@ F: Documentation/devicetree/bindings/media/xilinx/
> F: drivers/media/platform/xilinx/
> F: include/uapi/linux/xilinx-v4l2-controls.h
>
> +XILINX XDMA DRIVER
> +M: Lizhi Hou <lizhi.hou@xxxxxxx>
> +M: Brian Xu <brian.xu@xxxxxxx>
> +M: Raj Kumar Rampelli <raj.kumar.rampelli@xxxxxxx>
> +L: dmaengine@xxxxxxxxxxxxxxx
> +S: Supported
> +F: drivers/dma/xilinx/xdma-regs.h
> +F: drivers/dma/xilinx/xdma.c
> +F: include/linux/platform_data/amd_xdma.h
> +
> XILINX ZYNQMP DPDMA DRIVER
> M: Hyun Kwon <hyun.kwon@xxxxxxxxxx>
> M: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
> index 7524b62a8870..bb5b542c2f9a 100644
> --- a/drivers/dma/Kconfig
> +++ b/drivers/dma/Kconfig
> @@ -753,6 +753,20 @@ config XILINX_ZYNQMP_DPDMA
> driver provides the dmaengine required by the DisplayPort subsystem
> display driver.
>
> +config XILINX_XDMA
Please keep this sorted alphabetically, so should come before XILINX_Z*
> + tristate "Xilinx DMA/Bridge Subsystem DMA Engine"
> + depends on HAS_IOMEM
> + select DMA_ENGINE
> + select DMA_VIRTUAL_CHANNELS
> + select REGMAP_MMIO
> + help
> + Enable support for Xilinx DMA/Bridge Subsystem DMA engine. The DMA
> + provides high performance block data movement between Host memory
> + and the DMA subsystem. These direct memory transfers can be both in
> + the Host to Card (H2C) and Card to Host (C2H) transfers.
> + The core also provides up to 16 user interrupt wires that generate
> + interrupts to the host.
> +
> # driver files
> source "drivers/dma/bestcomm/Kconfig"
>
> diff --git a/drivers/dma/xilinx/Makefile b/drivers/dma/xilinx/Makefile
> index 767bb45f641f..c7a538a56643 100644
> --- a/drivers/dma/xilinx/Makefile
> +++ b/drivers/dma/xilinx/Makefile
> @@ -2,3 +2,4 @@
> obj-$(CONFIG_XILINX_DMA) += xilinx_dma.o
> obj-$(CONFIG_XILINX_ZYNQMP_DMA) += zynqmp_dma.o
> obj-$(CONFIG_XILINX_ZYNQMP_DPDMA) += xilinx_dpdma.o
> +obj-$(CONFIG_XILINX_XDMA) += xdma.o
Here as well
> diff --git a/drivers/dma/xilinx/xdma-regs.h b/drivers/dma/xilinx/xdma-regs.h
> new file mode 100644
> index 000000000000..33838b714bf6
> --- /dev/null
> +++ b/drivers/dma/xilinx/xdma-regs.h
> @@ -0,0 +1,173 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/*
> + * Copyright (C) 2017-2020 Xilinx, Inc. All rights reserved.
> + * Copyright (C) 2022, Advanced Micro Devices, Inc.
> + */
> +
> +#ifndef __DMA_XDMA_REGS_H
> +#define __DMA_XDMA_REGS_H
> +
> +/* The length of register space exposed to host */
> +#define XDMA_REG_SPACE_LEN 65536
> +
> +/*
> + * maximum number of DMA channels for each direction:
> + * Host to Card (H2C) or Card to Host (C2H)
> + */
> +#define XDMA_MAX_CHANNELS 4
> +
> +/* macros to get higher and lower 32-bit address */
> +#define XDMA_HI_ADDR_MASK GENMASK_ULL(63, 32)
> +#define XDMA_LO_ADDR_MASK GENMASK_ULL(31, 0)
Why not use upper_32_bits() and lower_32_bits() instead
> +
> +/*
> + * macros to define the number of descriptor blocks can be used in one
> + * DMA transfer request.
> + * the DMA engine uses a linked list of descriptor blocks that specify the
> + * source, destination, and length of the DMA transfers.
> + */
> +#define XDMA_DESC_BLOCK_NUM BIT(7)
> +#define XDMA_DESC_BLOCK_MASK (XDMA_DESC_BLOCK_NUM - 1)
> +
> +/* descriptor definitions */
> +#define XDMA_DESC_ADJACENT 32
> +#define XDMA_DESC_ADJACENT_MASK (XDMA_DESC_ADJACENT - 1)
> +#define XDMA_DESC_ADJACENT_BITS GENMASK(13, 8)
> +#define XDMA_DESC_MAGIC 0xad4bUL
> +#define XDMA_DESC_MAGIC_BITS GENMASK(31, 16)
> +#define XDMA_DESC_FLAGS_BITS GENMASK(7, 0)
> +#define XDMA_DESC_STOPPED BIT(0)
> +#define XDMA_DESC_COMPLETED BIT(1)
> +#define XDMA_DESC_BLEN_BITS 28
> +#define XDMA_DESC_BLEN_MAX (BIT(XDMA_DESC_BLEN_BITS) - PAGE_SIZE)
> +
> +/* macros to construct the descriptor control word */
> +#define XDMA_DESC_CONTROL(adjacent, flag) \
> + (FIELD_PREP(XDMA_DESC_MAGIC_BITS, XDMA_DESC_MAGIC) | \
> + FIELD_PREP(XDMA_DESC_ADJACENT_BITS, (adjacent) - 1) | \
> + FIELD_PREP(XDMA_DESC_FLAGS_BITS, (flag)))
> +#define XDMA_DESC_CONTROL_LAST \
> + XDMA_DESC_CONTROL(1, XDMA_DESC_STOPPED | XDMA_DESC_COMPLETED)
> +
> +/*
> + * Descriptor for a single contiguous memory block transfer.
> + *
> + * Multiple descriptors are linked by means of the next pointer. An additional
> + * extra adjacent number gives the amount of extra contiguous descriptors.
> + *
> + * The descriptors are in root complex memory, and the bytes in the 32-bit
> + * words must be in little-endian byte ordering.
> + */
> +struct xdma_hw_desc {
> + __le32 control;
> + __le32 bytes;
> + __le64 src_addr;
> + __le64 dst_addr;
> + __le64 next_desc;
> +};
> +
> +#define XDMA_DESC_SIZE sizeof(struct xdma_hw_desc)
> +#define XDMA_DESC_BLOCK_SIZE (XDMA_DESC_SIZE * XDMA_DESC_ADJACENT)
> +#define XDMA_DESC_BLOCK_ALIGN 4096
> +
> +/*
> + * Channel registers
> + */
> +#define XDMA_CHAN_IDENTIFIER 0x0
> +#define XDMA_CHAN_CONTROL 0x4
> +#define XDMA_CHAN_CONTROL_W1S 0x8
> +#define XDMA_CHAN_CONTROL_W1C 0xc
> +#define XDMA_CHAN_STATUS 0x40
> +#define XDMA_CHAN_COMPLETED_DESC 0x48
> +#define XDMA_CHAN_ALIGNMENTS 0x4c
> +#define XDMA_CHAN_INTR_ENABLE 0x90
> +#define XDMA_CHAN_INTR_ENABLE_W1S 0x94
> +#define XDMA_CHAN_INTR_ENABLE_W1C 0x9c
> +
> +#define XDMA_CHAN_STRIDE 0x100
> +#define XDMA_CHAN_H2C_OFFSET 0x0
> +#define XDMA_CHAN_C2H_OFFSET 0x1000
> +#define XDMA_CHAN_H2C_TARGET 0x0
> +#define XDMA_CHAN_C2H_TARGET 0x1
> +
> +/* macro to check if channel is available */
> +#define XDMA_CHAN_MAGIC 0x1fc0
> +#define XDMA_CHAN_CHECK_TARGET(id, target) \
> + (((u32)(id) >> 16) == XDMA_CHAN_MAGIC + (target))
> +
> +/* bits of the channel control register */
> +#define CHAN_CTRL_RUN_STOP BIT(0)
> +#define CHAN_CTRL_IE_DESC_STOPPED BIT(1)
> +#define CHAN_CTRL_IE_DESC_COMPLETED BIT(2)
> +#define CHAN_CTRL_IE_DESC_ALIGN_MISMATCH BIT(3)
> +#define CHAN_CTRL_IE_MAGIC_STOPPED BIT(4)
> +#define CHAN_CTRL_IE_IDLE_STOPPED BIT(6)
> +#define CHAN_CTRL_IE_READ_ERROR GENMASK(13, 9)
> +#define CHAN_CTRL_IE_DESC_ERROR GENMASK(23, 19)
> +#define CHAN_CTRL_NON_INCR_ADDR BIT(25)
> +#define CHAN_CTRL_POLL_MODE_WB BIT(26)
> +
> +#define CHAN_CTRL_START (CHAN_CTRL_RUN_STOP | \
> + CHAN_CTRL_IE_DESC_STOPPED | \
> + CHAN_CTRL_IE_DESC_COMPLETED | \
> + CHAN_CTRL_IE_DESC_ALIGN_MISMATCH | \
> + CHAN_CTRL_IE_MAGIC_STOPPED | \
> + CHAN_CTRL_IE_READ_ERROR | \
> + CHAN_CTRL_IE_DESC_ERROR)
> +
> +/* bits of the channel interrupt enable mask */
> +#define CHAN_IM_DESC_ERROR BIT(19)
> +#define CHAN_IM_READ_ERROR BIT(9)
> +#define CHAN_IM_IDLE_STOPPED BIT(6)
> +#define CHAN_IM_MAGIC_STOPPED BIT(4)
> +#define CHAN_IM_DESC_COMPLETED BIT(2)
> +#define CHAN_IM_DESC_STOPPED BIT(1)
> +
> +#define CHAN_IM_ALL (CHAN_IM_DESC_ERROR | CHAN_IM_READ_ERROR | \
> + CHAN_IM_IDLE_STOPPED | CHAN_IM_MAGIC_STOPPED | \
> + CHAN_IM_DESC_COMPLETED | CHAN_IM_DESC_STOPPED)
> +
> +/*
> + * Channel SGDMA registers
> + */
> +#define XDMA_SGDMA_IDENTIFIER 0x0
> +#define XDMA_SGDMA_DESC_LO 0x80
> +#define XDMA_SGDMA_DESC_HI 0x84
> +#define XDMA_SGDMA_DESC_ADJ 0x88
> +#define XDMA_SGDMA_DESC_CREDIT 0x8c
> +
> +#define XDMA_SGDMA_BASE(chan_base) ((chan_base) + 0x4000)
> +
> +/* bits of the SG DMA control register */
> +#define XDMA_CTRL_RUN_STOP BIT(0)
> +#define XDMA_CTRL_IE_DESC_STOPPED BIT(1)
> +#define XDMA_CTRL_IE_DESC_COMPLETED BIT(2)
> +#define XDMA_CTRL_IE_DESC_ALIGN_MISMATCH BIT(3)
> +#define XDMA_CTRL_IE_MAGIC_STOPPED BIT(4)
> +#define XDMA_CTRL_IE_IDLE_STOPPED BIT(6)
> +#define XDMA_CTRL_IE_READ_ERROR GENMASK(13, 9)
> +#define XDMA_CTRL_IE_DESC_ERROR GENMASK(23, 19)
> +#define XDMA_CTRL_NON_INCR_ADDR BIT(25)
> +#define XDMA_CTRL_POLL_MODE_WB BIT(26)
> +
> +/*
> + * interrupt registers
> + */
> +#define XDMA_IRQ_IDENTIFIER 0x0
> +#define XDMA_IRQ_USER_INT_EN 0x04
> +#define XDMA_IRQ_USER_INT_EN_W1S 0x08
> +#define XDMA_IRQ_USER_INT_EN_W1C 0x0c
> +#define XDMA_IRQ_CHAN_INT_EN 0x10
> +#define XDMA_IRQ_CHAN_INT_EN_W1S 0x14
> +#define XDMA_IRQ_CHAN_INT_EN_W1C 0x18
> +#define XDMA_IRQ_USER_INT_REQ 0x40
> +#define XDMA_IRQ_CHAN_INT_REQ 0x44
> +#define XDMA_IRQ_USER_INT_PEND 0x48
> +#define XDMA_IRQ_CHAN_INT_PEND 0x4c
> +#define XDMA_IRQ_USER_VEC_NUM 0x80
> +#define XDMA_IRQ_CHAN_VEC_NUM 0xa0
> +
> +#define XDMA_IRQ_BASE 0x2000
> +#define XDMA_IRQ_VEC_SHIFT 8
> +
> +#endif /* __DMA_XDMA_REGS_H */
> diff --git a/drivers/dma/xilinx/xdma.c b/drivers/dma/xilinx/xdma.c
> new file mode 100644
> index 000000000000..118528295fb7
> --- /dev/null
> +++ b/drivers/dma/xilinx/xdma.c
> @@ -0,0 +1,919 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * DMA driver for Xilinx DMA/Bridge Subsystem
> + *
> + * Copyright (C) 2017-2020 Xilinx, Inc. All rights reserved.
> + * Copyright (C) 2022, Advanced Micro Devices, Inc.
> + */
> +
> +/*
> + * The DMA/Bridge Subsystem for PCI Express allows for the movement of data
> + * between Host memory and the DMA subsystem. It does this by operating on
> + * 'descriptors' that contain information about the source, destination and
> + * amount of data to transfer. These direct memory transfers can be both in
> + * the Host to Card (H2C) and Card to Host (C2H) transfers. The DMA can be
> + * configured to have a single AXI4 Master interface shared by all channels
> + * or one AXI4-Stream interface for each channel enabled. Memory transfers are
> + * specified on a per-channel basis in descriptor linked lists, which the DMA
> + * fetches from host memory and processes. Events such as descriptor completion
> + * and errors are signaled using interrupts. The core also provides up to 16
> + * user interrupt wires that generate interrupts to the host.
> + */
> +
> +#include <linux/mod_devicetable.h>
> +#include <linux/bitfield.h>
> +#include <linux/dmapool.h>
> +#include <linux/regmap.h>
> +#include <linux/dmaengine.h>
> +#include <linux/platform_device.h>
> +#include <linux/platform_data/amd_xdma.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/pci.h>
> +#include "../virt-dma.h"
> +#include "xdma-regs.h"
> +
> +/* mmio regmap config for all XDMA registers */
> +static const struct regmap_config xdma_regmap_config = {
> + .reg_bits = 32,
> + .val_bits = 32,
> + .reg_stride = 4,
> + .max_register = XDMA_REG_SPACE_LEN,
> +};
Very nice..
> +
> +/**
> + * struct xdma_desc_block - Descriptor block
> + * @virt_addr: Virtual address of block start
> + * @dma_addr: DMA address of block start
> + */
> +struct xdma_desc_block {
> + void *virt_addr;
> + dma_addr_t dma_addr;
> +};
> +
> +/**
> + * struct xdma_chan - Driver specific DMA channel structure
> + * @vchan: Virtual channel
> + * @xdev_hdl: Pointer to DMA device structure
> + * @base: Offset of channel registers
> + * @desc_pool: Descriptor pool
> + * @busy: Busy flag of the channel
> + * @dir: Transferring direction of the channel
> + * @cfg: Transferring config of the channel
> + * @irq: IRQ assigned to the channel
> + */
> +struct xdma_chan {
> + struct virt_dma_chan vchan;
> + void *xdev_hdl;
> + u32 base;
> + struct dma_pool *desc_pool;
> + bool busy;
> + enum dma_transfer_direction dir;
> + struct dma_slave_config cfg;
> + u32 irq;
> +};
> +
> +/**
> + * struct xdma_desc - DMA desc structure
> + * @vdesc: Virtual DMA descriptor
> + * @chan: DMA channel pointer
> + * @dir: Transferring direction of the request
> + * @dev_addr: Physical address on DMA device side
> + * @desc_blocks: Hardware descriptor blocks
> + * @dblk_num: Number of hardware descriptor blocks
> + * @desc_num: Number of hardware descriptors
> + * @completed_desc_num: Completed hardware descriptors
> + */
> +struct xdma_desc {
> + struct virt_dma_desc vdesc;
> + struct xdma_chan *chan;
> + enum dma_transfer_direction dir;
> + u64 dev_addr;
> + struct xdma_desc_block *desc_blocks;
> + u32 dblk_num;
> + u32 desc_num;
> + u32 completed_desc_num;
> +};
> +
> +#define XDMA_DEV_STATUS_REG_DMA BIT(0)
> +#define XDMA_DEV_STATUS_INIT_MSIX BIT(1)
> +
> +/**
> + * struct xdma_device - DMA device structure
> + * @pdev: Platform device pointer
> + * @dma_dev: DMA device structure
> + * @regmap: MMIO regmap for DMA registers
> + * @h2c_chans: Host to Card channels
> + * @c2h_chans: Card to Host channels
> + * @h2c_chan_num: Number of H2C channels
> + * @c2h_chan_num: Number of C2H channels
> + * @irq_start: Start IRQ assigned to device
> + * @irq_num: Number of IRQ assigned to device
> + * @status: Initialization status
> + */
> +struct xdma_device {
> + struct platform_device *pdev;
> + struct dma_device dma_dev;
> + struct regmap *regmap;
> + struct xdma_chan *h2c_chans;
> + struct xdma_chan *c2h_chans;
> + u32 h2c_chan_num;
> + u32 c2h_chan_num;
> + u32 irq_start;
> + u32 irq_num;
> + u32 status;
> +};
> +
> +#define xdma_err(xdev, fmt, args...) \
> + dev_err(&(xdev)->pdev->dev, fmt, ##args)
> +#define XDMA_CHAN_NUM(_xd) ({ \
> + typeof(_xd) (xd) = (_xd); \
> + ((xd)->h2c_chan_num + (xd)->c2h_chan_num); })
> +
> +/* Read and Write DMA registers */
> +static inline int xdma_read_reg(struct xdma_device *xdev, u32 base, u32 reg,
> + u32 *val)
> +{
> + int ret;
> +
> + ret = regmap_read(xdev->regmap, base + reg, val);
> + if (ret)
> + xdma_err(xdev, "read reg %x:%x failed: %d", base, reg, ret);
> +
> + return ret;
> +}
> +
> +static inline int xdma_write_reg(struct xdma_device *xdev, u32 base, u32 reg,
> + u32 val)
> +{
> + int ret;
> +
> + ret = regmap_write(xdev->regmap, base + reg, val);
> + if (ret)
> + xdma_err(xdev, "write reg %x:%x failed: %d", base, reg, ret);
> +
> + return ret;
> +}
You are doing regmap_ ops, why do you need a wrapper around it? I think
we can drop the error lines too...
> +
> +/* Get the last desc in a desc block */
> +static inline void *xdma_blk_last_desc(struct xdma_desc_block *block)
> +{
> + return block->virt_addr + (XDMA_DESC_ADJACENT - 1) * XDMA_DESC_SIZE;
> +}
> +
> +/**
> + * xdma_link_desc_blocks - Link descriptor blocks for DMA transfer
> + * @sw_desc: Tx descriptor pointer
> + */
> +static void xdma_link_desc_blocks(struct xdma_desc *sw_desc)
> +{
> + struct xdma_desc_block *block;
> + u32 last_blk_desc, desc_control;
> + struct xdma_hw_desc *desc;
> + int i;
> +
> + desc_control = XDMA_DESC_CONTROL(XDMA_DESC_ADJACENT, 0);
> + for (i = 1; i < sw_desc->dblk_num; i++) {
Why is this starting from 1
> + block = &sw_desc->desc_blocks[i - 1];
> + desc = xdma_blk_last_desc(block);
> +
> + if (!(i & XDMA_DESC_BLOCK_MASK)) {
> + desc->control = cpu_to_le32(XDMA_DESC_CONTROL_LAST);
> + continue;
> + }
> + desc->control = cpu_to_le32(desc_control);
> + desc->next_desc = cpu_to_le64(block[1].dma_addr);
> + }
> +
> + /* update the last block */
> + last_blk_desc = (sw_desc->desc_num - 1) & XDMA_DESC_ADJACENT_MASK;
> + if (((sw_desc->dblk_num - 1) & XDMA_DESC_BLOCK_MASK) > 0) {
> + block = &sw_desc->desc_blocks[sw_desc->dblk_num - 2];
> + desc = xdma_blk_last_desc(block);
> + desc_control = XDMA_DESC_CONTROL(last_blk_desc + 1, 0);
> + desc->control = cpu_to_le32(desc_control);
> + }
> +
> + block = &sw_desc->desc_blocks[sw_desc->dblk_num - 1];
> + desc = block->virt_addr + last_blk_desc * XDMA_DESC_SIZE;
> + desc->control = cpu_to_le32(XDMA_DESC_CONTROL_LAST);
> +}
> +
> +static inline struct xdma_chan *to_xdma_chan(struct dma_chan *chan)
> +{
> + return container_of(chan, struct xdma_chan, vchan.chan);
> +}
> +
> +static inline struct xdma_desc *to_xdma_desc(struct virt_dma_desc *vdesc)
> +{
> + return container_of(vdesc, struct xdma_desc, vdesc);
> +}
> +
> +/**
> + * xdma_channel_init - Initialize DMA channel registers
> + * @chan: DMA channel pointer
> + */
> +static int xdma_channel_init(struct xdma_chan *chan)
> +{
> + struct xdma_device *xdev = chan->xdev_hdl;
> + int ret;
> +
> + ret = xdma_write_reg(xdev, chan->base, XDMA_CHAN_CONTROL_W1C,
> + CHAN_CTRL_NON_INCR_ADDR);
> + if (ret)
> + return ret;
> +
> + ret = xdma_write_reg(xdev, chan->base, XDMA_CHAN_INTR_ENABLE,
> + CHAN_IM_ALL);
> + if (ret)
> + return ret;
> +
> + return 0;
> +}
> +
> +/**
> + * xdma_free_desc - Free descriptor
> + * @vdesc: Virtual DMA descriptor
> + */
> +static void xdma_free_desc(struct virt_dma_desc *vdesc)
> +{
> + struct xdma_desc *sw_desc;
> + int i;
> +
> + sw_desc = to_xdma_desc(vdesc);
> + for (i = 0; i < sw_desc->dblk_num; i++) {
> + if (!sw_desc->desc_blocks[i].virt_addr)
> + break;
> + dma_pool_free(sw_desc->chan->desc_pool,
> + sw_desc->desc_blocks[i].virt_addr,
> + sw_desc->desc_blocks[i].dma_addr);
> + }
> + kfree(sw_desc->desc_blocks);
> + kfree(sw_desc);
> +}
> +
> +/**
> + * xdma_alloc_desc - Allocate descriptor
> + * @chan: DMA channel pointer
> + * @desc_num: Number of hardware descriptors
> + */
> +static struct xdma_desc *
> +xdma_alloc_desc(struct xdma_chan *chan, u32 desc_num)
> +{
> + struct xdma_desc *sw_desc;
> + struct xdma_hw_desc *desc;
> + dma_addr_t dma_addr;
> + u32 dblk_num;
> + void *addr;
> + int i, j;
> +
> + sw_desc = kzalloc(sizeof(*sw_desc), GFP_NOWAIT);
> + if (!sw_desc)
> + return NULL;
> +
> + sw_desc->chan = chan;
> + sw_desc->desc_num = desc_num;
> + dblk_num = DIV_ROUND_UP(desc_num, XDMA_DESC_ADJACENT);
> + sw_desc->desc_blocks = kcalloc(dblk_num, sizeof(*sw_desc->desc_blocks),
> + GFP_NOWAIT);
> + if (!sw_desc->desc_blocks)
> + goto failed;
> +
> + sw_desc->dblk_num = dblk_num;
> + for (i = 0; i < sw_desc->dblk_num; i++) {
> + addr = dma_pool_alloc(chan->desc_pool, GFP_NOWAIT, &dma_addr);
> + if (!addr)
> + goto failed;
> +
> + sw_desc->desc_blocks[i].virt_addr = addr;
> + sw_desc->desc_blocks[i].dma_addr = dma_addr;
> + for (j = 0, desc = addr; j < XDMA_DESC_ADJACENT; j++)
> + desc[j].control = cpu_to_le32(XDMA_DESC_CONTROL(1, 0));
> + }
> +
> + xdma_link_desc_blocks(sw_desc);
> +
> + return sw_desc;
> +
> +failed:
> + xdma_free_desc(&sw_desc->vdesc);
> + return NULL;
> +}
> +
> +/**
> + * xdma_xfer_start - Start DMA transfer
> + * @xdma_chan: DMA channel pointer
> + */
> +static int xdma_xfer_start(struct xdma_chan *xdma_chan)
> +{
> + struct virt_dma_desc *vd = vchan_next_desc(&xdma_chan->vchan);
> + struct xdma_device *xdev = xdma_chan->xdev_hdl;
> + struct xdma_desc_block *block;
> + u32 val, completed_blocks;
> + struct xdma_desc *desc;
> + int ret;
> +
> + /*
> + * check if there is not any submitted descriptor or channel is busy.
> + * vchan lock should be held where this function is called.
> + */
> + if (!vd || xdma_chan->busy)
> + return -EINVAL;
> +
> + /* clear run stop bit to get ready for transfer */
> + ret = xdma_write_reg(xdev, xdma_chan->base, XDMA_CHAN_CONTROL_W1C,
> + CHAN_CTRL_RUN_STOP);
> + if (ret)
> + return ret;
> +
> + desc = to_xdma_desc(vd);
> + if (desc->dir != xdma_chan->dir) {
> + xdma_err(xdev, "incorrect request direction");
> + return -EINVAL;
> + }
> +
> + /* set DMA engine to the first descriptor block */
> + completed_blocks = desc->completed_desc_num / XDMA_DESC_ADJACENT;
> + block = &desc->desc_blocks[completed_blocks];
> + val = FIELD_GET(XDMA_LO_ADDR_MASK, block->dma_addr);
> + ret = xdma_write_reg(xdev, XDMA_SGDMA_BASE(xdma_chan->base),
> + XDMA_SGDMA_DESC_LO, val);
> + if (ret)
> + return ret;
> +
> + val = FIELD_GET(XDMA_HI_ADDR_MASK, (u64)block->dma_addr);
> + ret = xdma_write_reg(xdev, XDMA_SGDMA_BASE(xdma_chan->base),
> + XDMA_SGDMA_DESC_HI, val);
> + if (ret)
> + return ret;
> +
> + if (completed_blocks + 1 == desc->dblk_num)
> + val = (desc->desc_num - 1) & XDMA_DESC_ADJACENT_MASK;
> + else
> + val = XDMA_DESC_ADJACENT - 1;
> + ret = xdma_write_reg(xdev, XDMA_SGDMA_BASE(xdma_chan->base),
> + XDMA_SGDMA_DESC_ADJ, val);
> + if (ret)
> + return ret;
> +
> + /* kick off DMA transfer */
> + ret = xdma_write_reg(xdev, xdma_chan->base, XDMA_CHAN_CONTROL,
> + CHAN_CTRL_START);
> + if (ret)
> + return ret;
> +
> + xdma_chan->busy = true;
> + return 0;
> +}
> +
> +/**
> + * xdma_config_channels - Detect and config DMA channels
Looking at fn, maybe alloc_channels would fit better... you are
allocating them.. configure sounds more runtime
> + * @xdev: DMA device pointer
> + * @dir: Channel direction
> + */
> +static int xdma_config_channels(struct xdma_device *xdev,
> + enum dma_transfer_direction dir)
> +{
> + struct xdma_platdata *pdata = dev_get_platdata(&xdev->pdev->dev);
> + u32 base, identifier, target;
> + struct xdma_chan **chans;
> + u32 *chan_num;
> + int i, j, ret;
> +
> + if (dir == DMA_MEM_TO_DEV) {
> + base = XDMA_CHAN_H2C_OFFSET;
> + target = XDMA_CHAN_H2C_TARGET;
> + chans = &xdev->h2c_chans;
> + chan_num = &xdev->h2c_chan_num;
> + } else if (dir == DMA_DEV_TO_MEM) {
> + base = XDMA_CHAN_C2H_OFFSET;
> + target = XDMA_CHAN_C2H_TARGET;
> + chans = &xdev->c2h_chans;
> + chan_num = &xdev->c2h_chan_num;
> + } else {
> + xdma_err(xdev, "invalid direction specified");
> + return -EINVAL;
> + }
> +
> + /* detect number of available DMA channels */
> + for (i = 0, *chan_num = 0; i < pdata->max_dma_channels; i++) {
> + ret = xdma_read_reg(xdev, base + i * XDMA_CHAN_STRIDE,
> + XDMA_CHAN_IDENTIFIER, &identifier);
> + if (ret)
> + return ret;
> +
> + /* check if it is available DMA channel */
> + if (XDMA_CHAN_CHECK_TARGET(identifier, target))
> + (*chan_num)++;
> + }
> +
> + if (!*chan_num) {
> + xdma_err(xdev, "does not probe any channel");
> + return -EINVAL;
> + }
> +
> + *chans = devm_kzalloc(&xdev->pdev->dev, sizeof(**chans) * (*chan_num),
> + GFP_KERNEL);
devm_kcalloc()?
> + if (!*chans)
> + return -ENOMEM;
> +
> + for (i = 0, j = 0; i < pdata->max_dma_channels; i++) {
> + ret = xdma_read_reg(xdev, base + i * XDMA_CHAN_STRIDE,
> + XDMA_CHAN_IDENTIFIER, &identifier);
> + if (ret)
> + return ret;
> +
> + if (!XDMA_CHAN_CHECK_TARGET(identifier, target))
> + continue;
> +
> + if (j == *chan_num) {
> + xdma_err(xdev, "invalid channel number");
> + return -EIO;
> + }
> +
> + /* init channel structure and hardware */
> + (*chans)[j].xdev_hdl = xdev;
> + (*chans)[j].base = base + i * XDMA_CHAN_STRIDE;
> + (*chans)[j].dir = dir;
Using a chan pointer locally might help you get rid of this and looks
and reads clean (bonus you get rid of errors in typos missing *)
> +
> + ret = xdma_channel_init(&(*chans)[j]);
> + if (ret)
> + return ret;
> + (*chans)[j].vchan.desc_free = xdma_free_desc;
> + vchan_init(&(*chans)[j].vchan, &xdev->dma_dev);
> +
> + j++;
> + }
> +
> + dev_info(&xdev->pdev->dev, "configured %d %s channels", j,
> + (dir == DMA_MEM_TO_DEV) ? "H2C" : "C2H");
> +
> + return 0;
> +}
> +
> +/**
> + * xdma_issue_pending - Issue pending transactions
> + * @chan: DMA channel pointer
> + */
> +static void xdma_issue_pending(struct dma_chan *chan)
> +{
> + struct xdma_chan *xdma_chan = to_xdma_chan(chan);
> + unsigned long flags;
> +
> + spin_lock_irqsave(&xdma_chan->vchan.lock, flags);
> + if (vchan_issue_pending(&xdma_chan->vchan))
> + xdma_xfer_start(xdma_chan);
> + spin_unlock_irqrestore(&xdma_chan->vchan.lock, flags);
> +}
> +
> +/**
> + * xdma_prep_device_sg - prepare a descriptor for a
> + * DMA transaction
single line pls
> + * @chan: DMA channel pointer
> + * @sgl: Transfer scatter gather list
> + * @sg_len: Length of scatter gather list
> + * @dir: Transfer direction
> + * @flags: transfer ack flags
> + * @context: APP words of the descriptor
> + */
> +static struct dma_async_tx_descriptor *
> +xdma_prep_device_sg(struct dma_chan *chan, struct scatterlist *sgl,
> + unsigned int sg_len, enum dma_transfer_direction dir,
> + unsigned long flags, void *context)
> +{
> + struct xdma_chan *xdma_chan = to_xdma_chan(chan);
> + struct dma_async_tx_descriptor *tx_desc;
> + u32 desc_num = 0, i, len, rest;
> + struct xdma_desc_block *dblk;
> + struct xdma_hw_desc *desc;
> + struct xdma_desc *sw_desc;
> + u64 dev_addr, *src, *dst;
> + struct scatterlist *sg;
> + u64 addr;
> +
> + for_each_sg(sgl, sg, sg_len, i)
> + desc_num += DIV_ROUND_UP(sg_dma_len(sg), XDMA_DESC_BLEN_MAX);
> +
> + sw_desc = xdma_alloc_desc(xdma_chan, desc_num);
> + if (!sw_desc)
> + return NULL;
> + sw_desc->dir = dir;
> +
> + if (dir == DMA_MEM_TO_DEV) {
> + dev_addr = xdma_chan->cfg.dst_addr;
> + src = &addr;
> + dst = &dev_addr;
> + } else {
> + dev_addr = xdma_chan->cfg.src_addr;
> + src = &dev_addr;
> + dst = &addr;
> + }
> +
> + dblk = sw_desc->desc_blocks;
> + desc = dblk->virt_addr;
> + desc_num = 1;
> + for_each_sg(sgl, sg, sg_len, i) {
> + addr = sg_dma_address(sg);
> + rest = sg_dma_len(sg);
> +
> + do {
> + len = min_t(u32, rest, XDMA_DESC_BLEN_MAX);
> + /* set hardware descriptor */
> + desc->bytes = cpu_to_le32(len);
> + desc->src_addr = cpu_to_le64(*src);
> + desc->dst_addr = cpu_to_le64(*dst);
> +
> + if (!(desc_num & XDMA_DESC_ADJACENT_MASK)) {
> + dblk++;
> + desc = dblk->virt_addr;
> + } else {
> + desc++;
> + }
> +
> + desc_num++;
> + dev_addr += len;
> + addr += len;
> + rest -= len;
> + } while (rest);
> + }
> +
> + tx_desc = vchan_tx_prep(&xdma_chan->vchan, &sw_desc->vdesc, flags);
> + if (!tx_desc)
> + goto failed;
> +
> + return tx_desc;
> +
> +failed:
> + xdma_free_desc(&sw_desc->vdesc);
> +
> + return NULL;
> +}
> +
> +/**
> + * xdma_device_config - Configure the DMA channel
> + * @chan: DMA channel
> + * @cfg: channel configuration
> + */
> +static int xdma_device_config(struct dma_chan *chan,
> + struct dma_slave_config *cfg)
> +{
> + struct xdma_chan *xdma_chan = to_xdma_chan(chan);
> +
> + memcpy(&xdma_chan->cfg, cfg, sizeof(*cfg));
> +
> + return 0;
> +}
> +
> +/**
> + * xdma_free_chan_resources - Free channel resources
> + * @chan: DMA channel
> + */
> +static void xdma_free_chan_resources(struct dma_chan *chan)
> +{
> + struct xdma_chan *xdma_chan = to_xdma_chan(chan);
> +
> + vchan_free_chan_resources(&xdma_chan->vchan);
> + dma_pool_destroy(xdma_chan->desc_pool);
> + xdma_chan->desc_pool = NULL;
> +}
> +
> +/**
> + * xdma_alloc_chan_resources - Allocate channel resources
> + * @chan: DMA channel
> + */
> +static int xdma_alloc_chan_resources(struct dma_chan *chan)
> +{
> + struct xdma_chan *xdma_chan = to_xdma_chan(chan);
> + struct xdma_device *xdev = xdma_chan->xdev_hdl;
> + struct device *dev = xdev->dma_dev.dev;
> +
> + while (dev && !dev_is_pci(dev))
> + dev = dev->parent;
> + if (!dev) {
> + xdma_err(xdev, "unable to find pci device");
> + return -EINVAL;
> + }
> +
> + xdma_chan->desc_pool = dma_pool_create(dma_chan_name(chan),
> + dev, XDMA_DESC_BLOCK_SIZE,
> + XDMA_DESC_BLOCK_ALIGN, 0);
> + if (!xdma_chan->desc_pool) {
> + xdma_err(xdev, "unable to allocate descriptor pool");
> + return -ENOMEM;
> + }
> +
> + return 0;
> +}
> +
> +/**
> + * xdma_channel_isr - XDMA channel interrupt handler
> + * @irq: IRQ number
> + * @dev_id: Pointer to the DMA channel structure
> + */
> +static irqreturn_t xdma_channel_isr(int irq, void *dev_id)
> +{
> + struct xdma_chan *xdma_chan = dev_id;
> + u32 complete_desc_num = 0;
> + struct virt_dma_desc *vd;
> + struct xdma_desc *desc;
> + int ret;
> +
> + spin_lock(&xdma_chan->vchan.lock);
> +
> + /* get submitted request */
> + vd = vchan_next_desc(&xdma_chan->vchan);
> + if (!vd)
> + goto out;
> +
> + xdma_chan->busy = false;
> + desc = to_xdma_desc(vd);
> +
> + ret = xdma_read_reg(xdma_chan->xdev_hdl, xdma_chan->base,
> + XDMA_CHAN_COMPLETED_DESC, &complete_desc_num);
> + if (ret)
> + goto out;
> +
> + desc->completed_desc_num += complete_desc_num;
> + /*
> + * if all data blocks are transferred, remove and complete the request
> + */
> + if (desc->completed_desc_num == desc->desc_num) {
> + list_del(&vd->node);
> + vchan_cookie_complete(vd);
> + goto out;
> + }
> +
> + if (desc->completed_desc_num > desc->desc_num ||
> + complete_desc_num != XDMA_DESC_BLOCK_NUM * XDMA_DESC_ADJACENT)
> + goto out;
> +
> + /* transfer the rest of data */
> + xdma_xfer_start(xdma_chan);
> +
> +out:
> + spin_unlock(&xdma_chan->vchan.lock);
> + return IRQ_HANDLED;
> +}
> +
> +/**
> + * xdma_irq_fini - Uninitialize IRQ
> + * @xdev: DMA device pointer
> + */
> +static void xdma_irq_fini(struct xdma_device *xdev)
> +{
> + int i;
> +
> + /* disable interrupt */
> + xdma_write_reg(xdev, XDMA_IRQ_BASE, XDMA_IRQ_CHAN_INT_EN_W1C, ~0);
> +
> + /* free irq handler */
> + for (i = 0; i < xdev->h2c_chan_num; i++)
> + free_irq(xdev->h2c_chans[i].irq, &xdev->h2c_chans[i]);
> +
> + for (i = 0; i < xdev->c2h_chan_num; i++)
> + free_irq(xdev->c2h_chans[i].irq, &xdev->c2h_chans[i]);
> +}
> +
> +/**
> + * xdma_set_vector_reg - configure hardware IRQ registers
> + * @xdev: DMA device pointer
> + * @vec_tbl_start: Start of IRQ registers
> + * @irq_start: Start of IRQ
> + * @irq_num: Number of IRQ
> + */
> +static int xdma_set_vector_reg(struct xdma_device *xdev, u32 vec_tbl_start,
> + u32 irq_start, u32 irq_num)
> +{
> + u32 shift, i, val = 0;
> + int ret;
> +
> + /* Each IRQ register is 32 bit and contains 4 IRQs */
> + while (irq_num > 0) {
> + for (i = 0; i < 4; i++) {
> + shift = XDMA_IRQ_VEC_SHIFT * i;
> + val |= irq_start << shift;
> + irq_start++;
> + irq_num--;
> + }
> +
> + /* write IRQ register */
> + ret = xdma_write_reg(xdev, XDMA_IRQ_BASE, vec_tbl_start, val);
> + if (ret)
> + return ret;
> + vec_tbl_start += sizeof(u32);
> + val = 0;
> + }
> +
> + return 0;
> +}
> +
> +/**
> + * xdma_irq_init - initialize IRQs
> + * @xdev: DMA device pointer
> + */
> +static int xdma_irq_init(struct xdma_device *xdev)
> +{
> + u32 irq = xdev->irq_start;
> + int i, j, ret;
> +
> + /* return failure if there are not enough IRQs */
> + if (xdev->irq_num < XDMA_CHAN_NUM(xdev)) {
> + xdma_err(xdev, "not enough irq");
> + return -EINVAL;
> + }
> +
> + /* setup H2C interrupt handler */
> + for (i = 0; i < xdev->h2c_chan_num; i++) {
> + ret = request_irq(irq, xdma_channel_isr, 0,
> + "xdma-h2c-channel", &xdev->h2c_chans[i]);
> + if (ret) {
> + xdma_err(xdev, "H2C channel%d request irq%d failed: %d",
> + i, irq, ret);
> + goto failed_init_h2c;
> + }
> + xdev->h2c_chans[i].irq = irq;
> + irq++;
> + }
> +
> + /* setup C2H interrupt handler */
> + for (j = 0; j < xdev->c2h_chan_num; j++) {
> + ret = request_irq(irq, xdma_channel_isr, 0,
> + "xdma-c2h-channel", &xdev->c2h_chans[j]);
> + if (ret) {
> + xdma_err(xdev, "H2C channel%d request irq%d failed: %d",
> + j, irq, ret);
> + goto failed_init_c2h;
> + }
> + xdev->c2h_chans[j].irq = irq;
> + irq++;
> + }
> +
> + /* config hardware IRQ registers */
> + ret = xdma_set_vector_reg(xdev, XDMA_IRQ_CHAN_VEC_NUM, 0,
> + XDMA_CHAN_NUM(xdev));
> + if (ret) {
> + xdma_err(xdev, "failed to set channel vectors: %d", ret);
> + goto failed_init_c2h;
> + }
> +
> + /* enable interrupt */
> + ret = xdma_write_reg(xdev, XDMA_IRQ_BASE, XDMA_IRQ_CHAN_INT_EN_W1S, ~0);
> + if (ret)
> + goto failed_init_c2h;
> +
> + return 0;
> +
> +failed_init_c2h:
> + while (j--)
> + free_irq(xdev->c2h_chans[j].irq, &xdev->c2h_chans[j]);
> +failed_init_h2c:
> + while (i--)
> + free_irq(xdev->h2c_chans[i].irq, &xdev->h2c_chans[i]);
> +
> + return ret;
> +}
> +
> +static bool xdma_filter_fn(struct dma_chan *chan, void *param)
> +{
> + struct xdma_chan *xdma_chan = to_xdma_chan(chan);
> + struct xdma_chan_info *chan_info = param;
> +
> + return chan_info->dir == xdma_chan->dir;
> +}
> +
> +/**
> + * xdma_remove - Driver remove function
> + * @pdev: Pointer to the platform_device structure
> + */
> +static int xdma_remove(struct platform_device *pdev)
> +{
> + struct xdma_device *xdev = platform_get_drvdata(pdev);
> +
> + if (xdev->status & XDMA_DEV_STATUS_INIT_MSIX)
> + xdma_irq_fini(xdev);
> +
> + if (xdev->status & XDMA_DEV_STATUS_REG_DMA)
> + dma_async_device_unregister(&xdev->dma_dev);
> +
> + return 0;
> +}
> +
> +/**
> + * xdma_probe - Driver probe function
> + * @pdev: Pointer to the platform_device structure
> + */
> +static int xdma_probe(struct platform_device *pdev)
> +{
> + struct xdma_platdata *pdata = dev_get_platdata(&pdev->dev);
> + struct xdma_device *xdev;
> + void __iomem *reg_base;
> + struct resource *res;
> + int ret = -ENODEV;
> +
> + if (pdata->max_dma_channels > XDMA_MAX_CHANNELS) {
> + dev_err(&pdev->dev, "invalid max dma channels %d",
> + pdata->max_dma_channels);
> + return -EINVAL;
> + }
> +
> + xdev = devm_kzalloc(&pdev->dev, sizeof(*xdev), GFP_KERNEL);
> + if (!xdev)
> + return -ENOMEM;
> +
> + platform_set_drvdata(pdev, xdev);
> + xdev->pdev = pdev;
> +
> + res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
> + if (!res) {
> + xdma_err(xdev, "failed to get irq resource");
> + goto failed;
> + }
> + xdev->irq_start = res->start;
> + xdev->irq_num = res->end - res->start + 1;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (!res) {
> + xdma_err(xdev, "failed to get io resource");
> + goto failed;
> + }
> +
> + reg_base = devm_ioremap_resource(&pdev->dev, res);
> + if (!reg_base) {
> + xdma_err(xdev, "ioremap failed");
> + goto failed;
> + }
> +
> + xdev->regmap = devm_regmap_init_mmio(&pdev->dev, reg_base,
> + &xdma_regmap_config);
> + if (!xdev->regmap) {
> + xdma_err(xdev, "config regmap failed: %d", ret);
> + goto failed;
> + }
> + INIT_LIST_HEAD(&xdev->dma_dev.channels);
> +
> + ret = xdma_config_channels(xdev, DMA_MEM_TO_DEV);
> + if (ret) {
> + xdma_err(xdev, "config H2C channels failed: %d", ret);
> + goto failed;
> + }
> +
> + ret = xdma_config_channels(xdev, DMA_DEV_TO_MEM);
> + if (ret) {
> + xdma_err(xdev, "config C2H channels failed: %d", ret);
> + goto failed;
> + }
> +
> + dma_cap_set(DMA_SLAVE, xdev->dma_dev.cap_mask);
> + dma_cap_set(DMA_PRIVATE, xdev->dma_dev.cap_mask);
> +
> + xdev->dma_dev.dev = &pdev->dev;
> + xdev->dma_dev.device_free_chan_resources = xdma_free_chan_resources;
> + xdev->dma_dev.device_alloc_chan_resources = xdma_alloc_chan_resources;
> + xdev->dma_dev.device_tx_status = dma_cookie_status;
> + xdev->dma_dev.device_prep_slave_sg = xdma_prep_device_sg;
> + xdev->dma_dev.device_config = xdma_device_config;
> + xdev->dma_dev.device_issue_pending = xdma_issue_pending;
> + xdev->dma_dev.filter.map = pdata->device_map;
> + xdev->dma_dev.filter.mapcnt = pdata->device_map_cnt;
> + xdev->dma_dev.filter.fn = xdma_filter_fn;
> +
> + ret = dma_async_device_register(&xdev->dma_dev);
> + if (ret) {
> + xdma_err(xdev, "failed to register Xilinx XDMA: %d", ret);
> + goto failed;
> + }
> + xdev->status |= XDMA_DEV_STATUS_REG_DMA;
> +
> + ret = xdma_irq_init(xdev);
> + if (ret) {
> + xdma_err(xdev, "failed to init msix: %d", ret);
> + goto failed;
> + }
> + xdev->status |= XDMA_DEV_STATUS_INIT_MSIX;
> +
> + return 0;
> +
> +failed:
> + xdma_remove(pdev);
> +
> + return ret;
> +}
> +
> +static const struct platform_device_id xdma_id_table[] = {
> + { "xdma", 0},
> + { },
> +};
> +
> +static struct platform_driver xdma_driver = {
> + .driver = {
> + .name = "xdma",
> + },
> + .id_table = xdma_id_table,
> + .probe = xdma_probe,
> + .remove = xdma_remove,
> +};
> +
> +module_platform_driver(xdma_driver);
who creates this platform device? Any reason why this is not a _real_
device?
> +
> +MODULE_DESCRIPTION("AMD XDMA driver");
> +MODULE_AUTHOR("XRT Team <runtimeca39d@xxxxxxx>");
> +MODULE_LICENSE("GPL");
> diff --git a/include/linux/platform_data/amd_xdma.h b/include/linux/platform_data/amd_xdma.h
> new file mode 100644
> index 000000000000..b5e23e14bac8
> --- /dev/null
> +++ b/include/linux/platform_data/amd_xdma.h
> @@ -0,0 +1,34 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/*
> + * Copyright (C) 2022, Advanced Micro Devices, Inc.
> + */
> +
> +#ifndef _PLATDATA_AMD_XDMA_H
> +#define _PLATDATA_AMD_XDMA_H
> +
> +#include <linux/dmaengine.h>
> +
> +/**
> + * struct xdma_chan_info - DMA channel information
> + * This information is used to match channel when request dma channel
> + * @dir: Channel transfer direction
> + */
> +struct xdma_chan_info {
> + enum dma_transfer_direction dir;
> +};
> +
> +#define XDMA_FILTER_PARAM(chan_info) ((void *)(chan_info))
> +
> +struct dma_slave_map;
> +
> +/**
> + * struct xdma_platdata - platform specific data for XDMA engine
> + * @max_dma_channels: Maximum dma channels in each direction
> + */
> +struct xdma_platdata {
> + u32 max_dma_channels;
> + u32 device_map_cnt;
> + struct dma_slave_map *device_map;
> +};
> +
> +#endif /* _PLATDATA_AMD_XDMA_H */
> --
> 2.27.0
--
~Vinod