Re: [Qemu-devel] [PATCH][SPARC] LEON3: Add emulation of AMBA plug&play

[Jiri Gaisler]

On 10/08/2014 05:38 PM, Andreas Färber wrote:
> Hi,
> 
> Am 08.10.2014 um 16:19 schrieb Fabien Chouteau:
>> From: Jiri Gaisler <address@hidden>
>>
>> AMBA plug&play is used by kernels to probe available devices (Timers,
>> UART, etc...). This is a static declaration of devices implemented in
>> QEMU. In the future, a more advanced version could compute those
>> information directly from the device tree.
> 
> Interesting. There's quite some magic numbers in the read functions; I
> wonder if you could read them via QOM if you actually give the devices a
> canonical path or search by type? You may want to peek at ACPI code.


The plug&play area is similar in function to the PCI configuration
space, indicating vendor/device ID's, address range, interrupt number
etc. of on-chip IP cores. The 'magic' numbers could be generated by
generic functions taking these parameters as inputs. This would
certainly make the code more readable, and easily extended in the
future. Would such a solution be acceptable?


> 
>>
>> Signed-off-by: Fabien Chouteau <address@hidden>
>> ---
>>  hw/sparc/Makefile.objs   |    1 +
>>  hw/sparc/grlib_ambapnp.c |  206 
>> ++++++++++++++++++++++++++++++++++++++++++++++
>>  hw/sparc/leon3.c         |    6 ++
>>  include/hw/sparc/grlib.h |   36 ++++++++
>>  4 files changed, 249 insertions(+)
>>  create mode 100644 hw/sparc/grlib_ambapnp.c
>>
>> diff --git a/hw/sparc/Makefile.objs b/hw/sparc/Makefile.objs
>> index c987b5b..e763701 100644
>> --- a/hw/sparc/Makefile.objs
>> +++ b/hw/sparc/Makefile.objs
>> @@ -1 +1,2 @@
>>  obj-y += sun4m.o leon3.o
>> +obj-$(CONFIG_GRLIB) += grlib_ambapnp.o
>> diff --git a/hw/sparc/grlib_ambapnp.c b/hw/sparc/grlib_ambapnp.c
>> new file mode 100644
>> index 0000000..dfadd5c
>> --- /dev/null
>> +++ b/hw/sparc/grlib_ambapnp.c
>> @@ -0,0 +1,206 @@
>> +/*
>> + * QEMU GRLIB AMBA Plug&Play Emulator
>> + *
>> + * Permission is hereby granted, free of charge, to any person obtaining a 
>> copy
>> + * of this software and associated documentation files (the "Software"), to 
>> deal
>> + * in the Software without restriction, including without limitation the 
>> rights
>> + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
>> + * copies of the Software, and to permit persons to whom the Software is
>> + * furnished to do so, subject to the following conditions:
>> + *
>> + * The above copyright notice and this permission notice shall be included 
>> in
>> + * all copies or substantial portions of the Software.
>> + *
>> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS 
>> OR
>> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
>> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
>> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR 
>> OTHER
>> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 
>> FROM,
>> + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
>> + * THE SOFTWARE.
>> + */
>> +
>> +#include "hw/sysbus.h"
>> +
>> +#define APBPNP_REG_SIZE 4096     /* Size of memory mapped registers */
>> +
>> +#define TYPE_GRLIB_APB_PNP "grlib,apbpnp"
> 
> If you move the two TYPE_* constants to grlib.h, you can reuse them.
> 
>> +#define GRLIB_APB_PNP(obj) \
>> +    OBJECT_CHECK(APBPNP, (obj), TYPE_GRLIB_APB_PNP)
>> +
>> +typedef struct APBPNP {
>> +    SysBusDevice parent_obj;
>> +    MemoryRegion iomem;
>> +} APBPNP;
>> +
>> +static uint64_t grlib_apbpnp_read(void *opaque, hwaddr addr,
>> +                                   unsigned size)
> 
> Indentation is off by one for all read/write functions.
> 
>> +{
>> +    uint64_t read_data;
>> +    addr &= 0xfff;
>> +
>> +    /* Unit registers */
>> +    switch (addr & 0xffc) {
>> +    case 0x00:
>> +        read_data = 0x0400f000; /* Memory controller */
>> +        break;
>> +    case 0x04:
>> +        read_data = 0x0000fff1;
>> +        break;
>> +    case 0x08:
>> +        read_data = 0x0100c023; /* APBUART */
>> +        break;
>> +    case 0x0C:
>> +        read_data = 0x0010fff1;
>> +        break;
>> +    case 0x10:
>> +        read_data = 0x0100d040; /* IRQMP */
>> +        break;
>> +    case 0x14:
>> +        read_data = 0x0020fff1;
>> +        break;
>> +    case 0x18:
>> +        read_data = 0x01011006; /* GPTIMER */
>> +        break;
>> +    case 0x1C:
>> +        read_data = 0x0030fff1;
>> +        break;
>> +
>> +    default:
>> +        read_data = 0;
>> +    }
>> +    if (size == 1) {
>> +        read_data >>= (24 - (addr & 3) * 8);
>> +        read_data &= 0x0ff;
>> +    }
>> +    return read_data;
>> +}
>> +
>> +static void grlib_apbpnp_write(void *opaque, hwaddr addr,
>> +                                uint64_t value, unsigned size)
>> +{
>> +}
>> +
>> +static const MemoryRegionOps grlib_apbpnp_ops = {
>> +    .write      = grlib_apbpnp_write,
>> +    .read       = grlib_apbpnp_read,
>> +    .endianness = DEVICE_NATIVE_ENDIAN,
>> +};
>> +
>> +static int grlib_apbpnp_init(SysBusDevice *dev)
>> +{
>> +    APBPNP *pnp = GRLIB_APB_PNP(dev);
>> +
>> +    memory_region_init_io(&pnp->iomem, OBJECT(pnp), &grlib_apbpnp_ops, pnp,
>> +                          "apbpnp", APBPNP_REG_SIZE);
>> +
>> +    sysbus_init_mmio(dev, &pnp->iomem);
> 
> APBPNP_REG_SIZE seems constant, so you could move both lines into an
> instance_init function.
> 
>> +
>> +    return 0;
>> +}
>> +
>> +static void grlib_apbpnp_class_init(ObjectClass *klass, void *data)
> 
> s/klass/oc/g
> 
>> +{
>> +    SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
> 
> sdc?
> 
>> +
>> +    k->init = grlib_apbpnp_init;
>> +}
>> +
>> +static const TypeInfo grlib_apbpnp_info = {
>> +    .name          = TYPE_GRLIB_APB_PNP,
>> +    .parent        = TYPE_SYS_BUS_DEVICE,
>> +    .instance_size = sizeof(APBPNP),
>> +    .class_init    = grlib_apbpnp_class_init,
>> +};
>> +
>> +static void grlib_apbpnp_register_types(void)
>> +{
>> +    type_register_static(&grlib_apbpnp_info);
>> +}
>> +
>> +type_init(grlib_apbpnp_register_types)
> 
> Please either split into two .c files here, ...
> 
>> +
>> +
>> +/* AHB PNP */
>> +
>> +#define AHBPNP_REG_SIZE (4096 - 8)  /* Size of memory mapped registers */
>> +
>> +#define TYPE_GRLIB_AHB_PNP "grlib,ahbpnp"
>> +#define GRLIB_AHB_PNP(obj) \
>> +    OBJECT_CHECK(AHBPNP, (obj), TYPE_GRLIB_AHB_PNP)
>> +
>> +typedef struct AHBPNP {
>> +    SysBusDevice parent_obj;
>> +    MemoryRegion iomem;
>> +} AHBPNP;
>> +
>> +static uint64_t grlib_ahbpnp_read(void *opaque, hwaddr addr,
>> +                                   unsigned size)
>> +{
>> +    addr &= 0xffc;
>> +
>> +    /* Unit registers */
>> +    switch (addr) {
>> +    case 0:
>> +        return 0x01003000;      /* LEON3 */
>> +    case 0x800:
>> +        return 0x0400f000;      /* Memory controller  */
>> +    case 0x810:
>> +        return 0x0003e002;
>> +    case 0x814:
>> +        return 0x2000e002;
>> +    case 0x818:
>> +        return 0x4003c002;
>> +    case 0x820:
>> +        return 0x01006000;      /* APB bridge @ 0x80000000 */
>> +    case 0x830:
>> +        return 0x8000fff2;
>> +
>> +    default:
>> +        return 0;
>> +    }
>> +}
>> +
>> +static void grlib_ahbpnp_write(void *opaque, hwaddr addr,
>> +                                uint64_t value, unsigned size)
>> +{
>> +}
>> +
>> +static const MemoryRegionOps grlib_ahbpnp_ops = {
>> +    .write      = grlib_ahbpnp_write,
>> +    .read       = grlib_ahbpnp_read,
>> +    .endianness = DEVICE_NATIVE_ENDIAN,
>> +};
>> +
>> +static int grlib_ahbpnp_init(SysBusDevice *dev)
> 
> "dev" is an unlucky naming in case DeviceState is ever needed.
> sbd? busdev?
> 
>> +{
>> +    AHBPNP *pnp = GRLIB_AHB_PNP(dev);
>> +
>> +    memory_region_init_io(&pnp->iomem, OBJECT(pnp), &grlib_ahbpnp_ops, pnp,
>> +                          "ahbpnp", AHBPNP_REG_SIZE);
>> +
>> +    sysbus_init_mmio(dev, &pnp->iomem);
> 
> Ditto for possibly moving to instance_init.
> 
>> +
>> +    return 0;
>> +}
>> +
>> +static void grlib_ahbpnp_class_init(ObjectClass *klass, void *data)
>> +{
>> +    SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
>> +
>> +    k->init = grlib_ahbpnp_init;
>> +}
>> +
>> +static const TypeInfo grlib_ahbpnp_info = {
>> +    .name          = TYPE_GRLIB_AHB_PNP,
>> +    .parent        = TYPE_SYS_BUS_DEVICE,
>> +    .instance_size = sizeof(AHBPNP),
>> +    .class_init    = grlib_ahbpnp_class_init,
>> +};
>> +
>> +static void grlib_ahbpnp_register_types(void)
>> +{
>> +    type_register_static(&grlib_ahbpnp_info);
>> +}
>> +
>> +type_init(grlib_ahbpnp_register_types)
> 
> ... or if unavoidable use just one type_init and registration function.
> 
>> diff --git a/hw/sparc/leon3.c b/hw/sparc/leon3.c
>> index 751392e..40de78f 100644
>> --- a/hw/sparc/leon3.c
>> +++ b/hw/sparc/leon3.c
>> @@ -207,6 +207,12 @@ static void leon3_generic_hw_init(MachineState *machine)
>>          }
>>      }
>>  
>> +    /* Allocate AHB PNP */
>> +    grlib_ahbpnp_create(0xFFFFF000);
>> +
>> +    /* Allocate APB PNP */
>> +    grlib_apbpnp_create(0x800FF000);
>> +
>>      /* Allocate timers */
>>      grlib_gptimer_create(0x80000300, 2, CPU_CLK, cpu_irqs, 6);
>>  
>> diff --git a/include/hw/sparc/grlib.h b/include/hw/sparc/grlib.h
>> index 470ce72..a004427 100644
>> --- a/include/hw/sparc/grlib.h
>> +++ b/include/hw/sparc/grlib.h
>> @@ -123,4 +123,40 @@ DeviceState *grlib_apbuart_create(hwaddr  base,
>>      return dev;
>>  }
>>  
>> +/* APB PNP */
>> +
>> +static inline
>> +DeviceState *grlib_apbpnp_create(hwaddr  base)
>> +{
>> +    DeviceState *dev;
>> +
>> +    dev = qdev_create(NULL, "grlib,apbpnp");
>> +
>> +    if (qdev_init(dev)) {
>> +        return NULL;
>> +    }
>> +
>> +    sysbus_mmio_map(SYS_BUS_DEVICE(dev), 0, base);
>> +
>> +    return dev;
>> +}
>> +
>> +/* AHB PNP */
>> +
>> +static inline
>> +DeviceState *grlib_ahbpnp_create(hwaddr  base)
>> +{
>> +    DeviceState *dev;
>> +
>> +    dev = qdev_create(NULL, "grlib,ahbpnp");
>> +
>> +    if (qdev_init(dev)) {
>> +        return NULL;
>> +    }
>> +
>> +    sysbus_mmio_map(SYS_BUS_DEVICE(dev), 0, base);
>> +
>> +    return dev;
>> +}
>> +
>>  #endif /* ! _GRLIB_H_ */
> 
> Are these functions really needed? Can't you just inline them?
> Also note that the return value is never actually checked.
> 
> Regards,
> Andreas
>