Hi Vinod Koul,
   Thanks for your review.

On 2026/7/14 20:03, Vinod Koul wrote:
On 14-07-26, 08:08, Xianwei Zhao via B4 Relay wrote:
From: Xianwei Zhao<[email protected]>

Amlogic A9 SoCs include a general-purpose DMA controller that can be used
by multiple peripherals, such as I2C PIO and I3C. Each peripheral group
is associated with a dedicated DMA channel in hardware.

Reviewed-by: Frank Li<[email protected]>
Signed-off-by: Xianwei Zhao<[email protected]>
---
  drivers/dma/Kconfig       |  10 +
  drivers/dma/Makefile      |   1 +
  drivers/dma/amlogic-dma.c | 726 ++++++++++++++++++++++++++++++++++++++++++++++
  3 files changed, 737 insertions(+)

diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index ae6a682c9f76..01f96a8257e5 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -85,6 +85,16 @@ config AMCC_PPC440SPE_ADMA
       help
         Enable support for the AMCC PPC440SPe RAID engines.

+config AMLOGIC_DMA
+     tristate "Amlogic general DMA support"
+     depends on ARCH_MESON || COMPILE_TEST
+     select DMA_ENGINE
+     select DMA_VIRTUAL_CHANNELS
+     select REGMAP_MMIO
+     help
+       Enable support for the Amlogic general DMA engines. THis DMA
+       controller is used some Amlogic SoCs, such as A9.
+
  config APPLE_ADMAC
       tristate "Apple ADMAC support"
       depends on ARCH_APPLE || COMPILE_TEST
diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index 14aa086629d5..f62d12b08e15 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -16,6 +16,7 @@ obj-$(CONFIG_DMATEST) += dmatest.o
  obj-$(CONFIG_ALTERA_MSGDMA) += altera-msgdma.o
  obj-$(CONFIG_AMBA_PL08X) += amba-pl08x.o
  obj-$(CONFIG_AMCC_PPC440SPE_ADMA) += ppc4xx/
+obj-$(CONFIG_AMLOGIC_DMA) += amlogic-dma.o
  obj-$(CONFIG_APPLE_ADMAC) += apple-admac.o
  obj-$(CONFIG_ARM_DMA350) += arm-dma350.o
  obj-$(CONFIG_AT_HDMAC) += at_hdmac.o
diff --git a/drivers/dma/amlogic-dma.c b/drivers/dma/amlogic-dma.c
new file mode 100644
index 000000000000..9de650a79aba
--- /dev/null
+++ b/drivers/dma/amlogic-dma.c
@@ -0,0 +1,726 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR MIT)
+/*
+ * Copyright (C) 2025 Amlogic, Inc. All rights reserved
2026 please

+/* DMA controller reg */
+#define RCH_INT_MASK         0x1000
+#define WCH_INT_MASK         0x1004
+#define CLEAR_W_BATCH                0x1014
+#define CLEAR_RCH            0x1024
+#define CLEAR_WCH            0x1028
+#define RCH_ACTIVE           0x1038
+#define WCH_ACTIVE           0x103c
+#define RCH_DONE             0x104c
+#define WCH_DONE             0x1050
+#define RCH_ERR                      0x1060
+#define RCH_LEN_ERR          0x1064
+#define WCH_ERR                      0x1068
+#define DMA_BATCH_END                0x1078
+#define WCH_EOC_DONE         0x1088
+#define WDMA_RESP_ERR                0x1098
+#define UPT_PKT_SYNC         0x10a8
+#define RCHN_CFG             0x10ac
+#define WCHN_CFG             0x10b0
+#define MEM_PD_CFG           0x10b4
+#define MEM_BUS_CFG          0x10b8
+#define DMA_GMV_CFG          0x10bc
+#define DMA_GMR_CFG          0x10c0
+
+#define MAX_CHAN_ID          32
+#define SG_MAX_LEN           (GENMASK(26, 0) & ~0x3)
So you define a mask for 0-26 and then clear everything expect last two
bits, why not define last two bits..? Something does not look right here


Will do, define  GENMASK(26, 2)

+static int aml_dma_probe(struct platform_device *pdev)
+{
+     struct device_node *np = pdev->dev.of_node;
+     struct dma_device *dma_dev;
+     struct aml_dma_dev *aml_dma;
+     int ret, i, len;
+     u32 chan_nr;
+
+     const struct regmap_config aml_regmap_config = {
+             .reg_bits = 32,
+             .val_bits = 32,
+             .reg_stride = 4,
+             .max_register = 0x3000,
+     };
+
+     ret = of_property_read_u32(np, "dma-channels", &chan_nr);
+     if (ret)
+             return dev_err_probe(&pdev->dev, ret, "failed to read 
dma-channels\n");
+     if (chan_nr > (MAX_CHAN_ID * 2))
+             return dev_err_probe(&pdev->dev, -EINVAL, "dma-channels 
unusual\n");
+
+     len = sizeof(struct aml_dma_dev) + sizeof(struct aml_dma_chan) * chan_nr;
+     aml_dma = devm_kzalloc(&pdev->dev, len, GFP_KERNEL);
+     if (!aml_dma)
+             return -ENOMEM;
+
+     aml_dma->chan_nr = chan_nr;
+
+     aml_dma->base = devm_platform_ioremap_resource(pdev, 0);
+     if (IS_ERR(aml_dma->base))
+             return PTR_ERR(aml_dma->base);
+
+     aml_dma->regmap = devm_regmap_init_mmio(&pdev->dev, aml_dma->base,
+                                             &aml_regmap_config);
+     if (IS_ERR_OR_NULL(aml_dma->regmap))
+             return PTR_ERR(aml_dma->regmap);
+
+     aml_dma->clk = devm_clk_get_enabled(&pdev->dev, NULL);
+     if (IS_ERR(aml_dma->clk))
+             return PTR_ERR(aml_dma->clk);
+
+     aml_dma->irq = platform_get_irq(pdev, 0);
+
+     aml_dma->pdev = pdev;
+     aml_dma->dma_device.dev = &pdev->dev;
+
+     dma_dev = &aml_dma->dma_device;
+     INIT_LIST_HEAD(&dma_dev->channels);
+
+     /* Initialize channel parameters */
+     for (i = 0; i < chan_nr; i++) {
+             struct aml_dma_chan *aml_chan = &aml_dma->aml_chans[i];
+
+             aml_chan->aml_dma = aml_dma;
+             aml_chan->vchan.desc_free = aml_dma_free_desc;
+             vchan_init(&aml_chan->vchan, &aml_dma->dma_device);
+     }
+     aml_dma->chan_used = 0;
+
+     dma_set_max_seg_size(dma_dev->dev, SG_MAX_LEN);
+     dma_cap_set(DMA_SLAVE, dma_dev->cap_mask);
+     dma_dev->device_alloc_chan_resources = aml_dma_alloc_chan_resources;
+     dma_dev->device_free_chan_resources = aml_dma_free_chan_resources;
+     dma_dev->device_tx_status = aml_dma_tx_status;
+     dma_dev->device_prep_slave_sg = aml_dma_prep_slave_sg;
+     dma_dev->device_pause = aml_dma_chan_pause;
+     dma_dev->device_resume = aml_dma_chan_resume;
+     dma_dev->device_terminate_all = aml_dma_terminate_all;
+     dma_dev->device_issue_pending = aml_dma_issue_pending;
+     /* PIO 4 bytes and I2C 1 byte */
+     dma_dev->dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES) | 
BIT(DMA_SLAVE_BUSWIDTH_1_BYTE);
+     dma_dev->directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
+     dma_dev->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
+
+     regmap_write(aml_dma->regmap, RCH_INT_MASK, 0xffffffff);
+     regmap_write(aml_dma->regmap, WCH_INT_MASK, 0xffffffff);
I think we have macros for 32bit masks, please use that here and other
places

Will do.

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