diff options
author | Yunhong Jiang <yunhong.jiang@intel.com> | 2015-08-04 12:17:53 -0700 |
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committer | Yunhong Jiang <yunhong.jiang@intel.com> | 2015-08-04 15:44:42 -0700 |
commit | 9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch) | |
tree | 1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/arch/m68k/mm/hwtest.c | |
parent | 98260f3884f4a202f9ca5eabed40b1354c489b29 (diff) |
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base.
It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and
the base is:
commit 0917f823c59692d751951bf5ea699a2d1e2f26a2
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Sat Jul 25 12:13:34 2015 +0200
Prepare v4.1.3-rt3
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
We lose all the git history this way and it's not good. We
should apply another opnfv project repo in future.
Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423
Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/arch/m68k/mm/hwtest.c')
-rw-r--r-- | kernel/arch/m68k/mm/hwtest.c | 93 |
1 files changed, 93 insertions, 0 deletions
diff --git a/kernel/arch/m68k/mm/hwtest.c b/kernel/arch/m68k/mm/hwtest.c new file mode 100644 index 000000000..fb8be4dd3 --- /dev/null +++ b/kernel/arch/m68k/mm/hwtest.c @@ -0,0 +1,93 @@ +/* Tests for presence or absence of hardware registers. + * This code was originally in atari/config.c, but I noticed + * that it was also in drivers/nubus/nubus.c and I wanted to + * use it in hp300/config.c, so it seemed sensible to pull it + * out into its own file. + * + * The test is for use when trying to read a hardware register + * that isn't present would cause a bus error. We set up a + * temporary handler so that this doesn't kill the kernel. + * + * There is a test-by-reading and a test-by-writing; I present + * them here complete with the comments from the original atari + * config.c... + * -- PMM <pmaydell@chiark.greenend.org.uk>, 05/1998 + */ + +/* This function tests for the presence of an address, specially a + * hardware register address. It is called very early in the kernel + * initialization process, when the VBR register isn't set up yet. On + * an Atari, it still points to address 0, which is unmapped. So a bus + * error would cause another bus error while fetching the exception + * vector, and the CPU would do nothing at all. So we needed to set up + * a temporary VBR and a vector table for the duration of the test. + */ + +#include <linux/module.h> + +int hwreg_present(volatile void *regp) +{ + int ret = 0; + unsigned long flags; + long save_sp, save_vbr; + long tmp_vectors[3]; + + local_irq_save(flags); + __asm__ __volatile__ ( + "movec %/vbr,%2\n\t" + "movel #Lberr1,%4@(8)\n\t" + "movec %4,%/vbr\n\t" + "movel %/sp,%1\n\t" + "moveq #0,%0\n\t" + "tstb %3@\n\t" + "nop\n\t" + "moveq #1,%0\n" + "Lberr1:\n\t" + "movel %1,%/sp\n\t" + "movec %2,%/vbr" + : "=&d" (ret), "=&r" (save_sp), "=&r" (save_vbr) + : "a" (regp), "a" (tmp_vectors) + ); + local_irq_restore(flags); + + return ret; +} +EXPORT_SYMBOL(hwreg_present); + +/* Basically the same, but writes a value into a word register, protected + * by a bus error handler. Returns 1 if successful, 0 otherwise. + */ + +int hwreg_write(volatile void *regp, unsigned short val) +{ + int ret; + unsigned long flags; + long save_sp, save_vbr; + long tmp_vectors[3]; + + local_irq_save(flags); + __asm__ __volatile__ ( + "movec %/vbr,%2\n\t" + "movel #Lberr2,%4@(8)\n\t" + "movec %4,%/vbr\n\t" + "movel %/sp,%1\n\t" + "moveq #0,%0\n\t" + "movew %5,%3@\n\t" + "nop\n\t" + /* + * If this nop isn't present, 'ret' may already be loaded + * with 1 at the time the bus error happens! + */ + "moveq #1,%0\n" + "Lberr2:\n\t" + "movel %1,%/sp\n\t" + "movec %2,%/vbr" + : "=&d" (ret), "=&r" (save_sp), "=&r" (save_vbr) + : "a" (regp), "a" (tmp_vectors), "g" (val) + ); + local_irq_restore(flags); + + return ret; +} +EXPORT_SYMBOL(hwreg_write); + |