[RFC PATCH 07/15] sd: emmc: add CMD21 tuning sequence

[Sai Pavan Boddu <sai.pavan.boddu@xilinx.com>]

eMMC cards support tuning sequence for entering HS200 mode.

Signed-off-by: Sai Pavan Boddu <sai.pavan.boddu@xilinx.com>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
---
 hw/sd/sd.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)

diff --git a/hw/sd/sd.c b/hw/sd/sd.c
index 7925174..90359f6 100644
--- a/hw/sd/sd.c
+++ b/hw/sd/sd.c
@@ -1378,6 +1378,14 @@ static sd_rsp_type_t sd_normal_command(SDState *sd, SDRequest req)
         }
         break;
 
+    case 21:    /* CMD21: mmc SEND TUNING_BLOCK */
+        if (sd->emmc && (sd->state == sd_transfer_state)) {
+            sd->state = sd_sendingdata_state;
+            sd->data_offset = 0;
+            return sd_r1;
+        }
+        break;
+
     case 23:    /* CMD23: SET_BLOCK_COUNT */
         if (sd->spec_version < SD_PHY_SPECv3_01_VERS) {
             break;
@@ -2112,6 +2120,30 @@ static const uint8_t sd_tuning_block_pattern[SD_TUNING_BLOCK_SIZE] = {
     0xbb, 0xff, 0xf7, 0xff,         0xf7, 0x7f, 0x7b, 0xde,
 };
 
+#define EXCSD_BUS_WIDTH_OFFSET 183
+#define BUS_WIDTH_8_MASK    0x4
+#define BUS_WIDTH_4_MASK    0x2
+#define MMC_TUNING_BLOCK_SIZE   128
+
+static const uint8_t mmc_tunning_block_pattern[128] = {
+       0xff, 0xff, 0x00, 0xff, 0xff, 0xff, 0x00, 0x00,
+       0xff, 0xff, 0xcc, 0xcc, 0xcc, 0x33, 0xcc, 0xcc,
+       0xcc, 0x33, 0x33, 0xcc, 0xcc, 0xcc, 0xff, 0xff,
+       0xff, 0xee, 0xff, 0xff, 0xff, 0xee, 0xee, 0xff,
+       0xff, 0xff, 0xdd, 0xff, 0xff, 0xff, 0xdd, 0xdd,
+       0xff, 0xff, 0xff, 0xbb, 0xff, 0xff, 0xff, 0xbb,
+       0xbb, 0xff, 0xff, 0xff, 0x77, 0xff, 0xff, 0xff,
+       0x77, 0x77, 0xff, 0x77, 0xbb, 0xdd, 0xee, 0xff,
+       0xff, 0xff, 0xff, 0x00, 0xff, 0xff, 0xff, 0x00,
+       0x00, 0xff, 0xff, 0xcc, 0xcc, 0xcc, 0x33, 0xcc,
+       0xcc, 0xcc, 0x33, 0x33, 0xcc, 0xcc, 0xcc, 0xff,
+       0xff, 0xff, 0xee, 0xff, 0xff, 0xff, 0xee, 0xee,
+       0xff, 0xff, 0xff, 0xdd, 0xff, 0xff, 0xff, 0xdd,
+       0xdd, 0xff, 0xff, 0xff, 0xbb, 0xff, 0xff, 0xff,
+       0xbb, 0xbb, 0xff, 0xff, 0xff, 0x77, 0xff, 0xff,
+       0xff, 0x77, 0x77, 0xff, 0x77, 0xbb, 0xdd, 0xee,
+};
+
 uint8_t sd_read_byte(SDState *sd)
 {
     /* TODO: Append CRCs */
@@ -2204,6 +2236,21 @@ uint8_t sd_read_byte(SDState *sd)
         ret = sd_tuning_block_pattern[sd->data_offset++];
         break;
 
+    case 21:    /* CMD21: SEND_TUNNING_BLOCK (MMC) */
+        if (sd->data_offset >= MMC_TUNING_BLOCK_SIZE - 1) {
+            sd->state = sd_transfer_state;
+        }
+        if (sd->ext_csd[EXCSD_BUS_WIDTH_OFFSET] & BUS_WIDTH_8_MASK) {
+            ret = mmc_tunning_block_pattern[sd->data_offset++];
+        } else {
+            /* Return LSB Nibbles of two byte from the 8bit tuning block
+             * for 4bit mode
+             */
+            ret = mmc_tunning_block_pattern[sd->data_offset++] & 0x0F;
+            ret |= (mmc_tunning_block_pattern[sd->data_offset++] & 0x0F) << 4;
+        }
+        break;
+
     case 22:	/* ACMD22: SEND_NUM_WR_BLOCKS */
         ret = sd->data[sd->data_offset ++];
 
-- 
2.7.4