From 7fe6b9bf81290f708919ffb6065daa16e5dbe7e3 Mon Sep 17 00:00:00 2001 From: David Gibson Date: Mon, 12 Dec 2011 18:24:32 +0000 Subject: [PATCH 42/44] pseries: Emit device tree nodes in reg order Although in theory the device tree has no inherent ordering, in practice the order of nodes in the device tree does effect the order that devices are detected by software. Currently the ordering is determined by the order the devices appear on the QEMU command line. Although that does give the user control over the ordering, it is fragile, especially when the user does not generate the command line manually - eg. when using libvirt etc. So order the device tree based on the reg value, ie. the address of on the VIO bus of the devices. This gives us a sane and stable ordering. Signed-off-by: Michael Ellerman Signed-off-by: David Gibson Signed-off-by: Alexander Graf [agraf] add braces (cherry picked from commit 05c194384f836240ea4c2da5fa3be43a54bff021) --- hw/spapr_vio.c | 50 +++++++++++++++++++++++++++++++++++++++++++++----- 1 files changed, 45 insertions(+), 5 deletions(-) diff --git a/hw/spapr_vio.c b/hw/spapr_vio.c index 2dcc036..8bd00ca 100644 --- a/hw/spapr_vio.c +++ b/hw/spapr_vio.c @@ -749,21 +749,61 @@ static void spapr_vio_register_devices(void) device_init(spapr_vio_register_devices) #ifdef CONFIG_FDT +static int compare_reg(const void *p1, const void *p2) +{ + VIOsPAPRDevice const *dev1, *dev2; + + dev1 = (VIOsPAPRDevice *)*(DeviceState **)p1; + dev2 = (VIOsPAPRDevice *)*(DeviceState **)p2; + + if (dev1->reg < dev2->reg) { + return -1; + } + if (dev1->reg == dev2->reg) { + return 0; + } + + /* dev1->reg > dev2->reg */ + return 1; +} + int spapr_populate_vdevice(VIOsPAPRBus *bus, void *fdt) { - DeviceState *qdev; - int ret = 0; + DeviceState *qdev, **qdevs; + int i, num, ret = 0; + /* Count qdevs on the bus list */ + num = 0; QTAILQ_FOREACH(qdev, &bus->bus.children, sibling) { - VIOsPAPRDevice *dev = (VIOsPAPRDevice *)qdev; + num++; + } + + /* Copy out into an array of pointers */ + qdevs = g_malloc(sizeof(qdev) * num); + num = 0; + QTAILQ_FOREACH(qdev, &bus->bus.children, sibling) { + qdevs[num++] = qdev; + } + + /* Sort the array */ + qsort(qdevs, num, sizeof(qdev), compare_reg); + + /* Hack alert. Give the devices to libfdt in reverse order, we happen + * to know that will mean they are in forward order in the tree. */ + for (i = num - 1; i >= 0; i--) { + VIOsPAPRDevice *dev = (VIOsPAPRDevice *)(qdevs[i]); ret = vio_make_devnode(dev, fdt); if (ret < 0) { - return ret; + goto out; } } - return 0; + ret = 0; +out: + free(qdevs); + + return ret; } #endif /* CONFIG_FDT */ -- 1.6.0.2