Restructure RPi files (#827)

- Restructure SPi files for linux and RPi
- Update RPi revision detection (#826)

configure

@@ -17,7 +17,7 @@ SPI driver options:
                                 Device path. [/dev/spidev0.0]
 
 Building options:
-    --soc=[BCM2835|BCM2836|AM33XX|A10|A13|A20|H3]
+    --soc=[BCM2835|BCM2836|BCM2837|AM33XX|A10|A13|A20|H3]
                                 SoC type to be used. [configure autodetected]
     --cpu-flags=<CPUFLAGS>      CPU defining/optimizing flags to be used. [configure autodetected]
     --extra-cflags=<CFLAGS>     Extra C flags passed to C compilation. []
@@ -126,21 +126,38 @@ function detect_machine {
     fi
 
     case $hardware in
-    BCM2708)
-        soc="BCM2835"
+    BCM*)
         if [[ $machine == "Raspberry"* ]]; then
-            tp="RPi"
-        fi
-        ;;
-    BCM2709)
-        soc="BCM2836"
-        if [[ $machine == "Raspberry"* ]]; then
-            local rev=($(detect_rpi_revision))
-            if [[ $rev == "a02082" || $rev == "a22082" ]]; then
-                tp="RPi3"
+            # Calculation done by joolswills(https://github.com/joolswills) for the RetroPie-Setup project
+            # and based on information from https://github.com/AndrewFromMelbourne/raspberry_pi_revision
+            local rev="0x$(sed -n '/^Revision/s/^.*: \(.*\)/\1/p' < /proc/cpuinfo)"
+            # if bit 23 is not set, we are on a rpi1 (bit 23 means the revision is a bitfield)
+            if [[ $((($rev >> 23) & 1)) -eq 0 ]]; then
+                soc="BCM2835"
+                tp="rpi1"
             else
-                tp="Rpi2"
+                # if bit 23 is set, get the cpu from bits 12-15
+                case "$((($rev >> 12) & 15))" in
+                    0)
+                        soc="BCM2835"
+                        tp="rpi1"
+                        ;;
+                    1)
+                        soc="BCM2836"
+                        tp="rpi2"
+                        ;;
+                    2)
+                        soc="BCM2837"
+                        tp="rpi3"
+                        ;;
+                esac
             fi
+        elif [[ $hardware == "BCM2708"* ]]; then
+            soc="BCM2835"
+        elif [[ $hardware == "BCM2709"* ]]; then
+            soc="BCM2836"
+        elif [[ $hardware == "BCM2710"* ]]; then
+            soc="BCM2837"
         fi
         ;;
     sun4i|Sun4iw1p1)
@@ -208,6 +225,9 @@ function gcc_cpu_flags {
     BCM2836)
         flags="-march=armv7-a -mtune=cortex-a7 -mfpu=neon-vfpv4 -mfloat-abi=hard"
         ;;
+    BCM2837)
+        flags="-march=armv8-a+crc -mtune=cortex-a53 -mfpu=neon-fp-armv8 -mfloat-abi=hard"
+        ;;
     AM33XX)
         flags="-march=armv7-a -mtune=cortex-a8 -mfpu=neon -mfloat-abi=hard"
         ;;
@@ -446,8 +466,8 @@ if [ -z "${CPUFLAGS}" ]; then
     CPUFLAGS=$(gcc_cpu_flags $SOC)
 fi
 
-if [[ $SOC == "BCM2835" || $SOC == "BCM2836" ]]; then
-    CPPFLAGS="-DLINUX_ARCH_RASPBERRYPI $CPPFLAGS"
+if [[ $SOC == "BCM2835" || $SOC == "BCM2836" || $SOC == "BCM2837" ]]; then
+    CPPFLAGS="-DLINUX_ARCH_RASPBERRYPI -DRPI_TYPE=\\\"$TYPE\\\" $CPPFLAGS"
 else
     echo "[SECTION] Checking GPIO Sysfs."
     if [[ $(eval 'ls /sys/class/gpio/export 2>/dev/null') ]]; then
@@ -459,7 +479,7 @@ fi
 
 if [ -z "${SPI_DRIVER}" ]; then
     echo "[SECTION] Detecting SPI driver."
-    if [[ $SOC == "BCM2835" || $SOC == "BCM2836" ]]; then
+    if [[ $SOC == "BCM2835" || $SOC == "BCM2836" || $SOC == "BCM2837" ]]; then
         SPI_DRIVER=BCM
     elif [[ $(eval 'ls /dev/spidev* 2>/dev/null') ]]; then
         SPI_DRIVER=SPIDEV