Merge branch 'bugfix/lcd_driver_with_flash_encryption' into 'master'

fix(dma): also consider buffer alignment when calculating the DMA nodes

Closes IDFGH-14453 and IDF-12101

See merge request espressif/esp-idf!36617

Author: suda-morris

components/esp_driver_bitscrambler/src/bitscrambler_loopback.c

@@ -9,6 +9,7 @@
 #include "driver/bitscrambler.h"
 #include "esp_private/gdma.h"
 #include "esp_private/gdma_link.h"
+#include "esp_private/esp_dma_utils.h"
 #include "esp_private/bitscrambler.h"
 #include "hal/dma_types.h"
 #include "hal/cache_hal.h"
@@ -98,7 +99,7 @@ esp_err_t bitscrambler_loopback_create(bitscrambler_handle_t *handle, int attach
     }
 
     bs->max_transfer_sz_bytes = max_transfer_sz_bytes;
-    int desc_ct = (max_transfer_sz_bytes + DMA_DESCRIPTOR_BUFFER_MAX_SIZE_4B_ALIGNED - 1) / DMA_DESCRIPTOR_BUFFER_MAX_SIZE_4B_ALIGNED;
+    size_t desc_ct = esp_dma_calculate_node_count(max_transfer_sz_bytes, 4, DMA_DESCRIPTOR_BUFFER_MAX_SIZE);
     int bus = g_bitscrambler_periph_desc[attach_to].bus;
 #ifdef SOC_GDMA_BUS_AXI
     size_t align = (bus == SOC_GDMA_BUS_AXI) ? 8 : 4;

components/esp_driver_parlio/src/parlio_tx.c

@@ -38,6 +38,7 @@
 #include "esp_private/esp_clk_tree_common.h"
 #include "esp_private/gdma.h"
 #include "esp_private/gdma_link.h"
+#include "esp_private/esp_dma_utils.h"
 
 static const char *TAG = "parlio-tx";
 
@@ -54,7 +55,6 @@ typedef struct parlio_tx_unit_t {
     esp_pm_lock_handle_t pm_lock;   // power management lock
     gdma_channel_handle_t dma_chan; // DMA channel
     gdma_link_list_handle_t dma_link; // DMA link list handle
-    size_t dma_nodes_num;           // number of DMA descriptor nodes
     size_t int_mem_align; // Alignment for internal memory
     size_t ext_mem_align; // Alignment for external memory
 #if CONFIG_PM_ENABLE
@@ -219,11 +219,12 @@ static esp_err_t parlio_tx_unit_init_dma(parlio_tx_unit_t *tx_unit, const parlio
     gdma_get_alignment_constraints(tx_unit->dma_chan, &tx_unit->int_mem_align, &tx_unit->ext_mem_align);
 
     // create DMA link list
-    size_t dma_nodes_num = tx_unit->dma_nodes_num;
+    size_t buffer_alignment = MAX(tx_unit->int_mem_align, tx_unit->ext_mem_align);
+    size_t num_dma_nodes = esp_dma_calculate_node_count(config->max_transfer_size, buffer_alignment, DMA_DESCRIPTOR_BUFFER_MAX_SIZE);
     gdma_link_list_config_t dma_link_config = {
-        .buffer_alignment = 1,
+        .buffer_alignment = buffer_alignment,
         .item_alignment = PARLIO_DMA_DESC_ALIGNMENT,
-        .num_items = dma_nodes_num,
+        .num_items = num_dma_nodes,
     };
 
     // throw the error to the caller
@@ -330,11 +331,6 @@ esp_err_t parlio_new_tx_unit(const parlio_tx_unit_config_t *config, parlio_tx_un
     unit = heap_caps_calloc(1, sizeof(parlio_tx_unit_t) + sizeof(parlio_tx_trans_desc_t) * config->trans_queue_depth, mem_caps);
     ESP_GOTO_ON_FALSE(unit, ESP_ERR_NO_MEM, err, TAG, "no memory for tx unit");
 
-    // create DMA descriptors
-    // DMA descriptors must be placed in internal SRAM
-    size_t dma_nodes_num = config->max_transfer_size / DMA_DESCRIPTOR_BUFFER_MAX_SIZE + 1;
-    unit->dma_nodes_num = dma_nodes_num;
-
     unit->max_transfer_bits = config->max_transfer_size * 8;
     unit->base.dir = PARLIO_DIR_TX;
     unit->data_width = data_width;

components/esp_hw_support/dma/async_memcpy_cp_dma.c

@@ -20,6 +20,7 @@
 #include "esp_async_memcpy.h"
 #include "esp_async_memcpy_priv.h"
 #include "esp_private/gdma_link.h"
+#include "esp_private/esp_dma_utils.h"
 #include "hal/cp_dma_hal.h"
 #include "hal/cp_dma_ll.h"
 
@@ -211,11 +212,13 @@ static esp_err_t mcp_cpdma_memcpy(async_memcpy_context_t *ctx, void *dst, void *
         trans->rx_link_list = NULL;
     }
 
+    size_t num_dma_nodes = esp_dma_calculate_node_count(n, 1, MCP_DMA_DESCRIPTOR_BUFFER_MAX_SIZE);
+
     // allocate gdma TX link
     gdma_link_list_config_t tx_link_cfg = {
         .buffer_alignment = 1, // CP_DMA doesn't have alignment requirement for internal memory
         .item_alignment = 4,   // CP_DMA requires 4 bytes alignment for each descriptor
-        .num_items = n / MCP_DMA_DESCRIPTOR_BUFFER_MAX_SIZE + 1,
+        .num_items = num_dma_nodes,
         .flags = {
             .check_owner = true,
             .items_in_ext_mem = false,
@@ -239,7 +242,7 @@ static esp_err_t mcp_cpdma_memcpy(async_memcpy_context_t *ctx, void *dst, void *
     gdma_link_list_config_t rx_link_cfg = {
         .buffer_alignment = 1, // CP_DMA doesn't have alignment requirement for internal memory
         .item_alignment = 4,   // CP_DMA requires 4 bytes alignment for each descriptor
-        .num_items = n / MCP_DMA_DESCRIPTOR_BUFFER_MAX_SIZE + 1,
+        .num_items = num_dma_nodes,
         .flags = {
             .check_owner = true,
             .items_in_ext_mem = false,

components/esp_hw_support/dma/async_memcpy_gdma.c

@@ -342,11 +342,16 @@ static esp_err_t mcp_gdma_memcpy(async_memcpy_context_t *ctx, void *dst, void *s
         trans->stash_buffer = NULL;
     }
 
+    size_t buffer_alignment = 0;
+    size_t num_dma_nodes = 0;
+
     // allocate gdma TX link
+    buffer_alignment = esp_ptr_internal(src) ? mcp_gdma->tx_int_mem_alignment : mcp_gdma->tx_ext_mem_alignment;
+    num_dma_nodes = esp_dma_calculate_node_count(n, buffer_alignment, MCP_DMA_DESCRIPTOR_BUFFER_MAX_SIZE);
     gdma_link_list_config_t tx_link_cfg = {
-        .buffer_alignment = esp_ptr_internal(src) ? mcp_gdma->tx_int_mem_alignment : mcp_gdma->tx_ext_mem_alignment,
+        .buffer_alignment = buffer_alignment,
         .item_alignment = dma_link_item_alignment,
-        .num_items = n / MCP_DMA_DESCRIPTOR_BUFFER_MAX_SIZE + 1,
+        .num_items = num_dma_nodes,
         .flags = {
             .check_owner = true,
             .items_in_ext_mem = false, // TODO: if the memcopy size is too large, we may need to allocate the link list items from external memory
@@ -381,10 +386,12 @@ static esp_err_t mcp_gdma_memcpy(async_memcpy_context_t *ctx, void *dst, void *s
     }
 
     // allocate gdma RX link
+    buffer_alignment = esp_ptr_internal(dst) ? mcp_gdma->rx_int_mem_alignment : mcp_gdma->rx_ext_mem_alignment;
+    num_dma_nodes = esp_dma_calculate_node_count(n, buffer_alignment, MCP_DMA_DESCRIPTOR_BUFFER_MAX_SIZE);
     gdma_link_list_config_t rx_link_cfg = {
-        .buffer_alignment = esp_ptr_internal(dst) ? mcp_gdma->rx_int_mem_alignment : mcp_gdma->rx_ext_mem_alignment,
+        .buffer_alignment = buffer_alignment,
         .item_alignment = dma_link_item_alignment,
-        .num_items = n / MCP_DMA_DESCRIPTOR_BUFFER_MAX_SIZE + 3,
+        .num_items = num_dma_nodes + 3, // add 3 extra items for the cache aligned buffers
         .flags = {
             .check_owner = true,
             .items_in_ext_mem = false, // TODO: if the memcopy size is too large, we may need to allocate the link list items from external memory

components/esp_hw_support/dma/esp_dma_utils.c

@@ -27,6 +27,8 @@ static const char *TAG = "dma_utils";
 
 esp_err_t esp_dma_split_rx_buffer_to_cache_aligned(void *rx_buffer, size_t buffer_len, dma_buffer_split_array_t *align_buf_array, uint8_t** ret_stash_buffer)
 {
+    esp_err_t ret = ESP_OK;
+    uint8_t* stash_buffer = NULL;
     ESP_RETURN_ON_FALSE(rx_buffer && buffer_len && align_buf_array, ESP_ERR_INVALID_ARG, TAG, "invalid argument");
 
     // read the cache line size of internal and external memory, we also use this information to check if a given memory is behind the cache
@@ -43,7 +45,7 @@ esp_err_t esp_dma_split_rx_buffer_to_cache_aligned(void *rx_buffer, size_t buffe
 
     // allocate the stash buffer from internal RAM
     // Note, the split_line_size can be 0, in this case, the stash_buffer is also NULL, which is fine
-    uint8_t* stash_buffer = heap_caps_calloc(2, split_line_size, MALLOC_CAP_DMA | MALLOC_CAP_INTERNAL | MALLOC_CAP_8BIT);
+    stash_buffer = heap_caps_calloc(2, split_line_size, MALLOC_CAP_DMA | MALLOC_CAP_INTERNAL | MALLOC_CAP_8BIT);
     ESP_RETURN_ON_FALSE(!(split_line_size && !stash_buffer), ESP_ERR_NO_MEM, TAG, "no mem for stash buffer");
 
     // clear align_array to avoid garbage data
@@ -99,12 +101,18 @@ esp_err_t esp_dma_split_rx_buffer_to_cache_aligned(void *rx_buffer, size_t buffe
     // invalidate the aligned buffer if necessary
     for (int i = 0; i < 3; i++) {
         if (need_cache_sync[i]) {
-            esp_cache_msync(align_buf_array->aligned_buffer[i].aligned_buffer, align_buf_array->aligned_buffer[i].length, ESP_CACHE_MSYNC_FLAG_DIR_M2C);
+            esp_err_t res = esp_cache_msync(align_buf_array->aligned_buffer[i].aligned_buffer, align_buf_array->aligned_buffer[i].length, ESP_CACHE_MSYNC_FLAG_DIR_M2C);
+            ESP_GOTO_ON_ERROR(res, err, TAG, "failed to do cache sync");
         }
     }
 
     *ret_stash_buffer = stash_buffer;
     return ESP_OK;
+err:
+    if (stash_buffer) {
+        free(stash_buffer);
+    }
+    return ret;
 }
 
 esp_err_t esp_dma_merge_aligned_rx_buffers(dma_buffer_split_array_t *align_array)
@@ -121,6 +129,16 @@ esp_err_t esp_dma_merge_aligned_rx_buffers(dma_buffer_split_array_t *align_array
     return ESP_OK;
 }
 
+size_t esp_dma_calculate_node_count(size_t buffer_size, size_t buffer_alignment, size_t max_buffer_size_per_node)
+{
+    // buffer_alignment should be power of 2
+    ESP_RETURN_ON_FALSE(buffer_alignment && ((buffer_alignment & (buffer_alignment - 1)) == 0), 0, TAG, "invalid buffer alignment");
+    // align down the max_buffer_size_per_node
+    max_buffer_size_per_node = max_buffer_size_per_node & ~(buffer_alignment - 1);
+    // calculate the number of nodes
+    return (buffer_size + max_buffer_size_per_node - 1) / max_buffer_size_per_node;
+}
+
 esp_err_t esp_dma_capable_malloc(size_t size, const esp_dma_mem_info_t *dma_mem_info, void **out_ptr, size_t *actual_size)
 {
     ESP_RETURN_ON_FALSE_ISR(dma_mem_info && out_ptr, ESP_ERR_INVALID_ARG, TAG, "null pointer");

components/esp_hw_support/dma/include/esp_private/esp_dma_utils.h

@@ -83,6 +83,16 @@ esp_err_t esp_dma_split_rx_buffer_to_cache_aligned(void *rx_buffer, size_t buffe
  */
 esp_err_t esp_dma_merge_aligned_rx_buffers(dma_buffer_split_array_t *align_buf_array);
 
+/**
+ * @brief Calculate the number of DMA linked list nodes required for a given buffer size
+ *
+ * @param[in] buffer_size Total size of the buffer
+ * @param[in] buffer_alignment Alignment requirement for the buffer
+ * @param[in] max_buffer_size_per_node Maximum buffer size that each node can handle
+ * @return Number of DMA linked list nodes required
+ */
+size_t esp_dma_calculate_node_count(size_t buffer_size, size_t buffer_alignment, size_t max_buffer_size_per_node);
+
 #ifdef __cplusplus
 }
 #endif

components/esp_hw_support/test_apps/dma/main/test_gdma.c

@@ -557,7 +557,7 @@ TEST_CASE("GDMA M2M Unaligned RX Buffer Test", "[GDMA][M2M]")
 
     gdma_link_list_handle_t tx_link_list = NULL;
     gdma_link_list_handle_t rx_link_list = NULL;
-    // create DMA link list for TX channel (a singly link with 3 nodes)
+    // create DMA link list for TX channel
     gdma_link_list_config_t tx_link_list_config = {
         .buffer_alignment = 32,
         .item_alignment = 8, // 8-byte alignment required by the AXI-GDMA

components/esp_lcd/i80/esp_lcd_panel_io_i2s.c

@@ -39,6 +39,7 @@
 #include "esp_private/periph_ctrl.h"
 #include "esp_private/i2s_platform.h"
 #include "esp_private/gdma_link.h"
+#include "esp_private/esp_dma_utils.h"
 #include "esp_private/gpio.h"
 #include "soc/lcd_periph.h"
 #include "hal/i2s_hal.h"
@@ -71,7 +72,7 @@ struct esp_lcd_i80_bus_t {
     int wr_gpio_num;       // GPIO used for WR line
     intr_handle_t intr;    // LCD peripheral interrupt handle
     esp_pm_lock_handle_t pm_lock; // lock APB frequency when necessary
-    size_t num_dma_nodes;  // Number of DMA descriptors
+    size_t max_transfer_bytes;    // Maximum number of bytes that can be transferred in one transaction
     gdma_link_list_handle_t dma_link; // DMA link list handle
     uint8_t *format_buffer;// The driver allocates an internal buffer for DMA to do data format transformer
     unsigned long resolution_hz;  // LCD_CLK resolution, determined by selected clock source
@@ -141,7 +142,7 @@ esp_err_t esp_lcd_new_i80_bus(const esp_lcd_i80_bus_config_t *bus_config, esp_lc
     // allocate i80 bus memory
     bus = heap_caps_calloc(1, sizeof(esp_lcd_i80_bus_t), LCD_I80_MEM_ALLOC_CAPS);
     ESP_GOTO_ON_FALSE(bus, ESP_ERR_NO_MEM, err, TAG, "no mem for i80 bus");
-    size_t num_dma_nodes = max_transfer_bytes / LCD_DMA_DESCRIPTOR_BUFFER_MAX_SIZE + 1;
+    size_t num_dma_nodes = esp_dma_calculate_node_count(max_transfer_bytes, 1, LCD_DMA_DESCRIPTOR_BUFFER_MAX_SIZE);
     // create DMA link list
     gdma_link_list_config_t dma_link_config = {
         .buffer_alignment = 1, // no special buffer alignment for LCD TX buffer
@@ -153,7 +154,7 @@ esp_err_t esp_lcd_new_i80_bus(const esp_lcd_i80_bus_config_t *bus_config, esp_lc
     };
     ESP_GOTO_ON_ERROR(gdma_new_link_list(&dma_link_config, &bus->dma_link), err, TAG, "create DMA link list failed");
     bus->bus_id = -1;
-    bus->num_dma_nodes = num_dma_nodes;
+    bus->max_transfer_bytes = max_transfer_bytes;
 #if SOC_I2S_TRANS_SIZE_ALIGN_WORD
     // transform format for LCD commands, parameters and color data, so we need a big buffer
     bus->format_buffer = heap_caps_calloc(1, max_transfer_bytes, MALLOC_CAP_INTERNAL | MALLOC_CAP_8BIT | MALLOC_CAP_DMA);
@@ -217,7 +218,7 @@ esp_err_t esp_lcd_new_i80_bus(const esp_lcd_i80_bus_config_t *bus_config, esp_lc
     bus->dc_gpio_num = bus_config->dc_gpio_num;
     bus->wr_gpio_num = bus_config->wr_gpio_num;
     *ret_bus = bus;
-    ESP_LOGD(TAG, "new i80 bus(%d) @%p, %zu dma nodes, resolution %luHz", bus->bus_id, bus, num_dma_nodes, bus->resolution_hz);
+    ESP_LOGD(TAG, "new i80 bus(%d) @%p, resolution %luHz", bus->bus_id, bus, bus->resolution_hz);
     return ESP_OK;
 
 err:
@@ -510,7 +511,7 @@ static esp_err_t panel_io_i80_tx_param(esp_lcd_panel_io_t *io, int lcd_cmd, cons
     esp_lcd_i80_bus_t *bus = next_device->bus;
     lcd_panel_io_i80_t *cur_device = bus->cur_device;
     lcd_i80_trans_descriptor_t *trans_desc = NULL;
-    assert(param_size <= (bus->num_dma_nodes * LCD_DMA_DESCRIPTOR_BUFFER_MAX_SIZE) && "parameter bytes too long, enlarge max_transfer_bytes");
+    assert(param_size <= bus->max_transfer_bytes && "parameter bytes too long, enlarge max_transfer_bytes");
     assert(param_size <= LCD_I80_IO_FORMAT_BUF_SIZE && "format buffer too small, increase LCD_I80_IO_FORMAT_BUF_SIZE");
     size_t num_trans_inflight = next_device->num_trans_inflight;
     // before issue a polling transaction, need to wait queued transactions finished
@@ -587,7 +588,7 @@ static esp_err_t panel_io_i80_tx_color(esp_lcd_panel_io_t *io, int lcd_cmd, cons
     esp_lcd_i80_bus_t *bus = next_device->bus;
     lcd_panel_io_i80_t *cur_device = bus->cur_device;
     lcd_i80_trans_descriptor_t *trans_desc = NULL;
-    assert(color_size <= (bus->num_dma_nodes * LCD_DMA_DESCRIPTOR_BUFFER_MAX_SIZE) && "color bytes too long, enlarge max_transfer_bytes");
+    assert(color_size <= bus->max_transfer_bytes && "color bytes too long, enlarge max_transfer_bytes");
     size_t num_trans_inflight = next_device->num_trans_inflight;
     // before issue a polling transaction, need to wait queued transactions finished
     for (size_t i = 0; i < num_trans_inflight; i++) {

components/esp_lcd/i80/esp_lcd_panel_io_i80.c

@@ -33,6 +33,7 @@
 #include "esp_private/gpio.h"
 #include "esp_private/gdma.h"
 #include "esp_private/gdma_link.h"
+#include "esp_private/esp_dma_utils.h"
 #include "esp_private/periph_ctrl.h"
 #include "esp_lcd_common.h"
 #include "soc/lcd_periph.h"
@@ -87,7 +88,7 @@ struct esp_lcd_i80_bus_t {
     uint8_t *format_buffer;  // The driver allocates an internal buffer for DMA to do data format transformer
     uint8_t *format_buffer_nc; // Non-cacheable version of format buffer
     size_t resolution_hz;    // LCD_CLK resolution, determined by selected clock source
-    size_t num_dma_nodes;    // Number of DMA nodes (descriptors)
+    size_t max_transfer_bytes; // Maximum number of bytes that can be transferred in one transaction
     gdma_channel_handle_t dma_chan; // DMA channel handle
     gdma_link_list_handle_t dma_link; // DMA link list handle
     size_t int_mem_align; // Alignment for internal memory
@@ -199,6 +200,7 @@ esp_err_t esp_lcd_new_i80_bus(const esp_lcd_i80_bus_config_t *bus_config, esp_lc
     lcd_ll_enable_interrupt(bus->hal.dev, LCD_LL_EVENT_TRANS_DONE, false); // disable all interrupts
     lcd_ll_clear_interrupt_status(bus->hal.dev, UINT32_MAX); // clear pending interrupt
     // install DMA service
+    bus->max_transfer_bytes = bus_config->max_transfer_bytes;
     ret = lcd_i80_init_dma_link(bus, bus_config);
     ESP_GOTO_ON_ERROR(ret, err, TAG, "install DMA failed");
     // disable RGB-LCD mode
@@ -223,7 +225,7 @@ esp_err_t esp_lcd_new_i80_bus(const esp_lcd_i80_bus_config_t *bus_config, esp_lc
     LIST_INIT(&bus->device_list); // initialize device list head
     bus->spinlock = (portMUX_TYPE)portMUX_INITIALIZER_UNLOCKED;
     *ret_bus = bus;
-    ESP_LOGD(TAG, "new i80 bus(%d) @%p, %zu dma nodes", bus_id, bus, bus->num_dma_nodes);
+    ESP_LOGD(TAG, "new i80 bus(%d) @%p", bus_id, bus);
     return ESP_OK;
 
 err:
@@ -449,7 +451,7 @@ static esp_err_t panel_io_i80_tx_param(esp_lcd_panel_io_t *io, int lcd_cmd, cons
     esp_lcd_i80_bus_t *bus = next_device->bus;
     lcd_panel_io_i80_t *cur_device = bus->cur_device;
     lcd_i80_trans_descriptor_t *trans_desc = NULL;
-    assert(param_size <= (bus->num_dma_nodes * LCD_DMA_DESCRIPTOR_BUFFER_MAX_SIZE) && "parameter bytes too long, enlarge max_transfer_bytes");
+    assert(param_size <= bus->max_transfer_bytes && "parameter bytes too long, enlarge max_transfer_bytes");
     assert(param_size <= LCD_I80_IO_FORMAT_BUF_SIZE && "format buffer too small, increase LCD_I80_IO_FORMAT_BUF_SIZE");
     uint32_t cmd_cycles = next_device->lcd_cmd_bits / bus->bus_width;
     // in case bus_width=16 and cmd_bits=8, we still need 1 cmd_cycle
@@ -514,7 +516,7 @@ static esp_err_t panel_io_i80_tx_color(esp_lcd_panel_io_t *io, int lcd_cmd, cons
     lcd_panel_io_i80_t *i80_device = __containerof(io, lcd_panel_io_i80_t, base);
     esp_lcd_i80_bus_t *bus = i80_device->bus;
     lcd_i80_trans_descriptor_t *trans_desc = NULL;
-    assert(color_size <= (bus->num_dma_nodes * LCD_DMA_DESCRIPTOR_BUFFER_MAX_SIZE) && "color bytes too long, enlarge max_transfer_bytes");
+    assert(color_size <= bus->max_transfer_bytes && "color bytes too long, enlarge max_transfer_bytes");
     uint32_t cache_line_size = 0;
     if (esp_ptr_external_ram(color)) {
         // check alignment
@@ -610,18 +612,18 @@ static esp_err_t lcd_i80_init_dma_link(esp_lcd_i80_bus_handle_t bus, const esp_l
     ESP_RETURN_ON_ERROR(gdma_config_transfer(bus->dma_chan, &trans_cfg), TAG, "config DMA transfer failed");
     gdma_get_alignment_constraints(bus->dma_chan, &bus->int_mem_align, &bus->ext_mem_align);
 
-    size_t num_dma_nodes = bus_config->max_transfer_bytes / LCD_DMA_DESCRIPTOR_BUFFER_MAX_SIZE + 1;
+    size_t buffer_alignment = MAX(bus->int_mem_align, bus->ext_mem_align);
+    size_t num_dma_nodes = esp_dma_calculate_node_count(bus->max_transfer_bytes, buffer_alignment, LCD_DMA_DESCRIPTOR_BUFFER_MAX_SIZE);
     // create DMA link list
     gdma_link_list_config_t dma_link_config = {
-        .buffer_alignment = MAX(bus->int_mem_align, bus->ext_mem_align),
+        .buffer_alignment = buffer_alignment,
         .item_alignment = LCD_GDMA_DESCRIPTOR_ALIGN,
         .num_items = num_dma_nodes,
         .flags = {
             .check_owner = true,
         },
     };
     ESP_RETURN_ON_ERROR(gdma_new_link_list(&dma_link_config, &bus->dma_link), TAG, "create DMA link list failed");
-    bus->num_dma_nodes = num_dma_nodes;
 
     return ESP_OK;
 }