From 96b5042704a9afdb91f28da81e4af5f6e63b0811 Mon Sep 17 00:00:00 2001
From: Sigurd Tullander <2935944-sigurdo@users.noreply.gitlab.com>
Date: Wed, 20 Nov 2024 14:24:23 +0100
Subject: [PATCH 1/2] Implement 1.8V-signalling switch

---
 Components/FileSystem/Source/fs_mc_mci.c | 42 +++++++++++++++++++++++-
 1 file changed, 41 insertions(+), 1 deletion(-)

diff --git a/Components/FileSystem/Source/fs_mc_mci.c b/Components/FileSystem/Source/fs_mc_mci.c
index 6ae35db8..f185c92a 100644
--- a/Components/FileSystem/Source/fs_mc_mci.c
+++ b/Components/FileSystem/Source/fs_mc_mci.c
@@ -1510,6 +1510,33 @@ static uint32_t mc_select_bus_width (MC_MCI *mc) {
   return (err);
 }
 
+/**
+    Switches signalling voltage to 1.8V.
+    Shall not be called if card or driver does not support 1.8V signalling.
+*/
+static uint32_t voltage_switch_1v8(MC_MCI *mc) {
+    int32_t stat = 0;
+    uint32_t arg = 0;
+    uint32_t r1[4];
+    stat = mc->Driver->SendCommand(MC_CMD_VOLTAGE_SWITCH, arg, ARM_MCI_RESPONSE_SHORT, r1);
+    if (stat == ARM_DRIVER_OK) {
+        // Wait for event
+        mc_wfe(MC_CMD_EVENTS, mc);
+        if ((mc->Event & MC_CMD_EVENTS) == ARM_MCI_EVENT_COMMAND_COMPLETE) {
+            stat = mc->Driver->Control(ARM_MCI_BUS_SPEED_MODE, ARM_MCI_BUS_UHS_SDR12);
+            if (stat == ARM_DRIVER_OK) {
+                // Idle clock 10ms
+                mci_idle_clock (true, mc);
+                fs_set_rtos_delay(10);
+                mci_idle_clock (false, mc);
+                return 0; // OK
+            }
+        }
+    }
+    EvrFsMcMCI_SendCommandError (mc->Instance, MC_CMD_SEND_OP_COND, arg);
+    return 1; // Error
+}
+
 
 /**
   Initialize memory card in native mode (non SPI)
@@ -1579,6 +1606,14 @@ static uint32_t mc_native_init (MC_MCI *mc) {
           if (r[0] & R3_S18A) {
             /* Switching to 1.8V Accepted, this is UHS-I card */
             mc->Property |= MC_PROP_SPEED_UHSI;
+            if (mc->Capabilities.uhs_signaling) {
+              // Actually switch to 1.8V
+              err = voltage_switch_1v8(mc);
+              if (err != 0) {
+                  // Voltage switch failed.
+                  return (false);
+              }
+            }
           }
           break;
         }
@@ -1798,7 +1833,12 @@ static uint32_t mc_native_init (MC_MCI *mc) {
             fs_set_rtos_delay(2);
             /* High-Speed mode enabled */
             speed = 50000000U;
-            mci_bus_speed_mode (ARM_MCI_BUS_HIGH_SPEED, mc);
+            if ((mc->Property & MC_PROP_SPEED_UHSI) && mc->Capabilities.uhs_signaling) {
+                mci_bus_speed_mode (ARM_MCI_BUS_UHS_SDR25, mc);
+            }
+            else {
+                mci_bus_speed_mode (ARM_MCI_BUS_HIGH_SPEED, mc);
+            }
             mci_bus_speed      (speed, mc);
             fs_set_rtos_delay(2);
           }

From af866a15c4b5b385d8560e0b675cf3a05d471d11 Mon Sep 17 00:00:00 2001
From: Sigurd Tullander <2935944-sigurdo@users.noreply.gitlab.com>
Date: Mon, 9 Dec 2024 15:01:39 +0100
Subject: [PATCH 2/2] Attempt switch to SDR50 or UHS104

---
 Components/FileSystem/Source/fs_mc_mci.c | 49 +++++++++++++++++++++++-
 1 file changed, 48 insertions(+), 1 deletion(-)

diff --git a/Components/FileSystem/Source/fs_mc_mci.c b/Components/FileSystem/Source/fs_mc_mci.c
index f185c92a..226b2ff8 100644
--- a/Components/FileSystem/Source/fs_mc_mci.c
+++ b/Components/FileSystem/Source/fs_mc_mci.c
@@ -1824,8 +1824,55 @@ static uint32_t mc_native_init (MC_MCI *mc) {
       sw_arg.access_mode     = CMD6_ACCESS_MODE_SDR25;
 
       if (mc_switch_func (sw_arg, mc->ExtCSD, mc) == 0) {
+        // Check if SDR104 support bit is set
+        if (mc->ExtCSD[13] & (1U << CMD6_ACCESS_MODE_SDR104)) {
+          sw_arg.mode = CMD6_MODE_SET;
+          sw_arg.access_mode = CMD6_ACCESS_MODE_SDR104;
+          if (mc_switch_func(sw_arg, mc->ExtCSD, mc) == 0) {
+            fs_set_rtos_delay(2);
+            speed = 200000000;
+            mci_bus_speed_mode(ARM_MCI_BUS_UHS_SDR104, mc);
+            mci_bus_speed(speed, mc);
+            fs_set_rtos_delay(2);
+            mc->Driver->Control(ARM_MCI_UHS_TUNING_OPERATION, 1);
+            while (mc->Driver->Control(ARM_MCI_UHS_TUNING_RESULT) == 1) {
+              // Is the middleware now responsible for feeding CMD19, or should this be handled
+              // automatically by the driver?
+            }
+          }
+          else {
+            /* Failed to switch to high-speed mode */
+            EvrFsMcMCI_HighSpeedSwitchError (mc->Instance);
+
+            /* Abort incomplete data transfer */
+            EvrFsMcMCI_TransferAbort (mc->Instance);
+            mc->Driver->AbortTransfer();
+          }
+        }
+        // Check if SDR50 support bit is set
+        else if (mc->ExtCSD[13] & (1U << CMD6_ACCESS_MODE_SDR50)) {
+          sw_arg.mode = CMD6_MODE_SET;
+          sw_arg.access_mode = CMD6_ACCESS_MODE_SDR50;
+          if (mc_switch_func(sw_arg, mc->ExtCSD, mc) == 0) {
+            fs_set_rtos_delay(2);
+            speed = 100000000;
+            mci_bus_speed_mode(ARM_MCI_BUS_UHS_SDR50, mc);
+            mci_bus_speed(speed, mc);
+            fs_set_rtos_delay(2);
+            // Tuning is officially required for SDR50 in SD spec, but communications seems to work without
+            // on the MIMXRT1176-EVK
+          }
+          else {
+            /* Failed to switch to high-speed mode */
+            EvrFsMcMCI_HighSpeedSwitchError (mc->Instance);
+
+            /* Abort incomplete data transfer */
+            EvrFsMcMCI_TransferAbort (mc->Instance);
+            mc->Driver->AbortTransfer();
+          }
+        }
         /* Check if High-Speed/SDR25 support bit is set */
-        if (mc->ExtCSD[13] & (1U << CMD6_ACCESS_MODE_SDR25)) {
+        else if (mc->ExtCSD[13] & (1U << CMD6_ACCESS_MODE_SDR25)) {
           /* Switch to SDR25 (High-Speed mode) */
           sw_arg.mode = CMD6_MODE_SET;