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reset.S @ 646

Last change on this file since 646 was 634, checked in by bouyer, 11 years ago
Pass the preloader's function vector address in a0 to the next stage. This way the next stage doesn't have to know the address of the preloader.
File size: 8.0 KB

Rev	Line
[586]	1	/*
[292]	2	* \file : reset.S
	3	* \date : 01/12/2012
	4	* \author: Cesar FUGUET & Manuel BOUYER & Alain Greiner
	5	*
[586]	6	* This is a generic reset code for a generic multi-clusters / multi-processors
	7	* TSAR architecture (up to 256 clusters / up to 4 processors per cluster).
[292]	8	*
[586]	9	* There is one XICU, one TTY, one DMA, and one memory bank per cluster.
	10	*
	11	* This preloader uses a stack segment allocated in cluster 0, defined
	12	* by the seg_reset_stack_base and seg_reset_stack_size parameters in ldscript.
	13	* - Processor 0 uses a larger stack: 64 Kbytes.
	14	* - Other processors use a smaller stack: 512 bytes.
	15	* => the seg_stack_size cannot be smaller than 0x90000 bytes (576 K).
	16	* Those stacks can be used by both the preloader and the boot-loader code.
	17	*
	18	* The replicated XICU is used to awake the sleeping processors:
[606]	19	* xicu_paddr_base = ICU_PADDR_BASE + (cluster_xy << 32)
[586]	20	*
	21	* It is intended to be used with various operating systems or nano kernels,
	22	* including NetBSD, ALMOS, and GIET_VM.
	23	*
	24	* - Each processor initializes its Status Register (SR) to disable interrupts.
	25	* - Each processor initializes its Count Register.
	26	* - Each processor initialises its private XICU WTI mask register.
	27	* - Each processor initializes its Stack Pointer.
	28	* - Only processor 0 executes the reset_load_elf function to load into memory
	29	* the system specific boot-loader stored on disk at BOOT_LOADER_LBA
	30	* - All other processors wait in a low power consumption mode that the
	31	* processor 0 wakes them using an IPI (Inter Processor Interruption)
[292]	32	*/
	33
	34	#include <defs.h>
	35	#include <mips32_registers.h>
	36
[606]	37	/* These define should be consistent with values defined in map.xml file */
[292]	38
[586]	39	.extern seg_reset_stack_base
	40	.extern seg_reset_stack_size
[292]	41
[586]	42	.section .reset,"ax",@progbits
	43
[348]	44	.extern dtb_addr
[586]	45	.extern reset_putc
	46	.extern reset_getc
	47	.extern reset_ioc_read
	48	.extern reset_elf_loader
[425]	49	.extern memcpy
[586]	50	.extern reset_puts
	51	.extern reset_putx
	52	.extern reset_putd
	53	.extern reset_ioc_init
[502]	54	.extern versionstr
[292]	55
[586]	56	.globl reset /* Makes reset an external symbol */
	57	.ent reset
[292]	58
	59	.align 2
	60	.set noreorder
	61
[586]	62	reset:
	63	b _reset /* 0xbfc0000 */
[292]	64	nop /* 0xbfc0004 */
	65
[586]	66	/* Addresses of the functions provided by this reset code */
[292]	67
[634]	68	preloader_vector:
[586]	69	.word RESET_VERSION /* 0xbfc0008 */
[292]	70	.word dtb_addr /* 0xbfc000c */
[586]	71	.word reset_putc /* 0xbfc0010 */
	72	.word reset_getc /* 0xbfc0014 */
	73	.word reset_ioc_read /* 0xbfc0018 */
	74	.word reset_elf_loader /* 0xbfc001C */
[425]	75	.word memcpy /* 0xbfc0020 */
[586]	76	.word reset_puts /* 0xbfc0024 */
	77	.word reset_putx /* 0xbfc0028 */
	78	.word reset_putd /* 0xbfc002C */
[292]	79
[586]	80	_reset:
[292]	81
[586]	82	/* All processors Disable interruptions, keep STATUSbev enabled */
	83
[292]	84	li k0, (1 << 22)
	85	mtc0 k0, CP0_STATUS
	86
[606]	87	/* All processors compute proc_id, lpid, cluster_xy */
[292]	88
	89	mfc0 k0, CP0_EBASE
	90	andi t0, k0, 0x3FF /* t0 <= proc_id (at most 1024 processors) */
	91
	92	move t3, t0
	93
	94	la k0, NB_PROCS /* k0 <= number of processors per cluster */
	95	divu t3, k0
[606]	96	mfhi t1 /* t1 <= lpid = proc_id % NB_PROCS */
	97	mflo t2 /* t2 <= cluster_xy = proc_id / NB_PROCS */
[292]	98
[586]	99	/* All processors initialise the count register in CP0 */
[292]	100
	101	mtc0 zero, CP0_COUNT
	102
[586]	103	/*
	104	* All processors enable the WTI for XICU
	105	* Each processor may have IRQ_PER_PROC irq outputs from the XICU
[606]	106	* In each cluster, the XICU base address depends on the cluster_xy
[292]	107	*/
[302]	108
[586]	109	la t3, ICU_PADDR_BASE /* t3 <= ICU base address */
	110	move t4, t1 /* t4 <= local_id */
	111	li t5, IRQ_PER_PROC /* t5 <= IRQ_PER_PROC */
[302]	112	multu t4, t5
[586]	113	mflo t6 /* t6 <= IRQ_PER_PROC * local_id */
	114	sll t4, t6, 2 /* t4 <= OUT_INDEX = t6 * 4 */
[302]	115
[586]	116	li t5, (0xC << 7) /* t5 <= FUNC = XICU_MSK_WTI */
	117	or t4, t4, t5 /* t4 <= FUNC \| INDEX \| 00 */
	118	or t5, t3, t4 /* t5 <= &XICU[MSK_WTI][OUT_INDEX] */
[292]	119
[586]	120	/* All processors set WTI mask using the physical address extension */
[292]	121
	122	li t4, 1
[586]	123	sllv t4, t4, t1 /* Set XICU[MSK_WTI][INDEX][local_id] */
[292]	124
[606]	125	mtc2 t2, CP2_PADDR_EXT /* set PADDR extension */
[586]	126	sw t4, 0(t5) /* XICU[MSK_WTI][INDEX] <= t4 */
	127	mtc2 zero, CP2_PADDR_EXT /* reset PADDR extension */
[567]	128
[586]	129	/* All processors initializes stack pointer, depending on proc_id */
	130
	131	la k0, seg_reset_stack_base
	132	li k1, 0x10000 /* k1 <= P0 stack size == 64 Kbytes */
	133	addu sp, k0, k1 /* P0 stack from base to (base + 64K) */
	134
	135	li k1, 0x200 /* k1 <= Pi stack size == 512 bytes */
	136	multu k1, t0
	137	mflo k0 /* k0 <= 256 * proc_id */
	138	addu sp, sp, k1
	139	addu sp, sp, k0 /* Pi stacks from base + 64K + proc_id256 /
	140
	141	/*
	142	* Only processor 0 in cluster 0 loads and executes the boot-loader
[292]	143	* We have:
[586]	144	* t0: global proc_id
	145	* t1: local proc_id
[606]	146	* t2: cluster_xy
[586]	147	* t3: xicu physical base address in cluster 0
[292]	148	*/
	149
	150	bne zero, t0, _reset_wait
	151	nop
	152
[586]	153	/* Processor 0 displays version for this reset code */
[292]	154
[587]	155	la a0, versionstr
	156	la k0, reset_puts
	157	jalr k0
	158	nop
[292]	159
[502]	160
[292]	161	#ifndef SOCLIB_IOC
	162
[586]	163	/* Processor 0 Initialize the block device if required */
[292]	164
[586]	165	la k0, reset_ioc_init
[292]	166	jalr k0
	167	nop
	168
	169	#endif
	170
[586]	171	/*
	172	* Processor 0 jumps to the reset_elf_loader routine
	173	* Passing as argument the block number in which is loaded the .elf file
[292]	174	*/
	175
[586]	176	la k0, reset_elf_loader
[292]	177	li a0, BOOT_LOADER_LBA
	178	jalr k0
	179	nop
	180
[586]	181	/*
	182	* Processor O jumps to the entry address defined in the .elf file,
	183	* and returned by reset_elf_loader function.
[634]	184	* First argument is pointer to the preloader function vectors
	185	* other function arguments are 0
[292]	186	*/
	187
[634]	188	la a0, preloader_vector
[292]	189	move a1, zero
	190	move a2, zero
	191	move a3, zero
	192	jr v0
	193	nop
	194
[586]	195	/*
	196	* All processor (but processor 0) wait in low power mode
	197	* until processor 0 wakes them using an IPI.
[292]	198	* We have:
	199	* t0: global id
	200	* t1: local id
	201	* t2: cluster id
[586]	202	* t3: xicu physical base address in cluster 0
[292]	203	*/
	204
[586]	205	_reset_wait:
[292]	206
[586]	207	sll t4, t1, 2 /* t4 <= local_id * 4 */
	208	addu t5, t4, t3 /* t5 <= &XICU[WTI_REG][local_id] */
	209
[292]	210	wait
	211
[586]	212	/*
	213	* All other processors, when exiting wait mode,
	214	* read from XICU the address to jump.
	215	* This address is the boot-loader entry address that has been
	216	* written in the mailbox by the IPI sent by processor 0
	217	*/
[567]	218
[606]	219	mtc2 t2, CP2_PADDR_EXT /* set PADDR extension */
[567]	220	lw k0, 0(t5) /* k0 <= XICU[WTI_REG][local_id] */
	221	mtc2 zero, CP2_PADDR_EXT /* reset PADDR extension */
	222
[292]	223	jr k0
	224	nop
	225
	226	/* Exception entry point */
[586]	227
[292]	228	.org 0x0380
	229	_excep:
[586]	230	mfc0 a0, CP0_STATUS /* first arg is status */
	231	mfc0 a1, CP0_CAUSE /* second arg is cause */
	232	mfc0 a2, CP0_EPC /* third argc is epc */
[292]	233	nop
	234	j handle_except
	235	nop
	236
[586]	237	.end reset
[292]	238
	239	.set reorder
[302]	240
	241	/*
	242	* vim: tabstop=4 : shiftwidth=4 : expandtab
	243	*/

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