Re: [Qemu-devel] [PATCH v4 5/6] hw/arm/sysbus-fdt: helpers for platform bus nodes addition

[Shannon Zhao <zhaoshenglong@huawei.com>]

On 2014/10/31 21:53, Eric Auger wrote:
> This new C module will be used by ARM machine files to generate
> platform bus node and their dynamic sysbus device tree nodes.
> 
> Dynamic sysbus device node addition is done in a machine init
> done notifier. arm_register_platform_bus_fdt_creator does the
> registration of this latter and is supposed to be called by
> ARM machine files that support platform bus and their dynamic
> sysbus. Addition of dynamic sysbus nodes is done only if the
> user did not provide any dtb.
> 
> Signed-off-by: Alexander Graf <agraf@suse.de>
> Signed-off-by: Eric Auger <eric.auger@linaro.org>
> 
> ---
> 
> v3 -> v4:
> - dyn_sysbus_devtree.c renamed into sysbus-fdt.c
> - use new PlatformBusDevice object
> - the dtb upgrade is done through modify_dtb. Before the fdt
>   was recreated from scratch. When the user provided a dtb this
>   latter was overwritten which was not correct.
> - an array contains the association between device type names
>   and their node creation function
> - I must aknowledge I did not find any cleaner way to implement
>   a FDT_BUILDER interface, as suggested by Paolo. The class method
>   would need to be initialized somewhere and since it cannot
>   happen in the device itself - according to Alex & Peter comments -,
>   I don't see when I shall associate the device type and its
>   interface implementation.
> 
> v2 -> v3:
> - add arm_ prefix
> - arm_sysbus_device_create_devtree becomes static
> 
> v1 -> v2:
> - Code moved in an arch specific file to accomodate architecture
>   dependent specificities.
> - remove platform_bus_base from PlatformDevtreeData
> 
> v1: code originally written by Alex Graf in e500.c and reused for
> ARM [Eric Auger]
> ---
>  hw/arm/Makefile.objs        |   1 +
>  hw/arm/sysbus-fdt.c         | 181 ++++++++++++++++++++++++++++++++++++++++++++
>  include/hw/arm/sysbus-fdt.h |  50 ++++++++++++
>  3 files changed, 232 insertions(+)
>  create mode 100644 hw/arm/sysbus-fdt.c
>  create mode 100644 include/hw/arm/sysbus-fdt.h
> 
> diff --git a/hw/arm/Makefile.objs b/hw/arm/Makefile.objs
> index 6088e53..0cc63e1 100644
> --- a/hw/arm/Makefile.objs
> +++ b/hw/arm/Makefile.objs
> @@ -3,6 +3,7 @@ obj-$(CONFIG_DIGIC) += digic_boards.o
>  obj-y += integratorcp.o kzm.o mainstone.o musicpal.o nseries.o
>  obj-y += omap_sx1.o palm.o realview.o spitz.o stellaris.o
>  obj-y += tosa.o versatilepb.o vexpress.o virt.o xilinx_zynq.o z2.o
> +obj-y += sysbus-fdt.o
>  
>  obj-y += armv7m.o exynos4210.o pxa2xx.o pxa2xx_gpio.o pxa2xx_pic.o
>  obj-$(CONFIG_DIGIC) += digic.o
> diff --git a/hw/arm/sysbus-fdt.c b/hw/arm/sysbus-fdt.c
> new file mode 100644
> index 0000000..d5476f1
> --- /dev/null
> +++ b/hw/arm/sysbus-fdt.c
> @@ -0,0 +1,181 @@
> +/*
> + * ARM Platform Bus device tree generation helpers
> + *
> + * Copyright (c) 2014 Linaro Limited
> + *
> + * Authors:
> + *  Alex Graf <agraf@suse.de>
> + *  Eric Auger <eric.auger@linaro.org>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2 or later, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
> + * more details.
> + *
> + * You should have received a copy of the GNU General Public License along with
> + * this program.  If not, see <http://www.gnu.org/licenses/>.
> + *
> + */
> +
> +#include "hw/arm/sysbus-fdt.h"
> +#include "qemu/error-report.h"
> +#include "sysemu/device_tree.h"
> +#include "hw/platform-bus.h"
[*]
> +#include "sysemu/sysemu.h"
> +#include "hw/platform-bus.h"
[*]
Duplicate include "hw/platform-bus.h"
> +
> +/*
> + * internal struct that contains the information to create dynamic
> + * sysbus device node
> + */
> +typedef struct PlatformBusFdtData {
> +    void *fdt; /* device tree handle */
> +    int irq_start; /* index of the first IRQ usable by platform bus devices */
> +    const char *pbus_node_name; /* name of the platform bus node */
> +    PlatformBusDevice *pbus;
> +} PlatformBusFdtData;
> +
> +/*
> + * struct used when calling the machine init done notifier
> + * that constructs the fdt nodes of platform bus devices
> + */
> +typedef struct PlatformBusFdtNotifierParams {
> +    ARMPlatformBusFdtParams *fdt_params;
> +    Notifier notifier;
> +} PlatformBusFdtNotifierParams;
> +
> +/* struct that associates a device type name and a node creation function */
> +typedef struct NodeCreationPair {
> +    const char *typename;
> +    int (*add_fdt_node_fn)(SysBusDevice *sbdev, void *opaque);
> +} NodeCreationPair;
> +
> +/* list of supported dynamic sysbus devices */
> +NodeCreationPair add_fdt_node_functions[] = {
> +        {"", NULL}, /*last element*/
> +};

Eric, I have a question about how to use this.
If I want to dynamically add a device, I must add a member in above array, such as {TYPE_PFD, pfd_add_fdt_node}.
And the "pfd_add_fdt_node" is defined by myself which is used to dynamically generate the device fdt node.

Am I right ?

Thanks,
Shannon

> +
> +/**
> + * add_fdt_node - add the device tree node of a dynamic sysbus device
> + *
> + * @sbdev: handle to the sysbus device
> + * @opaque: handle to the PlatformBusFdtData
> + *
> + * Checks the sysbus type belongs to the list of device types that
> + * are dynamically instantiable and in the positive call the node
> + * creation function.
> + */
> +static int add_fdt_node(SysBusDevice *sbdev, void *opaque)
> +{
> +    int i;
> +
> +    for (i = 0; i < ARRAY_SIZE(add_fdt_node_functions); i++) {
> +        if (!strcmp(object_get_typename(OBJECT(sbdev)),
> +                    add_fdt_node_functions[i].typename)) {
> +            add_fdt_node_functions[i].add_fdt_node_fn(sbdev, opaque);
> +            return 0;
> +        }
> +    }
> +    error_report("Device %s can not be dynamically instantiated",
> +                     qdev_fw_name(DEVICE(sbdev)));
> +    return 1;
> +}
> +
> +/**
> + * add_all_platform_bus_fdt_nodes - create all the platform bus nodes
> + *
> + * builds the parent platform bus node and all the nodes of dynamic
> + * sysbus devices attached * to it. It is a modify_dtb() function, ie.
> + * called * by arm_load_dtb()
> + */
> +static void add_all_platform_bus_fdt_nodes(const struct arm_boot_info *info,
> +                                           void *fdt)
> +{
> +    const char platcomp[] = "qemu,platform\0simple-bus";
> +    ARMPlatformBusSystemParams *system_params;
> +    ARMPlatformBusFdtParams *fdt_params = info->modify_dtb_opaque;
> +    PlatformBusDevice *pbus;
> +    DeviceState *dev;
> +    gchar *node;
> +    uint64_t addr, size;
> +    int irq_start;
> +
> +    if (!fdt_params) {
> +        return;
> +    }
> +
> +    system_params = fdt_params->system_params;
> +    node = g_strdup_printf("/platform@%"PRIx64,
> +                               system_params->platform_bus_base);
> +    addr = system_params->platform_bus_base;
> +    size = system_params->platform_bus_size;
> +    irq_start = system_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", fdt_params->intc);
> +
> +    dev = qdev_find_recursive(sysbus_get_default(), TYPE_PLATFORM_BUS_DEVICE);
> +    pbus = PLATFORM_BUS_DEVICE(dev);
> +
> +    /* We can only create dt nodes for dynamic devices when they're ready */
> +    if (pbus->done_gathering) {
> +        PlatformBusFdtData data = {
> +            .fdt = fdt,
> +            .irq_start = irq_start,
> +            .pbus_node_name = node,
> +            .pbus = pbus,
> +        };
> +
> +        /* Loop through all dynamic sysbus devices and create their node */
> +        foreach_dynamic_sysbus_device(add_fdt_node, &data);
> +    }
> +
> +    g_free(node);
> +}
> +
> +static void upgrade_dtb(ARMPlatformBusFdtParams *params)
> +{
> +    struct arm_boot_info *binfo = params->binfo;
> +
> +    /*
> +     * In case the user provided a dtb, we assume he already integrated the
> +     * dynamic sysbus nodes. This corresponds to a use case where the dynamic
> +     * sysbus nodes are complex and their generation is not yet supported. In
> +     * case the use can take in charge the guest dt while qemu takes in charge
> +     * the qom stuff.
> +     */
> +    if (!binfo->dtb_filename) {
> +        binfo->modify_dtb_opaque = params;
> +        binfo->modify_dtb = add_all_platform_bus_fdt_nodes;
> +        arm_load_dtb(binfo);
> +    }
> +}
> +
> +static void platform_bus_fdt_notify(Notifier *notifier, void *data)
> +{
> +    PlatformBusFdtNotifierParams *p =
> +        container_of(notifier, PlatformBusFdtNotifierParams, notifier);
> +    upgrade_dtb(p->fdt_params);
> +}
> +
> +void arm_register_platform_bus_fdt_creator(ARMPlatformBusFdtParams *fdt_params)
> +{
> +    PlatformBusFdtNotifierParams *p = g_new(PlatformBusFdtNotifierParams, 1);
> +
> +    p->fdt_params = fdt_params;
> +    p->notifier.notify = platform_bus_fdt_notify;
> +    qemu_add_machine_init_done_notifier(&p->notifier);
> +}
> diff --git a/include/hw/arm/sysbus-fdt.h b/include/hw/arm/sysbus-fdt.h
> new file mode 100644
> index 0000000..b9602f1
> --- /dev/null
> +++ b/include/hw/arm/sysbus-fdt.h
> @@ -0,0 +1,50 @@
> +/*
> + * Dynamic sysbus device tree node generation API
> + *
> + * Copyright Linaro Limited, 2014
> + *
> + * Authors:
> + *  Alex Graf <agraf@suse.de>
> + *  Eric Auger <eric.auger@linaro.org>
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2.  See
> + * the COPYING file in the top-level directory.
> + */
> +
> +#ifndef HW_ARM_SYSBUS_FDT_H
> +#define HW_ARM_SYSBUS_FDT_H
> +
> +#include "hw/arm/arm.h"
> +#include "qemu-common.h"
> +#include "hw/sysbus.h"
> +
> +/*
> + * struct that contains dimensioning parameters of the platform bus
> + */
> +typedef struct {
> +    hwaddr platform_bus_base; /* start address of the bus */
> +    hwaddr platform_bus_size; /* size of the bus */
> +    int platform_bus_first_irq; /* first hwirq assigned to the bus */
> +    int platform_bus_num_irqs; /* number of hwirq assigned to the bus */
> +} ARMPlatformBusSystemParams;
> +
> +/*
> + * struct that contains all relevant info to build the fdt nodes of
> + * platform bus and attached dynamic sysbus devices
> + * in the future might be augmented with additional info
> + * such as PHY, CLK handles ...
> + */
> +typedef struct {
> +    ARMPlatformBusSystemParams *system_params;
> +    struct arm_boot_info *binfo;
> +    const char *intc; /* parent interrupt controller name */
> +} ARMPlatformBusFdtParams;
> +
> +/**
> + * arm_register_platform_bus_fdt_creator - register a machine init done
> + * notifier that creates the device tree nodes of the platform bus and
> + * associated dynamic sysbus devices
> + */
> +void arm_register_platform_bus_fdt_creator(ARMPlatformBusFdtParams *fdt_params);
> +
> +#endif
> 


-- 
Shannon