avionic design with actual uboot and tooling

submodule of avionic design uboot bootloader and with included tools to
get you started , read readme.md and readme-tk1-loader.md

u-boot/board/spear/common/spr_lowlevel_init.S

@@ -0,0 +1,174 @@
+/*
+ * (C) Copyright 2006
+ * Vipin Kumar, ST Micoelectronics, vipin.kumar@st.com.
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <config.h>
+
+/*
+ * platform specific initializations are already done in Xloader
+ * Initializations already done include
+ * DDR, PLLs, IP's clock enable and reset release etc
+ */
+.globl lowlevel_init
+lowlevel_init:
+	mov	pc, lr
+
+/* void setfreq(unsigned int device, unsigned int frequency) */
+.global setfreq
+setfreq:
+	stmfd 	sp!,{r14}
+	stmfd 	sp!,{r0-r12}
+
+	mov  	r8,sp
+	ldr 	sp,SRAM_STACK_V
+
+	/* Saving the function arguements for later use */
+	mov  	r4,r0
+	mov  	r5,r1
+
+	/* Putting DDR into self refresh */
+	ldr 	r0,DDR_07_V
+	ldr	r1,[r0]
+	ldr	r2,DDR_ACTIVE_V
+	bic	r1, r1, r2
+	str	r1,[r0]
+	ldr 	r0,DDR_57_V
+	ldr	r1,[r0]
+	ldr	r2,CYCLES_MASK_V
+	bic	r1, r1, r2
+	ldr	r2,REFRESH_CYCLES_V
+	orr	r1, r1, r2, lsl #16
+	str	r1,[r0]
+	ldr 	r0,DDR_07_V
+	ldr	r1,[r0]
+	ldr	r2,SREFRESH_MASK_V
+	orr	r1, r1, r2
+	str	r1,[r0]
+
+	/* flush pipeline */
+	b	flush
+	.align 5
+flush:
+	/* Delay to ensure self refresh mode */
+	ldr	r0,SREFRESH_DELAY_V
+delay:
+	sub	r0,r0,#1
+	cmp	r0,#0
+	bne	delay
+
+	/* Putting system in slow mode */
+	ldr	r0,SCCTRL_V
+	mov	r1,#2
+	str	r1,[r0]
+
+	/* Changing PLL(1/2) frequency */
+	mov	r0,r4
+	mov	r1,r5
+
+	cmp	r4,#0
+	beq	pll1_freq
+
+	/* Change PLL2 (DDR frequency) */
+	ldr	r6,PLL2_FREQ_V
+	ldr	r7,PLL2_CNTL_V
+	b	pll2_freq
+
+pll1_freq:
+	/* Change PLL1 (CPU frequency) */
+	ldr	r6,PLL1_FREQ_V
+	ldr	r7,PLL1_CNTL_V
+
+pll2_freq:
+	mov	r0,r6
+	ldr	r1,[r0]
+	ldr	r2,PLLFREQ_MASK_V
+	bic	r1,r1,r2
+	mov	r2,r5,lsr#1
+	orr	r1,r1,r2,lsl#24
+	str	r1,[r0]
+
+	mov	r0,r7
+	ldr	r1,P1C0A_V
+	str	r1,[r0]
+	ldr	r1,P1C0E_V
+	str	r1,[r0]
+	ldr	r1,P1C06_V
+	str	r1,[r0]
+	ldr	r1,P1C0E_V
+	str	r1,[r0]
+
+lock:
+	ldr	r1,[r0]
+	and	r1,r1,#1
+	cmp	r1,#0
+	beq	lock
+
+	/* Putting system back to normal mode */
+	ldr	r0,SCCTRL_V
+	mov	r1,#4
+	str	r1,[r0]
+
+	/* Putting DDR back to normal */
+	ldr	r0,DDR_07_V
+	ldr	r1,[R0]
+	ldr	r2,SREFRESH_MASK_V
+	bic	r1, r1, r2
+	str	r1,[r0]
+	ldr	r2,DDR_ACTIVE_V
+	orr	r1, r1, r2
+	str	r1,[r0]
+
+	/* Delay to ensure self refresh mode */
+	ldr	r0,SREFRESH_DELAY_V
+1:
+	sub	r0,r0,#1
+	cmp	r0,#0
+	bne	1b
+
+	mov	sp,r8
+	/* Resuming back to code */
+	ldmia	sp!,{r0-r12}
+	ldmia	sp!,{pc}
+
+SCCTRL_V:
+	.word 0xfca00000
+PLL1_FREQ_V:
+	.word 0xfca8000C
+PLL1_CNTL_V:
+	.word 0xfca80008
+PLL2_FREQ_V:
+	.word 0xfca80018
+PLL2_CNTL_V:
+	.word 0xfca80014
+PLLFREQ_MASK_V:
+	.word 0xff000000
+P1C0A_V:
+	.word 0x1C0A
+P1C0E_V:
+	.word 0x1C0E
+P1C06_V:
+	.word 0x1C06
+
+SREFRESH_DELAY_V:
+	.word 0x9999
+SRAM_STACK_V:
+	.word 0xD2800600
+DDR_07_V:
+	.word 0xfc60001c
+DDR_ACTIVE_V:
+	.word 0x01000000
+DDR_57_V:
+	.word 0xfc6000e4
+CYCLES_MASK_V:
+	.word 0xffff0000
+REFRESH_CYCLES_V:
+	.word 0xf0f0
+SREFRESH_MASK_V:
+	.word 0x00010000
+
+.global setfreq_sz
+setfreq_sz:
+	.word setfreq_sz - setfreq