Re: [PATCH V10 1/1] dmaengine: amd: qdma: Add AMD QDMA driver

Lizhi Hou
2024-04-08T18:06:31Z

On 4/7/24 06:21, Vinod Koul wrote:
> On 05-03-24, 13:49, Lizhi Hou wrote:
>> From: Nishad Saraf <nishads@amd.com>
>>
>> Adds driver to enable PCIe board which uses AMD QDMA (the Queue-based
>> Direct Memory Access) subsystem. For example, Xilinx Alveo V70 AI
>> Accelerator devices.
>> https://www.xilinx.com/applications/data-center/v70.html
>>
>> The QDMA subsystem is used in conjunction with the PCI Express IP block
>> to provide high performance data transfer between host memory and the
>> card's DMA subsystem.
>>
>> +-------+ +-------+ +-----------+
>> PCIe | | | | | |
>> Tx/Rx | | | | AXI | |
>> <=======> | PCIE | <===> | QDMA | <====>| User Logic|
>> | | | | | |
>> +-------+ +-------+ +-----------+
>>
>> The primary mechanism to transfer data using the QDMA is for the QDMA
>> engine to operate on instructions (descriptors) provided by the host
>> operating system. Using the descriptors, the QDMA can move data in both
>> the Host to Card (H2C) direction, or the Card to Host (C2H) direction.
>> The QDMA provides a per-queue basis option whether DMA traffic goes
>> to an AXI4 memory map (MM) interface or to an AXI4-Stream interface.
>>
>> The hardware detail is provided by
>> https://docs.xilinx.com/r/en-US/pg302-qdma
>>
>> Implements dmaengine APIs to support MM DMA transfers.
>> - 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 descriptor metadata operations to set device address for DMA
>> transfer
>>
>> Signed-off-by: Nishad Saraf <nishads@amd.com>
>> Signed-off-by: Lizhi Hou <lizhi.hou@amd.com>
>> ---
>> MAINTAINERS | 8 +
>> drivers/dma/Kconfig | 2 +
>> drivers/dma/Makefile | 1 +
>> drivers/dma/amd/Kconfig | 14 +
>> drivers/dma/amd/Makefile | 6 +
>> drivers/dma/amd/qdma/Makefile | 8 +
>> drivers/dma/amd/qdma/qdma-comm-regs.c | 64 ++
>> drivers/dma/amd/qdma/qdma.c | 1162 ++++++++++++++++++++++++
>> drivers/dma/amd/qdma/qdma.h | 265 ++++++
>> include/linux/platform_data/amd_qdma.h | 36 +
>> 10 files changed, 1566 insertions(+)
>> create mode 100644 drivers/dma/amd/Kconfig
>> create mode 100644 drivers/dma/amd/Makefile
>> create mode 100644 drivers/dma/amd/qdma/Makefile
>> create mode 100644 drivers/dma/amd/qdma/qdma-comm-regs.c
>> create mode 100644 drivers/dma/amd/qdma/qdma.c
>> create mode 100644 drivers/dma/amd/qdma/qdma.h
>> create mode 100644 include/linux/platform_data/amd_qdma.h
>>
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index 9ed4d3868539..d438214685d9 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -1063,6 +1063,14 @@ L: dmaengine@vger.kernel.org
>> S: Maintained
>> F: drivers/dma/ptdma/
>>
>> +AMD QDMA DRIVER
>> +M: Nishad Saraf <nishads@amd.com>
>> +M: Lizhi Hou <lizhi.hou@amd.com>
>> +L: dmaengine@vger.kernel.org
>> +S: Supported
>> +F: drivers/dma/amd/qdma/
>> +F: include/linux/platform_data/amd_qdma.h
>> +
>> AMD SEATTLE DEVICE TREE SUPPORT
>> M: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
>> M: Tom Lendacky <thomas.lendacky@amd.com>
>> diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
>> index e928f2ca0f1e..62d09090b94d 100644
>> --- a/drivers/dma/Kconfig
>> +++ b/drivers/dma/Kconfig
>> @@ -748,6 +748,8 @@ config XILINX_ZYNQMP_DPDMA
>> display driver.
>>
>> # driver files
>> +source "drivers/dma/amd/Kconfig"
>> +
>> source "drivers/dma/bestcomm/Kconfig"
>>
>> source "drivers/dma/mediatek/Kconfig"
>> diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
>> index dfd40d14e408..f2c614fcf2a4 100644
>> --- a/drivers/dma/Makefile
>> +++ b/drivers/dma/Makefile
>> @@ -84,6 +84,7 @@ obj-$(CONFIG_ST_FDMA) += st_fdma.o
>> obj-$(CONFIG_FSL_DPAA2_QDMA) += fsl-dpaa2-qdma/
>> obj-$(CONFIG_INTEL_LDMA) += lgm/
>>
>> +obj-y += amd/
>> obj-y += mediatek/
>> obj-y += qcom/
>> obj-y += ti/
>> diff --git a/drivers/dma/amd/Kconfig b/drivers/dma/amd/Kconfig
>> new file mode 100644
>> index 000000000000..7d1f51d69675
>> --- /dev/null
>> +++ b/drivers/dma/amd/Kconfig
>> @@ -0,0 +1,14 @@
>> +# SPDX-License-Identifier: GPL-2.0-only
>> +
>> +config AMD_QDMA
>> + tristate "AMD Queue-based DMA"
>> + depends on HAS_IOMEM
>> + select DMA_ENGINE
>> + select DMA_VIRTUAL_CHANNELS
>> + select REGMAP_MMIO
>> + help
>> + Enable support for the AMD Queue-based DMA subsystem. The primary
>> + mechanism to transfer data using the QDMA is for the QDMA engine to
>> + operate on instructions (descriptors) provided by the host operating
>> + system. Using the descriptors, the QDMA can move data in either the
>> + Host to Card (H2C) direction or the Card to Host (C2H) direction.
>> diff --git a/drivers/dma/amd/Makefile b/drivers/dma/amd/Makefile
>> new file mode 100644
>> index 000000000000..99c77de9a9dd
>> --- /dev/null
>> +++ b/drivers/dma/amd/Makefile
>> @@ -0,0 +1,6 @@
>> +# SPDX-License-Identifier: GPL-2.0
>> +#
>> +# Copyright (C) 2023, Advanced Micro Devices, Inc.
> Copyright for Makefile?
Ok. I will remove the Copyright
>
>> +#
>> +
>> +obj-$(CONFIG_AMD_QDMA) += qdma/
>> diff --git a/drivers/dma/amd/qdma/Makefile b/drivers/dma/amd/qdma/Makefile
>> new file mode 100644
>> index 000000000000..ba53971d2714
>> --- /dev/null
>> +++ b/drivers/dma/amd/qdma/Makefile
>> @@ -0,0 +1,8 @@
>> +# SPDX-License-Identifier: GPL-2.0
>> +#
>> +# Copyright (C) 2023, Advanced Micro Devices, Inc.
> 2024
I will fix this.
>> +#
>> +
>> +obj-$(CONFIG_AMD_QDMA) += amd-qdma.o
>> +
>> +amd-qdma-$(CONFIG_AMD_QDMA) := qdma.o qdma-comm-regs.o
>> diff --git a/drivers/dma/amd/qdma/qdma-comm-regs.c b/drivers/dma/amd/qdma/qdma-comm-regs.c
>> new file mode 100644
>> index 000000000000..14c7a73268b4
>> --- /dev/null
>> +++ b/drivers/dma/amd/qdma/qdma-comm-regs.c
>> @@ -0,0 +1,64 @@
>> +// SPDX-License-Identifier: GPL-2.0-or-later
>> +/*
>> + * Copyright (C) 2023, Advanced Micro Devices, Inc.
>> + */
>> +
>> +#ifndef __QDMA_REGS_DEF_H
>> +#define __QDMA_REGS_DEF_H
>> +
>> +#include "qdma.h"
>> +
>> +const struct qdma_reg qdma_regos_default[QDMA_REGO_MAX] = {
>> + [QDMA_REGO_CTXT_DATA] = QDMA_REGO(0x804, 8),
>> + [QDMA_REGO_CTXT_CMD] = QDMA_REGO(0x844, 1),
>> + [QDMA_REGO_CTXT_MASK] = QDMA_REGO(0x824, 8),
>> + [QDMA_REGO_MM_H2C_CTRL] = QDMA_REGO(0x1004, 1),
>> + [QDMA_REGO_MM_C2H_CTRL] = QDMA_REGO(0x1204, 1),
>> + [QDMA_REGO_QUEUE_COUNT] = QDMA_REGO(0x120, 1),
>> + [QDMA_REGO_RING_SIZE] = QDMA_REGO(0x204, 1),
>> + [QDMA_REGO_H2C_PIDX] = QDMA_REGO(0x18004, 1),
>> + [QDMA_REGO_C2H_PIDX] = QDMA_REGO(0x18008, 1),
>> + [QDMA_REGO_INTR_CIDX] = QDMA_REGO(0x18000, 1),
>> + [QDMA_REGO_FUNC_ID] = QDMA_REGO(0x12c, 1),
>> + [QDMA_REGO_ERR_INT] = QDMA_REGO(0xb04, 1),
>> + [QDMA_REGO_ERR_STAT] = QDMA_REGO(0x248, 1),
>> +};
>> +
>> +const struct qdma_reg_field qdma_regfs_default[QDMA_REGF_MAX] = {
>> + /* QDMA_REGO_CTXT_DATA fields */
>> + [QDMA_REGF_IRQ_ENABLE] = QDMA_REGF(53, 53),
>> + [QDMA_REGF_WBK_ENABLE] = QDMA_REGF(52, 52),
>> + [QDMA_REGF_WBI_CHECK] = QDMA_REGF(34, 34),
>> + [QDMA_REGF_IRQ_ARM] = QDMA_REGF(16, 16),
>> + [QDMA_REGF_IRQ_VEC] = QDMA_REGF(138, 128),
>> + [QDMA_REGF_IRQ_AGG] = QDMA_REGF(139, 139),
>> + [QDMA_REGF_WBI_INTVL_ENABLE] = QDMA_REGF(35, 35),
>> + [QDMA_REGF_MRKR_DISABLE] = QDMA_REGF(62, 62),
>> + [QDMA_REGF_QUEUE_ENABLE] = QDMA_REGF(32, 32),
>> + [QDMA_REGF_QUEUE_MODE] = QDMA_REGF(63, 63),
>> + [QDMA_REGF_DESC_BASE] = QDMA_REGF(127, 64),
>> + [QDMA_REGF_DESC_SIZE] = QDMA_REGF(49, 48),
>> + [QDMA_REGF_RING_ID] = QDMA_REGF(47, 44),
>> + [QDMA_REGF_QUEUE_BASE] = QDMA_REGF(11, 0),
>> + [QDMA_REGF_QUEUE_MAX] = QDMA_REGF(44, 32),
>> + [QDMA_REGF_FUNCTION_ID] = QDMA_REGF(24, 17),
>> + [QDMA_REGF_INTR_AGG_BASE] = QDMA_REGF(66, 15),
>> + [QDMA_REGF_INTR_VECTOR] = QDMA_REGF(11, 1),
>> + [QDMA_REGF_INTR_SIZE] = QDMA_REGF(69, 67),
>> + [QDMA_REGF_INTR_VALID] = QDMA_REGF(0, 0),
>> + [QDMA_REGF_INTR_COLOR] = QDMA_REGF(14, 14),
>> + [QDMA_REGF_INTR_FUNCTION_ID] = QDMA_REGF(125, 114),
>> + /* QDMA_REGO_CTXT_CMD fields */
>> + [QDMA_REGF_CMD_INDX] = QDMA_REGF(19, 7),
>> + [QDMA_REGF_CMD_CMD] = QDMA_REGF(6, 5),
>> + [QDMA_REGF_CMD_TYPE] = QDMA_REGF(4, 1),
>> + [QDMA_REGF_CMD_BUSY] = QDMA_REGF(0, 0),
>> + /* QDMA_REGO_QUEUE_COUNT fields */
>> + [QDMA_REGF_QUEUE_COUNT] = QDMA_REGF(11, 0),
>> + /* QDMA_REGO_ERR_INT fields */
>> + [QDMA_REGF_ERR_INT_FUNC] = QDMA_REGF(11, 0),
>> + [QDMA_REGF_ERR_INT_VEC] = QDMA_REGF(22, 12),
>> + [QDMA_REGF_ERR_INT_ARM] = QDMA_REGF(24, 24),
>> +};
>> +
>> +#endif /* __QDMA_REGS_DEF_H */
>> diff --git a/drivers/dma/amd/qdma/qdma.c b/drivers/dma/amd/qdma/qdma.c
>> new file mode 100644
>> index 000000000000..a1427a72c002
>> --- /dev/null
>> +++ b/drivers/dma/amd/qdma/qdma.c
>> @@ -0,0 +1,1162 @@
>> +// SPDX-License-Identifier: GPL-2.0-or-later
>> +/*
>> + * DMA driver for AMD Queue-based DMA Subsystem
>> + *
>> + * Copyright (C) 2023, Advanced Micro Devices, Inc.
>> + */
>> +#include <linux/bitfield.h>
>> +#include <linux/bitops.h>
>> +#include <linux/dmaengine.h>
>> +#include <linux/module.h>
>> +#include <linux/mod_devicetable.h>
>> +#include <linux/dma-map-ops.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/platform_data/amd_qdma.h>
>> +#include <linux/regmap.h>
>> +
>> +#include "qdma.h"
>> +
>> +#define CHAN_STR(q) (((q)->dir == DMA_MEM_TO_DEV) ? "H2C" : "C2H")
>> +#define QDMA_REG_OFF(d, r) ((d)->roffs[r].off)
>> +
>> +/* MMIO regmap config for all QDMA registers */
>> +static const struct regmap_config qdma_regmap_config = {
>> + .reg_bits = 32,
>> + .val_bits = 32,
>> + .reg_stride = 4,
>> +};
>> +
>> +static inline struct qdma_queue *to_qdma_queue(struct dma_chan *chan)
>> +{
>> + return container_of(chan, struct qdma_queue, vchan.chan);
>> +}
>> +
>> +static inline struct qdma_mm_vdesc *to_qdma_vdesc(struct virt_dma_desc *vdesc)
>> +{
>> + return container_of(vdesc, struct qdma_mm_vdesc, vdesc);
>> +}
>> +
>> +static inline u32 qdma_get_intr_ring_idx(struct qdma_device *qdev)
>> +{
>> + u32 idx;
>> +
>> + idx = qdev->qintr_rings[qdev->qintr_ring_idx++].ridx;
>> + qdev->qintr_ring_idx %= qdev->qintr_ring_num;
>> +
>> + return idx;
>> +}
>> +
>> +static u64 qdma_get_field(const struct qdma_device *qdev, const u32 *data,
>> + enum qdma_reg_fields field)
>> +{
>> + const struct qdma_reg_field *f = &qdev->rfields[field];
>> + u16 low_pos, hi_pos, low_bit, hi_bit;
>> + u64 value = 0, mask;
>> +
>> + low_pos = f->lsb / BITS_PER_TYPE(*data);
>> + hi_pos = f->msb / BITS_PER_TYPE(*data);
>> +
>> + if (low_pos == hi_pos) {
>> + low_bit = f->lsb % BITS_PER_TYPE(*data);
>> + hi_bit = f->msb % BITS_PER_TYPE(*data);
> why not use {upper|lower}_xx_bits

f->lsb and f->msb is not multiple of 16 or 32.  The code here is to

get the value of data(f->msb : f->lsb).

>
>> + mask = GENMASK(hi_bit, low_bit);
>> + value = (data[low_pos] & mask) >> low_bit;
>> + } else if (hi_pos == low_pos + 1) {
>> + low_bit = f->lsb % BITS_PER_TYPE(*data);
>> + hi_bit = low_bit + (f->msb - f->lsb);
>> + value = ((u64)data[hi_pos] << BITS_PER_TYPE(*data)) |
>> + data[low_pos];
>> + mask = GENMASK_ULL(hi_bit, low_bit);
>> + value = (value & mask) >> low_bit;
>> + } else {
>> + hi_bit = f->msb % BITS_PER_TYPE(*data);
>> + mask = GENMASK(hi_bit, 0);
>> + value = data[hi_pos] & mask;
>> + low_bit = f->msb - f->lsb - hi_bit;
>> + value <<= low_bit;
>> + low_bit -= 32;
>> + value |= (u64)data[hi_pos - 1] << low_bit;
>> + mask = GENMASK(31, 32 - low_bit);
>> + value |= (data[hi_pos - 2] & mask) >> low_bit;
>> + }
>> +
>> + return value;
>> +}
>> +
>> +static void qdma_set_field(const struct qdma_device *qdev, u32 *data,
>> + enum qdma_reg_fields field, u64 value)
>> +{
>> + const struct qdma_reg_field *f = &qdev->rfields[field];
>> + u16 low_pos, hi_pos, low_bit;
>> +
>> + low_pos = f->lsb / BITS_PER_TYPE(*data);
>> + hi_pos = f->msb / BITS_PER_TYPE(*data);
>> + low_bit = f->lsb % BITS_PER_TYPE(*data);
>> +
>> + data[low_pos++] |= value << low_bit;
>> + if (low_pos <= hi_pos)
>> + data[low_pos++] |= (u32)(value >> (32 - low_bit));
>> + if (low_pos <= hi_pos)
>> + data[low_pos] |= (u32)(value >> (64 - low_bit));
>> +}
>> +
>> +static inline int qdma_reg_write(const struct qdma_device *qdev,
>> + const u32 *data, enum qdma_regs reg)
>> +{
>> + const struct qdma_reg *r = &qdev->roffs[reg];
>> + int ret;
>> +
>> + if (r->count > 1)
>> + ret = regmap_bulk_write(qdev->regmap, r->off, data, r->count);
>> + else
>> + ret = regmap_write(qdev->regmap, r->off, *data);
>> +
>> + return ret;
>> +}
>> +
>> +static inline int qdma_reg_read(const struct qdma_device *qdev, u32 *data,
>> + enum qdma_regs reg)
>> +{
>> + const struct qdma_reg *r = &qdev->roffs[reg];
>> + int ret;
>> +
>> + if (r->count > 1)
>> + ret = regmap_bulk_read(qdev->regmap, r->off, data, r->count);
>> + else
>> + ret = regmap_read(qdev->regmap, r->off, data);
>> +
>> + return ret;
>> +}
>> +
>> +static int qdma_context_cmd_execute(const struct qdma_device *qdev,
>> + enum qdma_ctxt_type type,
>> + enum qdma_ctxt_cmd cmd, u16 index)
>> +{
>> + u32 value = 0;
>> + int ret;
>> +
>> + qdma_set_field(qdev, &value, QDMA_REGF_CMD_INDX, index);
>> + qdma_set_field(qdev, &value, QDMA_REGF_CMD_CMD, cmd);
>> + qdma_set_field(qdev, &value, QDMA_REGF_CMD_TYPE, type);
>> +
>> + ret = qdma_reg_write(qdev, &value, QDMA_REGO_CTXT_CMD);
>> + if (ret)
>> + return ret;
>> +
>> + ret = regmap_read_poll_timeout(qdev->regmap,
>> + QDMA_REG_OFF(qdev, QDMA_REGO_CTXT_CMD),
>> + value,
>> + !qdma_get_field(qdev, &value,
>> + QDMA_REGF_CMD_BUSY),
>> + QDMA_POLL_INTRVL_US,
>> + QDMA_POLL_TIMEOUT_US);
>> + if (ret) {
>> + qdma_err(qdev, "Context command execution timed out");
>> + return ret;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static int qdma_context_write_data(const struct qdma_device *qdev,
>> + const u32 *data)
>> +{
>> + u32 mask[QDMA_CTXT_REGMAP_LEN];
>> + int ret;
>> +
>> + memset(mask, ~0, sizeof(mask));
>> +
>> + ret = qdma_reg_write(qdev, mask, QDMA_REGO_CTXT_MASK);
>> + if (ret)
>> + return ret;
>> +
>> + ret = qdma_reg_write(qdev, data, QDMA_REGO_CTXT_DATA);
>> + if (ret)
>> + return ret;
>> +
>> + return 0;
>> +}
>> +
>> +static void qdma_prep_sw_desc_context(const struct qdma_device *qdev,
>> + const struct qdma_ctxt_sw_desc *ctxt,
>> + u32 *data)
>> +{
>> + memset(data, 0, QDMA_CTXT_REGMAP_LEN * sizeof(*data));
>> + qdma_set_field(qdev, data, QDMA_REGF_DESC_BASE, ctxt->desc_base);
>> + qdma_set_field(qdev, data, QDMA_REGF_IRQ_VEC, ctxt->vec);
>> + qdma_set_field(qdev, data, QDMA_REGF_FUNCTION_ID, qdev->fid);
>> +
>> + qdma_set_field(qdev, data, QDMA_REGF_DESC_SIZE, QDMA_DESC_SIZE_32B);
>> + qdma_set_field(qdev, data, QDMA_REGF_RING_ID, QDMA_DEFAULT_RING_ID);
>> + qdma_set_field(qdev, data, QDMA_REGF_QUEUE_MODE, QDMA_QUEUE_OP_MM);
>> + qdma_set_field(qdev, data, QDMA_REGF_IRQ_ENABLE, 1);
>> + qdma_set_field(qdev, data, QDMA_REGF_WBK_ENABLE, 1);
>> + qdma_set_field(qdev, data, QDMA_REGF_WBI_CHECK, 1);
>> + qdma_set_field(qdev, data, QDMA_REGF_IRQ_ARM, 1);
>> + qdma_set_field(qdev, data, QDMA_REGF_IRQ_AGG, 1);
>> + qdma_set_field(qdev, data, QDMA_REGF_WBI_INTVL_ENABLE, 1);
>> + qdma_set_field(qdev, data, QDMA_REGF_QUEUE_ENABLE, 1);
>> + qdma_set_field(qdev, data, QDMA_REGF_MRKR_DISABLE, 1);
>> +}
>> +
>> +static void qdma_prep_intr_context(const struct qdma_device *qdev,
>> + const struct qdma_ctxt_intr *ctxt,
>> + u32 *data)
>> +{
>> + memset(data, 0, QDMA_CTXT_REGMAP_LEN * sizeof(*data));
>> + qdma_set_field(qdev, data, QDMA_REGF_INTR_AGG_BASE, ctxt->agg_base);
>> + qdma_set_field(qdev, data, QDMA_REGF_INTR_VECTOR, ctxt->vec);
>> + qdma_set_field(qdev, data, QDMA_REGF_INTR_SIZE, ctxt->size);
>> + qdma_set_field(qdev, data, QDMA_REGF_INTR_VALID, ctxt->valid);
>> + qdma_set_field(qdev, data, QDMA_REGF_INTR_COLOR, ctxt->color);
>> + qdma_set_field(qdev, data, QDMA_REGF_INTR_FUNCTION_ID, qdev->fid);
>> +}
>> +
>> +static void qdma_prep_fmap_context(const struct qdma_device *qdev,
>> + const struct qdma_ctxt_fmap *ctxt,
>> + u32 *data)
>> +{
>> + memset(data, 0, QDMA_CTXT_REGMAP_LEN * sizeof(*data));
>> + qdma_set_field(qdev, data, QDMA_REGF_QUEUE_BASE, ctxt->qbase);
>> + qdma_set_field(qdev, data, QDMA_REGF_QUEUE_MAX, ctxt->qmax);
>> +}
>> +
>> +/*
>> + * Program the indirect context register space
>> + *
>> + * Once the queue is enabled, context is dynamically updated by hardware. Any
>> + * modification of the context through this API when the queue is enabled can
>> + * result in unexpected behavior. Reading the context when the queue is enabled
>> + * is not recommended as it can result in reduced performance.
>> + */
>> +static int qdma_prog_context(struct qdma_device *qdev, enum qdma_ctxt_type type,
>> + enum qdma_ctxt_cmd cmd, u16 index, u32 *ctxt)
>> +{
>> + int ret;
>> +
>> + mutex_lock(&qdev->ctxt_lock);
>> + if (cmd == QDMA_CTXT_WRITE) {
>> + ret = qdma_context_write_data(qdev, ctxt);
>> + if (ret)
>> + goto failed;
>> + }
>> +
>> + ret = qdma_context_cmd_execute(qdev, type, cmd, index);
>> + if (ret)
>> + goto failed;
>> +
>> + if (cmd == QDMA_CTXT_READ) {
>> + ret = qdma_reg_read(qdev, ctxt, QDMA_REGO_CTXT_DATA);
>> + if (ret)
>> + goto failed;
>> + }
>> +
>> +failed:
>> + mutex_unlock(&qdev->ctxt_lock);
>> +
>> + return ret;
>> +}
>> +
>> +static int qdma_check_queue_status(struct qdma_device *qdev,
>> + enum dma_transfer_direction dir, u16 qid)
>> +{
>> + u32 status, data[QDMA_CTXT_REGMAP_LEN] = {0};
>> + enum qdma_ctxt_type type;
>> + int ret;
>> +
>> + if (dir == DMA_MEM_TO_DEV)
>> + type = QDMA_CTXT_DESC_SW_H2C;
>> + else
>> + type = QDMA_CTXT_DESC_SW_C2H;
>> +
>> + ret = qdma_prog_context(qdev, type, QDMA_CTXT_READ, qid, data);
>> + if (ret)
>> + return ret;
>> +
>> + status = qdma_get_field(qdev, data, QDMA_REGF_QUEUE_ENABLE);
>> + if (status) {
>> + qdma_err(qdev, "queue %d already in use", qid);
>> + return -EBUSY;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static int qdma_clear_queue_context(const struct qdma_queue *queue)
>> +{
>> + enum qdma_ctxt_type h2c_types[] = { QDMA_CTXT_DESC_SW_H2C,
>> + QDMA_CTXT_DESC_HW_H2C,
>> + QDMA_CTXT_DESC_CR_H2C,
>> + QDMA_CTXT_PFTCH, };
>> + enum qdma_ctxt_type c2h_types[] = { QDMA_CTXT_DESC_SW_C2H,
>> + QDMA_CTXT_DESC_HW_C2H,
>> + QDMA_CTXT_DESC_CR_C2H,
>> + QDMA_CTXT_PFTCH, };
>> + struct qdma_device *qdev = queue->qdev;
>> + enum qdma_ctxt_type *type;
>> + int ret, num, i;
>> +
>> + if (queue->dir == DMA_MEM_TO_DEV) {
>> + type = h2c_types;
>> + num = ARRAY_SIZE(h2c_types);
>> + } else {
>> + type = c2h_types;
>> + num = ARRAY_SIZE(c2h_types);
>> + }
>> + for (i = 0; i < num; i++) {
>> + ret = qdma_prog_context(qdev, type[i], QDMA_CTXT_CLEAR,
>> + queue->qid, NULL);
>> + if (ret) {
>> + qdma_err(qdev, "Failed to clear ctxt %d", type[i]);
>> + return ret;
>> + }
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static int qdma_setup_fmap_context(struct qdma_device *qdev)
>> +{
>> + u32 ctxt[QDMA_CTXT_REGMAP_LEN];
>> + struct qdma_ctxt_fmap fmap;
>> + int ret;
>> +
>> + ret = qdma_prog_context(qdev, QDMA_CTXT_FMAP, QDMA_CTXT_CLEAR,
>> + qdev->fid, NULL);
>> + if (ret) {
>> + qdma_err(qdev, "Failed clearing context");
>> + return ret;
>> + }
>> +
>> + fmap.qbase = 0;
>> + fmap.qmax = qdev->chan_num * 2;
>> + qdma_prep_fmap_context(qdev, &fmap, ctxt);
>> + ret = qdma_prog_context(qdev, QDMA_CTXT_FMAP, QDMA_CTXT_WRITE,
>> + qdev->fid, ctxt);
>> + if (ret)
>> + qdma_err(qdev, "Failed setup fmap, ret %d", ret);
>> +
>> + return ret;
>> +}
>> +
>> +static int qdma_setup_queue_context(struct qdma_device *qdev,
>> + const struct qdma_ctxt_sw_desc *sw_desc,
>> + enum dma_transfer_direction dir, u16 qid)
>> +{
>> + u32 ctxt[QDMA_CTXT_REGMAP_LEN];
>> + enum qdma_ctxt_type type;
>> + int ret;
>> +
>> + if (dir == DMA_MEM_TO_DEV)
>> + type = QDMA_CTXT_DESC_SW_H2C;
>> + else
>> + type = QDMA_CTXT_DESC_SW_C2H;
>> +
>> + qdma_prep_sw_desc_context(qdev, sw_desc, ctxt);
>> + /* Setup SW descriptor context */
>> + ret = qdma_prog_context(qdev, type, QDMA_CTXT_WRITE, qid, ctxt);
>> + if (ret)
>> + qdma_err(qdev, "Failed setup SW desc ctxt for queue: %d", qid);
>> +
>> + return ret;
>> +}
>> +
>> +/*
>> + * Enable or disable memory-mapped DMA engines
>> + * 1: enable, 0: disable
>> + */
>> +static int qdma_sgdma_control(struct qdma_device *qdev, u32 ctrl)
>> +{
>> + int ret;
>> +
>> + ret = qdma_reg_write(qdev, &ctrl, QDMA_REGO_MM_H2C_CTRL);
>> + ret |= qdma_reg_write(qdev, &ctrl, QDMA_REGO_MM_C2H_CTRL);
>> +
>> + return ret;
>> +}
>> +
>> +static int qdma_get_hw_info(struct qdma_device *qdev)
>> +{
>> + struct qdma_platdata *pdata = dev_get_platdata(&qdev->pdev->dev);
>> + u32 value = 0;
>> + int ret;
>> +
>> + ret = qdma_reg_read(qdev, &value, QDMA_REGO_QUEUE_COUNT);
>> + if (ret)
>> + return ret;
>> +
>> + value = qdma_get_field(qdev, &value, QDMA_REGF_QUEUE_COUNT) + 1;
>> + if (pdata->max_mm_channels * 2 > value) {
>> + qdma_err(qdev, "not enough hw queues %d", value);
>> + return -EINVAL;
>> + }
>> + qdev->chan_num = pdata->max_mm_channels;
>> +
>> + ret = qdma_reg_read(qdev, &qdev->fid, QDMA_REGO_FUNC_ID);
>> + if (ret)
>> + return ret;
>> +
>> + qdma_info(qdev, "max channel %d, function id %d",
>> + qdev->chan_num, qdev->fid);
>> +
>> + return 0;
>> +}
>> +
>> +static inline int qdma_update_pidx(const struct qdma_queue *queue, u16 pidx)
>> +{
>> + struct qdma_device *qdev = queue->qdev;
>> +
>> + return regmap_write(qdev->regmap, queue->pidx_reg,
>> + pidx | QDMA_QUEUE_ARM_BIT);
>> +}
>> +
>> +static inline int qdma_update_cidx(const struct qdma_queue *queue,
>> + u16 ridx, u16 cidx)
>> +{
>> + struct qdma_device *qdev = queue->qdev;
>> +
>> + return regmap_write(qdev->regmap, queue->cidx_reg,
>> + ((u32)ridx << 16) | cidx);
>> +}
>> +
>> +/**
>> + * qdma_free_vdesc - Free descriptor
>> + * @vdesc: Virtual DMA descriptor
>> + */
>> +static void qdma_free_vdesc(struct virt_dma_desc *vdesc)
>> +{
>> + struct qdma_mm_vdesc *vd = to_qdma_vdesc(vdesc);
>> +
>> + kfree(vd);
>> +}
>> +
>> +static int qdma_alloc_queues(struct qdma_device *qdev,
>> + enum dma_transfer_direction dir)
>> +{
>> + struct qdma_queue *q, **queues;
>> + u32 i, pidx_base;
>> + int ret;
>> +
>> + if (dir == DMA_MEM_TO_DEV) {
>> + queues = &qdev->h2c_queues;
>> + pidx_base = QDMA_REG_OFF(qdev, QDMA_REGO_H2C_PIDX);
>> + } else {
>> + queues = &qdev->c2h_queues;
>> + pidx_base = QDMA_REG_OFF(qdev, QDMA_REGO_C2H_PIDX);
>> + }
>> +
>> + *queues = devm_kcalloc(&qdev->pdev->dev, qdev->chan_num, sizeof(*q),
>> + GFP_KERNEL);
>> + if (!*queues)
>> + return -ENOMEM;
>> +
>> + for (i = 0; i < qdev->chan_num; i++) {
>> + ret = qdma_check_queue_status(qdev, dir, i);
>> + if (ret)
>> + return ret;
>> +
>> + q = &(*queues)[i];
>> + q->ring_size = QDMA_DEFAULT_RING_SIZE;
>> + q->idx_mask = q->ring_size - 2;
>> + q->qdev = qdev;
>> + q->dir = dir;
>> + q->qid = i;
>> + q->pidx_reg = pidx_base + i * QDMA_DMAP_REG_STRIDE;
>> + q->cidx_reg = QDMA_REG_OFF(qdev, QDMA_REGO_INTR_CIDX) +
>> + i * QDMA_DMAP_REG_STRIDE;
>> + q->vchan.desc_free = qdma_free_vdesc;
>> + vchan_init(&q->vchan, &qdev->dma_dev);
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static int qdma_device_verify(struct qdma_device *qdev)
>> +{
>> + u32 value;
>> + int ret;
>> +
>> + ret = regmap_read(qdev->regmap, QDMA_IDENTIFIER_REGOFF, &value);
>> + if (ret)
>> + return ret;
>> +
>> + value = FIELD_GET(QDMA_IDENTIFIER_MASK, value);
>> + if (value != QDMA_IDENTIFIER) {
>> + qdma_err(qdev, "Invalid identifier");
>> + return -ENODEV;
>> + }
>> + qdev->rfields = qdma_regfs_default;
>> + qdev->roffs = qdma_regos_default;
>> +
>> + return 0;
>> +}
>> +
>> +static int qdma_device_setup(struct qdma_device *qdev)
>> +{
>> + struct device *dev = &qdev->pdev->dev;
>> + u32 ring_sz = QDMA_DEFAULT_RING_SIZE;
>> + int ret = 0;
>> +
>> + while (dev && get_dma_ops(dev))
>> + dev = dev->parent;
>> + if (!dev) {
>> + qdma_err(qdev, "dma device not found");
>> + return -EINVAL;
>> + }
>> + set_dma_ops(&qdev->pdev->dev, get_dma_ops(dev));
>> +
>> + ret = qdma_setup_fmap_context(qdev);
>> + if (ret) {
>> + qdma_err(qdev, "Failed setup fmap context");
>> + return ret;
>> + }
>> +
>> + /* Setup global ring buffer size at QDMA_DEFAULT_RING_ID index */
>> + ret = qdma_reg_write(qdev, &ring_sz, QDMA_REGO_RING_SIZE);
>> + if (ret) {
>> + qdma_err(qdev, "Failed to setup ring %d of size %ld",
>> + QDMA_DEFAULT_RING_ID, QDMA_DEFAULT_RING_SIZE);
>> + return ret;
>> + }
>> +
>> + /* Enable memory-mapped DMA engine in both directions */
>> + ret = qdma_sgdma_control(qdev, 1);
>> + if (ret) {
>> + qdma_err(qdev, "Failed to SGDMA with error %d", ret);
>> + return ret;
>> + }
>> +
>> + ret = qdma_alloc_queues(qdev, DMA_MEM_TO_DEV);
>> + if (ret) {
>> + qdma_err(qdev, "Failed to alloc H2C queues, ret %d", ret);
>> + return ret;
>> + }
>> +
>> + ret = qdma_alloc_queues(qdev, DMA_DEV_TO_MEM);
>> + if (ret) {
>> + qdma_err(qdev, "Failed to alloc C2H queues, ret %d", ret);
>> + return ret;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +/**
>> + * qdma_free_queue_resources() - Free queue resources
>> + * @chan: DMA channel
>> + */
>> +static void qdma_free_queue_resources(struct dma_chan *chan)
>> +{
>> + struct qdma_queue *queue = to_qdma_queue(chan);
>> + struct qdma_device *qdev = queue->qdev;
>> + struct device *dev = qdev->dma_dev.dev;
>> +
>> + qdma_clear_queue_context(queue);
>> + vchan_free_chan_resources(&queue->vchan);
>> + dma_free_coherent(dev, queue->ring_size * QDMA_MM_DESC_SIZE,
>> + queue->desc_base, queue->dma_desc_base);
>> +}
>> +
>> +/**
>> + * qdma_alloc_queue_resources() - Allocate queue resources
>> + * @chan: DMA channel
>> + */
>> +static int qdma_alloc_queue_resources(struct dma_chan *chan)
>> +{
>> + struct qdma_queue *queue = to_qdma_queue(chan);
>> + struct qdma_device *qdev = queue->qdev;
>> + struct qdma_ctxt_sw_desc desc;
>> + size_t size;
>> + int ret;
>> +
>> + ret = qdma_clear_queue_context(queue);
>> + if (ret)
>> + return ret;
>> +
>> + size = queue->ring_size * QDMA_MM_DESC_SIZE;
>> + queue->desc_base = dma_alloc_coherent(qdev->dma_dev.dev, size,
>> + &queue->dma_desc_base,
>> + GFP_KERNEL);
>> + if (!queue->desc_base) {
>> + qdma_err(qdev, "Failed to allocate descriptor ring");
>> + return -ENOMEM;
>> + }
>> +
>> + /* Setup SW descriptor queue context for DMA memory map */
>> + desc.vec = qdma_get_intr_ring_idx(qdev);
>> + desc.desc_base = queue->dma_desc_base;
>> + ret = qdma_setup_queue_context(qdev, &desc, queue->dir, queue->qid);
>> + if (ret) {
>> + qdma_err(qdev, "Failed to setup SW desc ctxt for %s",
>> + chan->name);
>> + dma_free_coherent(qdev->dma_dev.dev, size, queue->desc_base,
>> + queue->dma_desc_base);
>> + return ret;
>> + }
>> +
>> + queue->pidx = 0;
>> + queue->cidx = 0;
>> +
>> + return 0;
>> +}
>> +
>> +static bool qdma_filter_fn(struct dma_chan *chan, void *param)
>> +{
>> + struct qdma_queue *queue = to_qdma_queue(chan);
>> + struct qdma_queue_info *info = param;
>> +
>> + return info->dir == queue->dir;
>> +}
>> +
>> +static int qdma_xfer_start(struct qdma_queue *queue)
>> +{
>> + struct qdma_device *qdev = queue->qdev;
>> + int ret;
>> +
>> + if (!vchan_next_desc(&queue->vchan))
>> + return 0;
>> +
>> + qdma_dbg(qdev, "Tnx kickoff with P: %d for %s%d",
>> + queue->issued_vdesc->pidx, CHAN_STR(queue), queue->qid);
>> +
>> + ret = qdma_update_pidx(queue, queue->issued_vdesc->pidx);
>> + if (ret) {
>> + qdma_err(qdev, "Failed to update PIDX to %d for %s queue: %d",
>> + queue->pidx, CHAN_STR(queue), queue->qid);
>> + }
>> +
>> + return ret;
>> +}
>> +
>> +static void qdma_issue_pending(struct dma_chan *chan)
>> +{
>> + struct qdma_queue *queue = to_qdma_queue(chan);
>> + unsigned long flags;
>> +
>> + spin_lock_irqsave(&queue->vchan.lock, flags);
>> + if (vchan_issue_pending(&queue->vchan)) {
>> + if (queue->submitted_vdesc) {
>> + queue->issued_vdesc = queue->submitted_vdesc;
>> + queue->submitted_vdesc = NULL;
>> + }
>> + qdma_xfer_start(queue);
>> + }
>> +
>> + spin_unlock_irqrestore(&queue->vchan.lock, flags);
>> +}
>> +
>> +static struct qdma_mm_desc *qdma_get_desc(struct qdma_queue *q)
>> +{
>> + struct qdma_mm_desc *desc;
>> +
>> + if (((q->pidx + 1) & q->idx_mask) == q->cidx)
>> + return NULL;
>> +
>> + desc = q->desc_base + q->pidx;
>> + q->pidx = (q->pidx + 1) & q->idx_mask;
>> +
>> + return desc;
>> +}
>> +
>> +static int qdma_hw_enqueue(struct qdma_queue *q, struct qdma_mm_vdesc *vdesc)
>> +{
>> + struct qdma_mm_desc *desc;
>> + struct scatterlist *sg;
>> + u64 addr, *src, *dst;
>> + u32 rest, len;
>> + int ret = 0;
>> + u32 i;
>> +
>> + if (!vdesc->sg_len)
>> + return 0;
>> +
>> + if (q->dir == DMA_MEM_TO_DEV) {
>> + dst = &vdesc->dev_addr;
>> + src = &addr;
>> + } else {
>> + dst = &addr;
>> + src = &vdesc->dev_addr;
>> + }
>> +
>> + for_each_sg(vdesc->sgl, sg, vdesc->sg_len, i) {
>> + addr = sg_dma_address(sg) + vdesc->sg_off;
>> + rest = sg_dma_len(sg) - vdesc->sg_off;
>> + while (rest) {
>> + len = min_t(u32, rest, QDMA_MM_DESC_MAX_LEN);
>> + desc = qdma_get_desc(q);
>> + if (!desc) {
>> + ret = -EBUSY;
>> + goto out;
>> + }
>> +
>> + desc->src_addr = cpu_to_le64(*src);
>> + desc->dst_addr = cpu_to_le64(*dst);
>> + desc->len = cpu_to_le32(len);
>> +
>> + vdesc->dev_addr += len;
>> + vdesc->sg_off += len;
>> + vdesc->pending_descs++;
>> + addr += len;
>> + rest -= len;
>> + }
>> + vdesc->sg_off = 0;
>> + }
>> +out:
>> + vdesc->sg_len -= i;
>> + vdesc->pidx = q->pidx;
>> + return ret;
>> +}
>> +
>> +static void qdma_fill_pending_vdesc(struct qdma_queue *q)
>> +{
>> + struct virt_dma_chan *vc = &q->vchan;
>> + struct qdma_mm_vdesc *vdesc = NULL;
>> + struct virt_dma_desc *vd;
>> + int ret;
>> +
>> + if (!list_empty(&vc->desc_issued)) {
>> + vd = &q->issued_vdesc->vdesc;
>> + list_for_each_entry_from(vd, &vc->desc_issued, node) {
>> + vdesc = to_qdma_vdesc(vd);
>> + ret = qdma_hw_enqueue(q, vdesc);
>> + if (ret) {
>> + q->issued_vdesc = vdesc;
>> + return;
>> + }
>> + }
>> + q->issued_vdesc = vdesc;
>> + }
>> +
>> + if (list_empty(&vc->desc_submitted))
>> + return;
>> +
>> + if (q->submitted_vdesc)
>> + vd = &q->submitted_vdesc->vdesc;
>> + else
>> + vd = list_first_entry(&vc->desc_submitted, typeof(*vd), node);
>> +
>> + list_for_each_entry_from(vd, &vc->desc_submitted, node) {
>> + vdesc = to_qdma_vdesc(vd);
>> + ret = qdma_hw_enqueue(q, vdesc);
>> + if (ret)
>> + break;
>> + }
>> + q->submitted_vdesc = vdesc;
>> +}
>> +
>> +static dma_cookie_t qdma_tx_submit(struct dma_async_tx_descriptor *tx)
>> +{
>> + struct virt_dma_chan *vc = to_virt_chan(tx->chan);
>> + struct qdma_queue *q = to_qdma_queue(&vc->chan);
>> + struct virt_dma_desc *vd;
>> + unsigned long flags;
>> + dma_cookie_t cookie;
>> +
>> + vd = container_of(tx, struct virt_dma_desc, tx);
>> + spin_lock_irqsave(&vc->lock, flags);
>> + cookie = dma_cookie_assign(tx);
>> +
>> + list_move_tail(&vd->node, &vc->desc_submitted);
>> + qdma_fill_pending_vdesc(q);
>> + spin_unlock_irqrestore(&vc->lock, flags);
>> +
>> + return cookie;
>> +}
>> +
>> +static void *qdma_get_metadata_ptr(struct dma_async_tx_descriptor *tx,
>> + size_t *payload_len, size_t *max_len)
>> +{
>> + struct qdma_mm_vdesc *vdesc;
>> +
>> + vdesc = container_of(tx, typeof(*vdesc), vdesc.tx);
>> + if (payload_len)
>> + *payload_len = sizeof(vdesc->dev_addr);
>> + if (max_len)
>> + *max_len = sizeof(vdesc->dev_addr);
>> +
>> + return &vdesc->dev_addr;
> Can you describe what metadata is being used here for?

The metadata is the device address the dma request will transfer

data to / from.  Please see the example usage here:

https://github.com/houlz0507/XRT-1/blob/qdma_v1_usage/src/runtime_src/core/pcie/driver/linux/xocl/subdev/qdma.c#L311

Before dmaengine_submit(), it specifies the device address.

>
>> +}
>> +
>> +static int qdma_set_metadata_len(struct dma_async_tx_descriptor *tx,
>> + size_t payload_len)
>> +{
>> + struct qdma_mm_vdesc *vdesc;
>> +
>> + vdesc = container_of(tx, typeof(*vdesc), vdesc.tx);
>> + if (payload_len != sizeof(vdesc->dev_addr))
>> + return -EINVAL;
>> +
>> + return 0;
>> +}
>> +
>> +static struct dma_descriptor_metadata_ops metadata_ops = {
>> + .get_ptr = qdma_get_metadata_ptr,
>> + .set_len = qdma_set_metadata_len,
>> +};
>> +
>> +static struct dma_async_tx_descriptor *
>> +qdma_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 qdma_queue *q = to_qdma_queue(chan);
>> + struct dma_async_tx_descriptor *tx;
>> + struct qdma_mm_vdesc *vdesc;
>> +
>> + vdesc = kzalloc(sizeof(*vdesc), GFP_NOWAIT);
>> + if (!vdesc)
>> + return NULL;
>> + vdesc->sgl = sgl;
>> + vdesc->sg_len = sg_len;
>> +
>> + tx = vchan_tx_prep(&q->vchan, &vdesc->vdesc, flags);
>> + tx->tx_submit = qdma_tx_submit;
>> + tx->metadata_ops = &metadata_ops;
>> +
>> + return tx;
>> +}
>> +
>> +static int qdma_arm_err_intr(const struct qdma_device *qdev)
>> +{
>> + u32 value = 0;
>> +
>> + qdma_set_field(qdev, &value, QDMA_REGF_ERR_INT_FUNC, qdev->fid);
>> + qdma_set_field(qdev, &value, QDMA_REGF_ERR_INT_VEC, qdev->err_irq_idx);
>> + qdma_set_field(qdev, &value, QDMA_REGF_ERR_INT_ARM, 1);
>> +
>> + return qdma_reg_write(qdev, &value, QDMA_REGO_ERR_INT);
>> +}
>> +
>> +static irqreturn_t qdma_error_isr(int irq, void *data)
>> +{
>> + struct qdma_device *qdev = data;
>> + u32 err_stat = 0;
>> + int ret;
>> +
>> + ret = qdma_reg_read(qdev, &err_stat, QDMA_REGO_ERR_STAT);
>> + if (ret) {
>> + qdma_err(qdev, "read error state failed, ret %d", ret);
>> + goto out;
>> + }
>> +
>> + qdma_err(qdev, "global error %d", err_stat);
>> + ret = qdma_reg_write(qdev, &err_stat, QDMA_REGO_ERR_STAT);
>> + if (ret)
>> + qdma_err(qdev, "clear error state failed, ret %d", ret);
>> +
>> +out:
>> + qdma_arm_err_intr(qdev);
>> + return IRQ_HANDLED;
>> +}
>> +
>> +static irqreturn_t qdma_queue_isr(int irq, void *data)
>> +{
>> + struct qdma_intr_ring *intr = data;
>> + struct qdma_queue *q = NULL;
>> + struct qdma_device *qdev;
>> + u32 index, comp_desc;
>> + u64 intr_ent;
>> + u8 color;
>> + int ret;
>> + u16 qid;
>> +
>> + qdev = intr->qdev;
>> + index = intr->cidx;
>> + while (1) {
>> + struct virt_dma_desc *vd;
>> + struct qdma_mm_vdesc *vdesc;
>> + unsigned long flags;
>> + u32 cidx;
>> +
>> + intr_ent = le64_to_cpu(intr->base[index]);
>> + color = FIELD_GET(QDMA_INTR_MASK_COLOR, intr_ent);
>> + if (color != intr->color)
>> + break;
>> +
>> + qid = FIELD_GET(QDMA_INTR_MASK_QID, intr_ent);
>> + if (FIELD_GET(QDMA_INTR_MASK_TYPE, intr_ent))
>> + q = qdev->c2h_queues;
>> + else
>> + q = qdev->h2c_queues;
>> + q += qid;
>> +
>> + cidx = FIELD_GET(QDMA_INTR_MASK_CIDX, intr_ent);
>> +
>> + spin_lock_irqsave(&q->vchan.lock, flags);
>> + comp_desc = (cidx - q->cidx) & q->idx_mask;
>> +
>> + vd = vchan_next_desc(&q->vchan);
>> + if (!vd)
>> + goto skip;
>> +
>> + vdesc = to_qdma_vdesc(vd);
>> + while (comp_desc > vdesc->pending_descs) {
>> + list_del(&vd->node);
>> + vchan_cookie_complete(vd);
>> + comp_desc -= vdesc->pending_descs;
>> + vd = vchan_next_desc(&q->vchan);
>> + vdesc = to_qdma_vdesc(vd);
>> + }
>> + vdesc->pending_descs -= comp_desc;
>> + if (!vdesc->pending_descs && QDMA_VDESC_QUEUED(vdesc)) {
>> + list_del(&vd->node);
>> + vchan_cookie_complete(vd);
>> + }
>> + q->cidx = cidx;
>> +
>> + qdma_fill_pending_vdesc(q);
>> + qdma_xfer_start(q);
>> +
>> +skip:
>> + spin_unlock_irqrestore(&q->vchan.lock, flags);
>> +
>> + /*
>> + * Wrap the index value and flip the expected color value if
>> + * interrupt aggregation PIDX has wrapped around.
>> + */
>> + index++;
>> + index &= QDMA_INTR_RING_IDX_MASK;
>> + if (!index)
>> + intr->color = !intr->color;
>> + }
>> +
>> + /*
>> + * Update the software interrupt aggregation ring CIDX if a valid entry
>> + * was found.
>> + */
>> + if (q) {
>> + qdma_dbg(qdev, "update intr ring%d %d", intr->ridx, index);
>> +
>> + /*
>> + * Record the last read index of status descriptor from the
>> + * interrupt aggregation ring.
>> + */
>> + intr->cidx = index;
>> +
>> + ret = qdma_update_cidx(q, intr->ridx, index);
>> + if (ret) {
>> + qdma_err(qdev, "Failed to update IRQ CIDX");
>> + return IRQ_NONE;
>> + }
>> + }
>> +
>> + return IRQ_HANDLED;
>> +}
>> +
>> +static int qdma_init_error_irq(struct qdma_device *qdev)
>> +{
>> + struct device *dev = &qdev->pdev->dev;
>> + int ret;
>> + u32 vec;
>> +
>> + vec = qdev->queue_irq_start - 1;
>> +
>> + ret = devm_request_threaded_irq(dev, vec, NULL, qdma_error_isr,
>> + IRQF_ONESHOT, "amd-qdma-error", qdev);
>> + if (ret) {
>> + qdma_err(qdev, "Failed to request error IRQ vector: %d", vec);
>> + return ret;
>> + }
>> +
>> + ret = qdma_arm_err_intr(qdev);
>> + if (ret)
>> + qdma_err(qdev, "Failed to arm err interrupt, ret %d", ret);
>> +
>> + return ret;
>> +}
>> +
>> +static int qdmam_alloc_qintr_rings(struct qdma_device *qdev)
>> +{
>> + u32 ctxt[QDMA_CTXT_REGMAP_LEN];
>> + struct device *dev = &qdev->pdev->dev;
>> + struct qdma_intr_ring *ring;
>> + struct qdma_ctxt_intr intr_ctxt;
>> + u32 vector;
>> + int ret, i;
>> +
>> + qdev->qintr_ring_num = qdev->queue_irq_num;
>> + qdev->qintr_rings = devm_kcalloc(dev, qdev->qintr_ring_num,
>> + sizeof(*qdev->qintr_rings),
>> + GFP_KERNEL);
>> + if (!qdev->qintr_rings)
>> + return -ENOMEM;
>> +
>> + vector = qdev->queue_irq_start;
>> + for (i = 0; i < qdev->qintr_ring_num; i++, vector++) {
>> + ring = &qdev->qintr_rings[i];
>> + ring->qdev = qdev;
>> + ring->msix_id = qdev->err_irq_idx + i + 1;
>> + ring->ridx = i;
>> + ring->color = 1;
>> + ring->base = dmam_alloc_coherent(dev, QDMA_INTR_RING_SIZE,
>> + &ring->dev_base, GFP_KERNEL);
>> + if (!ring->base) {
>> + qdma_err(qdev, "Failed to alloc intr ring %d", i);
>> + return -ENOMEM;
>> + }
>> + intr_ctxt.agg_base = QDMA_INTR_RING_BASE(ring->dev_base);
>> + intr_ctxt.size = (QDMA_INTR_RING_SIZE - 1) / 4096;
>> + intr_ctxt.vec = ring->msix_id;
>> + intr_ctxt.valid = true;
>> + intr_ctxt.color = true;
>> + ret = qdma_prog_context(qdev, QDMA_CTXT_INTR_COAL,
>> + QDMA_CTXT_CLEAR, ring->ridx, NULL);
>> + if (ret) {
>> + qdma_err(qdev, "Failed clear intr ctx, ret %d", ret);
>> + return ret;
>> + }
>> +
>> + qdma_prep_intr_context(qdev, &intr_ctxt, ctxt);
>> + ret = qdma_prog_context(qdev, QDMA_CTXT_INTR_COAL,
>> + QDMA_CTXT_WRITE, ring->ridx, ctxt);
>> + if (ret) {
>> + qdma_err(qdev, "Failed setup intr ctx, ret %d", ret);
>> + return ret;
>> + }
>> +
>> + ret = devm_request_threaded_irq(dev, vector, NULL,
>> + qdma_queue_isr, IRQF_ONESHOT,
>> + "amd-qdma-queue", ring);
>> + if (ret) {
>> + qdma_err(qdev, "Failed to request irq %d", vector);
>> + return ret;
>> + }
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static int qdma_intr_init(struct qdma_device *qdev)
>> +{
>> + int ret;
>> +
>> + ret = qdma_init_error_irq(qdev);
>> + if (ret) {
>> + qdma_err(qdev, "Failed to init error IRQs, ret %d", ret);
>> + return ret;
>> + }
>> +
>> + ret = qdmam_alloc_qintr_rings(qdev);
>> + if (ret) {
>> + qdma_err(qdev, "Failed to init queue IRQs, ret %d", ret);
>> + return ret;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static void amd_qdma_remove(struct platform_device *pdev)
>> +{
>> + struct qdma_device *qdev = platform_get_drvdata(pdev);
>> +
>> + qdma_sgdma_control(qdev, 0);
>> + dma_async_device_unregister(&qdev->dma_dev);
>> +
>> + mutex_destroy(&qdev->ctxt_lock);
>> +}
>> +
>> +static int amd_qdma_probe(struct platform_device *pdev)
>> +{
>> + struct qdma_platdata *pdata = dev_get_platdata(&pdev->dev);
>> + struct qdma_device *qdev;
>> + struct resource *res;
>> + void __iomem *regs;
>> + int ret;
>> +
>> + qdev = devm_kzalloc(&pdev->dev, sizeof(*qdev), GFP_KERNEL);
>> + if (!qdev)
>> + return -ENOMEM;
>> +
>> + platform_set_drvdata(pdev, qdev);
>> + qdev->pdev = pdev;
>> + mutex_init(&qdev->ctxt_lock);
>> +
>> + res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
>> + if (!res) {
>> + qdma_err(qdev, "Failed to get IRQ resource");
>> + ret = -ENODEV;
>> + goto failed;
>> + }
>> + qdev->err_irq_idx = pdata->irq_index;
>> + qdev->queue_irq_start = res->start + 1;
>> + qdev->queue_irq_num = resource_size(res) - 1;
>> +
>> + regs = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
>> + if (IS_ERR(regs)) {
>> + ret = PTR_ERR(regs);
>> + qdma_err(qdev, "Failed to map IO resource, err %d", ret);
>> + goto failed;
>> + }
>> +
>> + qdev->regmap = devm_regmap_init_mmio(&pdev->dev, regs,
>> + &qdma_regmap_config);
>> + if (IS_ERR(qdev->regmap)) {
>> + ret = PTR_ERR(qdev->regmap);
>> + qdma_err(qdev, "Regmap init failed, err %d", ret);
>> + goto failed;
>> + }
>> +
>> + ret = qdma_device_verify(qdev);
>> + if (ret)
>> + goto failed;
>> +
>> + ret = qdma_get_hw_info(qdev);
>> + if (ret)
>> + goto failed;
>> +
>> + INIT_LIST_HEAD(&qdev->dma_dev.channels);
>> +
>> + ret = qdma_device_setup(qdev);
>> + if (ret)
>> + goto failed;
>> +
>> + ret = qdma_intr_init(qdev);
>> + if (ret) {
>> + qdma_err(qdev, "Failed to initialize IRQs %d", ret);
>> + goto failed_disable_engine;
>> + }
>> +
>> + dma_cap_set(DMA_SLAVE, qdev->dma_dev.cap_mask);
>> + dma_cap_set(DMA_PRIVATE, qdev->dma_dev.cap_mask);
>> +
>> + qdev->dma_dev.dev = &pdev->dev;
>> + qdev->dma_dev.filter.map = pdata->device_map;
>> + qdev->dma_dev.filter.mapcnt = qdev->chan_num * 2;
>> + qdev->dma_dev.filter.fn = qdma_filter_fn;
>> + qdev->dma_dev.desc_metadata_modes = DESC_METADATA_ENGINE;
>> + qdev->dma_dev.device_alloc_chan_resources = qdma_alloc_queue_resources;
>> + qdev->dma_dev.device_free_chan_resources = qdma_free_queue_resources;
>> + qdev->dma_dev.device_prep_slave_sg = qdma_prep_device_sg;
>> + qdev->dma_dev.device_issue_pending = qdma_issue_pending;
>> + qdev->dma_dev.device_tx_status = dma_cookie_status;
>> + qdev->dma_dev.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
>> +
>> + ret = dma_async_device_register(&qdev->dma_dev);
>> + if (ret) {
>> + qdma_err(qdev, "Failed to register AMD QDMA: %d", ret);
>> + goto failed_disable_engine;
>> + }
>> +
>> + return 0;
>> +
>> +failed_disable_engine:
>> + qdma_sgdma_control(qdev, 0);
>> +failed:
>> + mutex_destroy(&qdev->ctxt_lock);
>> + qdma_err(qdev, "Failed to probe AMD QDMA driver");
>> + return ret;
>> +}
>> +
>> +static struct platform_driver amd_qdma_driver = {
>> + .driver = {
>> + .name = "amd-qdma",
>> + },
>> + .probe = amd_qdma_probe,
>> + .remove_new = amd_qdma_remove,
>> +};
>> +
>> +module_platform_driver(amd_qdma_driver);
>> +
>> +MODULE_DESCRIPTION("AMD QDMA driver");
>> +MODULE_AUTHOR("XRT Team <runtimeca39d@amd.com>");
>> +MODULE_LICENSE("GPL");
>> diff --git a/drivers/dma/amd/qdma/qdma.h b/drivers/dma/amd/qdma/qdma.h
>> new file mode 100644
>> index 000000000000..268fbad9f0a2
>> --- /dev/null
>> +++ b/drivers/dma/amd/qdma/qdma.h
>> @@ -0,0 +1,265 @@
>> +/* SPDX-License-Identifier: GPL-2.0-or-later */
>> +/*
>> + * DMA header for AMD Queue-based DMA Subsystem
>> + *
>> + * Copyright (C) 2023, Advanced Micro Devices, Inc.
>> + */
>> +
>> +#ifndef __QDMA_H
>> +#define __QDMA_H
>> +
>> +#include <linux/bitfield.h>
>> +#include <linux/dmaengine.h>
>> +#include <linux/kernel.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/regmap.h>
>> +
>> +#include "../../virt-dma.h"
>> +
>> +#define DISABLE 0
>> +#define ENABLE 1
>> +
>> +#define QDMA_MIN_IRQ 3
>> +#define QDMA_INTR_NAME_MAX_LEN 30
>> +#define QDMA_INTR_PREFIX "amd-qdma"
>> +
>> +#define QDMA_IDENTIFIER 0x1FD3
>> +#define QDMA_DEFAULT_RING_SIZE (BIT(10) + 1)
>> +#define QDMA_DEFAULT_RING_ID 0
>> +#define QDMA_POLL_INTRVL_US 10 /* 10us */
>> +#define QDMA_POLL_TIMEOUT_US (500 * 1000) /* 500ms */
>> +#define QDMA_DMAP_REG_STRIDE 16
>> +#define QDMA_CTXT_REGMAP_LEN 8 /* 8 regs */
>> +#define QDMA_MM_DESC_SIZE 32 /* Bytes */
>> +#define QDMA_MM_DESC_LEN_BITS 28
>> +#define QDMA_MM_DESC_MAX_LEN (BIT(QDMA_MM_DESC_LEN_BITS) - 1)
>> +#define QDMA_MIN_DMA_ALLOC_SIZE 4096
>> +#define QDMA_INTR_RING_SIZE BIT(13)
>> +#define QDMA_INTR_RING_IDX_MASK GENMASK(9, 0)
>> +#define QDMA_INTR_RING_BASE(_addr) ((_addr) >> 12)
>> +
>> +#define QDMA_IDENTIFIER_REGOFF 0x0
>> +#define QDMA_IDENTIFIER_MASK GENMASK(31, 16)
>> +#define QDMA_QUEUE_ARM_BIT BIT(16)
>> +
>> +#define qdma_err(qdev, fmt, args...) \
>> + dev_err(&(qdev)->pdev->dev, fmt, ##args)
>> +
>> +#define qdma_dbg(qdev, fmt, args...) \
>> + dev_dbg(&(qdev)->pdev->dev, fmt, ##args)
>> +
>> +#define qdma_info(qdev, fmt, args...) \
>> + dev_info(&(qdev)->pdev->dev, fmt, ##args)
>> +
>> +enum qdma_reg_fields {
>> + QDMA_REGF_IRQ_ENABLE,
>> + QDMA_REGF_WBK_ENABLE,
>> + QDMA_REGF_WBI_CHECK,
>> + QDMA_REGF_IRQ_ARM,
>> + QDMA_REGF_IRQ_VEC,
>> + QDMA_REGF_IRQ_AGG,
>> + QDMA_REGF_WBI_INTVL_ENABLE,
>> + QDMA_REGF_MRKR_DISABLE,
>> + QDMA_REGF_QUEUE_ENABLE,
>> + QDMA_REGF_QUEUE_MODE,
>> + QDMA_REGF_DESC_BASE,
>> + QDMA_REGF_DESC_SIZE,
>> + QDMA_REGF_RING_ID,
>> + QDMA_REGF_CMD_INDX,
>> + QDMA_REGF_CMD_CMD,
>> + QDMA_REGF_CMD_TYPE,
>> + QDMA_REGF_CMD_BUSY,
>> + QDMA_REGF_QUEUE_COUNT,
>> + QDMA_REGF_QUEUE_MAX,
>> + QDMA_REGF_QUEUE_BASE,
>> + QDMA_REGF_FUNCTION_ID,
>> + QDMA_REGF_INTR_AGG_BASE,
>> + QDMA_REGF_INTR_VECTOR,
>> + QDMA_REGF_INTR_SIZE,
>> + QDMA_REGF_INTR_VALID,
>> + QDMA_REGF_INTR_COLOR,
>> + QDMA_REGF_INTR_FUNCTION_ID,
>> + QDMA_REGF_ERR_INT_FUNC,
>> + QDMA_REGF_ERR_INT_VEC,
>> + QDMA_REGF_ERR_INT_ARM,
>> + QDMA_REGF_MAX
>> +};
>> +
>> +enum qdma_regs {
>> + QDMA_REGO_CTXT_DATA,
>> + QDMA_REGO_CTXT_CMD,
>> + QDMA_REGO_CTXT_MASK,
>> + QDMA_REGO_MM_H2C_CTRL,
>> + QDMA_REGO_MM_C2H_CTRL,
>> + QDMA_REGO_QUEUE_COUNT,
>> + QDMA_REGO_RING_SIZE,
>> + QDMA_REGO_H2C_PIDX,
>> + QDMA_REGO_C2H_PIDX,
>> + QDMA_REGO_INTR_CIDX,
>> + QDMA_REGO_FUNC_ID,
>> + QDMA_REGO_ERR_INT,
>> + QDMA_REGO_ERR_STAT,
>> + QDMA_REGO_MAX
>> +};
>> +
>> +struct qdma_reg_field {
>> + u16 lsb; /* Least significant bit of field */
>> + u16 msb; /* Most significant bit of field */
>> +};
>> +
>> +struct qdma_reg {
>> + u32 off;
>> + u32 count;
>> +};
>> +
>> +#define QDMA_REGF(_msb, _lsb) { \
>> + .lsb = (_lsb), \
>> + .msb = (_msb), \
>> +}
>> +
>> +#define QDMA_REGO(_off, _count) { \
>> + .off = (_off), \
>> + .count = (_count), \
>> +}
>> +
>> +enum qdma_desc_size {
>> + QDMA_DESC_SIZE_8B,
>> + QDMA_DESC_SIZE_16B,
>> + QDMA_DESC_SIZE_32B,
>> + QDMA_DESC_SIZE_64B,
>> +};
>> +
>> +enum qdma_queue_op_mode {
>> + QDMA_QUEUE_OP_STREAM,
>> + QDMA_QUEUE_OP_MM,
>> +};
>> +
>> +enum qdma_ctxt_type {
>> + QDMA_CTXT_DESC_SW_C2H,
>> + QDMA_CTXT_DESC_SW_H2C,
>> + QDMA_CTXT_DESC_HW_C2H,
>> + QDMA_CTXT_DESC_HW_H2C,
>> + QDMA_CTXT_DESC_CR_C2H,
>> + QDMA_CTXT_DESC_CR_H2C,
>> + QDMA_CTXT_WRB,
>> + QDMA_CTXT_PFTCH,
>> + QDMA_CTXT_INTR_COAL,
>> + QDMA_CTXT_RSVD,
>> + QDMA_CTXT_HOST_PROFILE,
>> + QDMA_CTXT_TIMER,
>> + QDMA_CTXT_FMAP,
>> + QDMA_CTXT_FNC_STS,
>> +};
>> +
>> +enum qdma_ctxt_cmd {
>> + QDMA_CTXT_CLEAR,
>> + QDMA_CTXT_WRITE,
>> + QDMA_CTXT_READ,
>> + QDMA_CTXT_INVALIDATE,
>> + QDMA_CTXT_MAX
>> +};
>> +
>> +struct qdma_ctxt_sw_desc {
>> + u64 desc_base;
>> + u16 vec;
>> +};
>> +
>> +struct qdma_ctxt_intr {
>> + u64 agg_base;
>> + u16 vec;
>> + u32 size;
>> + bool valid;
>> + bool color;
>> +};
>> +
>> +struct qdma_ctxt_fmap {
>> + u16 qbase;
>> + u16 qmax;
>> +};
>> +
>> +struct qdma_device;
>> +
>> +struct qdma_mm_desc {
>> + __le64 src_addr;
>> + __le32 len;
>> + __le32 reserved1;
>> + __le64 dst_addr;
>> + __le64 reserved2;
>> +} __packed;
>> +
>> +struct qdma_mm_vdesc {
>> + struct virt_dma_desc vdesc;
>> + struct qdma_queue *queue;
>> + struct scatterlist *sgl;
>> + u64 sg_off;
>> + u32 sg_len;
>> + u64 dev_addr;
>> + u32 pidx;
>> + u32 pending_descs;
>> +};
>> +
>> +#define QDMA_VDESC_QUEUED(vdesc) (!(vdesc)->sg_len)
>> +
>> +struct qdma_queue {
>> + struct qdma_device *qdev;
>> + struct virt_dma_chan vchan;
>> + enum dma_transfer_direction dir;
>> + struct dma_slave_config cfg;
>> + struct qdma_mm_desc *desc_base;
>> + struct qdma_mm_vdesc *submitted_vdesc;
>> + struct qdma_mm_vdesc *issued_vdesc;
>> + dma_addr_t dma_desc_base;
>> + u32 pidx_reg;
>> + u32 cidx_reg;
>> + u32 ring_size;
>> + u32 idx_mask;
>> + u16 qid;
>> + u32 pidx;
>> + u32 cidx;
>> +};
>> +
>> +struct qdma_intr_ring {
>> + struct qdma_device *qdev;
>> + __le64 *base;
>> + dma_addr_t dev_base;
>> + char msix_name[QDMA_INTR_NAME_MAX_LEN];
>> + u32 msix_vector;
>> + u16 msix_id;
>> + u32 ring_size;
>> + u16 ridx;
>> + u16 cidx;
>> + u8 color;
>> +};
>> +
>> +#define QDMA_INTR_MASK_PIDX GENMASK_ULL(15, 0)
>> +#define QDMA_INTR_MASK_CIDX GENMASK_ULL(31, 16)
>> +#define QDMA_INTR_MASK_DESC_COLOR GENMASK_ULL(32, 32)
>> +#define QDMA_INTR_MASK_STATE GENMASK_ULL(34, 33)
>> +#define QDMA_INTR_MASK_ERROR GENMASK_ULL(36, 35)
>> +#define QDMA_INTR_MASK_TYPE GENMASK_ULL(38, 38)
>> +#define QDMA_INTR_MASK_QID GENMASK_ULL(62, 39)
>> +#define QDMA_INTR_MASK_COLOR GENMASK_ULL(63, 63)
>> +
>> +struct qdma_device {
>> + struct platform_device *pdev;
>> + struct dma_device dma_dev;
>> + struct regmap *regmap;
>> + struct mutex ctxt_lock; /* protect ctxt registers */
>> + const struct qdma_reg_field *rfields;
>> + const struct qdma_reg *roffs;
>> + struct qdma_queue *h2c_queues;
>> + struct qdma_queue *c2h_queues;
>> + struct qdma_intr_ring *qintr_rings;
>> + u32 qintr_ring_num;
>> + u32 qintr_ring_idx;
>> + u32 chan_num;
>> + u32 queue_irq_start;
>> + u32 queue_irq_num;
>> + u32 err_irq_idx;
>> + u32 fid;
>> +};
>> +
>> +extern const struct qdma_reg qdma_regos_default[QDMA_REGO_MAX];
>> +extern const struct qdma_reg_field qdma_regfs_default[QDMA_REGF_MAX];
>> +
>> +#endif /* __QDMA_H */
>> diff --git a/include/linux/platform_data/amd_qdma.h b/include/linux/platform_data/amd_qdma.h
>> new file mode 100644
>> index 000000000000..59fa0c174f70
>> --- /dev/null
>> +++ b/include/linux/platform_data/amd_qdma.h
>> @@ -0,0 +1,36 @@
>> +/* SPDX-License-Identifier: GPL-2.0-or-later */
>> +/*
>> + * Copyright (C) 2023, Advanced Micro Devices, Inc.
>> + */
>> +
>> +#ifndef _PLATDATA_AMD_QDMA_H
>> +#define _PLATDATA_AMD_QDMA_H
>> +
>> +#include <linux/dmaengine.h>
>> +
>> +/**
>> + * struct qdma_queue_info - DMA queue information. This information is used to
>> + * match queue when DMA channel is requested
>> + * @dir: Channel transfer direction
>> + */
>> +struct qdma_queue_info {
>> + enum dma_transfer_direction dir;
>> +};
> why is dma_transfer_direction here, why not use prep_ calls for passing
> that around?

This is used for dma_dev.filter.fn callback. It is an extra check for
dma_request_chan().

It happens before prep_ calls.

>
>> +
>> +#define QDMA_FILTER_PARAM(qinfo) ((void *)(qinfo))
>> +
>> +struct dma_slave_map;
>> +
>> +/**
>> + * struct qdma_platdata - Platform specific data for QDMA engine
>> + * @max_mm_channels: Maximum number of MM DMA channels in each direction
>> + * @device_map: DMA slave map
>> + * @irq_index: The index of first IRQ
>> + */
>> +struct qdma_platdata {
>> + u32 max_mm_channels;
>> + u32 irq_index;
>> + struct dma_slave_map *device_map;
>> +};
> why should this be plat data?

The QDMA IP has the same usage cases with Xilinx XDMA IP.
(platform_data/amd_xdma.h)

The device driver for the product (such as Alveo) which uses XDMA IP
will instantiate the

platform driver and populate the platdata.

Thanks,

Lizhi

>