[PATCH for-7.1 16/18] hw/arm/exynos4210: Fold combiner splits into exynos4210_init_board_irqs()

[Peter Maydell]

At this point, the function exynos4210_init_board_irqs() splits input
IRQ lines to connect them to the input combiner, output combiner and
external GIC.  The function exynos4210_combiner_get_gpioin() splits
some of the combiner input lines further to connect them to multiple
different inputs on the combiner.

Because (unlike qemu_irq_split()) the TYPE_SPLIT_IRQ device has a
configurable number of outputs, we can do all this in one place, by
making exynos4210_init_board_irqs() add extra outputs to the splitter
device when it must be connected to more than one input on each
combiner.

We do this with a new data structure, the combinermap, which is an
array each of whose elements is a list of the interrupt IDs on the
combiner which must be tied together.  As we loop through each
interrupt ID, if we find that it is the first one in one of these
lists, we configure the splitter device with eonugh extra outputs and
wire them up to the other interrupt IDs in the list.

Conveniently, for all the cases where this is necessary, the
lowest-numbered interrupt ID in each group is in the range of the
external combiner, so we only need to code for this in the first of
the two loops in exynos4210_init_board_irqs().

The old code in exynos4210_combiner_get_gpioin() which is being
deleted here had several problems which don't exist in the new code
in its handling of the multi-core timer interrupts:
 (1) the case labels specified bits 4 ... 8, but bit '8' doesn't
     exist; these should have been 4 ... 7
 (2) it used the input irq[EXYNOS4210_COMBINER_GET_IRQ_NUM(1, bit + 4)]
     multiple times as the input of several different splitters,
     which isn't allowed
 (3) in an apparent cut-and-paste error, the cases for all the
     multi-core timer inputs used "bit + 4" even though the
     bit range for the case was (intended to be) 4 ... 7, which
     meant it was looking at non-existent bits 8 ... 11.
None of these exist in the new code.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 include/hw/arm/exynos4210.h |   6 +-
 hw/arm/exynos4210.c         | 178 +++++++++++++++++++++++-------------
 2 files changed, 119 insertions(+), 65 deletions(-)

diff --git a/include/hw/arm/exynos4210.h b/include/hw/arm/exynos4210.h
index 7da3eddea5f..f24617f681d 100644
--- a/include/hw/arm/exynos4210.h
+++ b/include/hw/arm/exynos4210.h
@@ -74,10 +74,12 @@
 
 /*
  * We need one splitter for every external combiner input, plus
- * one for every non-zero entry in combiner_grp_to_gic_id[].
+ * one for every non-zero entry in combiner_grp_to_gic_id[],
+ * minus one for every external combiner ID in second or later
+ * places in a combinermap[] line.
  * We'll assert in exynos4210_init_board_irqs() if this is wrong.
  */
-#define EXYNOS4210_NUM_SPLITTERS (EXYNOS4210_MAX_EXT_COMBINER_IN_IRQ + 54)
+#define EXYNOS4210_NUM_SPLITTERS (EXYNOS4210_MAX_EXT_COMBINER_IN_IRQ + 38)
 
 typedef struct Exynos4210Irq {
     qemu_irq int_combiner_irq[EXYNOS4210_MAX_INT_COMBINER_IN_IRQ];
diff --git a/hw/arm/exynos4210.c b/hw/arm/exynos4210.c
index 39e334e0773..05b28cf5905 100644
--- a/hw/arm/exynos4210.c
+++ b/hw/arm/exynos4210.c
@@ -254,6 +254,76 @@ combiner_grp_to_gic_id[64 - 
EXYNOS4210_MAX_EXT_COMBINER_OUT_IRQ][8] = {
 #define EXYNOS4210_COMBINER_GET_BIT_NUM(irq) \
     ((irq) - 8 * EXYNOS4210_COMBINER_GET_GRP_NUM(irq))
 
+/*
+ * Some interrupt lines go to multiple combiner inputs.
+ * This data structure defines those: each array element is
+ * a list of combiner inputs which are connected together;
+ * the one with the smallest interrupt ID value must be first.
+ * As with combiner_grp_to_gic_id[], we rely on (0, 0) not being
+ * wired to anything so we can use 0 as a terminator.
+ */
+#define IRQNO(G, B) EXYNOS4210_COMBINER_GET_IRQ_NUM(G, B)
+#define IRQNONE 0
+
+#define COMBINERMAP_SIZE 16
+
+static const int combinermap[COMBINERMAP_SIZE][6] = {
+    /* MDNIE_LCD1 */
+    { IRQNO(0, 4), IRQNO(1, 0), IRQNONE },
+    { IRQNO(0, 5), IRQNO(1, 1), IRQNONE },
+    { IRQNO(0, 6), IRQNO(1, 2), IRQNONE },
+    { IRQNO(0, 7), IRQNO(1, 3), IRQNONE },
+    /* TMU */
+    { IRQNO(2, 4), IRQNO(3, 4), IRQNONE },
+    { IRQNO(2, 5), IRQNO(3, 5), IRQNONE },
+    { IRQNO(2, 6), IRQNO(3, 6), IRQNONE },
+    { IRQNO(2, 7), IRQNO(3, 7), IRQNONE },
+    /* LCD1 */
+    { IRQNO(11, 4), IRQNO(12, 0), IRQNONE },
+    { IRQNO(11, 5), IRQNO(12, 1), IRQNONE },
+    { IRQNO(11, 6), IRQNO(12, 2), IRQNONE },
+    { IRQNO(11, 7), IRQNO(12, 3), IRQNONE },
+    /* Multi-core timer */
+    { IRQNO(1, 4), IRQNO(12, 4), IRQNO(35, 4), IRQNO(51, 4), IRQNO(53, 4), 
IRQNONE },
+    { IRQNO(1, 5), IRQNO(12, 5), IRQNO(35, 5), IRQNO(51, 5), IRQNO(53, 5), 
IRQNONE },
+    { IRQNO(1, 6), IRQNO(12, 6), IRQNO(35, 6), IRQNO(51, 6), IRQNO(53, 6), 
IRQNONE },
+    { IRQNO(1, 7), IRQNO(12, 7), IRQNO(35, 7), IRQNO(51, 7), IRQNO(53, 7), 
IRQNONE },
+};
+
+#undef IRQNO
+
+static const int *combinermap_entry(int irq)
+{
+    /*
+     * If the interrupt number passed in is the first entry in some
+     * line of the combinermap, return a pointer to that line;
+     * otherwise return NULL.
+     */
+    int i;
+    for (i = 0; i < COMBINERMAP_SIZE; i++) {
+        if (combinermap[i][0] == irq) {
+            return combinermap[i];
+        }
+    }
+    return NULL;
+}
+
+static int mapline_size(const int *mapline)
+{
+    /* Return number of entries in this mapline in total */
+    int i = 0;
+
+    if (!mapline) {
+        /* Not in the map? IRQ goes to exactly one combiner input */
+        return 1;
+    }
+    while (*mapline != IRQNONE) {
+        mapline++;
+        i++;
+    }
+    return i;
+}
+
 /*
  * Initialize board IRQs.
  * These IRQs contain splitted Int/External Combiner and External Gic IRQs.
@@ -265,6 +335,8 @@ static void exynos4210_init_board_irqs(Exynos4210State *s)
     DeviceState *extgicdev = DEVICE(&s->ext_gic);
     int splitcount = 0;
     DeviceState *splitter;
+    const int *mapline;
+    int numlines, splitin, in;
 
     for (n = 0; n < EXYNOS4210_MAX_EXT_COMBINER_IN_IRQ; n++) {
         irq_id = 0;
@@ -277,16 +349,46 @@ static void exynos4210_init_board_irqs(Exynos4210State *s)
             irq_id = EXT_GIC_ID_MCT_G1;
         }
 
+        if (s->irq_table[n]) {
+            /*
+             * This must be some non-first entry in a combinermap line,
+             * and we've already filled it in.
+             */
+            continue;
+        }
+        mapline = combinermap_entry(n);
+        /*
+         * We need to connect the IRQ to multiple inputs on both combiners
+         * and possibly also to the external GIC.
+         */
+        numlines = 2 * mapline_size(mapline);
+        if (irq_id) {
+            numlines++;
+        }
         assert(splitcount < EXYNOS4210_NUM_SPLITTERS);
         splitter = DEVICE(&s->splitter[splitcount]);
-        qdev_prop_set_uint16(splitter, "num-lines", irq_id ? 3 : 2);
+        qdev_prop_set_uint16(splitter, "num-lines", numlines);
         qdev_realize(splitter, NULL, &error_abort);
         splitcount++;
-        s->irq_table[n] = qdev_get_gpio_in(splitter, 0);
-        qdev_connect_gpio_out(splitter, 0, is->int_combiner_irq[n]);
-        qdev_connect_gpio_out(splitter, 1, is->ext_combiner_irq[n]);
+
+        in = n;
+        splitin = 0;
+        for (;;) {
+            s->irq_table[in] = qdev_get_gpio_in(splitter, 0);
+            qdev_connect_gpio_out(splitter, splitin, is->int_combiner_irq[in]);
+            qdev_connect_gpio_out(splitter, splitin + 1, 
is->ext_combiner_irq[in]);
+            splitin += 2;
+            if (!mapline) {
+                break;
+            }
+            mapline++;
+            in = *mapline;
+            if (in == IRQNONE) {
+                break;
+            }
+        }
         if (irq_id) {
-            qdev_connect_gpio_out(splitter, 2,
+            qdev_connect_gpio_out(splitter, splitin,
                                   qdev_get_gpio_in(extgicdev, irq_id - 32));
         }
     }
@@ -297,6 +399,14 @@ static void exynos4210_init_board_irqs(Exynos4210State *s)
         irq_id = combiner_grp_to_gic_id[grp -
                      EXYNOS4210_MAX_EXT_COMBINER_OUT_IRQ][bit];
 
+        if (s->irq_table[n]) {
+            /*
+             * This must be some non-first entry in a combinermap line,
+             * and we've already filled it in.
+             */
+            continue;
+        }
+
         if (irq_id) {
             assert(splitcount < EXYNOS4210_NUM_SPLITTERS);
             splitter = DEVICE(&s->splitter[splitcount]);
@@ -337,7 +447,6 @@ static void exynos4210_combiner_get_gpioin(Exynos4210Irq 
*irqs,
                                            DeviceState *dev, int ext)
 {
     int n;
-    int bit;
     int max;
     qemu_irq *irq;
 
@@ -345,64 +454,7 @@ static void exynos4210_combiner_get_gpioin(Exynos4210Irq 
*irqs,
         EXYNOS4210_MAX_INT_COMBINER_IN_IRQ;
     irq = ext ? irqs->ext_combiner_irq : irqs->int_combiner_irq;
 
-    /*
-     * Some IRQs of Int/External Combiner are going to two Combiners groups,
-     * so let split them.
-     */
     for (n = 0; n < max; n++) {
-
-        bit = EXYNOS4210_COMBINER_GET_BIT_NUM(n);
-
-        switch (n) {
-        /* MDNIE_LCD1 INTG1 */
-        case EXYNOS4210_COMBINER_GET_IRQ_NUM(1, 0) ...
-             EXYNOS4210_COMBINER_GET_IRQ_NUM(1, 3):
-            irq[n] = qemu_irq_split(qdev_get_gpio_in(dev, n),
-                    irq[EXYNOS4210_COMBINER_GET_IRQ_NUM(0, bit + 4)]);
-            continue;
-
-        /* TMU INTG3 */
-        case EXYNOS4210_COMBINER_GET_IRQ_NUM(3, 4):
-            irq[n] = qemu_irq_split(qdev_get_gpio_in(dev, n),
-                    irq[EXYNOS4210_COMBINER_GET_IRQ_NUM(2, bit)]);
-            continue;
-
-        /* LCD1 INTG12 */
-        case EXYNOS4210_COMBINER_GET_IRQ_NUM(12, 0) ...
-             EXYNOS4210_COMBINER_GET_IRQ_NUM(12, 3):
-            irq[n] = qemu_irq_split(qdev_get_gpio_in(dev, n),
-                    irq[EXYNOS4210_COMBINER_GET_IRQ_NUM(11, bit + 4)]);
-            continue;
-
-        /* Multi-Core Timer INTG12 */
-        case EXYNOS4210_COMBINER_GET_IRQ_NUM(12, 4) ...
-             EXYNOS4210_COMBINER_GET_IRQ_NUM(12, 8):
-               irq[n] = qemu_irq_split(qdev_get_gpio_in(dev, n),
-                       irq[EXYNOS4210_COMBINER_GET_IRQ_NUM(1, bit + 4)]);
-            continue;
-
-        /* Multi-Core Timer INTG35 */
-        case EXYNOS4210_COMBINER_GET_IRQ_NUM(35, 4) ...
-             EXYNOS4210_COMBINER_GET_IRQ_NUM(35, 8):
-            irq[n] = qemu_irq_split(qdev_get_gpio_in(dev, n),
-                    irq[EXYNOS4210_COMBINER_GET_IRQ_NUM(1, bit + 4)]);
-            continue;
-
-        /* Multi-Core Timer INTG51 */
-        case EXYNOS4210_COMBINER_GET_IRQ_NUM(51, 4) ...
-             EXYNOS4210_COMBINER_GET_IRQ_NUM(51, 8):
-            irq[n] = qemu_irq_split(qdev_get_gpio_in(dev, n),
-                    irq[EXYNOS4210_COMBINER_GET_IRQ_NUM(1, bit + 4)]);
-            continue;
-
-        /* Multi-Core Timer INTG53 */
-        case EXYNOS4210_COMBINER_GET_IRQ_NUM(53, 4) ...
-             EXYNOS4210_COMBINER_GET_IRQ_NUM(53, 8):
-            irq[n] = qemu_irq_split(qdev_get_gpio_in(dev, n),
-                    irq[EXYNOS4210_COMBINER_GET_IRQ_NUM(1, bit + 4)]);
-            continue;
-        }
-
         irq[n] = qdev_get_gpio_in(dev, n);
     }
 }
-- 
2.25.1