[PATCH v2 21/25] hw/sd: Add mmc switch function support

["Philippe Mathieu-Daudé" <philippe.mathieu.daude@gmail.com>]

From: Sai Pavan Boddu <sai.pavan.boddu@xilinx.com>

switch operation in mmc cards, updated 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 offset 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>
[ clg: - ported on SDProto framework ]
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
 hw/sd/sd.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)

diff --git a/hw/sd/sd.c b/hw/sd/sd.c
index 672af1e839..907d4f5760 100644
--- a/hw/sd/sd.c
+++ b/hw/sd/sd.c
@@ -476,6 +476,7 @@ static void sd_set_rca(SDState *sd)
 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)
@@ -873,6 +874,43 @@ 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;
@@ -2257,6 +2295,19 @@ static sd_rsp_type_t sd_emmc_cmd_SEND_TUNING_BLOCK(SDState *sd, SDRequest req)
     return sd_r1;
 }
 
+static sd_rsp_type_t sd_emmc_cmd_SWITCH_FUNCTION(SDState *sd, SDRequest req)
+{
+    switch (sd->state) {
+    case sd_transfer_state:
+        sd->state = sd_programming_state;
+        mmc_function_switch(sd, req.arg);
+        sd->state = sd_transfer_state;
+        return sd_r1b;
+    default:
+        return sd_invalid_state_for_cmd(sd, req);
+    }
+}
+
 static const SDProto sd_proto_emmc = {
     .name = "eMMC",
     .cmd = {
@@ -2265,6 +2316,7 @@ static const SDProto sd_proto_emmc = {
         [2]         = sd_emmc_cmd_ALL_SEND_CID,
         [3]         = sd_emmc_cmd_SEND_RELATIVE_ADDR,
         [5]         = sd_cmd_illegal,
+        [6]         = sd_emmc_cmd_SWITCH_FUNCTION,
         [19]        = sd_cmd_SEND_TUNING_BLOCK,
         [21]        = sd_emmc_cmd_SEND_TUNING_BLOCK,
         [41]        = sd_cmd_illegal,
-- 
2.36.1