From 232d98608ae09b56077f145122c46ecd9e58f1b1 Mon Sep 17 00:00:00 2001
From: michael <xiaoxufeng@espressif.com>
Date: Thu, 27 Sep 2018 15:43:00 +0800
Subject: [PATCH] sdmmc: add communication check for eMMC after frequency
 switch

---
 components/sdmmc/sdmmc_common.h |  1 +
 components/sdmmc/sdmmc_init.c   |  4 +++-
 components/sdmmc/sdmmc_mmc.c    | 30 ++++++++++++++++++++++++++++++
 3 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/components/sdmmc/sdmmc_common.h b/components/sdmmc/sdmmc_common.h
index d57403ccb..e07ebd910 100644
--- a/components/sdmmc/sdmmc_common.h
+++ b/components/sdmmc/sdmmc_common.h
@@ -117,6 +117,7 @@ esp_err_t sdmmc_init_io_bus_width(sdmmc_card_t* card);
 esp_err_t sdmmc_init_mmc_bus_width(sdmmc_card_t* card);
 esp_err_t sdmmc_init_card_hs_mode(sdmmc_card_t* card);
 esp_err_t sdmmc_init_host_frequency(sdmmc_card_t* card);
+esp_err_t sdmmc_init_mmc_check_csd(sdmmc_card_t* card);
 
 /* Various helper functions */
 static inline bool host_is_spi(const sdmmc_card_t* card)
diff --git a/components/sdmmc/sdmmc_init.c b/components/sdmmc/sdmmc_init.c
index 64cdff1df..789e6e5c1 100644
--- a/components/sdmmc/sdmmc_init.c
+++ b/components/sdmmc/sdmmc_init.c
@@ -117,7 +117,9 @@ esp_err_t sdmmc_card_init(const sdmmc_host_t* config, sdmmc_card_t* card)
 
     /* Sanity check after switching the bus mode and frequency */
     SDMMC_INIT_STEP(is_sdmem, sdmmc_check_scr);
-    /* TODO: add similar checks for eMMC and SDIO */
+    /* TODO: this is CMD line only, add data checks for eMMC */
+    SDMMC_INIT_STEP(is_mmc, sdmmc_init_mmc_check_csd);
+    /* TODO: add similar checks for SDIO */
 
     return ESP_OK;
 }
diff --git a/components/sdmmc/sdmmc_mmc.c b/components/sdmmc/sdmmc_mmc.c
index e123763f0..9d19926e3 100644
--- a/components/sdmmc/sdmmc_mmc.c
+++ b/components/sdmmc/sdmmc_mmc.c
@@ -231,3 +231,33 @@ esp_err_t sdmmc_mmc_switch(sdmmc_card_t* card, uint8_t set, uint8_t index, uint8
     return err;
 }
 
+esp_err_t sdmmc_init_mmc_check_csd(sdmmc_card_t* card)
+{
+    esp_err_t err;
+    assert(card->is_mem == 1);
+    assert(card->rca != 0);
+    //The card will not respond to send_csd command in the transfer state.
+    //Deselect it first.
+    err = sdmmc_send_cmd_select_card(card, 0);
+    if (err != ESP_OK) {
+        ESP_LOGE(TAG, "%s: select_card returned 0x%x", __func__, err);
+        return err;
+    }
+
+    sdmmc_csd_t csd;
+    /* Get the contents of CSD register to verify the communication over CMD line
+       is OK. */
+    err = sdmmc_send_cmd_send_csd(card, &csd);
+    if (err != ESP_OK) {
+        ESP_LOGE(TAG, "%s: send_csd returned 0x%x", __func__, err);
+        return err;
+    }
+
+    //Select the card again
+    err = sdmmc_send_cmd_select_card(card, card->rca);
+    if (err != ESP_OK) {
+        ESP_LOGE(TAG, "%s: select_card returned 0x%x", __func__, err);
+        return err;
+    }
+    return ESP_OK;
+}