sdhci: use clock timing presets

This allows the controller to set up its own timing registers with
default values automatically. It is especially useful when working with
multiple MMC devices, as the controller can switch to the right speed
automatically for each transaction.

Change-Id: I356f5fd289ce55d72ad1cbb5cd27f019ea6f767b
Reviewed-on: https://review.haiku-os.org/c/haiku/+/9697
Reviewed-by: Adrien Destugues <[email protected]>
Tested-by: Commit checker robot <[email protected]>

src/add-ons/kernel/busses/mmc/sdhci.cpp

@@ -124,7 +124,7 @@ SdhciBus::SdhciBus(struct registers* registers, uint8_t irq, bool poll)
 	if (PowerOn()) {
 		// Then we configure the clock to the frequency needed for
 		// initialization
-		SetClock(400);
+		SetClock(400, false);
 	}
 
 	fRegisters->timeout_control.SetDivider(fRegisters->capabilities.TimeoutClockFrequency(), 500);
@@ -390,8 +390,15 @@ SdhciBus::Reset()
 
 
 void
-SdhciBus::SetClock(int kilohertz)
+SdhciBus::SetClock(int kilohertz, bool allowAuto)
 {
+	if (allowAuto && (fRegisters->host_controller_version.specVersion > 2)) {
+		TRACE("Ignoring set_clock, controller support presets\n");
+		fRegisters->host_control_2 |= (1<<15);
+		TRACE("Host control 2 after enabling preset mode: %x\n", fRegisters->host_control_2);
+		return;
+	}
+
 	int base_clock = fRegisters->capabilities.BaseClockFrequency();
 	// Try to get as close to 400kHz as possible, but not faster
 	int divider = base_clock * 1000 / kilohertz;
@@ -654,7 +661,7 @@ SdhciBus::HandleInterrupt()
 		// so check the actual state before acting
 		if (fRegisters->present_state.IsCardInserted()) {
 			if (PowerOn())
-				SetClock(400);
+				SetClock(400, false);
 			release_sem_etc(fScanSemaphore, 1, B_DO_NOT_RESCHEDULE);
 		} else
 			TRACE("Card insertion interrupt, but card is removed\n");
@@ -857,7 +864,8 @@ status_t
 set_clock(void* controller, uint32_t kilohertz)
 {
 	SdhciBus* bus = (SdhciBus*)controller;
-	bus->SetClock(kilohertz);
+
+	bus->SetClock(kilohertz, true);
 	return B_OK;
 }
 

src/add-ons/kernel/busses/mmc/sdhci.h

@@ -29,7 +29,7 @@ class SdhciBus {
 			int32				HandleInterrupt();
 			status_t			InitCheck();
 			void				Reset();
-			void				SetClock(int kilohertz);
+			void				SetClock(int kilohertz, bool allowAuto);
 			status_t			DoIO(uint8_t command, IOOperation* operation,
 									bool offsetAsSectors);
 			void				SetScanSemaphore(sem_id sem);