fix(esp_eth): fixes EMAC MDC out of the range issue

Closes https://github.com/espressif/esp-idf/issues/17984

components/esp_eth/include/esp_eth_mac_esp.h

@@ -126,6 +126,7 @@ typedef struct {
 #if !SOC_EMAC_RMII_CLK_OUT_INTERNAL_LOOPBACK
     eth_mac_clock_config_t clock_config_out_in;     /*!< EMAC input clock configuration for internally generated output clock (when output clock is looped back externally) */
 #endif //SOC_EMAC_RMII_CLK_OUT_INTERNAL_LOOPBACK
+    int32_t mdc_freq_hz;                            /*!< EMAC MDC frequency range limit, if set to 0 or a negative value, the driver will can set the CSR clock range up to 2.5 MHz */
 } eth_esp32_emac_config_t;
 
 /**
@@ -185,6 +186,7 @@ typedef bool (*ts_target_exceed_cb_from_isr_t)(esp_eth_mediator_t *eth, void *us
         },                                                                    \
         .dma_burst_len = ETH_DMA_BURST_LEN_32,                                \
         .intr_priority = 0,                                                   \
+        .mdc_freq_hz = 0,                                                     \
     }
 #elif CONFIG_IDF_TARGET_ESP32P4
 #define ETH_ESP32_EMAC_DEFAULT_CONFIG()                                       \
@@ -205,6 +207,7 @@ typedef bool (*ts_target_exceed_cb_from_isr_t)(esp_eth_mediator_t *eth, void *us
         },                                                                    \
         .dma_burst_len = ETH_DMA_BURST_LEN_32,                                \
         .intr_priority = 0,                                                   \
+        .mdc_freq_hz = 0,                                                     \
         .emac_dataif_gpio =                                                   \
         {                                                                     \
             .rmii =                                                           \

components/esp_eth/src/mac/esp_eth_mac_esp.c

@@ -77,6 +77,7 @@ typedef struct {
     bool do_flow_ctrl;  // indicates whether we need to do software flow control
     bool use_pll;  // Only use (A/M)PLL in EMAC_DATA_INTERFACE_RMII && EMAC_CLK_OUT
     SemaphoreHandle_t multi_reg_mutex; // lock for multiple register access
+    int32_t mdc_freq_hz;
 #ifdef CONFIG_PM_ENABLE
     esp_pm_lock_handle_t pm_lock;
 #endif
@@ -618,7 +619,14 @@ static esp_err_t emac_esp32_init(esp_eth_mac_t *mac)
     }
     ESP_GOTO_ON_FALSE(to < emac->sw_reset_timeout_ms / 10, ESP_ERR_TIMEOUT, err, TAG, "reset timeout");
     /* set smi clock */
-    emac_hal_set_csr_clock_range(&emac->hal, esp_clk_apb_freq());
+    uint32_t csr_freq_hz;
+    soc_module_clk_t csr_clk_src = emac_ll_get_csr_clk_src();
+    ESP_GOTO_ON_ERROR(esp_clk_tree_src_get_freq_hz(csr_clk_src, ESP_CLK_TREE_SRC_FREQ_PRECISION_APPROX, &csr_freq_hz), err, TAG, "get CSR frequency failed");
+    if (emac->mdc_freq_hz <= 0) {
+        emac_hal_set_csr_clock_range(&emac->hal, csr_freq_hz);
+    } else {
+        emac_hal_find_set_closest_csr_clock_range(&emac->hal, emac->mdc_freq_hz, csr_freq_hz);
+    }
     /* init mac registers by default */
     emac_hal_init_mac_default(&emac->hal);
     /* init dma registers with selected EMAC-DMA configuration */
@@ -950,6 +958,8 @@ esp_eth_mac_t *esp_eth_mac_new_esp32(const eth_esp32_emac_config_t *esp32_config
     emac->dma_burst_len = esp32_config->dma_burst_len;
     emac->sw_reset_timeout_ms = config->sw_reset_timeout_ms;
 
+    emac->mdc_freq_hz = esp32_config->mdc_freq_hz;
+
     emac->flow_control_high_water_mark = FLOW_CONTROL_HIGH_WATER_MARK;
     emac->flow_control_low_water_mark = FLOW_CONTROL_LOW_WATER_MARK;
     emac->parent.set_mediator = emac_esp32_set_mediator;

components/esp_hal_emac/emac_hal.c

@@ -4,6 +4,7 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 #include <string.h>
+#include <stdlib.h>
 #include "soc/soc_caps.h"
 #include "esp_attr.h"
 #include "hal/emac_hal.h"
@@ -13,6 +14,15 @@
 #define EMAC_PTP_INIT_TIMEOUT_US (10)
 #endif // SOC_EMAC_IEEE1588V2_SUPPORTED
 
+static uint8_t emac_crs_div_table[] = {
+    42,
+    62,
+    16,
+    26,
+    102,
+    124,
+};
+
 static esp_err_t emac_hal_flush_trans_fifo(emac_hal_context_t *hal)
 {
     emac_ll_flush_trans_fifo_enable(hal->dma_regs, true);
@@ -39,6 +49,21 @@ void emac_hal_init(emac_hal_context_t *hal)
 #endif
 }
 
+void emac_hal_find_set_closest_csr_clock_range(emac_hal_context_t *hal, int mdc_freq_hz, int freq_hz)
+{
+    int min_diff = abs(freq_hz / emac_crs_div_table[0] - mdc_freq_hz);
+    uint32_t best_div = 0;
+
+    for (int i = 1; i < sizeof(emac_crs_div_table) / sizeof(emac_crs_div_table[0]); i++) {
+        int cur_diff = abs(freq_hz / emac_crs_div_table[i] - mdc_freq_hz);
+        if (cur_diff < min_diff) {
+            min_diff = cur_diff;
+            best_div = i;
+        }
+    }
+    emac_ll_set_csr_clock_division(hal->mac_regs, best_div);
+}
+
 void emac_hal_set_csr_clock_range(emac_hal_context_t *hal, int freq)
 {
     /* Tell MAC system clock Frequency in MHz, which will determine the frequency range of MDC(1MHz~2.5MHz) */

components/esp_hal_emac/esp32/include/hal/emac_ll.h

@@ -22,6 +22,7 @@
 #include "soc/emac_mac_struct.h"
 #include "soc/emac_ext_struct.h"
 #include "soc/dport_reg.h"
+#include "soc/clk_tree_defs.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -745,6 +746,12 @@ static inline void emac_ll_pause_frame_enable(emac_ext_dev_t *ext_regs, bool ena
 }
 /*************** End of ext regs operation *********************/
 
+static inline soc_module_clk_t emac_ll_get_csr_clk_src(void)
+{
+    // Source of the ESP32 EMAC CRS clock is APB clock.
+    return SOC_MOD_CLK_APB;
+}
+
 #ifdef __cplusplus
 }
 #endif

components/esp_hal_emac/esp32p4/include/hal/emac_ll.h

@@ -840,6 +840,12 @@ static inline void emac_ll_ts_target_int_trig_enable(emac_ptp_dev_t *ptp_regs)
 
 /************** End of ptp regs operation ********************/
 
+static inline soc_module_clk_t emac_ll_get_csr_clk_src(void)
+{
+    // Source of the ESP32P4 EMAC CRS clock is SYS clock.
+    return SOC_MOD_CLK_SYS;
+}
+
 /**
  * @brief Enable the bus clock for the EMAC module
  *

components/esp_hal_emac/include/hal/emac_hal.h

@@ -245,6 +245,10 @@ void emac_hal_init(emac_hal_context_t *hal);
 
 #define emac_hal_is_reset_done(hal) emac_ll_is_reset_done((hal)->dma_regs)
 
+#define emac_hal_get_csr_freq_hz(void) emac_ll_get_csr_freq_hz()
+
+void emac_hal_find_set_closest_csr_clock_range(emac_hal_context_t *hal, int mdc_freq_hz, int freq_hz);
+
 void emac_hal_set_csr_clock_range(emac_hal_context_t *hal, int freq);
 
 void emac_hal_init_mac_default(emac_hal_context_t *hal);

components/esp_hw_support/port/esp32p4/esp_clk_tree.c

@@ -8,6 +8,7 @@
 #include "esp_clk_tree.h"
 #include "esp_err.h"
 #include "esp_check.h"
+#include "soc/clk_tree_defs.h"
 #include "soc/rtc.h"
 #include "hal/clk_gate_ll.h"
 #include "hal/clk_tree_hal.h"
@@ -32,6 +33,12 @@ esp_err_t esp_clk_tree_src_get_freq_hz(soc_module_clk_t clk_src, esp_clk_tree_sr
     case SOC_MOD_CLK_XTAL:
         clk_src_freq = clk_hal_xtal_get_freq_mhz() * MHZ;
         break;
+    case SOC_MOD_CLK_SYS:
+        clk_src_freq = clk_hal_sys_get_freq_hz();
+        break;
+    case SOC_MOD_CLK_APB:
+        clk_src_freq = clk_hal_apb_get_freq_hz();
+        break;
     case SOC_MOD_CLK_PLL_F20M:
         clk_src_freq = CLK_LL_PLL_480M_FREQ_MHZ / clk_ll_pll_f20m_get_divider() * MHZ;
         break;

components/hal/esp32p4/clk_tree_hal.c

@@ -45,7 +45,7 @@ static uint32_t clk_hal_mem_get_freq_hz(void)
     return clk_hal_cpu_get_freq_hz() / clk_ll_mem_get_divider();
 }
 
-static uint32_t clk_hal_sys_get_freq_hz(void)
+uint32_t clk_hal_sys_get_freq_hz(void)
 {
     return clk_hal_mem_get_freq_hz() / clk_ll_sys_get_divider();
 }

components/hal/include/hal/clk_tree_hal.h

@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText: 2023-2024 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileCopyrightText: 2023-2025 Espressif Systems (Shanghai) CO LTD
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -35,7 +35,14 @@ uint32_t clk_hal_soc_root_get_freq_mhz(soc_cpu_clk_src_t cpu_clk_src);
 uint32_t clk_hal_cpu_get_freq_hz(void);
 
 /**
- * @brief Get APB_CLK frequency
+ * @brief Get SYS_CLK frequency, derived from MEM_CLK
+ *
+ * @return SYS clock frequency, in Hz. Returns 0 if internal clock configuration is invalid.
+ */
+uint32_t clk_hal_sys_get_freq_hz(void);
+
+/**
+ * @brief Get APB_CLK frequency, derived from SYS_CLK
  *
  * @return APB clock frequency, in Hz. Returns 0 if internal clock configuration is invalid.
  */

components/soc/esp32p4/include/soc/clk_tree_defs.h

@@ -160,6 +160,7 @@ typedef enum {
     SOC_MOD_CLK_RTC_FAST,                      /*!< RTC_FAST_CLK can be sourced from XTAL, RC_FAST, or LP_PLL by configuring soc_rtc_fast_clk_src_t */
     SOC_MOD_CLK_RTC_SLOW,                      /*!< RTC_SLOW_CLK can be sourced from RC_SLOW, XTAL32K, or RC32K by configuring soc_rtc_slow_clk_src_t */
     // For digital domain: peripherals
+    SOC_MOD_CLK_SYS,                           /*!< SYS_CLK is the system clock, derived from HP_ROOT clock source */
     SOC_MOD_CLK_APB,                           /*!< APB_CLK is highly dependent on the CPU_CLK source */
     SOC_MOD_CLK_PLL_F20M,                      /*!< PLL_F20M_CLK is derived from SPLL (clock gating + default divider 24), its default frequency is 20MHz */
     SOC_MOD_CLK_PLL_F25M,                      /*!< PLL_F25M_CLK is derived from MPLL (clock gating + configurable divider), it will have a frequency of 25MHz */