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-rw-r--r--arch/arm/kernel/pj4-cp0.c42
1 files changed, 39 insertions, 3 deletions
diff --git a/arch/arm/kernel/pj4-cp0.c b/arch/arm/kernel/pj4-cp0.c
index fc72086..8153e36 100644
--- a/arch/arm/kernel/pj4-cp0.c
+++ b/arch/arm/kernel/pj4-cp0.c
@@ -45,7 +45,7 @@ static int iwmmxt_do(struct notifier_block *self, unsigned long cmd, void *t)
return NOTIFY_DONE;
}
-static struct notifier_block iwmmxt_notifier_block = {
+static struct notifier_block __maybe_unused iwmmxt_notifier_block = {
.notifier_call = iwmmxt_do,
};
@@ -72,6 +72,33 @@ static void __init pj4_cp_access_write(u32 value)
: "=r" (temp) : "r" (value));
}
+static int __init pj4_get_iwmmxt_version(void)
+{
+ u32 cp_access, wcid;
+
+ cp_access = pj4_cp_access_read();
+ pj4_cp_access_write(cp_access | 0xf);
+
+ /* check if coprocessor 0 and 1 are available */
+ if ((pj4_cp_access_read() & 0xf) != 0xf) {
+ pj4_cp_access_write(cp_access);
+ return -ENODEV;
+ }
+
+ /* read iWMMXt coprocessor id register p1, c0 */
+ __asm__ __volatile__ ("mrc p1, 0, %0, c0, c0, 0\n" : "=r" (wcid));
+
+ pj4_cp_access_write(cp_access);
+
+ /* iWMMXt v1 */
+ if ((wcid & 0xffffff00) == 0x56051000)
+ return 1;
+ /* iWMMXt v2 */
+ if ((wcid & 0xffffff00) == 0x56052000)
+ return 2;
+
+ return -EINVAL;
+}
/*
* Disable CP0/CP1 on boot, and let call_fpe() and the iWMMXt lazy
@@ -79,17 +106,26 @@ static void __init pj4_cp_access_write(u32 value)
*/
static int __init pj4_cp0_init(void)
{
- u32 cp_access;
+ u32 __maybe_unused cp_access;
+ int vers;
if (!cpu_is_pj4())
return 0;
+ vers = pj4_get_iwmmxt_version();
+ if (vers < 0)
+ return 0;
+
+#ifndef CONFIG_IWMMXT
+ pr_info("PJ4 iWMMXt coprocessor detected, but kernel support is missing.\n");
+#else
cp_access = pj4_cp_access_read() & ~0xf;
pj4_cp_access_write(cp_access);
- printk(KERN_INFO "PJ4 iWMMXt coprocessor enabled.\n");
+ pr_info("PJ4 iWMMXt v%d coprocessor enabled.\n", vers);
elf_hwcap |= HWCAP_IWMMXT;
thread_register_notifier(&iwmmxt_notifier_block);
+#endif
return 0;
}
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