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| author | Vadzim Dambrouski <pftbest@gmail.com> | 2015-10-19 19:40:14 +0300 |
|---|---|---|
| committer | Albert ARIBAUD <albert.u.boot@aribaud.net> | 2015-11-10 09:45:33 +0100 |
| commit | 432a6241bdb70b98ead8f58bbf717d3f7fe699a8 (patch) | |
| tree | c1dc8eedb96b9c3248e71ce4141ee630a6070501 /arch | |
| parent | e490ad25eb3dc4f075ed33b4b00b1f97071fcf3d (diff) | |
| download | talos-obmc-uboot-432a6241bdb70b98ead8f58bbf717d3f7fe699a8.tar.gz talos-obmc-uboot-432a6241bdb70b98ead8f58bbf717d3f7fe699a8.zip | |
arm: add support for semihosting for ARMv7M targets
If you enable CONFIG_SEMIHOSTING for STM32F429 target, you will get compile
error looking like this:
arch/arm/lib/semihosting.c: In function 'smh_read':
{standard input}: Assembler messages:
{standard input}:34: Error: invalid swi expression
{standard input}:34: Error: value of 1193046 too large for field of 2 bytes at 0
scripts/Makefile.build:277: recipe for target 'arch/arm/lib/semihosting.o' failed
The source of the problem is "svc #0x123456" instruction. This instruction
can not be encoded using Thumb2 instruction set used by ARMv7M CPUs.
ARM documentation suggests using "bkpt #0xAB" instruction instead [1].
This patch fixes compile errors and adds support for semihosting for
STM32F429 or any other ARMv7M target.
This change was sested on STM32F429-DISCOVERY board using OpenOCD and
"smhload" u-boot command.
[1] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0471c/Bgbjhiea.html
Signed-off-by: Vadzim Dambrouski <pftbest@gmail.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm/lib/semihosting.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/arm/lib/semihosting.c b/arch/arm/lib/semihosting.c index c3e964eabc..ed5e8e426e 100644 --- a/arch/arm/lib/semihosting.c +++ b/arch/arm/lib/semihosting.c @@ -31,6 +31,8 @@ static noinline long smh_trap(unsigned int sysnum, void *addr) register long result asm("r0"); #if defined(CONFIG_ARM64) asm volatile ("hlt #0xf000" : "=r" (result) : "0"(sysnum), "r"(addr)); +#elif defined(CONFIG_CPU_V7M) + asm volatile ("bkpt #0xAB" : "=r" (result) : "0"(sysnum), "r"(addr)); #else /* Note - untested placeholder */ asm volatile ("svc #0x123456" : "=r" (result) : "0"(sysnum), "r"(addr)); |
