* [PATCH v6 2/2] dmaengine: atcdmac300: Add driver for Andes ATCDMAC300 DMA controller
2026-09-11 7:25 [PATCH v6 0/2] dmaengine: atcdmac300: Add Andes ATCDMAC300 DMA driver CL Wang
2026-09-11 7:25 ` [PATCH v6 1/2] dt-bindings: dmaengine: Add support for ATCDMAC300 DMA engine CL Wang
@ 2026-09-11 7:25 ` CL Wang
2026-09-11 7:57 ` sashiko-bot
1 sibling, 1 reply; 5+ messages in thread
From: CL Wang @ 2026-09-11 7:25 UTC (permalink / raw)
To: Vinod Koul, Rob Herring, Krzysztof Kozlowski, Conor Dooley
Cc: Frank Li, Kees Cook, Gustavo A . R . Silva, tim609, cl634,
dmaengine, devicetree, linux-hardening, linux-kernel
This patch adds support for the Andes ATCDMAC300 DMA controller.
The ATCDMAC300 is a memory-to-memory and peripheral DMA controller
that provides scatter-gather, cyclic, and slave transfer capabilities.
Signed-off-by: CL Wang <cl634@andestech.com>
---
Changes for v6:
- Rebase onto dmaengine/next; no functional changes from v5
- Fold the MAINTAINERS entry into this patch instead of carrying it
as a separate patch
Changes for v5:
- Update copyright year to 2026
- Remove redundant headers (init.h, iopoll.h, mod_devicetable.h)
- Move atcdmac_init_iocp() before of_dma_controller_register() in probe
- Change builtin_platform_driver() to module_platform_driver()
- Implement .remove callback to support safe module unloading
- Update Kconfig entry from bool to tristate
- Add MODULE_AUTHOR, MODULE_DESCRIPTION, MODULE_LICENSE macros
Changes for v4:
- No changes from v3
Changes for v3:
- Remove "andestech,atcdmac300" from of_device_id
- Replace deprecated tasklet with threaded IRQ using
devm_request_threaded_irq() and IRQF_ONESHOT to handle bottom-half
processing.
- Update locking mechanism from spin_lock_bh() to spin_lock_irqsave()
- Minor cleanups and correctness fixes
- Initialize descriptor pointers (first = NULL) explicitly
- Add missing headers (err.h, iopoll.h, log2.h, sprintf.h)
- Remove unused code paths related to tasklets
- Use builtin_platform_driver() instead of module_platform_driver()
- Remove "select DMATEST" from Kconfig
---
MAINTAINERS | 6 +
drivers/dma/Kconfig | 11 +
drivers/dma/Makefile | 1 +
drivers/dma/atcdmac300.c | 1518 ++++++++++++++++++++++++++++++++++++++
drivers/dma/atcdmac300.h | 296 ++++++++
5 files changed, 1832 insertions(+)
create mode 100644 drivers/dma/atcdmac300.c
create mode 100644 drivers/dma/atcdmac300.h
diff --git a/MAINTAINERS b/MAINTAINERS
index 3a19da74d00c..b99893f795be 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1974,6 +1974,12 @@ S: Supported
F: drivers/clk/analogbits/*
F: include/linux/clk/analogbits*
+ANDES ATCDMAC300 DMA DRIVER
+M: CL Wang <cl634@andestech.com>
+S: Supported
+F: Documentation/devicetree/bindings/dma/andestech,ae350-dma.yaml
+F: drivers/dma/atcdmac300*
+
ANDES ATCSPI200 SPI DRIVER
M: CL Wang <cl634@andestech.com>
S: Supported
diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index ae6a682c9f76..dabd2c8cc94f 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -100,6 +100,17 @@ config ARM_DMA350
help
Enable support for the Arm DMA-350 controller.
+config ATCDMAC300
+ tristate "Andes ATCDMAC300 DMA support"
+ depends on ARCH_ANDES
+ depends on OF
+ select DMA_ENGINE
+ help
+ Enable support for the Andes ATCDMAC300 DMA controller.
+ Select Y or M if your platform includes an ATCDMAC300 device that
+ requires DMA engine support. This driver supports DMA_SLAVE,
+ DMA_MEMCPY, and DMA_CYCLIC transfer modes.
+
config AT_HDMAC
tristate "Atmel AHB DMA support"
depends on ARCH_AT91 || COMPILE_TEST
diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index 14aa086629d5..c8fffb31efc4 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -18,6 +18,7 @@ obj-$(CONFIG_AMBA_PL08X) += amba-pl08x.o
obj-$(CONFIG_AMCC_PPC440SPE_ADMA) += ppc4xx/
obj-$(CONFIG_APPLE_ADMAC) += apple-admac.o
obj-$(CONFIG_ARM_DMA350) += arm-dma350.o
+obj-$(CONFIG_ATCDMAC300) += atcdmac300.o
obj-$(CONFIG_AT_HDMAC) += at_hdmac.o
obj-$(CONFIG_AT_XDMAC) += at_xdmac.o
obj-$(CONFIG_AXI_DMAC) += dma-axi-dmac.o
diff --git a/drivers/dma/atcdmac300.c b/drivers/dma/atcdmac300.c
new file mode 100644
index 000000000000..be3bb477bb3b
--- /dev/null
+++ b/drivers/dma/atcdmac300.c
@@ -0,0 +1,1518 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Andes ATCDMAC300 controller driver
+ *
+ * Copyright (C) 2026 Andes Technology Corporation
+ */
+#include <linux/bitfield.h>
+#include <linux/bits.h>
+#include <linux/dmaengine.h>
+#include <linux/dmapool.h>
+#include <linux/dma-mapping.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/log2.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_dma.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/slab.h>
+#include <linux/sprintf.h>
+#include <linux/regmap.h>
+#include "dmaengine.h"
+#include "atcdmac300.h"
+
+static int atcdmac_is_chan_enabled(struct atcdmac_chan *dmac_chan)
+{
+ struct atcdmac_dmac *dmac =
+ atcdmac_dev_to_dmac(dmac_chan->dma_chan.device);
+
+ return regmap_test_bits(dmac->regmap,
+ REG_CH_EN,
+ BIT(dmac_chan->chan_id));
+}
+
+static void atcdmac_enable_chan(struct atcdmac_chan *dmac_chan, bool enable)
+{
+ regmap_update_bits(dmac_chan->regmap, REG_CH_CTL_OFF, CHEN, enable);
+}
+
+static void atcdmac_abort_chan(struct atcdmac_chan *dmac_chan)
+{
+ regmap_write_bits(dmac_chan->dma_dev->regmap,
+ REG_CH_ABT,
+ BIT(dmac_chan->chan_id),
+ BIT(dmac_chan->chan_id));
+}
+
+static dma_cookie_t atcdmac_tx_submit(struct dma_async_tx_descriptor *tx)
+{
+ struct atcdmac_chan *dmac_chan = atcdmac_chan_to_dmac_chan(tx->chan);
+ struct atcdmac_desc *desc = atcdmac_txd_to_dma_desc(tx);
+ dma_cookie_t cookie;
+ unsigned long flags;
+
+ spin_lock_irqsave(&dmac_chan->lock, flags);
+ cookie = dma_cookie_assign(tx);
+ list_add_tail(&desc->desc_node, &dmac_chan->queue_list);
+ spin_unlock_irqrestore(&dmac_chan->lock, flags);
+
+ return cookie;
+}
+
+static struct atcdmac_desc *
+atcdmac_get_active_head(struct atcdmac_chan *dmac_chan)
+{
+ return list_first_entry(&dmac_chan->active_list,
+ struct atcdmac_desc,
+ desc_node);
+}
+
+static struct atcdmac_desc *atcdmac_alloc_desc(struct dma_chan *chan,
+ gfp_t gfp_flags)
+{
+ struct atcdmac_dmac *dmac = atcdmac_dev_to_dmac(chan->device);
+ struct atcdmac_desc *desc;
+ dma_addr_t phys;
+
+ desc = dma_pool_zalloc(dmac->dma_desc_pool, gfp_flags, &phys);
+ if (desc) {
+ INIT_LIST_HEAD(&desc->tx_list);
+ dma_async_tx_descriptor_init(&desc->txd, chan);
+ desc->txd.flags = DMA_CTRL_ACK;
+ desc->txd.tx_submit = atcdmac_tx_submit;
+ desc->txd.phys = phys;
+ }
+
+ return desc;
+}
+
+static struct atcdmac_desc *atcdmac_get_desc(struct atcdmac_chan *dmac_chan)
+{
+ struct atcdmac_desc *ret = NULL;
+ struct atcdmac_desc *desc_next;
+ struct atcdmac_desc *desc;
+ unsigned long flags;
+
+ spin_lock_irqsave(&dmac_chan->lock, flags);
+ list_for_each_entry_safe(desc, desc_next,
+ &dmac_chan->free_list,
+ desc_node) {
+ if (async_tx_test_ack(&desc->txd)) {
+ list_del_init(&desc->desc_node);
+ ret = desc;
+ break;
+ }
+ }
+ spin_unlock_irqrestore(&dmac_chan->lock, flags);
+
+ if (!ret) {
+ ret = atcdmac_alloc_desc(&dmac_chan->dma_chan, GFP_ATOMIC);
+ if (ret) {
+ spin_lock_irqsave(&dmac_chan->lock, flags);
+ dmac_chan->descs_allocated++;
+ spin_unlock_irqrestore(&dmac_chan->lock, flags);
+ } else {
+ dev_warn(atcdmac_chan_to_dev(&dmac_chan->dma_chan),
+ "not enough descriptors available\n");
+ }
+ }
+
+ return ret;
+}
+
+/**
+ * atcdmac_put_desc_nolock - move a descriptor to the free list
+ * @dmac_chan: DMA channel we work on
+ * @desc: Head of the descriptor chain to be added to the free list
+ *
+ * This function does not use a lock to protect any linked lists in
+ * 'struct atcdmac_chan', so please remember to add a proper lock when
+ * calling the function.
+ */
+static void atcdmac_put_desc_nolock(struct atcdmac_chan *dmac_chan,
+ struct atcdmac_desc *desc)
+{
+ struct atcdmac_desc *child, *tmp;
+
+ if (desc) {
+ list_for_each_entry_safe(child,
+ tmp,
+ &desc->tx_list,
+ desc_node) {
+ list_del_init(&child->desc_node);
+ child->at = NULL;
+ child->num_sg = 0;
+ INIT_LIST_HEAD(&child->tx_list);
+ list_add_tail(&child->desc_node,
+ &dmac_chan->free_list);
+ }
+
+ list_del_init(&desc->desc_node);
+ desc->at = NULL;
+ desc->num_sg = 0;
+ INIT_LIST_HEAD(&desc->tx_list);
+ list_add_tail(&desc->desc_node, &dmac_chan->free_list);
+ }
+}
+
+static void atcdmac_put_desc(struct atcdmac_chan *dmac_chan,
+ struct atcdmac_desc *desc)
+{
+ unsigned long flags;
+
+ if (!desc) {
+ dev_err(atcdmac_chan_to_dev(&dmac_chan->dma_chan),
+ "A NULL descriptor was found.\n");
+ return;
+ }
+
+ spin_lock_irqsave(&dmac_chan->lock, flags);
+ atcdmac_put_desc_nolock(dmac_chan, desc);
+ spin_unlock_irqrestore(&dmac_chan->lock, flags);
+}
+
+static void atcdmac_show_desc(struct atcdmac_chan *dmac_chan,
+ struct atcdmac_desc *desc)
+{
+ struct device *dev = atcdmac_chan_to_dev(&dmac_chan->dma_chan);
+
+ dev_dbg(dev, "Dump desc info of chan: %u\n", dmac_chan->chan_id);
+ dev_dbg(dev, "chan ctrl: 0x%08x\n", desc->regs.ctrl);
+ dev_dbg(dev, "trans size: 0x%08x\n", desc->regs.trans_size);
+ dev_dbg(dev, "src addr: hi:0x%08x lo:0x%08x\n",
+ desc->regs.src_addr_hi,
+ desc->regs.src_addr_lo);
+ dev_dbg(dev, "dst addr: hi:0x%08x lo:0x%08x\n",
+ desc->regs.dst_addr_hi,
+ desc->regs.dst_addr_lo);
+ dev_dbg(dev, "link addr: hi:0x%08x lo:0x%08x\n",
+ desc->regs.ll_ptr_hi,
+ desc->regs.ll_ptr_lo);
+}
+
+/**
+ * atcdmac_chain_desc - Chain a DMA descriptor into a linked-list
+ * @first: Pointer to the first descriptor in the chain
+ * @prev: Pointer to the previous descriptor in the chain
+ * @desc: The descriptor to be added to the chain
+ * @cyclic: Indicates if the transfer operates in cyclic mode
+ *
+ * This function appends a DMA descriptor (desc) to a linked-list of
+ * descriptors. If this is the first descriptor being added, it initializes
+ * the list and sets *first to point to desc. Otherwise, it links the
+ * new descriptor to the end of the list managed by *first.
+ *
+ * For non-cyclic descriptors, it updates the hardware linked list pointers
+ * (ll_ptr_lo and ll_ptr_hi) of the previous descriptor (*prev) to point to
+ * the physical address of the new descriptor.
+ *
+ * Finally, it adds the new descriptor to the list and updates *prev to
+ * point to the current descriptor (desc).
+ */
+static void atcdmac_chain_desc(struct atcdmac_desc **first,
+ struct atcdmac_desc **prev,
+ struct atcdmac_desc *desc,
+ bool cyclic)
+{
+ if (!(*first)) {
+ *first = desc;
+ desc->at = &desc->tx_list;
+ } else {
+ if (!cyclic) {
+ (*prev)->regs.ll_ptr_lo =
+ lower_32_bits(desc->txd.phys);
+ (*prev)->regs.ll_ptr_hi =
+ upper_32_bits(desc->txd.phys);
+ }
+ list_add_tail(&desc->desc_node, &(*first)->tx_list);
+ }
+ *prev = desc;
+
+ desc->regs.ll_ptr_hi = 0;
+ desc->regs.ll_ptr_lo = 0;
+}
+
+/**
+ * atcdmac_start_transfer - Start the DMA engine with the provided descriptor
+ * @dmac_chan: The DMA channel to be started
+ * @first_desc: The first descriptor in the list to begin the transfer
+ *
+ * This function configures the DMA engine by programming the hardware
+ * registers with the information from the provided descriptor (first_desc).
+ * It then starts the DMA transfer for the specified channel (dmac_chan).
+ *
+ * The first_desc contains the initial configuration for the transfer,
+ * including source and destination addresses, transfer size, and any linked
+ * list pointers for subsequent descriptors in the chain.
+ */
+static void atcdmac_start_transfer(struct atcdmac_chan *dmac_chan,
+ struct atcdmac_desc *first_desc)
+{
+ struct atcdmac_dmac *dmac = dmac_chan->dma_dev;
+ struct regmap *reg = dmac_chan->regmap;
+ unsigned long flags;
+
+ spin_lock_irqsave(&dmac->lock, flags);
+ dmac->used_chan |= BIT(dmac_chan->chan_id);
+ spin_unlock_irqrestore(&dmac->lock, flags);
+
+ regmap_write(reg, REG_CH_CTL_OFF, first_desc->regs.ctrl);
+ regmap_write(reg, REG_CH_SIZE_OFF, first_desc->regs.trans_size);
+ regmap_write(reg, REG_CH_SRC_LOW_OFF, first_desc->regs.src_addr_lo);
+ regmap_write(reg, REG_CH_DST_LOW_OFF, first_desc->regs.dst_addr_lo);
+ regmap_write(reg, REG_CH_LLP_LOW_OFF, first_desc->regs.ll_ptr_lo);
+ regmap_write(reg, REG_CH_SRC_HIGH_OFF, first_desc->regs.src_addr_hi);
+ regmap_write(reg, REG_CH_DST_HIGH_OFF, first_desc->regs.dst_addr_hi);
+ regmap_write(reg, REG_CH_LLP_HIGH_OFF, first_desc->regs.ll_ptr_hi);
+ atcdmac_enable_chan(dmac_chan, 1);
+}
+
+/**
+ * atcdmac_start_next_trans - Retrieve and initiate the next DMA transfer
+ * @dmac_chan: Pointer to the DMA channel structure
+ *
+ * In non-cyclic mode, if active_list is empty, the function moves
+ * descriptors from queue_list (if available) to active_list and starts
+ * the transfer. If both lists are empty, it marks the channel as unused.
+ * If there are already active descriptors in active_list, the function
+ * retrieves the next DMA descriptor from it and starts the transfer.
+ *
+ * In cyclic mode, the function retrieves the next DMA descriptor
+ * from the linked list of tx_list to maintain continuous transfers.
+ */
+static void atcdmac_start_next_trans(struct atcdmac_chan *dmac_chan)
+{
+ struct atcdmac_desc *next_tx = NULL;
+ struct atcdmac_desc *dma_desc;
+
+ if (dmac_chan->cyclic) {
+ /* Get the next DMA descriptor from tx_list. */
+ dma_desc = atcdmac_get_active_head(dmac_chan);
+ dma_desc->at = dma_desc->at->next;
+ if ((uintptr_t)dma_desc->at == (uintptr_t)&dma_desc->tx_list)
+ next_tx = list_entry(dma_desc->at,
+ struct atcdmac_desc,
+ tx_list);
+ else
+ next_tx = list_entry(dma_desc->at,
+ struct atcdmac_desc,
+ desc_node);
+ } else {
+ if (list_empty(&dmac_chan->active_list)) {
+ if (!list_empty(&dmac_chan->queue_list)) {
+ list_splice_init(&dmac_chan->queue_list,
+ &dmac_chan->active_list);
+ next_tx = atcdmac_get_active_head(dmac_chan);
+ }
+ } else {
+ next_tx = atcdmac_get_active_head(dmac_chan);
+ }
+ }
+
+ if (next_tx) {
+ dmac_chan->chan_used = 1;
+ atcdmac_start_transfer(dmac_chan, next_tx);
+ } else {
+ dmac_chan->chan_used = 0;
+ }
+}
+
+static void atcdmac_run_tx_complete_actions(struct atcdmac_desc *desc,
+ enum dmaengine_tx_result result)
+{
+ struct dma_async_tx_descriptor *txd = &desc->txd;
+ struct dmaengine_result res;
+
+ res.result = result;
+ dma_cookie_complete(txd);
+ dma_descriptor_unmap(txd);
+ dmaengine_desc_get_callback_invoke(txd, &res);
+ dma_run_dependencies(txd);
+}
+
+/**
+ * atcdmac_advance_work - Process the completed transaction and move to the
+ * next descriptor
+ * @dmac_chan: DMA channel where the transaction has completed
+ *
+ * This function is responsible for performing necessary operations after
+ * a DMA transaction completes successfully. It retrieves the next descriptor
+ * from the active list, initiates its transfer, and communicates the result
+ * of the completed transaction to the DMA engine framework.
+ */
+static void atcdmac_advance_work(struct atcdmac_chan *dmac_chan)
+{
+ struct atcdmac_dmac *dmac =
+ atcdmac_dev_to_dmac(dmac_chan->dma_chan.device);
+ struct atcdmac_desc *desc_next, *dma_desc, *desc;
+ struct dmaengine_result res;
+ LIST_HEAD(completed);
+ unsigned long flags;
+ unsigned short stop;
+
+ spin_lock_irqsave(&dmac_chan->lock, flags);
+ if (list_empty(&dmac_chan->active_list)) {
+ spin_unlock_irqrestore(&dmac_chan->lock, flags);
+ return;
+ }
+
+ dma_desc = atcdmac_get_active_head(dmac_chan);
+ stop = READ_ONCE(dmac->stop_mask) & BIT(dmac_chan->chan_id);
+ if (dmac_chan->cyclic) {
+ if (!stop)
+ atcdmac_start_next_trans(dmac_chan);
+
+ spin_unlock_irqrestore(&dmac_chan->lock, flags);
+ res.result = DMA_TRANS_NOERROR;
+ dmaengine_desc_get_callback_invoke(&dma_desc->txd, &res);
+ } else {
+ if (list_is_singular(&dmac_chan->active_list)) {
+ list_splice_init(&dmac_chan->active_list, &completed);
+ list_splice_init(&dmac_chan->queue_list,
+ &dmac_chan->active_list);
+ } else {
+ list_move_tail(&dma_desc->desc_node, &completed);
+ }
+
+ if (!stop)
+ atcdmac_start_next_trans(dmac_chan);
+
+ spin_unlock_irqrestore(&dmac_chan->lock, flags);
+
+ list_for_each_entry_safe(desc,
+ desc_next,
+ &completed,
+ desc_node) {
+ atcdmac_run_tx_complete_actions(desc,
+ DMA_TRANS_NOERROR);
+ atcdmac_put_desc(dmac_chan, desc);
+ }
+ }
+}
+
+/**
+ * atcdmac_handle_error - Handle errors reported by the DMA controller
+ * @dmac_chan: DMA channel where the error occurred
+ *
+ * This function is invoked when the DMA controller detects an error during a
+ * transaction. This function ensures that the DMA channel can recover from
+ * errors while reporting issues to aid in debugging. It prevents the DMA
+ * controller from operating on potentially invalid memory regions and
+ * attempts to maintain system stability.
+ */
+static void atcdmac_handle_error(struct atcdmac_chan *dmac_chan)
+{
+ struct device *dev = atcdmac_chan_to_dev(&dmac_chan->dma_chan);
+ struct atcdmac_dmac *dmac =
+ atcdmac_dev_to_dmac(dmac_chan->dma_chan.device);
+ struct atcdmac_desc *bad_desc;
+ unsigned long flags;
+ unsigned short stop;
+
+ spin_lock_irqsave(&dmac_chan->lock, flags);
+
+ /*
+ * If the active list is empty, the descriptor has already been
+ * handled by another function (e.g., atcdmac_terminate_all()).
+ * Therefore, no further action is needed.
+ */
+ if (!list_empty(&dmac_chan->active_list)) {
+ /*
+ * Identify the problematic descriptor at the head of the
+ * active list and remove it from the list for further
+ * processing.
+ */
+ bad_desc = atcdmac_get_active_head(dmac_chan);
+ list_del_init(&bad_desc->desc_node);
+
+ /*
+ * Transfer any pending descriptors from the queue list to the
+ * active list, allowing them to be processed in subsequent
+ * operations.
+ */
+ list_splice_init(&dmac_chan->queue_list,
+ dmac_chan->active_list.prev);
+
+ stop = READ_ONCE(dmac->stop_mask) & BIT(dmac_chan->chan_id);
+ if (!list_empty(&dmac_chan->active_list) && stop == 0)
+ atcdmac_start_transfer(dmac_chan, atcdmac_get_active_head(dmac_chan));
+ else
+ dmac_chan->chan_used = 0;
+
+ spin_unlock_irqrestore(&dmac_chan->lock, flags);
+
+ /*
+ * Show the detailed information of the bad descriptor and
+ * return "DMA_TRANS_ABORTED" to the DMA engine framework.
+ */
+ dev_err(dev, "DMA transaction failed, possible DMA desc error\n");
+ atcdmac_show_desc(dmac_chan, bad_desc);
+ atcdmac_run_tx_complete_actions(bad_desc, DMA_TRANS_ABORTED);
+
+ atcdmac_put_desc(dmac_chan, bad_desc);
+
+ return;
+ }
+
+ spin_unlock_irqrestore(&dmac_chan->lock, flags);
+}
+
+static irqreturn_t atcdmac_irq_thread(int irq, void *dev_id)
+{
+ struct atcdmac_dmac *dmac = dev_id;
+ struct atcdmac_chan *dmac_chan;
+ int i;
+ bool handled = false;
+
+ for (i = 0; i < dmac->num_ch; i++) {
+ dmac_chan = &dmac->chan[i];
+
+ if (test_and_clear_bit(ATCDMAC_STA_TC, &dmac_chan->status)) {
+ atcdmac_advance_work(dmac_chan);
+ handled = true;
+ }
+
+ if (test_and_clear_bit(ATCDMAC_STA_ERR, &dmac_chan->status)) {
+ atcdmac_handle_error(dmac_chan);
+ handled = true;
+ }
+
+ /*
+ * ATCDMAC_STA_ABORT only occurs when the DMA channel is
+ * terminated or freed, and all descriptors and callbacks
+ * have already been processed. Therefore, no additional
+ * handling is required.
+ */
+ if (test_and_clear_bit(ATCDMAC_STA_ABORT, &dmac_chan->status))
+ handled = true;
+ }
+
+ return handled ? IRQ_HANDLED : IRQ_NONE;
+}
+
+static irqreturn_t atcdmac_interrupt(int irq, void *dev_id)
+{
+ struct atcdmac_dmac *dmac = dev_id;
+ struct atcdmac_chan *dmac_chan;
+ unsigned int status;
+ unsigned int int_ch;
+ int ret = IRQ_NONE;
+ int i;
+
+ regmap_read(dmac->regmap, REG_INT_STA, &status);
+ int_ch = READ_ONCE(dmac->used_chan) & DMA_INT_ALL(status);
+
+ while (int_ch) {
+ spin_lock(&dmac->lock);
+ dmac->used_chan = READ_ONCE(dmac->used_chan) & ~int_ch;
+ spin_unlock(&dmac->lock);
+ regmap_write(dmac->regmap, REG_INT_STA, DMA_INT_CLR(int_ch));
+
+ for (i = 0; i < dmac->num_ch; i++) {
+ if (int_ch & BIT(i)) {
+ int_ch &= ~BIT(i);
+ dmac_chan = &dmac->chan[i];
+
+ if (status & DMA_TC(i))
+ set_bit(ATCDMAC_STA_TC,
+ &dmac_chan->status);
+
+ if (status & DMA_ERR(i))
+ set_bit(ATCDMAC_STA_ERR,
+ &dmac_chan->status);
+
+ if (status & DMA_ABT(i))
+ set_bit(ATCDMAC_STA_ABORT,
+ &dmac_chan->status);
+
+ ret = IRQ_WAKE_THREAD;
+ }
+ if (!int_ch)
+ break;
+ }
+
+ regmap_read(dmac->regmap, REG_INT_STA, &status);
+ int_ch = READ_ONCE(dmac->used_chan) & DMA_INT_ALL(status);
+ }
+
+ return ret;
+}
+
+/**
+ * atcdmac_issue_pending - Trigger the execution of queued DMA transactions
+ * @chan: DMA channel on which to issue pending transactions
+ *
+ * This function checks if the DMA channel is currently idle and if there are
+ * descriptors waiting in the queue_list. If the channel is idle and the
+ * queue_list is not empty, it moves the first queued descriptor to the active
+ * list and starts the DMA transfer by calling atcdmac_start_transfer().
+ */
+static void atcdmac_issue_pending(struct dma_chan *chan)
+{
+ struct atcdmac_chan *dmac_chan = atcdmac_chan_to_dmac_chan(chan);
+ struct atcdmac_dmac *dmac =
+ atcdmac_dev_to_dmac(dmac_chan->dma_chan.device);
+ unsigned long flags;
+ unsigned short stop;
+
+ spin_lock_irqsave(&dmac_chan->lock, flags);
+ stop = READ_ONCE(dmac->stop_mask) & BIT(dmac_chan->chan_id);
+ if (dmac_chan->chan_used == 0 && stop == 0 &&
+ !list_empty(&dmac_chan->queue_list)) {
+ dmac_chan->chan_used = 1;
+ list_move(dmac_chan->queue_list.next, &dmac_chan->active_list);
+ atcdmac_start_transfer(dmac_chan,
+ atcdmac_get_active_head(dmac_chan));
+ }
+
+ spin_unlock_irqrestore(&dmac_chan->lock, flags);
+}
+
+static unsigned char atcdmac_map_buswidth(enum dma_slave_buswidth addr_width)
+{
+ switch (addr_width) {
+ case DMA_SLAVE_BUSWIDTH_1_BYTE:
+ return 0;
+ case DMA_SLAVE_BUSWIDTH_2_BYTES:
+ return 1;
+ case DMA_SLAVE_BUSWIDTH_4_BYTES:
+ return 2;
+ case DMA_SLAVE_BUSWIDTH_8_BYTES:
+ return 3;
+ case DMA_SLAVE_BUSWIDTH_16_BYTES:
+ return 4;
+ case DMA_SLAVE_BUSWIDTH_32_BYTES:
+ return 5;
+ default:
+ return 0;
+ }
+}
+
+static unsigned int atcdmac_map_tran_width(dma_addr_t src,
+ dma_addr_t dst,
+ size_t len,
+ unsigned int max_align_bytes)
+{
+ unsigned int align = src | dst | len | max_align_bytes;
+ unsigned int width;
+
+ if (!(align & 0x1F))
+ width = WIDTH_32_BYTES;
+ else if (!(align & 0xF))
+ width = WIDTH_16_BYTES;
+ else if (!(align & 0x7))
+ width = WIDTH_8_BYTES;
+ else if (!(align & 0x3))
+ width = WIDTH_4_BYTES;
+ else if (!(align & 0x1))
+ width = WIDTH_2_BYTES;
+ else
+ width = WIDTH_1_BYTE;
+
+ return width;
+}
+
+/**
+ * atcdmac_convert_burst - Convert burst size to a power of two index
+ * @burst_size: Actual burst size in bytes
+ *
+ * This function converts a burst size (e.g., 1, 2, 4, 8...) into the
+ * corresponding hardware-encoded value, which represents the index of
+ * the power of two.
+ *
+ * Return: The zero-based power-of-two index corresponding to @burst_size.
+ *
+ * Example:
+ * If burst_size is 8 (binary 1000), the most significant bit is at position
+ * 4, so the function returns 3 (i.e., 4 - 1).
+ */
+static unsigned char atcdmac_convert_burst(unsigned int burst_size)
+{
+ return fls(burst_size) - 1;
+}
+
+static struct atcdmac_desc *
+atcdmac_build_desc(struct atcdmac_chan *dmac_chan,
+ dma_addr_t src,
+ dma_addr_t dst,
+ unsigned int ctrl,
+ unsigned int trans_size,
+ unsigned int num_sg)
+{
+ struct atcdmac_desc *desc;
+
+ desc = atcdmac_get_desc(dmac_chan);
+ if (!desc)
+ return NULL;
+
+ desc->regs.src_addr_lo = lower_32_bits(src);
+ desc->regs.src_addr_hi = upper_32_bits(src);
+ desc->regs.dst_addr_lo = lower_32_bits(dst);
+ desc->regs.dst_addr_hi = upper_32_bits(dst);
+ desc->regs.ctrl = ctrl;
+ desc->regs.trans_size = trans_size;
+ desc->num_sg = num_sg;
+
+ return desc;
+}
+
+/**
+ * atcdmac_prep_dma_memcpy - Prepare a DMA memcpy operation for the specified
+ * channel
+ * @chan: DMA channel to configure for the operation
+ * @dst: Physical destination address for the transfer
+ * @src: Physical source address for the transfer
+ * @len: Size of the data to transfer, in bytes
+ * @flags: Status flags for the transfer descriptor
+ *
+ * This function sets up a DMA memcpy operation to transfer data from the
+ * specified source address to the destination address. It returns a DMA
+ * descriptor that represents the configured transaction.
+ */
+static struct dma_async_tx_descriptor *
+atcdmac_prep_dma_memcpy(struct dma_chan *chan,
+ dma_addr_t dst,
+ dma_addr_t src,
+ size_t len,
+ unsigned long flags)
+{
+ struct atcdmac_chan *dmac_chan = atcdmac_chan_to_dmac_chan(chan);
+ struct atcdmac_dmac *dmac = atcdmac_dev_to_dmac(chan->device);
+ struct atcdmac_desc *desc;
+ unsigned int src_width;
+ unsigned int dst_width;
+ unsigned int ctrl;
+ unsigned char src_max_burst;
+
+ if (unlikely(!len)) {
+ dev_warn(atcdmac_chan_to_dev(chan),
+ "Failed to prepare DMA operation: len is zero\n");
+ return NULL;
+ }
+
+ src_max_burst =
+ atcdmac_convert_burst((unsigned int)SRC_BURST_SIZE_1024);
+ src_width = atcdmac_map_tran_width(src,
+ dst,
+ len,
+ 1 << dmac->data_width);
+ dst_width = src_width;
+ ctrl = SRC_BURST_SIZE(src_max_burst) |
+ SRC_ADDR_MODE_INCR |
+ DST_ADDR_MODE_INCR |
+ DST_WIDTH(dst_width) |
+ SRC_WIDTH(src_width);
+
+ desc = atcdmac_build_desc(dmac_chan, src, dst, ctrl,
+ len >> src_width, 1);
+ if (!desc)
+ goto err_desc_get;
+
+ return &desc->txd;
+
+err_desc_get:
+ dev_warn(atcdmac_chan_to_dev(chan), "Failed to allocate descriptor\n");
+ return NULL;
+}
+
+static int atcdmac_get_slave_cfg(struct dma_slave_config *sconfig,
+ enum dma_transfer_direction dir,
+ struct atcdmac_slave_cfg *cfg)
+{
+ if (dir == DMA_MEM_TO_DEV) {
+ cfg->reg = sconfig->dst_addr;
+ cfg->burst_bytes = sconfig->dst_addr_width * sconfig->dst_maxburst;
+ cfg->dev_width = sconfig->dst_addr_width;
+ cfg->width_src = atcdmac_map_buswidth(sconfig->src_addr_width);
+ cfg->width_dst = atcdmac_map_buswidth(sconfig->dst_addr_width);
+ } else if (dir == DMA_DEV_TO_MEM) {
+ cfg->reg = sconfig->src_addr;
+ cfg->burst_bytes = sconfig->src_addr_width * sconfig->src_maxburst;
+ cfg->dev_width = sconfig->src_addr_width;
+ cfg->width_src = atcdmac_map_buswidth(sconfig->src_addr_width);
+ cfg->width_dst = atcdmac_map_buswidth(sconfig->dst_addr_width);
+ } else {
+ return -EINVAL;
+ }
+ return 0;
+}
+
+static struct atcdmac_desc *
+atcdmac_build_slave_desc(struct atcdmac_chan *dmac_chan,
+ const struct atcdmac_slave_cfg *cfg,
+ dma_addr_t mem, unsigned int len,
+ enum dma_transfer_direction dir,
+ unsigned int data_width, unsigned int num_desc)
+{
+ unsigned int width_cal;
+ unsigned short burst_size;
+ unsigned int ctrl;
+ dma_addr_t src, dst;
+
+ width_cal = atcdmac_map_tran_width(mem, cfg->reg, len,
+ (1 << data_width) | cfg->burst_bytes);
+ if (dir == DMA_MEM_TO_DEV) {
+ if (cfg->burst_bytes < (1 << width_cal)) {
+ burst_size = cfg->burst_bytes;
+ width_cal = WIDTH_1_BYTE;
+ } else {
+ burst_size = cfg->burst_bytes / (1 << width_cal);
+ }
+ ctrl = SRC_ADDR_MODE_INCR | DST_ADDR_MODE_FIXED |
+ DST_HS | DST_REQ(dmac_chan->req_num) |
+ SRC_WIDTH(width_cal) | DST_WIDTH(cfg->width_dst) |
+ SRC_BURST_SIZE(ilog2(burst_size));
+ src = mem;
+ dst = cfg->reg;
+ } else {
+ burst_size = cfg->burst_bytes / cfg->dev_width;
+ ctrl = SRC_ADDR_MODE_FIXED | DST_ADDR_MODE_INCR |
+ SRC_HS | SRC_REQ(dmac_chan->req_num) |
+ SRC_WIDTH(cfg->width_src) | DST_WIDTH(width_cal) |
+ SRC_BURST_SIZE(ilog2(burst_size));
+ src = cfg->reg;
+ dst = mem;
+ width_cal = cfg->width_src;
+ }
+ return atcdmac_build_desc(dmac_chan, src, dst, ctrl,
+ len >> width_cal, num_desc);
+}
+
+/**
+ * atcdmac_prep_device_sg - Prepare descriptors for memory/device DMA
+ * transactions
+ * @chan: DMA channel to configure for the operation
+ * @sgl: Scatter-gather list representing the memory regions to transfer
+ * @sg_len: Number of entries in the scatter-gather list
+ * @direction: Direction of the DMA transfer
+ * @flags: Status flags for the transfer descriptor
+ * @context: transaction context (ignored)
+ *
+ * This function prepares a DMA transaction by setting up the required
+ * descriptors based on the provided scatter-gather list and parameters.
+ * It supports memory-to-device and device-to-memory DMA transfers.
+ */
+static struct dma_async_tx_descriptor *
+atcdmac_prep_device_sg(struct dma_chan *chan,
+ struct scatterlist *sgl,
+ unsigned int sg_len,
+ enum dma_transfer_direction direction,
+ unsigned long flags,
+ void *context)
+{
+ struct atcdmac_chan *dmac_chan = atcdmac_chan_to_dmac_chan(chan);
+ struct atcdmac_dmac *dmac = atcdmac_dev_to_dmac(chan->device);
+ struct atcdmac_slave_cfg cfg;
+ struct atcdmac_desc *first = NULL;
+ struct atcdmac_desc *prev = NULL;
+ struct scatterlist *sg;
+ unsigned int i;
+
+ if (unlikely(!sg_len)) {
+ dev_warn(atcdmac_chan_to_dev(chan), "sg_len is zero\n");
+ return NULL;
+ }
+
+ if (atcdmac_get_slave_cfg(&dmac_chan->dma_sconfig, direction, &cfg)) {
+ dev_err(atcdmac_chan_to_dev(chan),
+ "Invalid transfer direction %d\n", direction);
+ return NULL;
+ }
+
+ for_each_sg(sgl, sg, sg_len, i) {
+ struct atcdmac_desc *desc;
+ dma_addr_t mem = sg_dma_address(sg);
+ unsigned int len = sg_dma_len(sg);
+
+ if (unlikely(!len)) {
+ dev_err(atcdmac_chan_to_dev(chan),
+ "sg(%u) data len is zero\n", i);
+ goto err;
+ }
+
+ desc = atcdmac_build_slave_desc(dmac_chan, &cfg, mem, len,
+ direction, dmac->data_width,
+ sg_len);
+ if (!desc)
+ goto err_desc_get;
+
+ atcdmac_chain_desc(&first, &prev, desc, false);
+ }
+
+ first->txd.cookie = -EBUSY;
+ first->txd.flags = flags;
+
+ return &first->txd;
+
+err_desc_get:
+ dev_warn(atcdmac_chan_to_dev(chan), "Failed to allocate descriptor\n");
+ if (first)
+ first->num_sg = i;
+
+err:
+ if (first)
+ atcdmac_put_desc(dmac_chan, first);
+ return NULL;
+}
+
+static struct dma_async_tx_descriptor *
+atcdmac_prep_dma_cyclic(struct dma_chan *chan,
+ dma_addr_t buf_addr,
+ size_t buf_len,
+ size_t period_len,
+ enum dma_transfer_direction direction,
+ unsigned long flags)
+{
+ struct atcdmac_chan *dmac_chan = atcdmac_chan_to_dmac_chan(chan);
+ struct atcdmac_dmac *dmac = atcdmac_dev_to_dmac(chan->device);
+ struct atcdmac_slave_cfg cfg;
+ struct atcdmac_desc *first = NULL;
+ struct atcdmac_desc *prev = NULL;
+ unsigned int num_periods;
+ unsigned int period;
+
+ if (period_len == 0 || buf_len == 0) {
+ dev_warn(atcdmac_chan_to_dev(chan),
+ "invalid cyclic params buf_len=%zu period_len=%zu\n",
+ buf_len, period_len);
+ return NULL;
+ }
+
+ if (atcdmac_get_slave_cfg(&dmac_chan->dma_sconfig, direction, &cfg)) {
+ dev_err(atcdmac_chan_to_dev(chan),
+ "Invalid transfer direction %d\n", direction);
+ return NULL;
+ }
+
+ num_periods = (buf_len + period_len - 1) / period_len;
+
+ for (period = 0; period < buf_len; period += period_len) {
+ struct atcdmac_desc *desc;
+ dma_addr_t mem = buf_addr + period;
+ unsigned int len = min_t(unsigned int, period_len,
+ buf_len - period);
+
+ desc = atcdmac_build_slave_desc(dmac_chan, &cfg, mem, len,
+ direction, dmac->data_width,
+ num_periods);
+ if (!desc)
+ goto err_desc_get;
+ atcdmac_chain_desc(&first, &prev, desc, true);
+ }
+
+ first->txd.flags = flags;
+ dmac_chan->cyclic = true;
+
+ return &first->txd;
+
+err_desc_get:
+ dev_warn(atcdmac_chan_to_dev(chan), "Failed to allocate descriptor\n");
+ if (first)
+ atcdmac_put_desc(dmac_chan, first);
+
+ return NULL;
+}
+
+static int atcdmac_set_device_config(struct dma_chan *chan,
+ struct dma_slave_config *sconfig)
+{
+ struct atcdmac_chan *dmac_chan = atcdmac_chan_to_dmac_chan(chan);
+
+ /* Check if this chan is configured for device transfers */
+ if (!dmac_chan->dev_chan)
+ return -EINVAL;
+
+ /* Must be powers of two according to ATCDMAC300 spec */
+ if (!is_power_of_2(sconfig->src_maxburst) ||
+ !is_power_of_2(sconfig->dst_maxburst) ||
+ !is_power_of_2(sconfig->src_addr_width) ||
+ !is_power_of_2(sconfig->dst_addr_width))
+ return -EINVAL;
+
+ memcpy(&dmac_chan->dma_sconfig, sconfig, sizeof(*sconfig));
+
+ return 0;
+}
+
+static int atcdmac_terminate_all(struct dma_chan *chan)
+{
+ struct atcdmac_chan *dmac_chan = atcdmac_chan_to_dmac_chan(chan);
+ struct atcdmac_desc *desc_cur, *desc_next;
+ LIST_HEAD(list);
+ unsigned long flags;
+ unsigned int val;
+ int ret;
+
+ spin_lock_irqsave(&dmac_chan->lock, flags);
+ atcdmac_abort_chan(dmac_chan);
+ atcdmac_enable_chan(dmac_chan, 0);
+ ret = regmap_read_poll_timeout_atomic(dmac_chan->dma_dev->regmap,
+ REG_CH_EN,
+ val,
+ !(val & BIT(dmac_chan->chan_id)),
+ 10,
+ ATCDMAC_CHAN_TIMEOUT_US);
+ if (ret)
+ dev_err(atcdmac_chan_to_dev(chan),
+ "Timed out waiting for channel to disable\n");
+
+ list_splice_init(&dmac_chan->queue_list, &list);
+ list_splice_init(&dmac_chan->active_list, &list);
+ dmac_chan->chan_used = 0;
+ spin_unlock_irqrestore(&dmac_chan->lock, flags);
+
+ list_for_each_entry_safe(desc_cur, desc_next, &list, desc_node) {
+ atcdmac_run_tx_complete_actions(desc_cur, DMA_TRANS_ABORTED);
+ atcdmac_put_desc(dmac_chan, desc_cur);
+ }
+
+ return ret;
+}
+
+static enum dma_status atcdmac_get_tx_status(struct dma_chan *chan,
+ dma_cookie_t cookie,
+ struct dma_tx_state *state)
+{
+ return dma_cookie_status(chan, cookie, state);
+}
+
+static int atcdmac_wait_chan_idle(struct atcdmac_dmac *dmac,
+ unsigned short chan_mask,
+ unsigned int timeout_us)
+{
+ unsigned int val;
+ int ret;
+
+ ret = regmap_read_poll_timeout(dmac->regmap,
+ REG_CH_EN,
+ val,
+ !(val & chan_mask),
+ 50,
+ timeout_us);
+ if (ret)
+ dev_err(dmac->dma_device.dev,
+ "Timeout waiting for device ready %d\n", ret);
+
+ return ret;
+}
+
+/**
+ * atcdmac_alloc_chan_resources - Allocate resources for a DMA channel
+ * @chan: The DMA channel for which resources are being allocated
+ *
+ * This function sets up and allocates the necessary resources for the
+ * specified DMA channel (chan). It ensures the channel is prepared to
+ * handle DMA requests from clients by allocating descriptors and any other
+ * required resources.
+ *
+ * Return: The number of descriptors successfully allocated, or a negative
+ * error code on failure.
+ */
+static int atcdmac_alloc_chan_resources(struct dma_chan *chan)
+{
+ struct atcdmac_chan *dmac_chan = atcdmac_chan_to_dmac_chan(chan);
+ struct atcdmac_dmac *dmac = atcdmac_dev_to_dmac(chan->device);
+ struct atcdmac_desc *desc;
+ int i;
+
+ if (atcdmac_is_chan_enabled(dmac_chan)) {
+ dev_err(atcdmac_chan_to_dev(chan),
+ "DMA channel is not in an idle state\n");
+ return -EBUSY;
+ }
+
+ if (!list_empty(&dmac_chan->free_list))
+ return dmac_chan->descs_allocated;
+
+ /*
+ * Spin-lock protection is not necessary during DMA channel
+ * initialization, as the channel is not yet in use at this stage,
+ * and the shared resources are not accessed by other threads.
+ */
+ for (i = 0; i < ATCDMAC_DESC_PER_CHAN; i++) {
+ desc = atcdmac_alloc_desc(chan, GFP_KERNEL);
+ if (!desc) {
+ dev_warn(dmac->dma_device.dev,
+ "Insufficient descriptors: only %d descriptors available\n",
+ i);
+ break;
+ }
+ list_add_tail(&desc->desc_node, &dmac_chan->free_list);
+ }
+ dmac_chan->descs_allocated = i;
+ dmac_chan->cyclic = false;
+ dma_cookie_init(chan);
+ spin_lock_irq(&dmac->lock);
+ dmac->stop_mask &= ~BIT(dmac_chan->chan_id);
+ spin_unlock_irq(&dmac->lock);
+
+ return dmac_chan->descs_allocated;
+}
+
+/**
+ * atcdmac_free_chan_resources - Release a DMA channel's resources
+ * @chan: The DMA channel to release
+ *
+ * This function ensures that any remaining DMA descriptors in the
+ * active_list and queue_list are properly reclaimed. It releases all
+ * resources associated with the specified DMA channel and resets the
+ * channel's management structures to their initial states.
+ */
+static void atcdmac_free_chan_resources(struct dma_chan *chan)
+{
+ struct atcdmac_chan *dmac_chan = atcdmac_chan_to_dmac_chan(chan);
+ struct atcdmac_dmac *dmac = atcdmac_dev_to_dmac(chan->device);
+ struct atcdmac_desc *desc_next, *desc;
+ unsigned long flags;
+
+ WARN_ON_ONCE(atcdmac_is_chan_enabled(dmac_chan));
+
+ spin_lock_irq(&dmac->lock);
+ dmac->stop_mask |= BIT(dmac_chan->chan_id);
+ spin_unlock_irq(&dmac->lock);
+
+ atcdmac_terminate_all(chan);
+
+ spin_lock_irqsave(&dmac_chan->lock, flags);
+ list_for_each_entry_safe(desc,
+ desc_next,
+ &dmac_chan->free_list,
+ desc_node) {
+ list_del(&desc->desc_node);
+ dma_pool_free(dmac->dma_desc_pool, desc, desc->txd.phys);
+ }
+
+ INIT_LIST_HEAD(&dmac_chan->free_list);
+ dmac_chan->descs_allocated = 0;
+ dmac_chan->status = 0;
+ dmac_chan->chan_used = 0;
+ dmac_chan->dev_chan = 0;
+ spin_unlock_irqrestore(&dmac_chan->lock, flags);
+}
+
+static bool atcdmac_filter_chan(struct dma_chan *chan, void *dma_dev)
+{
+ if (dma_dev == chan->device->dev)
+ return true;
+
+ return false;
+}
+
+static struct dma_chan *atcdmac_dma_xlate_handler(struct of_phandle_args *dmac,
+ struct of_dma *of_dma)
+{
+ struct platform_device *dmac_pdev;
+ struct atcdmac_chan *dmac_chan;
+ struct dma_chan *chan;
+ dma_cap_mask_t mask;
+
+ dmac_pdev = of_find_device_by_node(dmac->np);
+ if (!dmac_pdev)
+ return NULL;
+
+ dma_cap_zero(mask);
+ dma_cap_set(DMA_SLAVE, mask);
+ chan = dma_request_channel(mask, atcdmac_filter_chan, &dmac_pdev->dev);
+ put_device(&dmac_pdev->dev);
+
+ if (!chan)
+ return NULL;
+
+ dmac_chan = atcdmac_chan_to_dmac_chan(chan);
+ dmac_chan->dev_chan = true;
+ dmac_chan->req_num = dmac->args[0] & 0xff;
+
+ return chan;
+}
+
+/**
+ * atcdmac_reset_and_wait_chan_idle - Reset the DMA controller and wait for
+ * all channels to become idle
+ * @dmac: Pointer to the DMA controller structure
+ *
+ * This function performs a reset of the DMA controller and ensures that all
+ * DMA channels are disabled.
+ */
+static int atcdmac_reset_and_wait_chan_idle(struct atcdmac_dmac *dmac)
+{
+ regmap_update_bits(dmac->regmap, REG_CTL, DMAC_RESET, 1);
+ msleep(20);
+ regmap_update_bits(dmac->regmap, REG_CTL, DMAC_RESET, 0);
+
+ return atcdmac_wait_chan_idle(dmac,
+ BIT(dmac->num_ch) - 1,
+ ATCDMAC_CHAN_TIMEOUT_US);
+}
+
+static int atcdmac_restore_iocp(struct atcdmac_dmac *dmac)
+{
+ if (!dmac->regmap_iocp)
+ return 0;
+
+ return regmap_write(dmac->regmap_iocp,
+ 0,
+ IOCP_CACHE_DMAC0_AW |
+ IOCP_CACHE_DMAC0_AR |
+ IOCP_CACHE_DMAC1_AW |
+ IOCP_CACHE_DMAC1_AR);
+}
+
+static int atcdmac_init_iocp(struct platform_device *pdev,
+ struct atcdmac_dmac *dmac)
+{
+ const struct regmap_config iocp_regmap_config = {
+ .name = "iocp",
+ .reg_bits = 32,
+ .val_bits = 32,
+ .reg_stride = 4,
+ .pad_bits = 0,
+ .max_register = 0,
+ .cache_type = REGCACHE_NONE,
+ };
+ struct resource *res;
+ void __iomem *regs;
+
+ res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "iocp");
+ if (!res) {
+ dmac->regmap_iocp = NULL;
+ return 0;
+ }
+
+ regs = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(regs)) {
+ dmac->regmap_iocp = NULL;
+ return dev_err_probe(&pdev->dev, PTR_ERR(regs),
+ "Failed to create ioremap for IOCP\n");
+ }
+
+ dmac->regmap_iocp = devm_regmap_init_mmio(&pdev->dev,
+ regs,
+ &iocp_regmap_config);
+ if (IS_ERR(dmac->regmap_iocp)) {
+ int ret = PTR_ERR(dmac->regmap_iocp);
+
+ dmac->regmap_iocp = NULL;
+ return dev_err_probe(&pdev->dev, ret,
+ "Failed to create regmap for IOCP\n");
+ }
+
+ return atcdmac_restore_iocp(dmac);
+}
+
+static void atcdmac_init_dma_device(struct platform_device *pdev,
+ struct atcdmac_dmac *dmac)
+{
+ struct dma_device *device = &dmac->dma_device;
+
+ device->device_alloc_chan_resources = atcdmac_alloc_chan_resources;
+ device->device_free_chan_resources = atcdmac_free_chan_resources;
+ device->device_tx_status = atcdmac_get_tx_status;
+ device->device_issue_pending = atcdmac_issue_pending;
+ device->device_prep_dma_memcpy = atcdmac_prep_dma_memcpy;
+ device->device_prep_slave_sg = atcdmac_prep_device_sg;
+ device->device_config = atcdmac_set_device_config;
+ device->device_terminate_all = atcdmac_terminate_all;
+ device->device_prep_dma_cyclic = atcdmac_prep_dma_cyclic;
+
+ device->dev = &pdev->dev;
+ device->src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
+ BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
+ BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
+ device->dst_addr_widths = device->src_addr_widths;
+ device->directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
+ device->residue_granularity = DMA_RESIDUE_GRANULARITY_DESCRIPTOR;
+
+ dma_cap_set(DMA_SLAVE, device->cap_mask);
+ dma_cap_set(DMA_MEMCPY, device->cap_mask);
+ dma_cap_set(DMA_CYCLIC, device->cap_mask);
+}
+
+static int atcdmac_init_channels(struct platform_device *pdev,
+ struct atcdmac_dmac *dmac)
+{
+ struct regmap_config chan_regmap_config = {
+ .reg_bits = 32,
+ .val_bits = 32,
+ .reg_stride = 4,
+ .pad_bits = 0,
+ .cache_type = REGCACHE_NONE,
+ .max_register = REG_CH_LLP_HIGH_OFF,
+ };
+ struct atcdmac_chan *dmac_chan;
+ int ret;
+ int i;
+
+ INIT_LIST_HEAD(&dmac->dma_device.channels);
+
+ for (i = 0; i < dmac->num_ch; i++) {
+ char *regmap_name = kasprintf(GFP_KERNEL, "chan%d", i);
+
+ if (!regmap_name)
+ return -ENOMEM;
+
+ dmac_chan = &dmac->chan[i];
+ chan_regmap_config.name = regmap_name;
+ dmac_chan->regmap =
+ devm_regmap_init_mmio(&pdev->dev,
+ dmac->regs + REG_CH_OFF(i),
+ &chan_regmap_config);
+ kfree(regmap_name);
+
+ if (IS_ERR(dmac_chan->regmap)) {
+ ret = PTR_ERR(dmac_chan->regmap);
+ dev_err_probe(&pdev->dev, ret,
+ "Failed to create regmap for DMA chan%d\n",
+ i);
+ return ret;
+ }
+
+ spin_lock_init(&dmac_chan->lock);
+ dmac_chan->dma_chan.device = &dmac->dma_device;
+ dmac_chan->dma_dev = dmac;
+ dmac_chan->chan_id = i;
+ dmac_chan->chan_used = 0;
+
+ INIT_LIST_HEAD(&dmac_chan->active_list);
+ INIT_LIST_HEAD(&dmac_chan->queue_list);
+ INIT_LIST_HEAD(&dmac_chan->free_list);
+
+ list_add_tail(&dmac_chan->dma_chan.device_node,
+ &dmac->dma_device.channels);
+ dma_cookie_init(&dmac_chan->dma_chan);
+ }
+
+ return 0;
+}
+
+static int atcdmac_init_desc_pool(struct platform_device *pdev,
+ struct atcdmac_dmac *dmac)
+{
+ dmac->dma_desc_pool = dmam_pool_create(dev_name(&pdev->dev),
+ &pdev->dev,
+ sizeof(struct atcdmac_desc),
+ 64,
+ 4096);
+ if (!dmac->dma_desc_pool)
+ return dev_err_probe(&pdev->dev, -ENOMEM,
+ "Failed to create memory pool for DMA descriptors\n");
+ return 0;
+}
+
+static int atcdmac_init_irq(struct platform_device *pdev,
+ struct atcdmac_dmac *dmac)
+{
+ int irq = platform_get_irq(pdev, 0);
+
+ if (irq < 0)
+ return irq;
+
+ return devm_request_threaded_irq(&pdev->dev,
+ irq,
+ atcdmac_interrupt,
+ atcdmac_irq_thread,
+ IRQF_SHARED | IRQF_ONESHOT,
+ dev_name(&pdev->dev),
+ dmac);
+}
+
+static int atcdmac_init_ioremap_and_regmap(struct platform_device *pdev,
+ struct atcdmac_dmac **out_dmac)
+{
+ const struct regmap_config dmac_regmap_config = {
+ .name = dev_name(&pdev->dev),
+ .reg_bits = 32,
+ .val_bits = 32,
+ .reg_stride = 4,
+ .pad_bits = 0,
+ .cache_type = REGCACHE_NONE,
+ .max_register = REG_CH_EN,
+ };
+ struct atcdmac_dmac *dmac;
+ struct regmap *regmap;
+ void __iomem *regs;
+ size_t size;
+ unsigned int val;
+ int ret = 0;
+ unsigned char num_ch;
+
+ regs = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(regs))
+ return dev_err_probe(&pdev->dev, PTR_ERR(regs),
+ "Failed to ioremap I/O resource\n");
+
+ regmap = devm_regmap_init_mmio(&pdev->dev, regs, &dmac_regmap_config);
+ if (IS_ERR(regmap))
+ return dev_err_probe(&pdev->dev, PTR_ERR(regmap),
+ "Failed to create regmap for I/O\n");
+
+ regmap_read(regmap, REG_CFG, &val);
+ num_ch = val & CH_NUM;
+ size = sizeof(*dmac) + num_ch * sizeof(struct atcdmac_chan);
+ dmac = devm_kzalloc(&pdev->dev, size, GFP_KERNEL);
+ if (!dmac)
+ return -ENOMEM;
+
+ dmac->regmap = regmap;
+ dmac->num_ch = num_ch;
+ dmac->regs = regs;
+
+ /*
+ * Adjust the AXI bus data width (from the DMAC Configuration
+ * Register) to align with the transfer width encoding (in the
+ * Channel n Control Register). For example, an AXI width of 0
+ * (32-bit) corresponds to a transfer width of 2 (word transfer).
+ */
+ dmac->data_width = FIELD_GET(DATA_WIDTH, val) + 2;
+ spin_lock_init(&dmac->lock);
+
+ platform_set_drvdata(pdev, dmac);
+ if (dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64)))
+ ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
+ if (ret)
+ return dev_err_probe(&pdev->dev, ret,
+ "Failed to set DMA mask\n");
+
+ *out_dmac = dmac;
+
+ return ret;
+}
+
+static int atcdmac_probe(struct platform_device *pdev)
+{
+ struct atcdmac_dmac *dmac;
+ int ret;
+
+ ret = atcdmac_init_ioremap_and_regmap(pdev, &dmac);
+ if (ret)
+ return ret;
+
+ ret = atcdmac_reset_and_wait_chan_idle(dmac);
+ if (ret)
+ return ret;
+
+ ret = atcdmac_init_desc_pool(pdev, dmac);
+ if (ret)
+ return ret;
+
+ ret = atcdmac_init_channels(pdev, dmac);
+ if (ret)
+ return ret;
+
+ atcdmac_init_dma_device(pdev, dmac);
+
+ ret = dma_async_device_register(&dmac->dma_device);
+ if (ret)
+ return ret;
+
+ ret = atcdmac_init_irq(pdev, dmac);
+ if (ret)
+ goto err_dma_async_register;
+
+ ret = atcdmac_init_iocp(pdev, dmac);
+ if (ret)
+ goto err_dma_async_register;
+
+ ret = of_dma_controller_register(pdev->dev.of_node,
+ atcdmac_dma_xlate_handler,
+ dmac);
+ if (ret)
+ goto err_dma_async_register;
+
+ return 0;
+
+err_dma_async_register:
+ dma_async_device_unregister(&dmac->dma_device);
+
+ return ret;
+}
+
+static int atcdmac_resume(struct device *dev)
+{
+ struct dma_chan *chan;
+ struct dma_chan *chan_next;
+ struct atcdmac_dmac *dmac = dev_get_drvdata(dev);
+ struct atcdmac_chan *dmac_chan;
+ unsigned long flags;
+ int ret;
+
+ ret = atcdmac_reset_and_wait_chan_idle(dmac);
+ if (ret)
+ return ret;
+
+ ret = atcdmac_restore_iocp(dmac);
+ if (ret)
+ return ret;
+
+ spin_lock_irqsave(&dmac->lock, flags);
+ dmac->stop_mask = 0;
+ spin_unlock_irqrestore(&dmac->lock, flags);
+ list_for_each_entry_safe(chan,
+ chan_next,
+ &dmac->dma_device.channels,
+ device_node) {
+ dmac_chan = atcdmac_chan_to_dmac_chan(chan);
+ spin_lock_irqsave(&dmac_chan->lock, flags);
+ atcdmac_start_next_trans(dmac_chan);
+ spin_unlock_irqrestore(&dmac_chan->lock, flags);
+ }
+
+ return 0;
+}
+
+static int atcdmac_suspend(struct device *dev)
+{
+ struct atcdmac_dmac *dmac = dev_get_drvdata(dev);
+ int ret;
+ unsigned long flags;
+
+ spin_lock_irqsave(&dmac->lock, flags);
+ dmac->stop_mask = BIT(dmac->num_ch) - 1;
+ spin_unlock_irqrestore(&dmac->lock, flags);
+ ret = atcdmac_wait_chan_idle(dmac,
+ dmac->stop_mask,
+ ATCDMAC_CHAN_TIMEOUT_US * dmac->num_ch);
+
+ return ret;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(atcdmac_pm_ops,
+ atcdmac_suspend,
+ atcdmac_resume);
+
+static void atcdmac_remove(struct platform_device *pdev)
+{
+ struct atcdmac_dmac *dmac = platform_get_drvdata(pdev);
+
+ /*
+ * Quiesce the controller first so the devm-managed IRQ, which is
+ * released only after remove() returns, has nothing left to service.
+ */
+ atcdmac_reset_and_wait_chan_idle(dmac);
+ of_dma_controller_free(pdev->dev.of_node);
+ dma_async_device_unregister(&dmac->dma_device);
+}
+
+static const struct of_device_id atcdmac_dt_ids[] = {
+ { .compatible = "andestech,ae350-dma", },
+ { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, atcdmac_dt_ids);
+
+static struct platform_driver atcdmac_driver = {
+ .probe = atcdmac_probe,
+ .remove = atcdmac_remove,
+ .driver = {
+ .name = "atcdmac300",
+ .of_match_table = atcdmac_dt_ids,
+ .pm = pm_sleep_ptr(&atcdmac_pm_ops),
+ },
+};
+module_platform_driver(atcdmac_driver);
+
+MODULE_AUTHOR("CL Wang <cl634@andestech.com>");
+MODULE_DESCRIPTION("Andes ATCDMAC300 controller driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/dma/atcdmac300.h b/drivers/dma/atcdmac300.h
new file mode 100644
index 000000000000..3aee00e02130
--- /dev/null
+++ b/drivers/dma/atcdmac300.h
@@ -0,0 +1,296 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Header file for Andes ATCDMAC300 DMA controller driver
+ *
+ * Copyright (C) 2025 Andes Technology Corporation
+ */
+#ifndef ATCDMAC300_H
+#define ATCDMAC300_H
+
+#include <linux/bitfield.h>
+#include <linux/dmaengine.h>
+#include <linux/dmapool.h>
+#include <linux/interrupt.h>
+#include <linux/regmap.h>
+#include <linux/spinlock.h>
+
+/*
+ * Register Map Definitions for ATCDMAC300 DMA Controller
+ *
+ * These macros define the offsets and bit masks for various registers
+ * within the ATCDMAC300 DMA controller.
+ */
+
+/* Global DMAC Registers */
+#define REG_CFG 0x10
+#define CH_NUM GENMASK(3, 0)
+#define DATA_WIDTH GENMASK(25, 24)
+
+#define REG_CTL 0x20
+#define DMAC_RESET BIT(0)
+
+#define REG_CH_ABT 0x24
+
+#define REG_INT_STA 0x30
+#define TC_OFFSET 16
+#define ABT_OFFSET 8
+#define ERR_OFFSET 0
+#define DMA_TC(val) BIT(TC_OFFSET + (val))
+#define DMA_ABT(val) BIT(ABT_OFFSET + (val))
+#define DMA_ERR(val) BIT(ERR_OFFSET + (val))
+#define DMA_TC_FIELD GENMASK(TC_OFFSET + 7, TC_OFFSET)
+#define DMA_ABT_FIELD GENMASK(ABT_OFFSET + 7, ABT_OFFSET)
+#define DMA_ERR_FIELD GENMASK(ERR_OFFSET + 7, ERR_OFFSET)
+#define DMA_INT_ALL(val) (FIELD_GET(DMA_TC_FIELD, (val)) | \
+ FIELD_GET(DMA_ABT_FIELD, (val)) | \
+ FIELD_GET(DMA_ERR_FIELD, (val)))
+#define DMA_INT_CLR(val) (FIELD_PREP(DMA_TC_FIELD, (val)) | \
+ FIELD_PREP(DMA_ABT_FIELD, (val)) | \
+ FIELD_PREP(DMA_ERR_FIELD, (val)))
+
+#define REG_CH_EN 0x34
+
+#define REG_CH_OFF(ch) ((ch) * 0x20 + 0x40)
+#define REG_CH_CTL_OFF 0x0
+#define REG_CH_SIZE_OFF 0x4
+#define REG_CH_SRC_LOW_OFF 0x8
+#define REG_CH_SRC_HIGH_OFF 0xC
+#define REG_CH_DST_LOW_OFF 0x10
+#define REG_CH_DST_HIGH_OFF 0x14
+#define REG_CH_LLP_LOW_OFF 0x18
+#define REG_CH_LLP_HIGH_OFF 0x1C
+
+#define SRC_BURST_SIZE_1 BIT(0)
+#define SRC_BURST_SIZE_2 BIT(1)
+#define SRC_BURST_SIZE_4 BIT(2)
+#define SRC_BURST_SIZE_8 BIT(3)
+#define SRC_BURST_SIZE_16 BIT(4)
+#define SRC_BURST_SIZE_32 BIT(5)
+#define SRC_BURST_SIZE_64 BIT(6)
+#define SRC_BURST_SIZE_128 BIT(7)
+#define SRC_BURST_SIZE_256 BIT(8)
+#define SRC_BURST_SIZE_512 BIT(9)
+#define SRC_BURST_SIZE_1024 BIT(10)
+#define SRC_BURST_SIZE_MASK GENMASK(27, 24)
+#define SRC_BURST_SIZE(size) FIELD_PREP(SRC_BURST_SIZE_MASK, size)
+
+#define WIDTH_1_BYTE 0x0
+#define WIDTH_2_BYTES 0x1
+#define WIDTH_4_BYTES 0x2
+#define WIDTH_8_BYTES 0x3
+#define WIDTH_16_BYTES 0x4
+#define WIDTH_32_BYTES 0x5
+#define SRC_WIDTH_MASK GENMASK(23, 21)
+#define SRC_WIDTH(width) FIELD_PREP(SRC_WIDTH_MASK, width)
+#define SRC_WIDTH_GET(val) FIELD_GET(SRC_WIDTH_MASK, val)
+#define DST_WIDTH_MASK GENMASK(20, 18)
+#define DST_WIDTH(width) FIELD_PREP(DST_WIDTH_MASK, width)
+#define DST_WIDTH_GET(val) FIELD_GET(DST_WIDTH_MASK, val)
+
+/* DMA handshake mode */
+#define SRC_HS BIT(17)
+#define DST_HS BIT(16)
+
+/* Address control */
+#define SRC_ADDR_CTRL_MASK GENMASK(15, 14)
+#define SRC_ADDR_MODE_INCR FIELD_PREP(SRC_ADDR_CTRL_MASK, 0x0)
+#define SRC_ADDR_MODE_DECR FIELD_PREP(SRC_ADDR_CTRL_MASK, 0x1)
+#define SRC_ADDR_MODE_FIXED FIELD_PREP(SRC_ADDR_CTRL_MASK, 0x2)
+#define DST_ADDR_CTRL_MASK GENMASK(13, 12)
+#define DST_ADDR_MODE_INCR FIELD_PREP(DST_ADDR_CTRL_MASK, 0x0)
+#define DST_ADDR_MODE_DECR FIELD_PREP(DST_ADDR_CTRL_MASK, 0x1)
+#define DST_ADDR_MODE_FIXED FIELD_PREP(DST_ADDR_CTRL_MASK, 0x2)
+
+/* DMA request select */
+#define SRC_REQ_SEL_MASK GENMASK(11, 8)
+#define SRC_REQ(req_num) FIELD_PREP(SRC_REQ_SEL_MASK, (req_num))
+#define DST_REQ_SEL_MASK GENMASK(7, 4)
+#define DST_REQ(req_num) FIELD_PREP(DST_REQ_SEL_MASK, (req_num))
+
+/* Channel abort interrupt mask */
+#define INT_ABT_MASK BIT(3)
+/* Channel error interrupt mask */
+#define INT_ERR_MASK BIT(2)
+/* Channel terminal count interrupt mask */
+#define INT_TC_MASK BIT(1)
+
+/* Channel Enable */
+#define CHEN BIT(0)
+
+#define IOCP_CACHE_DMAC0_AW GENMASK(3, 0)
+#define IOCP_CACHE_DMAC0_AR GENMASK(7, 4)
+#define IOCP_CACHE_DMAC1_AW GENMASK(11, 8)
+#define IOCP_CACHE_DMAC1_AR GENMASK(15, 12)
+
+#define ATCDMAC_DESC_PER_CHAN 64
+#define ATCDMAC_CHAN_TIMEOUT_US 100000
+/*
+ * Status for bottom-half processing.
+ */
+enum dma_sta {
+ ATCDMAC_STA_TC = 0,
+ ATCDMAC_STA_ERR,
+ ATCDMAC_STA_ABORT
+};
+
+/**
+ * struct atcdmac_regs - Hardware DMA descriptor registers.
+ *
+ * @ctrl: Channel Control Register.
+ * @trans_size: Transfer Size Register.
+ * @src_addr_lo: Source Address Register (low 32-bit).
+ * @src_addr_hi: Source Address Register (high 32-bit).
+ * @dst_addr_lo: Destination Address Register (low 32-bit).
+ * @dst_addr_hi: Destination Address Register (high 32-bit).
+ * @ll_ptr_lo: Linked List Pointer Register (low 32-bit).
+ * @ll_ptr_hi: Linked List Pointer Register (high 32-bit).
+ */
+struct atcdmac_regs {
+ unsigned int ctrl;
+ unsigned int trans_size;
+ unsigned int src_addr_lo;
+ unsigned int src_addr_hi;
+ unsigned int dst_addr_lo;
+ unsigned int dst_addr_hi;
+ unsigned int ll_ptr_lo;
+ unsigned int ll_ptr_hi;
+};
+
+/**
+ * struct atcdmac_desc - Internal representation of a DMA descriptor.
+ *
+ * @regs: Hardware registers for this descriptor.
+ * @txd: DMA transaction descriptor for dmaengine framework.
+ * @desc_node: Node for linking descriptors in software lists.
+ * @tx_list: List head for chaining multiple descriptors in a single transfer.
+ * @at: Next descriptor in a cyclic transfer (for internal use).
+ * @num_sg: Number of scatterlist entries this descriptor handles.
+ */
+struct atcdmac_desc {
+ struct atcdmac_regs regs;
+ struct dma_async_tx_descriptor txd;
+ struct list_head desc_node;
+ struct list_head tx_list;
+ struct list_head *at;
+ unsigned short num_sg;
+};
+
+/**
+ * struct atcdmac_chan - Private data for each DMA channel.
+ *
+ * @dma_chan: Common DMA engine channel object members
+ * @dma_dev: Pointer to the struct atcdmac_dmac
+ * @dma_sconfig: DMA transfer config for device-to-memory or memory-to-device
+ * @regmap: Regmap for the DMA channel register
+ * @active_list: List of descriptors being processed by the DMA engine
+ * @queue_list: List of descriptors ready to be submitted to the DMA engine
+ * @free_list: List of descriptors available for reuse by the channel
+ * @lock: Protects data access in atomic operations
+ * @status: Transmit status info, shared between top-half and threaded IRQ
+ * @descs_allocated: Number of descriptors currently allocated in the pool
+ * @chan_id: Channel ID number
+ * @req_num: Request number assigned to the channel
+ * @chan_used: Indicates whether the DMA channel is currently in use
+ * @cyclic: Indicates if the transfer operates in cyclic mode
+ * @dev_chan: Indicates if the DMA channel transfers data between device
+ * and memory
+ */
+struct atcdmac_chan {
+ struct dma_chan dma_chan;
+ struct atcdmac_dmac *dma_dev;
+ struct dma_slave_config dma_sconfig;
+ struct regmap *regmap;
+
+ struct list_head active_list;
+ struct list_head queue_list;
+ struct list_head free_list;
+
+ spinlock_t lock; /* protects active_list, queue_list, status */
+ unsigned long status;
+ unsigned short descs_allocated;
+ unsigned char chan_id;
+ unsigned char req_num;
+ bool chan_used;
+ bool cyclic;
+ bool dev_chan;
+};
+
+/**
+ * struct atcdmac_dmac - Representation of the ATCDMAC300 DMA controller
+ * @dma_device: DMA device object for integration with DMA engine framework
+ * @regmap: Regmap for main DMA controller registers
+ * @regmap_iocp: Regmap for IOCP registers
+ * @dma_desc_pool: DMA descriptor pool for allocating and managing descriptors
+ * @regs: Memory-mapped base address of the main DMA controller registers
+ * @lock: Protects data access in atomic operations
+ * @used_chan: Bitmask of DMA channels actively issuing DMA descriptors
+ * @stop_mask: Stops the DMA channel after the current transaction completes
+ * @data_width: Max data bus width supported by the DMA controller
+ * @num_ch: Total number of DMA channels available in the controller
+ * @chan: Array of DMA channel structures, sized by the controller's channel
+ * count
+ */
+struct atcdmac_dmac {
+ struct dma_device dma_device;
+ struct regmap *regmap;
+ struct regmap *regmap_iocp;
+ struct dma_pool *dma_desc_pool;
+ void __iomem *regs;
+ spinlock_t lock; /* protects used_chan, stop_mask */
+ unsigned short used_chan;
+ unsigned short stop_mask;
+ unsigned char data_width;
+ unsigned char num_ch;
+ struct atcdmac_chan chan[] __counted_by(num_ch);
+};
+
+/**
+ * struct atcdmac_slave_cfg - Pre-computed per-transfer slave DMA configuration
+ *
+ * @reg: Device-side register address (source for DEV_TO_MEM, destination
+ * for MEM_TO_DEV).
+ * @burst_bytes: Burst size in bytes (addr_width * maxburst from
+ * dma_slave_config). Used to derive the hardware burst-count
+ * field and to select the optimal transfer width.
+ * @dev_width: Device-side bus width in bytes (src_addr_width for DEV_TO_MEM,
+ * dst_addr_width for MEM_TO_DEV). Used to convert @burst_bytes
+ * into a hardware burst-count for the device side.
+ * @width_src: Hardware-encoded source transfer width (output of
+ * atcdmac_map_buswidth() on the source bus width).
+ * @width_dst: Hardware-encoded destination transfer width (output of
+ * atcdmac_map_buswidth() on the destination bus width).
+ */
+struct atcdmac_slave_cfg {
+ dma_addr_t reg;
+ unsigned int burst_bytes;
+ unsigned int dev_width;
+ unsigned int width_src;
+ unsigned int width_dst;
+};
+
+/*
+ * Helper functions to convert between dmaengine and internal structures.
+ */
+static inline struct atcdmac_desc *
+atcdmac_txd_to_dma_desc(struct dma_async_tx_descriptor *txd)
+{
+ return container_of(txd, struct atcdmac_desc, txd);
+}
+
+static inline struct atcdmac_chan *
+atcdmac_chan_to_dmac_chan(struct dma_chan *chan)
+{
+ return container_of(chan, struct atcdmac_chan, dma_chan);
+}
+
+static inline struct atcdmac_dmac *atcdmac_dev_to_dmac(struct dma_device *dev)
+{
+ return container_of(dev, struct atcdmac_dmac, dma_device);
+}
+
+static inline struct device *atcdmac_chan_to_dev(struct dma_chan *chan)
+{
+ return &chan->dev->device;
+}
+
+#endif
--
2.34.1
^ permalink raw reply related [flat|nested] 5+ messages in thread