[PATCH v3 11/21] sd: emmc: Add mmc switch function support

[Sai Pavan Boddu]

switch operation in eMMC card updates the ext_csd register to
request changes in card operations. Here we implement similar
sequence but requests are mostly dummy and make no change.

Implement SWITCH_ERROR if the write operation extends goes beyond length
of ext_csd.

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 | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 50 insertions(+), 6 deletions(-)

diff --git a/hw/sd/sd.c b/hw/sd/sd.c
index 8a7d0de..bf963ec 100644
--- a/hw/sd/sd.c
+++ b/hw/sd/sd.c
@@ -523,6 +523,7 @@ static void sd_set_rca(SDState *sd, uint16_t value)
 FIELD(CSR, AKE_SEQ_ERROR,               3,  1)
 FIELD(CSR, APP_CMD,                     5,  1)
 FIELD(CSR, FX_EVENT,                    6,  1)
+FIELD(CSR, SWITCH_ERROR,                7,  1)
 FIELD(CSR, READY_FOR_DATA,              8,  1)
 FIELD(CSR, CURRENT_STATE,               9,  4)
 FIELD(CSR, ERASE_RESET,                13,  1)
@@ -886,6 +887,43 @@ static uint32_t sd_wpbits(SDState *sd, uint64_t addr)
     return ret;
 }
 
+enum {
+    MMC_CMD6_ACCESS_COMMAND_SET = 0,
+    MMC_CMD6_ACCESS_SET_BITS,
+    MMC_CMD6_ACCESS_CLEAR_BITS,
+    MMC_CMD6_ACCESS_WRITE_BYTE,
+};
+
+static void mmc_function_switch(SDState *sd, uint32_t arg)
+{
+    uint32_t access = extract32(arg, 24, 2);
+    uint32_t index = extract32(arg, 16, 8);
+    uint32_t value = extract32(arg, 8, 8);
+    uint8_t b = sd->ext_csd[index];
+
+    switch (access) {
+    case MMC_CMD6_ACCESS_COMMAND_SET:
+        qemu_log_mask(LOG_UNIMP, "MMC Command set switching not supported\n");
+        return;
+    case MMC_CMD6_ACCESS_SET_BITS:
+        b |= value;
+        break;
+    case MMC_CMD6_ACCESS_CLEAR_BITS:
+        b &= ~value;
+        break;
+    case MMC_CMD6_ACCESS_WRITE_BYTE:
+        b = value;
+        break;
+    }
+
+    if (index >= 192) {
+        sd->card_status |= R_CSR_SWITCH_ERROR_MASK;
+        return;
+    }
+
+    sd->ext_csd[index] = b;
+}
+
 static void sd_function_switch(SDState *sd, uint32_t arg)
 {
     int i, mode, new_func;
@@ -1105,12 +1143,18 @@ static sd_rsp_type_t sd_normal_command(SDState *sd, 
SDRequest req)
     case 6: /* CMD6:   SWITCH_FUNCTION */
         switch (sd->mode) {
         case sd_data_transfer_mode:
-            sd_function_switch(sd, req.arg);
-            sd->state = sd_sendingdata_state;
-            sd->data_start = 0;
-            sd->data_offset = 0;
-            return sd_r1;
-
+            if (sd->emmc) {
+                sd->state = sd_programming_state;
+                mmc_function_switch(sd, req.arg);
+                sd->state = sd_transfer_state;
+                return sd_r1b;
+            } else {
+                sd_function_switch(sd, req.arg);
+                sd->state = sd_sendingdata_state;
+                sd->data_start = 0;
+                sd->data_offset = 0;
+                return sd_r1;
+            }
         default:
             break;
         }
-- 
2.7.4