HAL_ChibiOS: support microSD slowdown

allow use of BRD_SD_SLOWDOWN to slow down clock on microSD

libraries/AP_HAL_ChibiOS/HAL_ChibiOS_Class.cpp

@@ -163,9 +163,6 @@ static THD_FUNCTION(main_loop,arg)
     ChibiOS::SPIDevice::test_clock_freq();
 #endif 
 
-    //Setup SD Card and Initialise FATFS bindings
-    sdcard_init();
-
     hal.uartB->begin(38400);
     hal.uartC->begin(57600);
     hal.analogin->init();

libraries/AP_HAL_ChibiOS/SPIDevice.cpp

@@ -15,6 +15,7 @@
 #include "SPIDevice.h"
 
 #include <AP_HAL/AP_HAL.h>
+#include <AP_Math/AP_Math.h>
 #include <AP_HAL/utility/OwnPtr.h>
 #include "Util.h"
 #include "Scheduler.h"
@@ -138,6 +139,15 @@ bool SPIDevice::set_speed(AP_HAL::Device::Speed speed)
     return true;
 }
 
+/*
+  setup a bus slowdown factor for high speed mode
+ */
+void SPIDevice::set_slowdown(uint8_t slowdown)
+{
+    slowdown = constrain_int16(slowdown+1, 1, 32);
+    freq_flag_high = derive_freq_flag(device_desc.highspeed / slowdown);
+}
+
 /*
   low level transfer function
  */

libraries/AP_HAL_ChibiOS/SPIDevice.h

@@ -34,6 +34,7 @@ public:
     void dma_allocate(Shared_DMA *ctx);
     void dma_deallocate(Shared_DMA *ctx);
     bool spi_started;
+    uint8_t slowdown;
     
     // we need an additional lock in the dma_allocate and
     // dma_deallocate functions to cope with 3-way contention as we
@@ -109,6 +110,9 @@ public:
     static void test_clock_freq(void);
 #endif
 
+    // setup a bus clock slowdown factor
+    void set_slowdown(uint8_t slowdown) override;
+
 private:
     SPIBus &bus;
     SPIDesc &device_desc;

libraries/AP_HAL_ChibiOS/Util.cpp

@@ -23,6 +23,7 @@
 #include "hwdef/common/stm32_util.h"
 #include "hwdef/common/flash.h"
 #include <AP_ROMFS/AP_ROMFS.h>
+#include "sdcard.h"
 
 #if HAL_WITH_IO_MCU
 #include <AP_BoardConfig/AP_BoardConfig.h>
@@ -250,3 +251,13 @@ bool Util::get_system_id(char buf[40])
     buf[39] = 0;
     return true;
 }
+
+#ifdef USE_POSIX
+/*
+  initialise filesystem
+ */
+bool Util::fs_init(void)
+{
+    return sdcard_init();
+}
+#endif

libraries/AP_HAL_ChibiOS/Util.h

@@ -51,6 +51,13 @@ public:
     void toneAlarm_set_buzzer_tone(float frequency, float volume, uint32_t duration_ms) override;
 #endif
 
+#ifdef USE_POSIX
+    /*
+      initialise (or re-initialise) filesystem storage
+     */
+    bool fs_init(void) override;
+#endif
+    
 private:
 #ifdef HAL_PWM_ALARM
     struct ToneAlarmPwmGroup {

libraries/AP_HAL_ChibiOS/sdcard.cpp

@@ -17,60 +17,83 @@
 #include "SPIDevice.h"
 #include "sdcard.h"
 #include "hwdef/common/spi_hook.h"
+#include <AP_BoardConfig/AP_BoardConfig.h>
 
 extern const AP_HAL::HAL& hal;
 
 #ifdef USE_POSIX
 static FATFS SDC_FS; // FATFS object
-static bool sdcard_init_done;
+static bool sdcard_running;
 #endif
 
-#if HAL_USE_MMC_SPI
+#if HAL_USE_SDC
+static SDCConfig sdcconfig = {
+  NULL,
+  SDC_MODE_4BIT,
+  0
+};
+#elif HAL_USE_MMC_SPI
 MMCDriver MMCD1;
 static AP_HAL::OwnPtr<AP_HAL::SPIDevice> device;
 static MMCConfig mmcconfig;
 static SPIConfig lowspeed;
 static SPIConfig highspeed;
-static bool sdcard_running;
 #endif
 
 /*
-  initialise microSD card if avaialble
+  initialise microSD card if avaialble. This is called during
+  AP_BoardConfig initialisation. The parameter BRD_SD_SLOWDOWN
+  controls a scaling factor on the microSD clock
  */
-void sdcard_init()
+bool sdcard_init()
 {
 #ifdef USE_POSIX
-    if (sdcard_init_done) {
+    uint8_t sd_slowdown = AP_BoardConfig::get_sdcard_slowdown();
-        return;
-    }
-    sdcard_init_done = true;
 #if HAL_USE_SDC
 
+    if (SDCD1.bouncebuffer == nullptr) {
         bouncebuffer_init(&SDCD1.bouncebuffer, 512);
-    
-    sdcStart(&SDCD1, NULL);
-
-    if(sdcConnect(&SDCD1) == HAL_FAILED) {
-        printf("Err: Failed to initialize SDIO!\n");
-    } else {
-        if (f_mount(&SDC_FS, "/", 1) != FR_OK) {
-            printf("Err: Failed to mount SD Card!\n");
-            sdcDisconnect(&SDCD1);
-        } else {
-            printf("Successfully mounted SDCard..\n");
     }
-        //Create APM Directory
+
+    if (sdcard_running) {
+        sdcard_stop();
+    }
+
+    const uint8_t tries = 3;
+    for (uint8_t i=0; i<tries; i++) {
+        hal.scheduler->delay(10);
+        sdcconfig.slowdown = sd_slowdown;
+        sdcStart(&SDCD1, &sdcconfig);
+        if(sdcConnect(&SDCD1) == HAL_FAILED) {
+            sdcStop(&SDCD1);
+            continue;
+        }
+        if (f_mount(&SDC_FS, "/", 1) != FR_OK) {
+            sdcDisconnect(&SDCD1);
+            sdcStop(&SDCD1);
+            continue;
+        }
+        printf("Successfully mounted SDCard (slowdown=%u)\n", (unsigned)sd_slowdown);
+
+        // Create APM Directory if needed
         mkdir("/APM", 0777);
+        sdcard_running = true;
+        return true;
     }
 #elif HAL_USE_MMC_SPI
-    device = AP_HAL::get_HAL().spi->get_device("sdcard");
+    if (sdcard_running) {
-    if (!device) {
+        sdcard_stop();
-        printf("No sdcard SPI device found\n");
-        return;
     }
 
     sdcard_running = true;
 
+    device = AP_HAL::get_HAL().spi->get_device("sdcard");
+    if (!device) {
+        printf("No sdcard SPI device found\n");
+        return false;
+    }
+    device->set_slowdown(sd_slowdown);
+    
     mmcObjectInit(&MMCD1);
 
     mmcconfig.spip =
@@ -78,23 +101,33 @@ void sdcard_init()
     mmcconfig.hscfg = &highspeed;
     mmcconfig.lscfg = &lowspeed;
 
+    /*
+      try up to 3 times to init microSD interface
+     */
+    const uint8_t tries = 3;
+    for (uint8_t i=0; i<tries; i++) {
+        hal.scheduler->delay(10);
         mmcStart(&MMCD1, &mmcconfig);
 
         if (mmcConnect(&MMCD1) == HAL_FAILED) {
-        printf("Err: Failed to initialize SDCARD_SPI!\n");
+            mmcStop(&MMCD1);
-        sdcard_running = false;
+            continue;
-    } else {
+        }
         if (f_mount(&SDC_FS, "/", 1) != FR_OK) {
-            printf("Err: Failed to mount SD Card!\n");
             mmcDisconnect(&MMCD1);
-        } else {
+            mmcStop(&MMCD1);
-            printf("Successfully mounted SDCard..\n");
+            continue;
         }
-        //Create APM Directory
+        printf("Successfully mounted SDCard (slowdown=%u)\n", (unsigned)sd_slowdown);
+
+        // Create APM Directory if needed
         mkdir("/APM", 0777);
+        return true;
     }
+    sdcard_running = false;
 #endif
 #endif
+    return false;
 }
 
 /*
@@ -106,7 +139,13 @@ void sdcard_stop(void)
     // unmount
     f_mount(nullptr, "/", 1);
 #endif
-#if HAL_USE_MMC_SPI
+#if HAL_USE_SDC
+    if (sdcard_running) {
+        sdcDisconnect(&SDCD1);
+        sdcStop(&SDCD1);
+        sdcard_running = false;
+    }
+#elif HAL_USE_MMC_SPI
     if (sdcard_running) {
         mmcDisconnect(&MMCD1);
         mmcStop(&MMCD1);

libraries/AP_HAL_ChibiOS/sdcard.h

@@ -15,5 +15,5 @@
  */
 #pragma once
 
-void sdcard_init();
+bool sdcard_init();
 void sdcard_stop();