hw: irq controller and timer improvements for Rpi

* renamed rpi pic to Bcm2835_pic
* renamed rpi3 pic to Bcm2837_pic
* added bcm2837 control for setting prescaler value (to fix timer_accuracy)
* changed handling of all interrupts for rpi3 by cascading to bcm2835 pic
* rpi3 irq controller base address made consistent with rpi
* added usb controller memory region for pic on rpi3 (for SOF interrupts)

Ref #3415

repos/base/include/drivers/platform/bcm2837_control.h

@@ -0,0 +1,61 @@
+/*
+ * \brief  Driver for the platform specific functionality for bcm2837
+ * \author Tomasz Gajewski
+ * \date   2019-12-28
+ */
+
+/*
+ * Copyright (C) 2011-2019 Genode Labs GmbH
+ *
+ * This file is part of the Genode OS framework, which is distributed
+ * under the terms of the GNU Affero General Public License version 3.
+ */
+
+#ifndef _INCLUDE__DRIVERS__PLATFORM__BCM2837_CONTROL_H_
+#define _INCLUDE__DRIVERS__PLATFORM__BCM2837_CONTROL_H_
+
+/* Genode includes */
+#include <util/mmio.h>
+
+
+namespace Genode { class Bcm2837_control; }
+
+
+class Genode::Bcm2837_control : Mmio
+{
+	public:
+
+		struct ControlRegister : public Register<0x0, 32>
+		{
+			struct CoreTimeClockSource : Bitfield<8,1> { };
+			struct TimerIncrement     : Bitfield<9,1> { };
+		};
+
+		struct CoreTimerPrescaler : public Register<0x8, 32>
+		{
+		};
+
+		inline Bcm2837_control(addr_t const base);
+
+		inline void initialize_timer_frequency();
+};
+
+
+Genode::Bcm2837_control::Bcm2837_control(addr_t const base)
+:
+	Mmio(base)
+{ }
+
+
+void Genode::Bcm2837_control::initialize_timer_frequency()
+{
+	/*
+	 * Set prescaler value to achieve divider value equal to 1.
+	 * Value taken from chapter "3.1.1 Timer clock" from QA7_rev3.4.pdf
+	 * document describing the BCM2836 chip.
+	 */
+	write<CoreTimerPrescaler>(0x80000000);
+}
+
+
+#endif /* _INCLUDE__DRIVERS__PLATFORM__BCM2837_CONTROL_H_ */