Add routine to set the Raspberry Pi clock to 250MHz (loads faster than the default 19.2MHz).

--HG--
branch : dtrg-videocore
rename : plat/rpi/libsys/pi_user_to_phys.s => plat/rpi/libsys/pi_fast_mode.s

plat/rpi/build.mk

@@ -23,6 +23,7 @@ platform-libsys := \
 	pi_phys_to_user.s \
 	pi_user_to_phys.s \
 	pi_uart.s \
+	pi_fast_mode.s \
 	creat.c \
 	close.c \
 	open.c \

plat/rpi/include/pi.h

@@ -32,5 +32,17 @@ extern void* pi_phys_to_user(void* ptr);
 /* Converts a pointer from a user address to a physical address. */
 extern void* pi_user_to_phys(void* ptr);
 
+/* Change the clock speed from 19.2MHz to 250MHz. Must be called *before*
+ * pi_init_uart(). */
+extern void pi_fast_mode(void);
+
+/* Initialise the RAM. */
+extern void pi_init_ram(void);
+
+/* The current clock speed (used by pi_init_uart to calculate the correct
+ * UART settings). */
+
+extern int pi_clock_speed;
+
 #endif
 

plat/rpi/libsys/pi_fast_mode.s

@@ -0,0 +1,70 @@
+#
+/*
+ * Raspberry Pi support library for the ACK
+ * © 2013 David Given
+ * This file is redistributable under the terms of the 3-clause BSD license.
+ * See the file 'Copying' in the root of the distribution for the full text.
+ */
+
+#include "libsysasm.h"
+
+.sect .text
+
+#define PASSWD 0x5a000000
+#define PLLC 5
+#define OSC 1
+
+#define A2W                 0x7e102000
+#define A2W_PLLC_MULT       0x7e102020
+#define A2W_PLLC_MULT2      0x7e102120
+#define A2W_PLLC_MULT_FRACT 0x7e102220
+#define A2W_PLLx_DIV        0x7e102620
+
+#define CM                  0x7e101000
+#define CM_VPU_CTL          0x7e101008
+#define CM_VPU_DIV          0x7e10100c
+#define CM_TIME_DIV         0x7e1010ec
+#define CM_TIME_CTL         0x7e1010e8
+
+#define hash #
+#define copy(A) A
+#define poke(A, V) \
+	mov r0, copy(hash) V; mov r1, copy(hash) A; st r0, (r1)
+
+! Changes the clock speed to 250MHz.
+
+.define _pi_fast_mode
+_pi_fast_mode:
+	poke(A2W + 0x190, 0x5a000001)
+	poke(A2W_PLLC_MULT_FRACT, PASSWD | 87380)
+	poke(A2W_PLLC_MULT2, PASSWD | 52 | 0x1000)
+	poke(A2W + 0x3c, 0x5a000100)
+	poke(A2W + 0x38, 0x5a000000)
+	poke(A2W + 0x34, 0x5a144000)
+	poke(A2W + 0x30, 0x5a000000)
+	poke(CM + 0x108, 0x5a000200)
+	poke(CM + 0x108, 0x5a0002aa)
+	poke(A2W + 0x2c, 0x5a000000)
+	poke(A2W + 0x28, 0x5a400000)
+	poke(A2W + 0x24, 0x5a000005)
+	poke(A2W_PLLC_MULT, PASSWD | 52 | 0x555000)
+	poke(A2W_PLLC_MULT2, PASSWD | 52 | 0x21000)
+	poke(A2W + 0x2c, 0x5a000042)
+	poke(A2W + 0x28, 0x5a500401)
+	poke(A2W + 0x24, 0x5a004005)
+	poke(A2W_PLLC_MULT, PASSWD | 52 | 0x555000)
+	poke(A2W_PLLx_DIV, PASSWD | 2)
+	poke(CM + 0x108, 0x5a0002ab)
+	poke(CM + 0x108, 0x5a0002aa)
+	poke(CM + 0x108, 0x5a0002a8)
+	poke(CM_VPU_CTL, PASSWD | 0x200 | OSC | 0x40)
+	poke(CM_VPU_DIV, PASSWD | [4 << 12])
+	poke(CM_VPU_CTL, PASSWD | PLLC | 0x40)
+	poke(CM_VPU_CTL, PASSWD | PLLC | 0x50)
+	poke(CM_TIME_DIV, PASSWD | [19 << 12] | 819)
+	poke(CM_TIME_CTL, PASSWD | OSC | 0x10)
+
+	mov r0, #250000000
+	st r0, _pi_clock_speed
+	b lr
+

plat/rpi/libsys/pi_uart.s

@@ -14,9 +14,6 @@
 ! So be careful with your serial/terminal, some adjustment may be necessary.
 TARGET_BAUD_RATE = 115200
 
-! System clock is running directly off the 19.2MHz crystal at initial reset
-SYSTEM_CLOCK = 19200000
-
 GPFSEL1 = 0x7e200004
 GPSET0 = 0x7e20001C
 GPCLR0 = 0x7e200028
@@ -102,7 +99,10 @@ delay2:
 	st	r0, (r1)
 
 	mov	r1, #AUX_MU_BAUD_REG
-	mov	r0, #[[SYSTEM_CLOCK/[TARGET_BAUD_RATE*8]]-1]
+	ld r0, _pi_clock_speed
+	mov r2, #TARGET_BAUD_RATE*8
+	divu r0, r0, r2
+	sub r0, #1
 	st	r0, (r1)
 
 	mov	r1, #AUX_MU_LCR_REG
@@ -176,3 +176,10 @@ recvwait:
 	b lr
 
 .comm __uart_status, 1
+
+.sect .data
+.define _pi_clock_speed
+
+! System clock is running directly off the 19.2MHz crystal at initial reset
+_pi_clock_speed:
+	.data4 19200000