kernel/arch/arm/mm/proc-arm925.S

/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 *  linux/arch/arm/mm/arm925.S: MMU functions for ARM925
 *
 *  Copyright (C) 1999,2000 ARM Limited
 *  Copyright (C) 2000 Deep Blue Solutions Ltd.
 *  Copyright (C) 2002 RidgeRun, Inc.
 *  Copyright (C) 2002-2003 MontaVista Software, Inc.
 *
 *  Update for Linux-2.6 and cache flush improvements
 *  Copyright (C) 2004 Nokia Corporation by Tony Lindgren <tony@atomide.com>
 *
 *  hacked for non-paged-MM by Hyok S. Choi, 2004.
 *
 * These are the low level assembler for performing cache and TLB
 * functions on the arm925.
 *
 *  CONFIG_CPU_ARM925_CPU_IDLE -> nohlt
 *
 * Some additional notes based on deciphering the TI TRM on OMAP-5910:
 *
 * NOTE1: The TI925T Configuration Register bit "D-cache clean and flush
 *	  entry mode" must be 0 to flush the entries in both segments
 *	  at once. This is the default value. See TRM 2-20 and 2-24 for
 *	  more information.
 *
 * NOTE2: Default is the "D-cache clean and flush entry mode". It looks
 *	  like the "Transparent mode" must be on for partial cache flushes
 *	  to work in this mode. This mode only works with 16-bit external
 *	  memory. See TRM 2-24 for more information.
 *
 * NOTE3: Write-back cache flushing seems to be flakey with devices using
 *        direct memory access, such as USB OHCI. The workaround is to use
 *        write-through cache with CONFIG_CPU_DCACHE_WRITETHROUGH (this is
 *        the default for OMAP-1510).
 */

#include <linux/linkage.h>
#include <linux/init.h>
#include <linux/pgtable.h>
#include <asm/assembler.h>
#include <asm/hwcap.h>
#include <asm/pgtable-hwdef.h>
#include <asm/page.h>
#include <asm/ptrace.h>
#include "proc-macros.S"

/*
 * The size of one data cache line.
 */
#define CACHE_DLINESIZE	16

/*
 * The number of data cache segments.
 */
#define CACHE_DSEGMENTS	2

/*
 * The number of lines in a cache segment.
 */
#define CACHE_DENTRIES	256

/*
 * This is the size at which it becomes more efficient to
 * clean the whole cache, rather than using the individual
 * cache line maintenance instructions.
 */
#define CACHE_DLIMIT	8192

	.text
/*
 * cpu_arm925_proc_init()
 */
ENTRY(cpu_arm925_proc_init)
	ret	lr

/*
 * cpu_arm925_proc_fin()
 */
ENTRY(cpu_arm925_proc_fin)
	mrc	p15, 0, r0, c1, c0, 0		@ ctrl register
	bic	r0, r0, #0x1000			@ ...i............
	bic	r0, r0, #0x000e			@ ............wca.
	mcr	p15, 0, r0, c1, c0, 0		@ disable caches
	ret	lr

/*
 * cpu_arm925_reset(loc)
 *
 * Perform a soft reset of the system.  Put the CPU into the
 * same state as it would be if it had been reset, and branch
 * to what would be the reset vector.
 *
 * loc: location to jump to for soft reset
 */
	.align	5
	.pushsection	.idmap.text, "ax"
ENTRY(cpu_arm925_reset)
	/* Send software reset to MPU and DSP */
	mov	ip, #0xff000000
	orr	ip, ip, #0x00fe0000
	orr	ip, ip, #0x0000ce00
	mov	r4, #1
	strh	r4, [ip, #0x10]
ENDPROC(cpu_arm925_reset)
	.popsection

	mov	ip, #0
	mcr	p15, 0, ip, c7, c7, 0		@ invalidate I,D caches
	mcr	p15, 0, ip, c7, c10, 4		@ drain WB
#ifdef CONFIG_MMU
	mcr	p15, 0, ip, c8, c7, 0		@ invalidate I & D TLBs
#endif
	mrc	p15, 0, ip, c1, c0, 0		@ ctrl register
	bic	ip, ip, #0x000f			@ ............wcam
	bic	ip, ip, #0x1100			@ ...i...s........
	mcr	p15, 0, ip, c1, c0, 0		@ ctrl register
	ret	r0

/*
 * cpu_arm925_do_idle()
 *
 * Called with IRQs disabled
 */
	.align	10
ENTRY(cpu_arm925_do_idle)
	mov	r0, #0
	mrc	p15, 0, r1, c1, c0, 0		@ Read control register
	mcr	p15, 0, r0, c7, c10, 4		@ Drain write buffer
	bic	r2, r1, #1 << 12
	mcr	p15, 0, r2, c1, c0, 0		@ Disable I cache
	mcr	p15, 0, r0, c7, c0, 4		@ Wait for interrupt
	mcr	p15, 0, r1, c1, c0, 0		@ Restore ICache enable
	ret	lr

/*
 *	flush_icache_all()
 *
 *	Unconditionally clean and invalidate the entire icache.
 */
ENTRY(arm925_flush_icache_all)
	mov	r0, #0
	mcr	p15, 0, r0, c7, c5, 0		@ invalidate I cache
	ret	lr
ENDPROC(arm925_flush_icache_all)

/*
 *	flush_user_cache_all()
 *
 *	Clean and invalidate all cache entries in a particular
 *	address space.
 */
ENTRY(arm925_flush_user_cache_all)
	/* FALLTHROUGH */

/*
 *	flush_kern_cache_all()
 *
 *	Clean and invalidate the entire cache.
 */
ENTRY(arm925_flush_kern_cache_all)
	mov	r2, #VM_EXEC
	mov	ip, #0
__flush_whole_cache:
#ifdef CONFIG_CPU_DCACHE_WRITETHROUGH
	mcr	p15, 0, ip, c7, c6, 0		@ invalidate D cache
#else
	/* Flush entries in both segments at once, see NOTE1 above */
	mov	r3, #(CACHE_DENTRIES - 1) << 4	@ 256 entries in segment
2:	mcr	p15, 0, r3, c7, c14, 2		@ clean+invalidate D index
	subs	r3, r3, #1 << 4
	bcs	2b				@ entries 255 to 0
#endif
	tst	r2, #VM_EXEC
	mcrne	p15, 0, ip, c7, c5, 0		@ invalidate I cache
	mcrne	p15, 0, ip, c7, c10, 4		@ drain WB
	ret	lr

/*
 *	flush_user_cache_range(start, end, flags)
 *
 *	Clean and invalidate a range of cache entries in the
 *	specified address range.
 *
 *	- start	- start address (inclusive)
 *	- end	- end address (exclusive)
 *	- flags	- vm_flags describing address space
 */
ENTRY(arm925_flush_user_cache_range)
	mov	ip, #0
	sub	r3, r1, r0			@ calculate total size
	cmp	r3, #CACHE_DLIMIT
	bgt	__flush_whole_cache
1:	tst	r2, #VM_EXEC
#ifdef CONFIG_CPU_DCACHE_WRITETHROUGH
	mcr	p15, 0, r0, c7, c6, 1		@ invalidate D entry
	mcrne	p15, 0, r0, c7, c5, 1		@ invalidate I entry
	add	r0, r0, #CACHE_DLINESIZE
	mcr	p15, 0, r0, c7, c6, 1		@ invalidate D entry
	mcrne	p15, 0, r0, c7, c5, 1		@ invalidate I entry
	add	r0, r0, #CACHE_DLINESIZE
#else
	mcr	p15, 0, r0, c7, c14, 1		@ clean and invalidate D entry
	mcrne	p15, 0, r0, c7, c5, 1		@ invalidate I entry
	add	r0, r0, #CACHE_DLINESIZE
	mcr	p15, 0, r0, c7, c14, 1		@ clean and invalidate D entry
	mcrne	p15, 0, r0, c7, c5, 1		@ invalidate I entry
	add	r0, r0, #CACHE_DLINESIZE
#endif
	cmp	r0, r1
	blo	1b
	tst	r2, #VM_EXEC
	mcrne	p15, 0, ip, c7, c10, 4		@ drain WB
	ret	lr

/*
 *	coherent_kern_range(start, end)
 *
 *	Ensure coherency between the Icache and the Dcache in the
 *	region described by start, end.  If you have non-snooping
 *	Harvard caches, you need to implement this function.
 *
 *	- start	- virtual start address
 *	- end	- virtual end address
 */
ENTRY(arm925_coherent_kern_range)
	/* FALLTHROUGH */

/*
 *	coherent_user_range(start, end)
 *
 *	Ensure coherency between the Icache and the Dcache in the
 *	region described by start, end.  If you have non-snooping
 *	Harvard caches, you need to implement this function.
 *
 *	- start	- virtual start address
 *	- end	- virtual end address
 */
ENTRY(arm925_coherent_user_range)
	bic	r0, r0, #CACHE_DLINESIZE - 1
1:	mcr	p15, 0, r0, c7, c10, 1		@ clean D entry
	mcr	p15, 0, r0, c7, c5, 1		@ invalidate I entry
	add	r0, r0, #CACHE_DLINESIZE
	cmp	r0, r1
	blo	1b
	mcr	p15, 0, r0, c7, c10, 4		@ drain WB
	mov	r0, #0
	ret	lr

/*
 *	flush_kern_dcache_area(void *addr, size_t size)
 *
 *	Ensure no D cache aliasing occurs, either with itself or
 *	the I cache
 *
 *	- addr	- kernel address
 *	- size	- region size
 */
ENTRY(arm925_flush_kern_dcache_area)
	add	r1, r0, r1
1:	mcr	p15, 0, r0, c7, c14, 1		@ clean+invalidate D entry
	add	r0, r0, #CACHE_DLINESIZE
	cmp	r0, r1
	blo	1b
	mov	r0, #0
	mcr	p15, 0, r0, c7, c5, 0		@ invalidate I cache
	mcr	p15, 0, r0, c7, c10, 4		@ drain WB
	ret	lr

/*
 *	dma_inv_range(start, end)
 *
 *	Invalidate (discard) the specified virtual address range.
 *	May not write back any entries.  If 'start' or 'end'
 *	are not cache line aligned, those lines must be written
 *	back.
 *
 *	- start	- virtual start address
 *	- end	- virtual end address
 *
 * (same as v4wb)
 */
arm925_dma_inv_range:
#ifndef CONFIG_CPU_DCACHE_WRITETHROUGH
	tst	r0, #CACHE_DLINESIZE - 1
	mcrne	p15, 0, r0, c7, c10, 1		@ clean D entry
	tst	r1, #CACHE_DLINESIZE - 1
	mcrne	p15, 0, r1, c7, c10, 1		@ clean D entry
#endif
	bic	r0, r0, #CACHE_DLINESIZE - 1
1:	mcr	p15, 0, r0, c7, c6, 1		@ invalidate D entry
	add	r0, r0, #CACHE_DLINESIZE
	cmp	r0, r1
	blo	1b
	mcr	p15, 0, r0, c7, c10, 4		@ drain WB
	ret	lr

/*
 *	dma_clean_range(start, end)
 *
 *	Clean the specified virtual address range.
 *
 *	- start	- virtual start address
 *	- end	- virtual end address
 *
 * (same as v4wb)
 */
arm925_dma_clean_range:
#ifndef CONFIG_CPU_DCACHE_WRITETHROUGH
	bic	r0, r0, #CACHE_DLINESIZE - 1
1:	mcr	p15, 0, r0, c7, c10, 1		@ clean D entry
	add	r0, r0, #CACHE_DLINESIZE
	cmp	r0, r1
	blo	1b
#endif
	mcr	p15, 0, r0, c7, c10, 4		@ drain WB
	ret	lr

/*
 *	dma_flush_range(start, end)
 *
 *	Clean and invalidate the specified virtual address range.
 *
 *	- start	- virtual start address
 *	- end	- virtual end address
 */
ENTRY(arm925_dma_flush_range)
	bic	r0, r0, #CACHE_DLINESIZE - 1
1:
#ifndef CONFIG_CPU_DCACHE_WRITETHROUGH
	mcr	p15, 0, r0, c7, c14, 1		@ clean+invalidate D entry
#else
	mcr	p15, 0, r0, c7, c6, 1		@ invalidate D entry
#endif
	add	r0, r0, #CACHE_DLINESIZE
	cmp	r0, r1
	blo	1b
	mcr	p15, 0, r0, c7, c10, 4		@ drain WB
	ret	lr

/*
 *	dma_map_area(start, size, dir)
 *	- start	- kernel virtual start address
 *	- size	- size of region
 *	- dir	- DMA direction
 */
ENTRY(arm925_dma_map_area)
	add	r1, r1, r0
	cmp	r2, #DMA_TO_DEVICE
	beq	arm925_dma_clean_range
	bcs	arm925_dma_inv_range
	b	arm925_dma_flush_range
ENDPROC(arm925_dma_map_area)

/*
 *	dma_unmap_area(start, size, dir)
 *	- start	- kernel virtual start address
 *	- size	- size of region
 *	- dir	- DMA direction
 */
ENTRY(arm925_dma_unmap_area)
	ret	lr
ENDPROC(arm925_dma_unmap_area)

	.globl	arm925_flush_kern_cache_louis
	.equ	arm925_flush_kern_cache_louis, arm925_flush_kern_cache_all

	@ define struct cpu_cache_fns (see <asm/cacheflush.h> and proc-macros.S)
	define_cache_functions arm925

ENTRY(cpu_arm925_dcache_clean_area)
#ifndef CONFIG_CPU_DCACHE_WRITETHROUGH
1:	mcr	p15, 0, r0, c7, c10, 1		@ clean D entry
	add	r0, r0, #CACHE_DLINESIZE
	subs	r1, r1, #CACHE_DLINESIZE
	bhi	1b
#endif
	mcr	p15, 0, r0, c7, c10, 4		@ drain WB
	ret	lr

/* =============================== PageTable ============================== */

/*
 * cpu_arm925_switch_mm(pgd)
 *
 * Set the translation base pointer to be as described by pgd.
 *
 * pgd: new page tables
 */
	.align	5
ENTRY(cpu_arm925_switch_mm)
#ifdef CONFIG_MMU
	mov	ip, #0
#ifdef CONFIG_CPU_DCACHE_WRITETHROUGH
	mcr	p15, 0, ip, c7, c6, 0		@ invalidate D cache
#else
	/* Flush entries in bothe segments at once, see NOTE1 above */
	mov	r3, #(CACHE_DENTRIES - 1) << 4	@ 256 entries in segment
2:	mcr	p15, 0, r3, c7, c14, 2		@ clean & invalidate D index
	subs	r3, r3, #1 << 4
	bcs	2b				@ entries 255 to 0
#endif
	mcr	p15, 0, ip, c7, c5, 0		@ invalidate I cache
	mcr	p15, 0, ip, c7, c10, 4		@ drain WB
	mcr	p15, 0, r0, c2, c0, 0		@ load page table pointer
	mcr	p15, 0, ip, c8, c7, 0		@ invalidate I & D TLBs
#endif
	ret	lr

/*
 * cpu_arm925_set_pte_ext(ptep, pte, ext)
 *
 * Set a PTE and flush it out
 */
	.align	5
ENTRY(cpu_arm925_set_pte_ext)
#ifdef CONFIG_MMU
	armv3_set_pte_ext
	mov	r0, r0
#ifndef CONFIG_CPU_DCACHE_WRITETHROUGH
	mcr	p15, 0, r0, c7, c10, 1		@ clean D entry
#endif
	mcr	p15, 0, r0, c7, c10, 4		@ drain WB
#endif /* CONFIG_MMU */
	ret	lr

	.type	__arm925_setup, #function
__arm925_setup:
	mov	r0, #0

	/* Transparent on, D-cache clean & flush mode. See  NOTE2 above */
        orr     r0,r0,#1 << 1			@ transparent mode on
        mcr     p15, 0, r0, c15, c1, 0          @ write TI config register

	mov	r0, #0
	mcr	p15, 0, r0, c7, c7		@ invalidate I,D caches on v4
	mcr	p15, 0, r0, c7, c10, 4		@ drain write buffer on v4
#ifdef CONFIG_MMU
	mcr	p15, 0, r0, c8, c7		@ invalidate I,D TLBs on v4
#endif

#ifdef CONFIG_CPU_DCACHE_WRITETHROUGH
	mov	r0, #4				@ disable write-back on caches explicitly
	mcr	p15, 7, r0, c15, c0, 0
#endif

	adr	r5, arm925_crval
	ldmia	r5, {r5, r6}
	mrc	p15, 0, r0, c1, c0		@ get control register v4
	bic	r0, r0, r5
	orr	r0, r0, r6
#ifdef CONFIG_CPU_CACHE_ROUND_ROBIN
	orr	r0, r0, #0x4000			@ .1.. .... .... ....
#endif
	ret	lr
	.size	__arm925_setup, . - __arm925_setup

	/*
	 *  R
	 * .RVI ZFRS BLDP WCAM
	 * .011 0001 ..11 1101
	 * 
	 */
	.type	arm925_crval, #object
arm925_crval:
	crval	clear=0x00007f3f, mmuset=0x0000313d, ucset=0x00001130

	__INITDATA
	@ define struct processor (see <asm/proc-fns.h> and proc-macros.S)
	define_processor_functions arm925, dabort=v4t_early_abort, pabort=legacy_pabort

	.section ".rodata"

	string	cpu_arch_name, "armv4t"
	string	cpu_elf_name, "v4"
	string	cpu_arm925_name, "ARM925T"

	.align

	.section ".proc.info.init", "a"

.macro arm925_proc_info name:req, cpu_val:req, cpu_mask:req, cpu_name:req, cache
	.type	__\name\()_proc_info,#object
__\name\()_proc_info:
	.long	\cpu_val
	.long	\cpu_mask
	.long   PMD_TYPE_SECT | \
		PMD_SECT_CACHEABLE | \
		PMD_BIT4 | \
		PMD_SECT_AP_WRITE | \
		PMD_SECT_AP_READ
	.long   PMD_TYPE_SECT | \
		PMD_BIT4 | \
		PMD_SECT_AP_WRITE | \
		PMD_SECT_AP_READ
	initfn	__arm925_setup, __\name\()_proc_info
	.long	cpu_arch_name
	.long	cpu_elf_name
	.long	HWCAP_SWP | HWCAP_HALF | HWCAP_THUMB
	.long	cpu_arm925_name
	.long	arm925_processor_functions
	.long	v4wbi_tlb_fns
	.long	v4wb_user_fns
	.long	arm925_cache_fns
	.size	__\name\()_proc_info, . - __\name\()_proc_info
.endm

	arm925_proc_info arm925, 0x54029250, 0xfffffff0, cpu_arm925_name
	arm925_proc_info arm915, 0x54029150, 0xfffffff0, cpu_arm925_name