mmc: read extcsd and check if requested change of RST_N_FUNCTION is possible

[karo-tx-uboot.git] / drivers / mmc / mmc.c

diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index 0c2fe351ba1d16d3543340538bdb09e201c98fc9..c0bab82714c50f2649af8095077464b3b5741423 100644 (file)
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -1881,6 +1881,19 @@ int mmc_set_part_conf(struct mmc *mmc, u8 ack, u8 part_num, u8 access)
  */
 int mmc_set_rst_n_function(struct mmc *mmc, u8 enable)
 {
+       int ret;
+       ALLOC_CACHE_ALIGN_BUFFER(u8, ext_csd, MMC_MAX_BLOCK_LEN);
+
+       ret = mmc_send_ext_csd(mmc, ext_csd);
+       if (ret)
+               return ret;
+
+       if (ext_csd[EXT_CSD_RST_N_FUNCTION] != 0 &&
+               ext_csd[EXT_CSD_RST_N_FUNCTION] != enable) {
+               printf("RST_N_FUNCTION is already set to %u; cannot change to %u\n",
+                       ext_csd[EXT_CSD_RST_N_FUNCTION], enable);
+               return -EINVAL;
+       }
        return mmc_switch(mmc, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_RST_N_FUNCTION,
                          enable);
 }