On 07/08/2014 03:43 PM, Alexander Graf wrote:
>
> On 07.07.14 09:08, Eric Auger wrote:
>> This new module implements routines which help in dynamic instantiation
>> of sysbus devices. Machine files can use those generic routines.
>>
>> ---
>>
>> Dynamic sysbus device allocation fully written by Alex Graf.
>>
>> [Eric Auger]
>> Those functions were initially in ppc e500 machine file. Now moved to a
>> separate module.
>>
>> PPCE500Params is replaced by a generic struct named PlatformParams
>>
>> Signed-off-by: Alexander Graf <agraf@xxxxxxx>
>> Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx>
>> ---
>> hw/misc/Makefile.objs | 1 +
>> hw/misc/platform_devices.c | 217
>> +++++++++++++++++++++++++++++++++++++
>> include/hw/misc/platform_devices.h | 61 +++++++++++
>> 3 files changed, 279 insertions(+)
>> create mode 100644 hw/misc/platform_devices.c
>> create mode 100644 include/hw/misc/platform_devices.h
>>
>> diff --git a/hw/misc/Makefile.objs b/hw/misc/Makefile.objs
>> index e47fea8..d081606 100644
>> --- a/hw/misc/Makefile.objs
>> +++ b/hw/misc/Makefile.objs
>> @@ -40,3 +40,4 @@ obj-$(CONFIG_SLAVIO) += slavio_misc.o
>> obj-$(CONFIG_ZYNQ) += zynq_slcr.o
>> obj-$(CONFIG_PVPANIC) += pvpanic.o
>> +obj-y += platform_devices.o
>> diff --git a/hw/misc/platform_devices.c b/hw/misc/platform_devices.c
>> new file mode 100644
>> index 0000000..96ab272
>> --- /dev/null
>> +++ b/hw/misc/platform_devices.c
>> @@ -0,0 +1,217 @@
>> +#include "hw/misc/platform_devices.h"
>> +#include "hw/sysbus.h"
>> +#include "qemu/error-report.h"
>> +
>> +#define PAGE_SHIFT 12
>> +
>> +int sysbus_device_create_devtree(Object *obj, void *opaque)
>> +{
>> + PlatformDevtreeData *data = opaque;
>> + Object *dev;
>> + SysBusDevice *sbdev;
>> + bool matched = false;
>> +
>> + dev = object_dynamic_cast(obj, TYPE_SYS_BUS_DEVICE);
>> + sbdev = (SysBusDevice *)dev;
>> +
>> + if (!sbdev) {
>> + /* Container, traverse it for children */
>> + return object_child_foreach(obj,
>> sysbus_device_create_devtree, data);
>> + }
>> +
>> + if (!matched) {
>> + error_report("Device %s is not supported by this machine yet.",
>> + qdev_fw_name(DEVICE(dev)));
>> + exit(1);
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +void platform_bus_create_devtree(PlatformParams *params, void *fdt,
>> + const char *mpic)
>> +{
>> + gchar *node = g_strdup_printf("/platform@%"PRIx64,
>> + params->platform_bus_base);
>> + const char platcomp[] = "qemu,platform\0simple-bus";
>> + PlatformDevtreeData data;
>> + Object *container;
>> + uint64_t addr = params->platform_bus_base;
>> + uint64_t size = params->platform_bus_size;
>> + int irq_start = params->platform_bus_first_irq;
>> +
>> + /* Create a /platform node that we can put all devices into */
>> +
>> + qemu_fdt_add_subnode(fdt, node);
>> + qemu_fdt_setprop(fdt, node, "compatible", platcomp,
>> sizeof(platcomp));
>> +
>> + /* Our platform bus region is less than 32bit big, so 1 cell is
>> enough for
>> + address and size */
>> + qemu_fdt_setprop_cells(fdt, node, "#size-cells", 1);
>> + qemu_fdt_setprop_cells(fdt, node, "#address-cells", 1);
>> + qemu_fdt_setprop_cells(fdt, node, "ranges", 0, addr >> 32, addr,
>> size);
>> +
>> + qemu_fdt_setprop_phandle(fdt, node, "interrupt-parent", mpic);
>> +
>> + /* Loop through all devices and create nodes for known ones */
>> + data.fdt = fdt;
>> + data.mpic = mpic;
>> + data.irq_start = irq_start;
>> + data.node = node;
>> +
>> + container = container_get(qdev_get_machine(), "/peripheral");
>> + sysbus_device_create_devtree(container, &data);
>> + container = container_get(qdev_get_machine(), "/peripheral-anon");
>> + sysbus_device_create_devtree(container, &data);
>> +
>> + g_free(node);
>> +}
>
> Device trees are pretty platform (and even machine) specific. Just to
> give you an example - the interrupt specifier on most e500 systems
> really is 4 cells big:
>
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/powerpc/fsl/mpic.txt#n80
>
>
> | Interrupt specifiers consists of 4 cells encoded as
> follows:
>
> <1st-cell> interrupt-number
>
> Identifies the interrupt source. The meaning
> depends on the type of interrupt.
>
> Note: If the interrupt-type cell is undefined
> (i.e. #interrupt-cells = 2), this cell
> should be interpreted the same as for
> interrupt-type 0-- i.e. an external or
> normal SoC device interrupt.
>
> <2nd-cell> level-sense information, encoded as follows:
> 0 = low-to-high edge triggered
> 1 = active low level-sensitive
> 2 = active high level-sensitive
> 3 = high-to-low edge triggered
>
> <3rd-cell> interrupt-type
>
> The following types are supported:
>
> 0 = external or normal SoC device interrupt
>
> The interrupt-number cell contains
> the SoC device interrupt number. The
> type-specific cell is undefined. The
> interrupt-number is derived from the
> MPIC a block of registers referred to as
> the "Interrupt Source Configuration Registers".
> Each source has 32-bytes of registers
> (vector/priority and destination) in this
> region. So interrupt 0 is at offset 0x0,
> interrupt 1 is at offset 0x20, and so on.
>
> 1 = error interrupt
>
> The interrupt-number cell contains
> the SoC device interrupt number for
> the error interrupt. The type-specific
> cell identifies the specific error
> interrupt number.
>
> 2 = MPIC inter-processor interrupt (IPI)
>
> The interrupt-number cell identifies
> the MPIC IPI number. The type-specific
> cell is undefined.
>
> 3 = MPIC timer interrupt
>
> The interrupt-number cell identifies
> the MPIC timer number. The type-specific
> cell is undefined.
>
> <4th-cell> type-specific information
>
> The type-specific cell is encoded as follows:
>
> - For interrupt-type 1 (error interrupt),
> the type-specific cell contains the
> bit number of the error interrupt in the
> Error Interrupt Summary Register.
> |
>
>
>
>
> while on ARM you have a GIC which works like this:
>
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/arm/gic.txt#n20
>
>
> |- #interrupt-cells : Specifies the number of cells needed to encode an
> interrupt source. The type shall be a <u32> and the value shall be 3.
>
> The 1st cell is the interrupt type; 0 for SPI interrupts, 1 for PPI
> interrupts.
>
> The 2nd cell contains the interrupt number for the interrupt type.
> SPI interrupts are in the range [0-987]. PPI interrupts are in the
> range [0-15].
>
> The 3rd cell is the flags, encoded as follows:
> bits[3:0] trigger type and level flags.
> 1 = low-to-high edge triggered
> 2 = high-to-low edge triggered
> 4 = active high level-sensitive
> 8 = active low level-sensitive
> bits[15:8] PPI interrupt cpu mask. Each bit corresponds to each of
> the 8 possible cpus attached to the GIC. A bit set to '1' indicated
> the interrupt is wired to that CPU. Only valid for PPI interrupts.
> |
>
>
>
> Both have vastly different semantics. The number of cells is different,
> the value of the cells is different. Even the definition how to
> represent edge vs level triggered interrupts differs.
>
> I don't think this will stop with interrupts. Maybe someone wants to add
> a special machine check flag to addresses on a platform and then
> "ranges" and "regs" will have different semantics on different
> platforms. There is a lot that can go wrong when you try to unify this
> code.
Hi Alex,
thank you for giving such an example. Indeed I was not aware there were
such huge discrepancies. I guess this comment mostly holds for the
actual device node generation (what I specialized in the parent QEMU
device) and not for the "qemu, platform simple-bus" node generation?
>
>> +
>> +int platform_bus_map_irq(PlatformParams *params, SysBusDevice *sbdev,
>> + int n, unsigned long *used_irqs,
>> + qemu_irq *platform_irqs)
>> +{
>> + int max_irqs = params->platform_bus_num_irqs;
>> + char *prop = g_strdup_printf("irq[%d]", n);
>> + int irqn = object_property_get_int(OBJECT(sbdev), prop, NULL);
>> +
>> + if (irqn == SYSBUS_DYNAMIC) {
>> + /* Find the first available IRQ */
>> + irqn = find_first_zero_bit(used_irqs, max_irqs);
>> + }
>> +
>> + if ((irqn >= max_irqs) || test_and_set_bit(irqn, used_irqs)) {
>> + hw_error("IRQ %d is already allocated or no free IRQ left",
>> irqn);
>> + }
>> +
>> + sysbus_connect_irq(sbdev, n, platform_irqs[irqn]);
>> + object_property_set_int(OBJECT(sbdev), irqn, prop, NULL);
>> +
>> + g_free(prop);
>> + return 0;
>> +}
>> +
>> +int platform_bus_map_mmio(PlatformParams *params, SysBusDevice *sbdev,
>> + int n, unsigned long *used_mem,
>> + MemoryRegion *pmem)
>> +{
>> + MemoryRegion *device_mem = sbdev->mmio[n].memory;
>> + uint64_t size = memory_region_size(device_mem);
>> + uint64_t page_size = (1 << PAGE_SHIFT);
>> + uint64_t page_mask = page_size - 1;
>> + uint64_t size_pages = (size + page_mask) >> PAGE_SHIFT;
>> + uint64_t max_size = params->platform_bus_size;
>> + uint64_t max_pages = max_size >> PAGE_SHIFT;
>> + char *prop = g_strdup_printf("mmio[%d]", n);
>> + hwaddr addr = object_property_get_int(OBJECT(sbdev), prop, NULL);
>> + int page;
>> + int i;
>> +
>> + page = addr >> PAGE_SHIFT;
>> + if (addr == SYSBUS_DYNAMIC) {
>> + uint64_t size_pages_align;
>> +
>> + /* Align the region to at least its own size granularity */
>> + if (is_power_of_2(size_pages)) {
>> + size_pages_align = size_pages;
>> + } else {
>> + size_pages_align = pow2floor(size_pages) << 1;
>> + }
>> +
>> + /* Find the first available region that fits */
>> + page = bitmap_find_next_zero_area(used_mem, max_pages, 0,
>> size_pages,
>> + size_pages_align);
>> +
>> + addr = (uint64_t)page << PAGE_SHIFT;
>> + }
>> +
>> + if (page >= max_pages || test_bit(page, used_mem) ||
>> + (find_next_bit(used_mem, max_pages, page) < size_pages)) {
>> + hw_error("Memory [%"PRIx64":%"PRIx64" is already allocated or "
>> + "no slot left", addr, size);
>> + }
>> +
>> + for (i = page; i < (page + size_pages); i++) {
>> + set_bit(i, used_mem);
>> + }
>> +
>> + memory_region_add_subregion(pmem, addr, device_mem);
>> + sbdev->mmio[n].addr = addr;
>> + object_property_set_int(OBJECT(sbdev), addr, prop, NULL);
>> +
>> + g_free(prop);
>> + return 0;
>> +}
>> +
>> +int sysbus_device_check(Object *obj, void *opaque)
>> +{
>> + PlatformBusInitData *init = opaque;
>> + Object *dev;
>> + SysBusDevice *sbdev;
>> + int i;
>> +
>> + dev = object_dynamic_cast(obj, TYPE_SYS_BUS_DEVICE);
>> + sbdev = (SysBusDevice *)dev;
>> +
>> + if (!sbdev) {
>> + /* Container, traverse it for children */
>> + return object_child_foreach(obj, sysbus_device_check, opaque);
>> + }
>> +
>> + /* Connect sysbus device to virtual platform bus */
>> + for (i = 0; i < sbdev->num_irq; i++) {
>> + if (!sbdev->irqp[i]) {
>> + /* This IRQ is an incoming IRQ, we can't wire those here */
>> + continue;
>> + }
>> + platform_bus_map_irq(init->params, sbdev, i,
>> + init->used_irqs, init->irqs);
>> + }
>> +
>> + for (i = 0; i < sbdev->num_mmio; i++) {
>> + platform_bus_map_mmio(init->params, sbdev, i,
>> + init->used_mem, init->mem);
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +void platform_bus_init(PlatformParams *params,
>> + MemoryRegion *address_space_mem,
>> + qemu_irq *mpic)
>> +{
>> + uint64_t max_size = params->platform_bus_size;
>> + uint64_t max_pages = max_size >> PAGE_SHIFT;
>> + DECLARE_BITMAP(used_irqs, params->platform_bus_num_irqs);
>> + DECLARE_BITMAP(used_mem, max_pages);
>> + MemoryRegion *platform_region = g_new(MemoryRegion, 1);
>> + Object *container;
>> + PlatformBusInitData init = {
>> + .used_irqs = used_irqs,
>> + .used_mem = used_mem,
>> + .mem = platform_region,
>> + .irqs = &mpic[params->platform_bus_first_irq],
>> + .params = params,
>> + };
>> +
>> + memory_region_init(platform_region, NULL, "platform devices",
>> + params->platform_bus_size);
>> +
>> + bitmap_clear(used_irqs, 0, params->platform_bus_num_irqs);
>> + bitmap_clear(used_mem, 0, max_pages);
>> +
>> + /* Loop through all sysbus devices that were spawened outside the
>> machine */
>> + container = container_get(qdev_get_machine(), "/peripheral");
>> + sysbus_device_check(container, &init);
>> + container = container_get(qdev_get_machine(), "/peripheral-anon");
>> + sysbus_device_check(container, &init);
>> +
>> + memory_region_add_subregion(address_space_mem,
>> params->platform_bus_base,
>> + platform_region);
>> +}
>
> However, I do think it's a good idea to generalize the "platform bus"
> device if you want to reuse it on ARM. The mmio / irq allocator is
> pretty straight forward and should be generic enough for you to use.
I need clarification here: do you talk about your very first patch
"Platform Device Support" or the code above with a proper solution for
device tree generation?
>
> If you do this, please don't duplicate the code but rather move it from
> the e500 file into your new one :).
OK. do you mean modifying the e500.c code to call those routines? My
concern is about testing.
Thanks again for your comments
Best Regards
Eric
>
>
> Alex
>
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