summaryrefslogtreecommitdiffstats
path: root/arch/x86/kernel/mfgpt_32.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/x86/kernel/mfgpt_32.c')
-rw-r--r--arch/x86/kernel/mfgpt_32.c52
1 files changed, 37 insertions, 15 deletions
diff --git a/arch/x86/kernel/mfgpt_32.c b/arch/x86/kernel/mfgpt_32.c
index 07c0f82..3b59951 100644
--- a/arch/x86/kernel/mfgpt_32.c
+++ b/arch/x86/kernel/mfgpt_32.c
@@ -33,6 +33,8 @@
#include <linux/module.h>
#include <asm/geode.h>
+#define MFGPT_DEFAULT_IRQ 7
+
static struct mfgpt_timer_t {
unsigned int avail:1;
} mfgpt_timers[MFGPT_MAX_TIMERS];
@@ -157,29 +159,48 @@ int geode_mfgpt_toggle_event(int timer, int cmp, int event, int enable)
}
EXPORT_SYMBOL_GPL(geode_mfgpt_toggle_event);
-int geode_mfgpt_set_irq(int timer, int cmp, int irq, int enable)
+int geode_mfgpt_set_irq(int timer, int cmp, int *irq, int enable)
{
- u32 val, dummy;
- int offset;
+ u32 zsel, lpc, dummy;
+ int shift;
if (timer < 0 || timer >= MFGPT_MAX_TIMERS)
return -EIO;
- if (geode_mfgpt_toggle_event(timer, cmp, MFGPT_EVENT_IRQ, enable))
+ /*
+ * Unfortunately, MFGPTs come in pairs sharing their IRQ lines. If VSA
+ * is using the same CMP of the timer's Siamese twin, the IRQ is set to
+ * 2, and we mustn't use nor change it.
+ * XXX: Likewise, 2 Linux drivers might clash if the 2nd overwrites the
+ * IRQ of the 1st. This can only happen if forcing an IRQ, calling this
+ * with *irq==0 is safe. Currently there _are_ no 2 drivers.
+ */
+ rdmsr(MSR_PIC_ZSEL_LOW, zsel, dummy);
+ shift = ((cmp == MFGPT_CMP1 ? 0 : 4) + timer % 4) * 4;
+ if (((zsel >> shift) & 0xF) == 2)
return -EIO;
- rdmsr(MSR_PIC_ZSEL_LOW, val, dummy);
+ /* Choose IRQ: if none supplied, keep IRQ already set or use default */
+ if (!*irq)
+ *irq = (zsel >> shift) & 0xF;
+ if (!*irq)
+ *irq = MFGPT_DEFAULT_IRQ;
- offset = (timer % 4) * 4;
-
- val &= ~((0xF << offset) | (0xF << (offset + 16)));
+ /* Can't use IRQ if it's 0 (=disabled), 2, or routed to LPC */
+ if (*irq < 1 || *irq == 2 || *irq > 15)
+ return -EIO;
+ rdmsr(MSR_PIC_IRQM_LPC, lpc, dummy);
+ if (lpc & (1 << *irq))
+ return -EIO;
+ /* All chosen and checked - go for it */
+ if (geode_mfgpt_toggle_event(timer, cmp, MFGPT_EVENT_IRQ, enable))
+ return -EIO;
if (enable) {
- val |= (irq & 0x0F) << (offset);
- val |= (irq & 0x0F) << (offset + 16);
+ zsel = (zsel & ~(0xF << shift)) | (*irq << shift);
+ wrmsr(MSR_PIC_ZSEL_LOW, zsel, dummy);
}
- wrmsr(MSR_PIC_ZSEL_LOW, val, dummy);
return 0;
}
@@ -242,7 +263,7 @@ EXPORT_SYMBOL_GPL(geode_mfgpt_alloc_timer);
static unsigned int mfgpt_tick_mode = CLOCK_EVT_MODE_SHUTDOWN;
static u16 mfgpt_event_clock;
-static int irq = 7;
+static int irq;
static int __init mfgpt_setup(char *str)
{
get_option(&str, &irq);
@@ -346,7 +367,7 @@ int __init mfgpt_timer_setup(void)
mfgpt_event_clock = timer;
/* Set up the IRQ on the MFGPT side */
- if (geode_mfgpt_setup_irq(mfgpt_event_clock, MFGPT_CMP2, irq)) {
+ if (geode_mfgpt_setup_irq(mfgpt_event_clock, MFGPT_CMP2, &irq)) {
printk(KERN_ERR "mfgpt-timer: Could not set up IRQ %d\n", irq);
return -EIO;
}
@@ -374,13 +395,14 @@ int __init mfgpt_timer_setup(void)
&mfgpt_clockevent);
printk(KERN_INFO
- "mfgpt-timer: registering the MFGPT timer as a clock event.\n");
+ "mfgpt-timer: Registering MFGPT timer %d as a clock event, using IRQ %d\n",
+ timer, irq);
clockevents_register_device(&mfgpt_clockevent);
return 0;
err:
- geode_mfgpt_release_irq(mfgpt_event_clock, MFGPT_CMP2, irq);
+ geode_mfgpt_release_irq(mfgpt_event_clock, MFGPT_CMP2, &irq);
printk(KERN_ERR
"mfgpt-timer: Unable to set up the MFGPT clock source\n");
return -EIO;
OpenPOWER on IntegriCloud