intelfb: add vsync interrupt support
[03/05] intelfb: Implement basic interrupt handling
Functions have been added to enable and disable interrupts using the MMIO registers. Currently only pipe A vsync interrupts are enabled.
A generalized vsync accounting struct is defined, with the intent that it can encapsulate per-pipe vsync related info in the future. Currently a single instance is hard-coded.
The interrupt service routine currently only looks for vsync interrupts on pipe A, and increments a counter and wakes up anyone waiting on it.
This implementation is heavily influenced by similar implementations in the atyfb and matroxfb drivers.
Signed-off-by: Eric Hustvedt <ehustvedt@cecropia.com>
diff --git a/drivers/video/intelfb/intelfbhw.c b/drivers/video/intelfb/intelfbhw.c
index 05aded6..1a698a7 100644
--- a/drivers/video/intelfb/intelfbhw.c
+++ b/drivers/video/intelfb/intelfbhw.c
@@ -34,6 +34,7 @@
#include <linux/pci.h>
#include <linux/vmalloc.h>
#include <linux/pagemap.h>
+#include <linux/interrupt.h>
#include <asm/io.h>
@@ -1943,3 +1944,78 @@
addr += 16;
}
}
+
+static irqreturn_t
+intelfbhw_irq(int irq, void *dev_id, struct pt_regs *fp) {
+ int handled = 0;
+ u16 tmp;
+ struct intelfb_info *dinfo = (struct intelfb_info *)dev_id;
+
+ spin_lock(&dinfo->int_lock);
+
+ tmp = INREG16(IIR);
+ tmp &= VSYNC_PIPE_A_INTERRUPT;
+
+ if (tmp == 0) {
+ spin_unlock(&dinfo->int_lock);
+ return IRQ_RETVAL(handled);
+ }
+
+ OUTREG16(IIR, tmp);
+
+ if (tmp & VSYNC_PIPE_A_INTERRUPT) {
+ dinfo->vsync.count++;
+ wake_up_interruptible(&dinfo->vsync.wait);
+ handled = 1;
+ }
+
+ spin_unlock(&dinfo->int_lock);
+
+ return IRQ_RETVAL(handled);
+}
+
+int
+intelfbhw_enable_irq(struct intelfb_info *dinfo, int reenable) {
+
+ if (!test_and_set_bit(0, &dinfo->irq_flags)) {
+ if (request_irq(dinfo->pdev->irq, intelfbhw_irq, SA_SHIRQ, "intelfb", dinfo)) {
+ clear_bit(0, &dinfo->irq_flags);
+ return -EINVAL;
+ }
+
+ spin_lock_irq(&dinfo->int_lock);
+ OUTREG16(HWSTAM, 0xfffe);
+ OUTREG16(IMR, 0x0);
+ OUTREG16(IER, VSYNC_PIPE_A_INTERRUPT);
+ spin_unlock_irq(&dinfo->int_lock);
+ } else if (reenable) {
+ u16 ier;
+
+ spin_lock_irq(&dinfo->int_lock);
+ ier = INREG16(IER);
+ if ((ier & VSYNC_PIPE_A_INTERRUPT)) {
+ DBG_MSG("someone disabled the IRQ [%08X]\n", ier);
+ OUTREG(IER, VSYNC_PIPE_A_INTERRUPT);
+ }
+ spin_unlock_irq(&dinfo->int_lock);
+ }
+ return 0;
+}
+
+void
+intelfbhw_disable_irq(struct intelfb_info *dinfo) {
+ u16 tmp;
+
+ if (test_and_clear_bit(0, &dinfo->irq_flags)) {
+ spin_lock_irq(&dinfo->int_lock);
+ OUTREG16(HWSTAM, 0xffff);
+ OUTREG16(IMR, 0xffff);
+ OUTREG16(IER, 0x0);
+
+ tmp = INREG16(IIR);
+ OUTREG16(IIR, tmp);
+ spin_unlock_irq(&dinfo->int_lock);
+
+ free_irq(dinfo->pdev->irq, dinfo);
+ }
+}