esp-open-rtos/extras/rboot-ota/rboot-cache.S

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/* OTA-compatible Cache_Read_Enable function
*
* This gets called from the SDK when it wants to enable the flash mapping.
*
* In recent SDK versions it's been replaced with a Cache_Read_Enable_New
* function that takes note of OTA stuff.
*
* For esp-open-rtos we just replace the ROM function with this wrapper.
*
*
* Part of esp-open-rtos
* Copyright (C) 2015 Superhouse Automation Pty Ltd
* BSD Licensed as described in the file LICENSE
*/
#ifdef OTA
#define RBOOT_CONFIG_BASE (0x40200000 + 0x1000)
#define RBOOT_ROMS_OFFS 0x8 /* offset of rboot_config_t.roms array in config */
#define RBOOT_MEGABYTE_DEFAULT 0x80
.section .data
.global rboot_megabyte
rboot_megabyte:
.byte RBOOT_MEGABYTE_DEFAULT
.section .data
.local cache_return_save
.align 4
cache_return_save:
.word 0
.text
.section .iram1.text, "x"
.literal_position
.align 4
.global Cache_Read_Enable
.type Cache_Read_Enable, @function /* it's not really a function, but treat it like one */
Cache_Read_Enable:
movi a2, cache_return_save
s32i a0, a2, 0 /* save a0 here */
movi a2, rboot_megabyte
l8ui a2, a2, 0
bnei a2, RBOOT_MEGABYTE_DEFAULT, .Lalready_initialised
/* map the first megabyte of flash */
movi a2, 0
movi a3, 0
movi a4, 1
call0 rom_Cache_Read_Enable
movi a3, RBOOT_CONFIG_BASE
l32i a2, a3, 0 /* 32-bit flash read */
extui a2, a2, 24, 8 /* 3rd byte is 'current' field of config */
slli a2, a2, 2 /* Left shift by two, becomes offset into rom array */
add a4, a2, a3 /* Add the base config address */
l32i a4, a4, RBOOT_ROMS_OFFS /* Read from the ROM array */
extui a4, a4, 20, 8 /* now a4 is number of megabytes */
/* save to rboot_megabyte */
movi a3, rboot_megabyte
s8i a4, a3, 0
/* re-disable cache? */
call0 Cache_Read_Disable
.Lalready_initialised:
movi a4, rboot_megabyte
l32i a4, a4, 0
extui a2, a4, 0, 1 /* a2 is now lsb of a4 (odd/even) */
srli a3, a4, 1 /* a3 is half value of mb */
movi a4, 1
call0 rom_Cache_Read_Enable
movi a0, cache_return_save /* restore a0 return address */
l32i a0, a0, 0
ret.n
#endif