core: use set_clr_card_detect to disable SD card pull-up resistor

core/embed/trezorhal/sdcard-set_clr_card_detect.h

@@ -0,0 +1,61 @@
+#include "stm32f4xx_ll_sdmmc.h"
+
+// this function is adapted from stm32f4xx_ll_sdmmc.c
+
+static uint32_t SDMMC_GetCmdResp1(SDIO_TypeDef *SDIOx, uint8_t SD_CMD,
+                                  uint32_t Timeout) {
+  /* 8 is the number of required instructions cycles for the below loop
+  statement. The Timeout is expressed in ms */
+  register uint32_t count = Timeout * (SystemCoreClock / 8U / 1000U);
+
+  do {
+    if (count-- == 0U) {
+      return SDMMC_ERROR_TIMEOUT;
+    }
+  } while (!__SDIO_GET_FLAG(
+      SDIOx, SDIO_FLAG_CCRCFAIL | SDIO_FLAG_CMDREND | SDIO_FLAG_CTIMEOUT));
+
+  if (__SDIO_GET_FLAG(SDIOx, SDIO_FLAG_CTIMEOUT)) {
+    __SDIO_CLEAR_FLAG(SDIOx, SDIO_FLAG_CTIMEOUT);
+    return SDMMC_ERROR_CMD_RSP_TIMEOUT;
+  } else if (__SDIO_GET_FLAG(SDIOx, SDIO_FLAG_CCRCFAIL)) {
+    __SDIO_CLEAR_FLAG(SDIOx, SDIO_FLAG_CCRCFAIL);
+    return SDMMC_ERROR_CMD_CRC_FAIL;
+  }
+
+  /* Check response received is of desired command */
+  if (SDIO_GetCommandResponse(SDIOx) != SD_CMD) {
+    return SDMMC_ERROR_CMD_CRC_FAIL;
+  }
+
+  /* Clear all the static flags */
+  __SDIO_CLEAR_FLAG(SDIOx, SDIO_STATIC_FLAGS);
+
+  /* We have received response, retrieve it for analysis  */
+  uint32_t response_r1 = SDIO_GetResponse(SDIOx, SDIO_RESP1);
+
+  if ((response_r1 & SDMMC_OCR_ERRORBITS) == SDMMC_ALLZERO) {
+    return SDMMC_ERROR_NONE;
+  } else {
+    return SDMMC_ERROR_GENERAL_UNKNOWN_ERR;
+  }
+}
+
+// this function is inspired by functions in stm32f4xx_ll_sdmmc.c
+
+uint32_t SDMMC_CmdSetClrCardDetect(SDIO_TypeDef *SDIOx, uint32_t Argument) {
+  SDIO_CmdInitTypeDef sdmmc_cmdinit;
+  uint32_t errorstate = SDMMC_ERROR_NONE;
+
+  sdmmc_cmdinit.Argument = (uint32_t)Argument;
+  sdmmc_cmdinit.CmdIndex = SDMMC_CMD_SD_APP_SET_CLR_CARD_DETECT;
+  sdmmc_cmdinit.Response = SDIO_RESPONSE_SHORT;
+  sdmmc_cmdinit.WaitForInterrupt = SDIO_WAIT_NO;
+  sdmmc_cmdinit.CPSM = SDIO_CPSM_ENABLE;
+  SDIO_SendCommand(SDIOx, &sdmmc_cmdinit);
+
+  errorstate = SDMMC_GetCmdResp1(SDIOx, SDMMC_CMD_SD_APP_SET_CLR_CARD_DETECT,
+                                 SDIO_CMDTIMEOUT);
+
+  return errorstate;
+}

core/embed/trezorhal/sdcard.c

@@ -47,6 +47,7 @@
 
 #include <string.h>
 
+#include "sdcard-set_clr_card_detect.h"
 #include "sdcard.h"
 
 static SD_HandleTypeDef sd_handle;
@@ -143,6 +144,17 @@ secbool sdcard_power_on(void) {
     HAL_Delay(50);
   }
 
+  // disable the card's internal CD/DAT3 card detect pull-up resistor
+  // to send ACMD42, we have to send CMD55 (APP_CMD) with with the card's RCA as
+  // the argument followed by CMD42 (SET_CLR_CARD_DETECT)
+  if (SDMMC_CmdAppCommand(sd_handle.Instance, sd_handle.SdCard.RelCardAdd
+                                                  << 16U) != SDMMC_ERROR_NONE) {
+    goto error;
+  }
+  if (SDMMC_CmdSetClrCardDetect(sd_handle.Instance, 0) != SDMMC_ERROR_NONE) {
+    goto error;
+  }
+
   // configure the SD bus width for wide operation
   if (HAL_SD_ConfigWideBusOperation(&sd_handle, SDIO_BUS_WIDE_4B) != HAL_OK) {
     HAL_SD_DeInit(&sd_handle);