From b889192bbb5169d93d35c2564813c7ea4d5fde41 Mon Sep 17 00:00:00 2001
From: wimrijnders <wrijnders@gmail.com>
Date: Thu, 12 Jul 2018 11:53:48 +0200
Subject: [PATCH 01/13] BUGFIX: Enable QPU when accessing Register Map

Accessing the register map won't work in the VideoCore is powered up.
This adds code to `detectPlatform` to ensure that VideoCore is enabled before
reading the registers.

In addition:

- Adjusted some code for better debugging. Notably, a call to `perror` has been
  added in `MailBox.cpp`.
- Left in debug printf's where useful. There are commented out in general.
- Added RegisterMap::enabled(), which checks if registers are accessible.

The latter is actually a useful method to determine if the VideoCore is running.
---
 Lib/VideoCore/Mailbox.cpp     |  6 +++++-
 Lib/VideoCore/RegisterMap.cpp | 36 +++++++++++++++++++++++++++++++++--
 Lib/VideoCore/RegisterMap.h   |  5 +++--
 Tools/detectPlatform.cpp      | 12 ++++++++++++
 4 files changed, 54 insertions(+), 5 deletions(-)

diff --git a/Lib/VideoCore/Mailbox.cpp b/Lib/VideoCore/Mailbox.cpp
index ba12e1a..aa9ae27 100644
--- a/Lib/VideoCore/Mailbox.cpp
+++ b/Lib/VideoCore/Mailbox.cpp
@@ -42,6 +42,8 @@ namespace QPULib {
 
 void *mapmem(unsigned base, unsigned size)
 {
+   //printf("mapmem requested base: 0x%x, size: %d\n", base, size);
+
    int mem_fd;
    unsigned offset = base % PAGE_SIZE;
    base = base - offset;
@@ -63,7 +65,9 @@ void *mapmem(unsigned base, unsigned size)
 #endif  // DEBUG
 
    if (mem == MAP_FAILED) {
-      printf("mmap error %p\n", mem);
+      printf("mmap error value %p: ", mem);
+      fflush(stdout);
+      perror(nullptr);  // Prints error message on stdout
       exit (-1);
    }
    close(mem_fd);
diff --git a/Lib/VideoCore/RegisterMap.cpp b/Lib/VideoCore/RegisterMap.cpp
index 6050e11..8ef5cf0 100644
--- a/Lib/VideoCore/RegisterMap.cpp
+++ b/Lib/VideoCore/RegisterMap.cpp
@@ -35,7 +35,6 @@ RegisterMap::RegisterMap() {
 
 
 RegisterMap::~RegisterMap() {
-	// printf("Closing down register map\n");
 	unmapmem((void *) m_addr, m_size);
 	bcm_host_deinit();
 }
@@ -45,6 +44,14 @@ RegisterMap::~RegisterMap() {
  * @brief Get the 32-bit value at the given offset in the map
  */
 uint32_t RegisterMap::read(int offset) const {
+#ifdef DEBUG
+	// Do a spot check on the loaded memory
+	if (m_addr[V3D_BASE] == 0XDEADBEEF) {
+		printf("RegisterMap can not read QPU registers, the VideoCore is not enabled.\n");
+		exit(-1);
+	}
+#endif
+
 	return m_addr[V3D_BASE + offset];
 }
 
@@ -55,7 +62,28 @@ uint32_t RegisterMap::read(int offset) const {
  * This avoids having to use `instance()->` for every read access.
  */
 uint32_t RegisterMap::readRegister(int offset) {
-	return instance()->read(V3D_IDENT1);
+  //printf("Called readRegister, m_instance: %p\n", m_instance.get());
+	return instance()->read(offset);
+}
+
+
+/**
+ * @brief Check if the register map is accessible.
+ *
+ * This depends on the VideoCore being enabled. Enabling and disabling
+ * is done with mailbox call `qpu_enable()`.
+ *
+ * This method can thus be used to detect if the VideoCore is running.
+ *
+ * @return true if register map accessible, false otherwise
+ */
+bool RegisterMap::enabled() {
+	// Detect the signature in register 0
+	uint32_t reg = readRegister(V3D_IDENT0);
+	char *p = (char *) &reg;
+	//printf("Reg 0: '%c%c%c'\n", p[0], p[1], p[2]);
+
+	return (p[0] == 'V' && p[1] == '3' && p[2] == 'D');
 }
 
 
@@ -73,10 +101,14 @@ int RegisterMap::numQPUPerSlice() {
 
 
 RegisterMap *RegisterMap::instance() {
+  //printf("Called instance(), m_instance: %p\n", m_instance.get());
+
 	if (m_instance.get() == nullptr) {
+		//printf("RegisterMap initializing singleton\n");
 		m_instance.reset(new RegisterMap);
 	}
 
+ // printf("m_instance post: %p\n", m_instance.get());
 	return m_instance.get();
 }
 
diff --git a/Lib/VideoCore/RegisterMap.h b/Lib/VideoCore/RegisterMap.h
index 5c293f2..0dad1e7 100644
--- a/Lib/VideoCore/RegisterMap.h
+++ b/Lib/VideoCore/RegisterMap.h
@@ -24,8 +24,9 @@ class RegisterMap {
 
 	~RegisterMap();
 
-	static int numSlices();
-	static int numQPUPerSlice();
+	static bool enabled();
+	static int  numSlices();
+	static int  numQPUPerSlice();
 
 private:
 	RegisterMap();
diff --git a/Tools/detectPlatform.cpp b/Tools/detectPlatform.cpp
index 28cd8e6..f0721e8 100644
--- a/Tools/detectPlatform.cpp
+++ b/Tools/detectPlatform.cpp
@@ -57,12 +57,24 @@ int main(int argc, char *argv[]) {
 	unsigned revision = get_version(mb);
 	printf("Hardware revision: %04x\n", revision);
 
+	bool wasEnabled = RegisterMap::enabled();
+	if (!wasEnabled) {
+		// VideoCore needs to be enabled, otherwise the registers can't be accessed.
+		//printf("VideoCore not running, enabling for this app\n");
+		qpu_enable(mb, 1);
+	}
+
 	if (geteuid() == 0) {  // Only do this as root (sudo)
 		printf("Number of slices: %d\n", RegisterMap::numSlices());
 		printf("Number of QPU's per slice: %d\n", RegisterMap::numQPUPerSlice());
 	} else {
 		printf("You can see more if you use sudo\n");
   }
+
+	if (!wasEnabled) {
+		//printf("Disabling the VideoCore again\n");
+		qpu_enable(mb, 0);
+	}
 #endif  // QPU_MODE
 
 	return 0;

From 847c7b106f758b03e73ab8e8f3499a0e23715bad Mon Sep 17 00:00:00 2001
From: wimrijnders <wrijnders@gmail.com>
Date: Sun, 15 Jul 2018 11:13:20 +0200
Subject: [PATCH 02/13] Set define for bcm-headers; further refinement of
 start/stop videcore

---
 Lib/VideoCore/RegisterMap.cpp | 33 +++++++++++++++++++++++++++++----
 Tools/detectPlatform.cpp      | 20 +++++++++++++-------
 2 files changed, 42 insertions(+), 11 deletions(-)

diff --git a/Lib/VideoCore/RegisterMap.cpp b/Lib/VideoCore/RegisterMap.cpp
index 8ef5cf0..42e9875 100644
--- a/Lib/VideoCore/RegisterMap.cpp
+++ b/Lib/VideoCore/RegisterMap.cpp
@@ -5,7 +5,22 @@
 #include <cstring>
 #include <stdio.h>
 #include <unistd.h>
+
+// This ugly part is to ensure '__linux__' is set for older versions
+// for the bcm-include.
+#if !defined(__linux__)
+#define LINUX_PREVIOUSLY_UNDEFINED
+#define __linux__
+#endif
+
 #include <bcm_host.h>
+
+#if defined(LINUX_PREVIOUSLY_UNDEFINED)
+#define __linux__
+#undef LINUX_PREVIOUSLY_UNDEFINED
+#endif
+// End ugly part
+
 #include "Mailbox.h"  // for mapmem()
 
 namespace QPULib {
@@ -47,8 +62,7 @@ uint32_t RegisterMap::read(int offset) const {
 #ifdef DEBUG
 	// Do a spot check on the loaded memory
 	if (m_addr[V3D_BASE] == 0XDEADBEEF) {
-		printf("RegisterMap can not read QPU registers, the VideoCore is not enabled.\n");
-		exit(-1);
+		printf("WARNING: RegisterMap can not read QPU registers, the VideoCore is not enabled.\n");
 	}
 #endif
 
@@ -81,9 +95,20 @@ bool RegisterMap::enabled() {
 	// Detect the signature in register 0
 	uint32_t reg = readRegister(V3D_IDENT0);
 	char *p = (char *) &reg;
-	//printf("Reg 0: '%c%c%c'\n", p[0], p[1], p[2]);
+#ifdef DEBUG
+	printf("Reg 0: '%c%c%c'\n", p[0], p[1], p[2]);
+#endif
+
+	bool canRead = (p[0] == 'V' && p[1] == '3' && p[2] == 'D');
+
+#ifdef PROB_NOT_REQUIRED
+	if (!canRead) {
+		// Reset singleton for a next attempt
+		m_instance.reset(nullptr);
+	}
+#endif  // PROB_NOT_REQUIRED
 
-	return (p[0] == 'V' && p[1] == '3' && p[2] == 'D');
+	return canRead;
 }
 
 
diff --git a/Tools/detectPlatform.cpp b/Tools/detectPlatform.cpp
index f0721e8..692ae7f 100644
--- a/Tools/detectPlatform.cpp
+++ b/Tools/detectPlatform.cpp
@@ -57,14 +57,20 @@ int main(int argc, char *argv[]) {
 	unsigned revision = get_version(mb);
 	printf("Hardware revision: %04x\n", revision);
 
-	bool wasEnabled = RegisterMap::enabled();
-	if (!wasEnabled) {
-		// VideoCore needs to be enabled, otherwise the registers can't be accessed.
-		//printf("VideoCore not running, enabling for this app\n");
-		qpu_enable(mb, 1);
-	}
-
+	bool wasEnabled = true;  // Default to prevent final call to qpu_enable()
 	if (geteuid() == 0) {  // Only do this as root (sudo)
+		wasEnabled = RegisterMap::enabled();
+		if (!wasEnabled) {
+			// VideoCore needs to be enabled, otherwise the registers can't be accessed.
+			//printf("VideoCore not running, enabling for this app\n");
+			qpu_enable(mb, 1);
+
+			// Videocore apparently needs some time on initial startup
+      // After first, it starts up fast.
+			// Would be better if we could detect the very first call
+			sleep(3);
+		}
+
 		printf("Number of slices: %d\n", RegisterMap::numSlices());
 		printf("Number of QPU's per slice: %d\n", RegisterMap::numQPUPerSlice());
 	} else {

From 275e32529c44714a68d8bb389cda526b60e86760 Mon Sep 17 00:00:00 2001
From: wimrijnders <wimrijnders@gmail.com>
Date: Mon, 16 Jul 2018 22:41:53 +0200
Subject: [PATCH 03/13] Added some commenting, fixed facepalm-typo

---
 Lib/VideoCore/RegisterMap.cpp | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/Lib/VideoCore/RegisterMap.cpp b/Lib/VideoCore/RegisterMap.cpp
index 42e9875..01f0c35 100644
--- a/Lib/VideoCore/RegisterMap.cpp
+++ b/Lib/VideoCore/RegisterMap.cpp
@@ -6,8 +6,14 @@
 #include <stdio.h>
 #include <unistd.h>
 
+//
 // This ugly part is to ensure '__linux__' is set for older versions
-// for the bcm-include.
+// for the bcm-include.i
+//
+// Apparently, old distro's have a gcc version
+// which does not support the __linux__ directive, which is required
+// to include certain header files for the Pi.
+//
 #if !defined(__linux__)
 #define LINUX_PREVIOUSLY_UNDEFINED
 #define __linux__
@@ -16,7 +22,7 @@
 #include <bcm_host.h>
 
 #if defined(LINUX_PREVIOUSLY_UNDEFINED)
-#define __linux__
+#undef __linux__
 #undef LINUX_PREVIOUSLY_UNDEFINED
 #endif
 // End ugly part

From 33c79d7951ba3e9b3a7f6b31193caf4fea18a9e2 Mon Sep 17 00:00:00 2001
From: wimrijnders <wimrijnders@gmail.com>
Date: Mon, 16 Jul 2018 22:48:30 +0200
Subject: [PATCH 04/13] typo fix

---
 Lib/VideoCore/RegisterMap.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Lib/VideoCore/RegisterMap.cpp b/Lib/VideoCore/RegisterMap.cpp
index 01f0c35..abed718 100644
--- a/Lib/VideoCore/RegisterMap.cpp
+++ b/Lib/VideoCore/RegisterMap.cpp
@@ -8,7 +8,7 @@
 
 //
 // This ugly part is to ensure '__linux__' is set for older versions
-// for the bcm-include.i
+// for the bcm-include.
 //
 // Apparently, old distro's have a gcc version
 // which does not support the __linux__ directive, which is required

From 56381e3c47c91895630a53fbf5478bd9c685f562 Mon Sep 17 00:00:00 2001
From: wimrijnders <wimrijnders@gmail.com>
Date: Wed, 18 Jul 2018 09:24:00 +0200
Subject: [PATCH 05/13] Dependency fix in Makefile, better checking of define's
 used in bcm headers

---
 Lib/VideoCore/RegisterMap.cpp | 44 +++++++++++++++++++++++++----------
 Makefile                      |  2 +-
 2 files changed, 33 insertions(+), 13 deletions(-)

diff --git a/Lib/VideoCore/RegisterMap.cpp b/Lib/VideoCore/RegisterMap.cpp
index abed718..e50c6ed 100644
--- a/Lib/VideoCore/RegisterMap.cpp
+++ b/Lib/VideoCore/RegisterMap.cpp
@@ -5,29 +5,49 @@
 #include <cstring>
 #include <stdio.h>
 #include <unistd.h>
+#include "Mailbox.h"  // mapmem()
 
 //
-// This ugly part is to ensure '__linux__' is set for older versions
-// for the bcm-include.
+// This ugly part is to ensure:
 //
-// Apparently, old distro's have a gcc version
-// which does not support the __linux__ directive, which is required
-// to include certain header files for the Pi.
+// -  '__unix__' *is* set
+// -  '__ANDROID__' is *not* set
 //
-#if !defined(__linux__)
-#define LINUX_PREVIOUSLY_UNDEFINED
-#define __linux__
+//  ... for older versions of the bcm-include.
+//
+// Apparently, old distro's have a gcc version which assumes
+// th presence/absence of these directives, which may prevent
+// including certain system header files for the Pi.
+//
+#pragma message "__unix__ is NOT defined"
+#if !defined(__unix__)
+#pragma message "__unix__ is NOT defined"
+#define UNIX_PREVIOUSLY_UNDEFINED
+#define __unix__
+#endif
+
+#if defined(__ANDROID__)
+#pragma message "__ANDROID__ is defined"
+#define ANDROID_PREVIOUSLY_DEFINED
+#undef __ANDROID__
 #endif
 
 #include <bcm_host.h>
 
-#if defined(LINUX_PREVIOUSLY_UNDEFINED)
-#undef __linux__
-#undef LINUX_PREVIOUSLY_UNDEFINED
+#if defined(ANDROID_PREVIOUSLY_DEFINED)
+#define __ANDROID__
+#undef ANDROID_PREVIOUSLY_DEFINED
 #endif
+
+#if defined(UNIX_PREVIOUSLY_UNDEFINED)
+#undef __unix__
+#undef UNIX_PREVIOUSLY_UNDEFINED
+#endif
+
+//
 // End ugly part
+//
 
-#include "Mailbox.h"  // for mapmem()
 
 namespace QPULib {
 
diff --git a/Makefile b/Makefile
index 7a92cbc..0a144c5 100644
--- a/Makefile
+++ b/Makefile
@@ -229,7 +229,7 @@ $(OBJ_DIR)/bin/runTests: $(UNIT_TESTS) $(EXAMPLES_OBJ) | $(QPU_LIB)
 	@echo Compiling unit tests
 	@$(CXX) $(CXX_FLAGS) -Wno-psabi $^ -L$(OBJ_DIR) -lQPULib $(LIBS) -o $@
 
-test : $(OBJ_DIR)/bin/runTests | AutoTest
+test : $(OBJ_DIR)/bin/runTests | AutoTest detectPlatform
 	@echo Running unit tests with '$(RUN_TESTS)'
 	@$(RUN_TESTS)
 

From b4e1b599179e3f4999520a6b491dd38641ed4677 Mon Sep 17 00:00:00 2001
From: wimrijnders <wimrijnders@gmail.com>
Date: Wed, 18 Jul 2018 09:25:17 +0200
Subject: [PATCH 06/13] Typo

---
 Lib/VideoCore/RegisterMap.cpp | 1 -
 1 file changed, 1 deletion(-)

diff --git a/Lib/VideoCore/RegisterMap.cpp b/Lib/VideoCore/RegisterMap.cpp
index e50c6ed..0f195dd 100644
--- a/Lib/VideoCore/RegisterMap.cpp
+++ b/Lib/VideoCore/RegisterMap.cpp
@@ -19,7 +19,6 @@
 // th presence/absence of these directives, which may prevent
 // including certain system header files for the Pi.
 //
-#pragma message "__unix__ is NOT defined"
 #if !defined(__unix__)
 #pragma message "__unix__ is NOT defined"
 #define UNIX_PREVIOUSLY_UNDEFINED

From cac6e7f015ad2bc13bf06af7d321b49fecf0693e Mon Sep 17 00:00:00 2001
From: wimrijnders <wimrijnders@gmail.com>
Date: Thu, 19 Jul 2018 23:14:09 +0200
Subject: [PATCH 07/13] Better fix for old Pi compile errors with bcm_host

---
 Lib/VideoCore/RegisterMap.cpp | 69 ++++++++++++++++++++---------------
 Makefile                      | 20 +++++++++-
 2 files changed, 57 insertions(+), 32 deletions(-)

diff --git a/Lib/VideoCore/RegisterMap.cpp b/Lib/VideoCore/RegisterMap.cpp
index 0f195dd..0e9a9b8 100644
--- a/Lib/VideoCore/RegisterMap.cpp
+++ b/Lib/VideoCore/RegisterMap.cpp
@@ -7,45 +7,54 @@
 #include <unistd.h>
 #include "Mailbox.h"  // mapmem()
 
+#ifdef OLD_PI
+#pragma message "This is an old pi!"
 //
-// This ugly part is to ensure:
+// For old Pi's, calls bcm_host_get_peripheral_address() and
+// bcm_host_get_peripheral_size() don't exist, so we need
+// to supply them ourselves.
 //
-// -  '__unix__' *is* set
-// -  '__ANDROID__' is *not* set
-//
-//  ... for older versions of the bcm-include.
-//
-// Apparently, old distro's have a gcc version which assumes
-// th presence/absence of these directives, which may prevent
-// including certain system header files for the Pi.
-//
-#if !defined(__unix__)
-#pragma message "__unix__ is NOT defined"
-#define UNIX_PREVIOUSLY_UNDEFINED
-#define __unix__
-#endif
 
-#if defined(__ANDROID__)
-#pragma message "__ANDROID__ is defined"
-#define ANDROID_PREVIOUSLY_DEFINED
-#undef __ANDROID__
-#endif
 
-#include <bcm_host.h>
+/**
+ * This returns the ARM-side physical address where peripherals are mapped.
+ *
+ * Values:
+ *
+ * - 0x20000000  - Pi Zero, Zero W, and the first generation of the Pi and Compute Module
+ * - 0x3f000000  - Pi 2, Pi 3 and Compute Module 3
+ *
+ * NOTE: We only return the second value for now, to get QPULib to compile on an old Pi 2 distro.
+ *       Other values may be added as needed.
+ */
+unsigned bcm_host_get_peripheral_address() {
+	return 0x3f000000;
+}
 
-#if defined(ANDROID_PREVIOUSLY_DEFINED)
-#define __ANDROID__
-#undef ANDROID_PREVIOUSLY_DEFINED
-#endif
 
-#if defined(UNIX_PREVIOUSLY_UNDEFINED)
-#undef __unix__
-#undef UNIX_PREVIOUSLY_UNDEFINED
-#endif
+// following is the same for all Pi models
+unsigned bcm_host_get_peripheral_size() { return 0x01000000; }
 
 //
-// End ugly part
+// This is the only things we need from bcm_host.h, we declare
+// them explicitly to avoid dragging in all the stuff that throws compile errors.
 //
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void bcm_host_init(void);
+void bcm_host_deinit(void);
+
+#ifdef __cplusplus
+}
+#endif
+// End things we need from bcm_host.h, we declare
+
+#else  // OLD_PI
+// Following works for newer distro's
+#include <bcm_host.h>
+#endif  // OLD_PI
 
 
 namespace QPULib {
diff --git a/Makefile b/Makefile
index 0a144c5..6f917a7 100644
--- a/Makefile
+++ b/Makefile
@@ -40,9 +40,25 @@ else
 $(info Building on a Pi platform)
 endif
 
-  CXX_FLAGS += -DQPU_MODE -I /opt/vc/include
-  OBJ_DIR := $(OBJ_DIR)-qpu
+  CXX_FLAGS += -DQPU_MODE
 	LIBS := -L /opt/vc/lib -l bcm_host
+
+  OBJ_DIR := $(OBJ_DIR)-qpu
+
+
+#
+# Detect if Pi has bcm_host support (new) or not (old)
+# If old, pass in -DOLD_PI to compilation
+#
+OLD_PI := $(shell grep bcm_host_get_peripheral_address /opt/vc/include/bcm_host.h && echo "no" || echo "yes")
+ifeq ($(OLD_PI), yes)
+$(info old pi)
+CXX_FLAGS+= -DOLD_PI
+else
+$(info new pi)
+	CXX_FLAGS += -I /opt/vc/include
+endif
+
 else
   CXX_FLAGS += -DEMULATION_MODE
 endif

From 628ec3f5d83c12867abafbc492d8f8a4dfba3948 Mon Sep 17 00:00:00 2001
From: wimrijnders <wimrijnders@gmail.com>
Date: Thu, 19 Jul 2018 23:22:29 +0200
Subject: [PATCH 08/13] small fixes, typo's

---
 Lib/VideoCore/RegisterMap.cpp | 6 +++---
 Makefile                      | 6 ++----
 2 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/Lib/VideoCore/RegisterMap.cpp b/Lib/VideoCore/RegisterMap.cpp
index 0e9a9b8..12e89bc 100644
--- a/Lib/VideoCore/RegisterMap.cpp
+++ b/Lib/VideoCore/RegisterMap.cpp
@@ -8,7 +8,7 @@
 #include "Mailbox.h"  // mapmem()
 
 #ifdef OLD_PI
-#pragma message "This is an old pi!"
+//#pragma message "This is an old pi!"
 //
 // For old Pi's, calls bcm_host_get_peripheral_address() and
 // bcm_host_get_peripheral_size() don't exist, so we need
@@ -36,7 +36,7 @@ unsigned bcm_host_get_peripheral_address() {
 unsigned bcm_host_get_peripheral_size() { return 0x01000000; }
 
 //
-// This is the only things we need from bcm_host.h, we declare
+// These are the only things we need from bcm_host.h, we declare
 // them explicitly to avoid dragging in all the stuff that throws compile errors.
 //
 #ifdef __cplusplus
@@ -49,7 +49,7 @@ void bcm_host_deinit(void);
 #ifdef __cplusplus
 }
 #endif
-// End things we need from bcm_host.h, we declare
+// End things we need from bcm_host.h
 
 #else  // OLD_PI
 // Following works for newer distro's
diff --git a/Makefile b/Makefile
index 6f917a7..d4902fb 100644
--- a/Makefile
+++ b/Makefile
@@ -33,7 +33,6 @@ ifeq ($(QPU), 1)
 
 # Check platform before building. Can't be indented, otherwise make complains.
 RET := $(shell Tools/detectPlatform.sh 1>/dev/null && echo "yes" || echo "no")
-#$(info  info: '$(RET)')
 ifneq ($(RET), yes)
 $(error QPU-mode specified on a non-Pi platform; aborting)
 else
@@ -45,17 +44,16 @@ endif
 
   OBJ_DIR := $(OBJ_DIR)-qpu
 
-
 #
 # Detect if Pi has bcm_host support (new) or not (old)
 # If old, pass in -DOLD_PI to compilation
 #
 OLD_PI := $(shell grep bcm_host_get_peripheral_address /opt/vc/include/bcm_host.h && echo "no" || echo "yes")
 ifeq ($(OLD_PI), yes)
-$(info old pi)
+#$(info old pi)
 CXX_FLAGS+= -DOLD_PI
 else
-$(info new pi)
+#$(info new pi)
 	CXX_FLAGS += -I /opt/vc/include
 endif
 

From 77b8081c092c1da2562d60db8ae30eaab482795a Mon Sep 17 00:00:00 2001
From: wimrijnders <wimrijnders@gmail.com>
Date: Sun, 22 Jul 2018 22:36:35 +0200
Subject: [PATCH 09/13] Don't use bcm headerrs by default

---
 Lib/VideoCore/RegisterMap.cpp | 10 +++++-----
 Makefile                      | 13 +++++++------
 2 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/Lib/VideoCore/RegisterMap.cpp b/Lib/VideoCore/RegisterMap.cpp
index 12e89bc..266f290 100644
--- a/Lib/VideoCore/RegisterMap.cpp
+++ b/Lib/VideoCore/RegisterMap.cpp
@@ -7,7 +7,10 @@
 #include <unistd.h>
 #include "Mailbox.h"  // mapmem()
 
-#ifdef OLD_PI
+#ifdef USE_BCM_HEADERS
+// Following works for newer distro's
+#include <bcm_host.h>
+#else  // USE_BCM_HEADERS
 //#pragma message "This is an old pi!"
 //
 // For old Pi's, calls bcm_host_get_peripheral_address() and
@@ -51,10 +54,7 @@ void bcm_host_deinit(void);
 #endif
 // End things we need from bcm_host.h
 
-#else  // OLD_PI
-// Following works for newer distro's
-#include <bcm_host.h>
-#endif  // OLD_PI
+#endif  // USE_BCM_HEADERS
 
 
 namespace QPULib {
diff --git a/Makefile b/Makefile
index daad60b..24936f2 100644
--- a/Makefile
+++ b/Makefile
@@ -48,13 +48,14 @@ endif
 # Detect if Pi has bcm_host support (new) or not (old)
 # If old, pass in -DOLD_PI to compilation
 #
-OLD_PI := $(shell grep bcm_host_get_peripheral_address /opt/vc/include/bcm_host.h && echo "no" || echo "yes")
-ifeq ($(OLD_PI), yes)
-#$(info old pi)
-CXX_FLAGS+= -DOLD_PI
+#USE_BCM_HEADERS:= $(shell grep bcm_host_get_peripheral_address /opt/vc/include/bcm_host.h && echo "no" || echo "yes")
+USE_BCM_HEADERS:=no
+ifeq ($(USE_BCM_HEADERS), no)
+$(info not using bcm headers)
 else
-#$(info new pi)
-	CXX_FLAGS += -I /opt/vc/include
+$(info using bcm headers)
+CXX_FLAGS+= -DUSE_BCM_HEADERS
+CXX_FLAGS += -I /opt/vc/include
 endif
 
 else

From c3ea4f297aa4c7239038d70f72a78e880bc924f6 Mon Sep 17 00:00:00 2001
From: wimrijnders <wimrijnders@gmail.com>
Date: Sun, 22 Jul 2018 23:11:46 +0200
Subject: [PATCH 10/13] Replaced inline init with ctor initializer list for
 RegisterMap

---
 Lib/VideoCore/RegisterMap.cpp | 2 +-
 Lib/VideoCore/RegisterMap.h   | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/Lib/VideoCore/RegisterMap.cpp b/Lib/VideoCore/RegisterMap.cpp
index 266f290..d2dbac9 100644
--- a/Lib/VideoCore/RegisterMap.cpp
+++ b/Lib/VideoCore/RegisterMap.cpp
@@ -69,7 +69,7 @@ enum {
 std::unique_ptr<RegisterMap> RegisterMap::m_instance;
 
 
-RegisterMap::RegisterMap() {
+RegisterMap::RegisterMap() : m_addr(nullptr) {
 	bcm_host_init();
 	unsigned addr = bcm_host_get_peripheral_address();
 	m_size = bcm_host_get_peripheral_size();
diff --git a/Lib/VideoCore/RegisterMap.h b/Lib/VideoCore/RegisterMap.h
index 0dad1e7..50b17fc 100644
--- a/Lib/VideoCore/RegisterMap.h
+++ b/Lib/VideoCore/RegisterMap.h
@@ -31,7 +31,7 @@ class RegisterMap {
 private:
 	RegisterMap();
 
-	volatile uint32_t *m_addr{nullptr};
+	volatile uint32_t *m_addr;
 	unsigned m_size{0};
 
 	static std::unique_ptr<RegisterMap> m_instance;

From e3351a99ef098d53fb3a658f1206da1e35deb69c Mon Sep 17 00:00:00 2001
From: wimrijnders <wimrijnders@gmail.com>
Date: Mon, 23 Jul 2018 09:32:43 +0200
Subject: [PATCH 11/13] Initialization of other instance var to ctor init list

---
 Lib/VideoCore/RegisterMap.cpp | 2 +-
 Lib/VideoCore/RegisterMap.h   | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/Lib/VideoCore/RegisterMap.cpp b/Lib/VideoCore/RegisterMap.cpp
index d2dbac9..aa8a72c 100644
--- a/Lib/VideoCore/RegisterMap.cpp
+++ b/Lib/VideoCore/RegisterMap.cpp
@@ -69,7 +69,7 @@ enum {
 std::unique_ptr<RegisterMap> RegisterMap::m_instance;
 
 
-RegisterMap::RegisterMap() : m_addr(nullptr) {
+RegisterMap::RegisterMap() : m_addr(nullptr), m_size(0) {
 	bcm_host_init();
 	unsigned addr = bcm_host_get_peripheral_address();
 	m_size = bcm_host_get_peripheral_size();
diff --git a/Lib/VideoCore/RegisterMap.h b/Lib/VideoCore/RegisterMap.h
index 50b17fc..b976e9b 100644
--- a/Lib/VideoCore/RegisterMap.h
+++ b/Lib/VideoCore/RegisterMap.h
@@ -32,7 +32,7 @@ class RegisterMap {
 	RegisterMap();
 
 	volatile uint32_t *m_addr;
-	unsigned m_size{0};
+	unsigned m_size;
 
 	static std::unique_ptr<RegisterMap> m_instance;
 

From 87280693bb8af5236d9ff28eeacc346eb6b7a2a1 Mon Sep 17 00:00:00 2001
From: wimrijnders <wimrijnders@gmail.com>
Date: Tue, 24 Jul 2018 07:43:42 +0200
Subject: [PATCH 12/13] Added exhaustive checking on hardware revision for
 peripheral address

---
 Lib/VideoCore/RegisterMap.cpp | 64 ++++++++++++++++++++++++++++++++---
 Makefile                      | 21 +++++++++---
 2 files changed, 75 insertions(+), 10 deletions(-)

diff --git a/Lib/VideoCore/RegisterMap.cpp b/Lib/VideoCore/RegisterMap.cpp
index aa8a72c..e831ada 100644
--- a/Lib/VideoCore/RegisterMap.cpp
+++ b/Lib/VideoCore/RegisterMap.cpp
@@ -3,8 +3,9 @@
 #include "RegisterMap.h"
 #include <cassert>
 #include <cstring>
-#include <stdio.h>
 #include <unistd.h>
+#include <stdlib.h>   // needed for 'old' compilers, no harm done for new
+#include <errno.h>    // idem
 #include "Mailbox.h"  // mapmem()
 
 #ifdef USE_BCM_HEADERS
@@ -20,18 +21,71 @@
 
 
 /**
- * This returns the ARM-side physical address where peripherals are mapped.
+ * @brief This returns the ARM-side physical address where peripherals are mapped.
  *
  * Values:
  *
  * - 0x20000000  - Pi Zero, Zero W, and the first generation of the Pi and Compute Module
  * - 0x3f000000  - Pi 2, Pi 3 and Compute Module 3
  *
- * NOTE: We only return the second value for now, to get QPULib to compile on an old Pi 2 distro.
- *       Other values may be added as needed.
+ * Source: https://www.elinux.org/RPi_HardwareHistory
+ *
+ * At time of writing (20180723), the list of handled revisions is complete.
+ * New values may be added as new models appear.
  */
 unsigned bcm_host_get_peripheral_address() {
-	return 0x3f000000;
+	unsigned md = QPULib::mbox_open();
+	unsigned revision = QPULib::get_version(md);
+	QPULib::mbox_close(md);
+	printf("bcm_host_get_peripheral_address revision: %x\n", revision);
+
+	switch(revision) {
+		case 0x0007: 	  // A
+		case 0x0008:
+		case 0x0009:
+		case 0x0012: 	  // A+
+		case 0x0015:
+		case 0x900021:
+		case 0x0002: 	  // B
+		case 0x0003:
+		case 0x0004:
+		case 0x0005:
+		case 0x0006:
+		case 0x000d:
+		case 0x000e:
+		case 0x000f:
+		case 0x0010:    // B+
+		case 0x0013:
+		case 0x900032:
+		case 0x0011:    // Compute Module 1
+		case 0x0014:
+		case 0x900092:  // Zero
+		case 0x900093:
+		case 0x920093:
+		case 0x9000c1:  // Zero W
+ 			return 0x20000000;
+		
+		case 0xa01040:  // 2 Model B
+		case 0xa01041:
+		case 0xa21041:
+		case 0xa22042:
+		case 0xa02082:  // 3 Model B
+		case 0xa22082:
+		case 0xa32082:
+		case 0xa020d3:  // 3 Model B+ 
+		case 0xa020a0:  // Compute Module 3 (and CM3 Lite)
+			return 0x3f000000;
+
+		default:
+#ifdef DEBUG
+			printf("bcm_host_get_peripheral_address unknown hardware revision %x\n", revision);
+			exit(-1);
+#else
+			// All newer models have this address, so let's assume it 
+			// for new revision numbers.
+			return 0x3f000000;
+#endif
+	}
 }
 
 
diff --git a/Makefile b/Makefile
index 24936f2..dd508a4 100644
--- a/Makefile
+++ b/Makefile
@@ -1,14 +1,26 @@
 #
-# There are four builds possible, with output directories:
+# NOTES
+# =====
+#
+# * There are four builds possible, with output directories:
 #
 #   obj              - using emulator
 #   obj-debug        - output debug info, using emulator
 #   obj-qpu          - using hardware
 #   obj-debug-qpu    - output debug info, using hardware
 #
-# To compile for debugging, add flag '-g' to CXX_FLAGS.
 #
-###########################################################
+# * To compile for debugging, add flag '-g' to CXX_FLAGS.
+#
+#
+# * USE_BCM_HEADERS is set to 'no' by default here. This
+#   is to allow a proper build on old distro's (e.g. Raspbian wheezy).
+#
+#   For newer distro's it is recommended to comment this out and use the 
+#   longer assignment to USE_BCM_HEADERS. This works on 'Raspian stretch`,
+#   for 'jessie' it's unknown.
+#
+###########################################################################
 
 # Root directory of QPULib repository
 ROOT = Lib
@@ -46,7 +58,6 @@ endif
 
 #
 # Detect if Pi has bcm_host support (new) or not (old)
-# If old, pass in -DOLD_PI to compilation
 #
 #USE_BCM_HEADERS:= $(shell grep bcm_host_get_peripheral_address /opt/vc/include/bcm_host.h && echo "no" || echo "yes")
 USE_BCM_HEADERS:=no
@@ -55,7 +66,7 @@ $(info not using bcm headers)
 else
 $(info using bcm headers)
 CXX_FLAGS+= -DUSE_BCM_HEADERS
-CXX_FLAGS += -I /opt/vc/include
+CXX_FLAGS+= -I /opt/vc/include
 endif
 
 else

From d815813fe3c5bba61dbb3b3a044e42a07208c756 Mon Sep 17 00:00:00 2001
From: wimrijnders <wimrijnders@gmail.com>
Date: Tue, 24 Jul 2018 09:11:57 +0200
Subject: [PATCH 13/13] Added stdio.h again to RegisterMap

---
 Lib/VideoCore/RegisterMap.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Lib/VideoCore/RegisterMap.cpp b/Lib/VideoCore/RegisterMap.cpp
index e831ada..9f46bee 100644
--- a/Lib/VideoCore/RegisterMap.cpp
+++ b/Lib/VideoCore/RegisterMap.cpp
@@ -6,6 +6,7 @@
 #include <unistd.h>
 #include <stdlib.h>   // needed for 'old' compilers, no harm done for new
 #include <errno.h>    // idem
+#include <stdio.h>    // idem
 #include "Mailbox.h"  // mapmem()
 
 #ifdef USE_BCM_HEADERS