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authorPeter Maydell <peter.maydell@linaro.org>2018-06-15 14:57:14 +0100
committerPeter Maydell <peter.maydell@linaro.org>2018-06-15 15:23:34 +0100
commitf81804a52b5d4609f68ea367a55a2ccb4cc99f77 (patch)
tree7fd073b56b67ac6edf5e330ace0c05858884553c /hw/core/or-irq.c
parent95f875654ae8b433b50a2bc7858e34af957cbaa4 (diff)
hw/core/or-irq: Support more than 16 inputs to an OR gate
For the IoTKit MPC support, we need to wire together the interrupt outputs of 17 MPCs; this exceeds the current value of MAX_OR_LINES. Increase MAX_OR_LINES to 32 (which should be enough for anyone). The tricky part is retaining the migration compatibility for existing OR gates; we add a subsection which is only used for larger OR gates, and define it such that we can freely increase MAX_OR_LINES in future (or even move to a dynamically allocated levels[] array without an upper size limit) without breaking compatibility. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Message-id: 20180604152941.20374-10-peter.maydell@linaro.org
Diffstat (limited to 'hw/core/or-irq.c')
-rw-r--r--hw/core/or-irq.c39
1 files changed, 37 insertions, 2 deletions
diff --git a/hw/core/or-irq.c b/hw/core/or-irq.c
index f9d76c4641..a86901b673 100644
--- a/hw/core/or-irq.c
+++ b/hw/core/or-irq.c
@@ -66,14 +66,49 @@ static void or_irq_init(Object *obj)
qdev_init_gpio_out(DEVICE(obj), &s->out_irq, 1);
}
+/* The original version of this device had a fixed 16 entries in its
+ * VMState array; devices with more inputs than this need to
+ * migrate the extra lines via a subsection.
+ * The subsection migrates as much of the levels[] array as is needed
+ * (including repeating the first 16 elements), to avoid the awkwardness
+ * of splitting it in two to meet the requirements of VMSTATE_VARRAY_UINT16.
+ */
+#define OLD_MAX_OR_LINES 16
+#if MAX_OR_LINES < OLD_MAX_OR_LINES
+#error MAX_OR_LINES must be at least 16 for migration compatibility
+#endif
+
+static bool vmstate_extras_needed(void *opaque)
+{
+ qemu_or_irq *s = OR_IRQ(opaque);
+
+ return s->num_lines >= OLD_MAX_OR_LINES;
+}
+
+static const VMStateDescription vmstate_or_irq_extras = {
+ .name = "or-irq-extras",
+ .version_id = 1,
+ .minimum_version_id = 1,
+ .needed = vmstate_extras_needed,
+ .fields = (VMStateField[]) {
+ VMSTATE_VARRAY_UINT16_UNSAFE(levels, qemu_or_irq, num_lines, 0,
+ vmstate_info_bool, bool),
+ VMSTATE_END_OF_LIST(),
+ },
+};
+
static const VMStateDescription vmstate_or_irq = {
.name = TYPE_OR_IRQ,
.version_id = 1,
.minimum_version_id = 1,
.fields = (VMStateField[]) {
- VMSTATE_BOOL_ARRAY(levels, qemu_or_irq, MAX_OR_LINES),
+ VMSTATE_BOOL_SUB_ARRAY(levels, qemu_or_irq, 0, OLD_MAX_OR_LINES),
VMSTATE_END_OF_LIST(),
- }
+ },
+ .subsections = (const VMStateDescription*[]) {
+ &vmstate_or_irq_extras,
+ NULL
+ },
};
static Property or_irq_properties[] = {