Changeset fd67c9f in mainline for kernel/genarch

Timestamp:

2019-04-06T08:10:27Z (7 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

534bcdf

Parents:

ef56a43

Message:

Handle PIC spurious IRQs with care

Location:

kernel/genarch

Files:

• include/genarch/drivers/i8259/i8259.h (modified) (3 diffs)
• src/drivers/i8259/i8259.c (modified) (3 diffs)

kernel/genarch/include/genarch/drivers/i8259/i8259.h

@@ -38 +38 @@
 #include <typedefs.h>
 #include <arch/interrupt.h>
+#include <stdbool.h>
 
 /* ICW1 bits */
@@ -43 +44 @@
 #define PIC_ICW1_NEEDICW4  (1 << 0)
 
+/* OCW3 bits */
+#define PIC_OCW3           (1 << 3)
+#define PIC_OCW3_READ_ISR  (3 << 0)
+
 /* OCW4 bits */
 #define PIC_OCW4           (0 << 3)
 #define PIC_OCW4_NSEOI     (1 << 5)
+
+#define PIC_IRQ_COUNT      8
+#define PIC_SPURIOUS_IRQ   7
 
 typedef struct {
@@ -56 +64 @@
 extern void pic_disable_irqs(uint16_t);
 extern void pic_eoi(unsigned int);
+extern bool pic_is_spurious(unsigned int);
+extern void pic_handle_spurious(unsigned int);
 
 #endif

kernel/genarch/src/drivers/i8259/i8259.c

@@ -90 +90 @@
                     (uint8_t) (x & (~(irqmask & 0xff))));
         }
-        if (irqmask >> 8) {
+        if (irqmask >> PIC_IRQ_COUNT) {
                 x = pio_read_8(&saved_pic1->port2);
                 pio_write_8(&saved_pic1->port2,
-                    (uint8_t) (x & (~(irqmask >> 8))));
+                    (uint8_t) (x & (~(irqmask >> PIC_IRQ_COUNT))));
         }
 }
@@ -106 +106 @@
                     (uint8_t) (x | (irqmask & 0xff)));
         }
-        if (irqmask >> 8) {
+        if (irqmask >> PIC_IRQ_COUNT) {
                 x = pio_read_8(&saved_pic1->port2);
-                pio_write_8(&saved_pic1->port2, (uint8_t) (x | (irqmask >> 8)));
+                pio_write_8(&saved_pic1->port2,
+                    (uint8_t) (x | (irqmask >> PIC_IRQ_COUNT)));
         }
 }
@@ -114 +115 @@
 void pic_eoi(unsigned int irq)
 {
-        if (irq >= 8)
+        if (irq >= PIC_IRQ_COUNT)
                 pio_write_8(&saved_pic1->port1, PIC_OCW4 | PIC_OCW4_NSEOI);
         pio_write_8(&saved_pic0->port1, PIC_OCW4 | PIC_OCW4_NSEOI);
 }
 
+bool pic_is_spurious(unsigned int irq)
+{
+        pio_write_8(&saved_pic0->port1, PIC_OCW3 | PIC_OCW3_READ_ISR);
+        pio_write_8(&saved_pic1->port1, PIC_OCW3 | PIC_OCW3_READ_ISR);
+        uint8_t isr_lo = pio_read_8(&saved_pic0->port1);
+        uint8_t isr_hi = pio_read_8(&saved_pic1->port1);
+        return !(((isr_hi << PIC_IRQ_COUNT) | isr_lo) & (1 << irq));
+}
+
+void pic_handle_spurious(unsigned int irq)
+{
+        /* For spurious IRQs from pic1, we need to isssue an EOI to pic0 */
+        if (irq >= PIC_IRQ_COUNT)
+                pio_write_8(&saved_pic0->port1, PIC_OCW4 | PIC_OCW4_NSEOI);
+}
+
 /** @}
  */