view target-utils/libcommon/osmodelay.S @ 923:10b4bed10192

gsm-fw/L1: fix for the DSP patch corruption bug The L1 code we got from the LoCosto fw contains a feature for DSP CPU load measurement. This feature is a LoCosto-ism, i.e., not applicable to earlier DBB chips (Calypso) with their respective earlier DSP ROMs. Most of the code dealing with that feature is conditionalized as #if (DSP >= 38), but one spot was missed, and the MCU code was writing into an API word dealing with this feature. In TCS211 this DSP API word happens to be used by the DSP code patch, hence that write was corrupting the patched DSP code.
author Mychaela Falconia <falcon@ivan.Harhan.ORG>
date Mon, 19 Oct 2015 17:13:56 +0000
parents 07b686248ab7
children
line wrap: on
line source

/*
 * This assembly module provides a replica of OsmocomBB's bogo-millisecond
 * delay_ms() function.  It is literally a copy of what OsmocomBB's delay_ms()
 * compiles to with their gcc version and their optimization settings, as seen
 * by doing arm-elf-objdump on their lib/delay.o.
 *
 * This hack is intended for those cases where we have to copy OsmocomBB's
 * black magic voodoo operations with no ability to understand what is actually
 * needed, such as SPCA552E initialization on the Pirelli DP-L10.
 */

	.text
	.code	32
	.globl	osmo_delay_ms
osmo_delay_ms:
	mov     r3, #0
	sub     sp, sp, #4
	str     r3, [sp]
	ldr     r3, =1300
	mul     r3, r0, r3
	b       2f
1:	ldr     r2, [sp]
	ldr     r2, [sp]
	add     r2, r2, #1
	str     r2, [sp]
2:	ldr     r2, [sp]
	cmp     r2, r3
	bcc     1b
	add     sp, sp, #4
	bx      lr