Re: [PATCH 07/11] hw/ppc/e500: Implement pflash handling

[B]

Am 16. September 2022 17:05:13 UTC schrieb Bernhard Beschow <shentey@gmail.com>:
>Am 16. September 2022 15:00:06 UTC schrieb Bin Meng <bmeng.cn@gmail.com>:
>>On Thu, Sep 15, 2022 at 11:36 PM Bernhard Beschow <shentey@gmail.com> wrote:
>>>
>>> Allows e500 boards to have their root file system reside on flash using
>>> only builtin devices.
>>>
>>> Note that the flash memory area is only created when a -pflash argument is
>>> given, and that the size is determined by the given file. The idea is to
>>> put users into control.
>>>
>>> Signed-off-by: Bernhard Beschow <shentey@gmail.com>
>>> ---
>>>  docs/system/ppc/ppce500.rst | 12 +++++++++
>>>  hw/ppc/Kconfig              |  1 +
>>>  hw/ppc/e500.c               | 54 +++++++++++++++++++++++++++++++++++++
>>>  3 files changed, 67 insertions(+)
>>>
>>> diff --git a/docs/system/ppc/ppce500.rst b/docs/system/ppc/ppce500.rst
>>> index ba6bcb7314..c3f55c6f3d 100644
>>> --- a/docs/system/ppc/ppce500.rst
>>> +++ b/docs/system/ppc/ppce500.rst
>>> @@ -119,6 +119,18 @@ To boot the 32-bit Linux kernel:
>>>        -initrd /path/to/rootfs.cpio \
>>>        -append "root=/dev/ram"
>>>
>>> +Rather than using a root file system on ram disk, it is possible to have 
>>> it on
>>> +emulated flash. Given an ext2 image whose size must be a power of two, it 
>>> can
>>> +be used as follows:
>>> +
>>> +.. code-block:: bash
>>> +
>>> +  $ qemu-system-ppc64 -M ppce500 -cpu e500mc -smp 4 -m 2G \
>>
>>qemu-system-ppc{64|32}
>
>Will fix.
>
>>> +      -display none -serial stdio \
>>> +      -kernel vmlinux \
>>> +      -drive if=pflash,file=/path/to/rootfs.ext2,format=raw \
>>> +      -append "rootwait root=/dev/mtdblock0"
>>> +
>>>  Running U-Boot
>>>  --------------
>>>
>>> diff --git a/hw/ppc/Kconfig b/hw/ppc/Kconfig
>>> index 791fe78a50..769a1ead1c 100644
>>> --- a/hw/ppc/Kconfig
>>> +++ b/hw/ppc/Kconfig
>>> @@ -126,6 +126,7 @@ config E500
>>>      select ETSEC
>>>      select GPIO_MPC8XXX
>>>      select OPENPIC
>>> +    select PFLASH_CFI01
>>>      select PLATFORM_BUS
>>>      select PPCE500_PCI
>>>      select SERIAL
>>> diff --git a/hw/ppc/e500.c b/hw/ppc/e500.c
>>> index 864b6f3d92..7843a4e04b 100644
>>> --- a/hw/ppc/e500.c
>>> +++ b/hw/ppc/e500.c
>>> @@ -23,8 +23,10 @@
>>>  #include "e500-ccsr.h"
>>>  #include "net/net.h"
>>>  #include "qemu/config-file.h"
>>> +#include "hw/block/flash.h"
>>>  #include "hw/char/serial.h"
>>>  #include "hw/pci/pci.h"
>>> +#include "sysemu/block-backend-io.h"
>>>  #include "sysemu/sysemu.h"
>>>  #include "sysemu/kvm.h"
>>>  #include "sysemu/reset.h"
>>> @@ -267,6 +269,34 @@ static void sysbus_device_create_devtree(SysBusDevice 
>>> *sbdev, void *opaque)
>>>      }
>>>  }
>>>
>>> +static void create_devtree_flash(SysBusDevice *sbdev,
>>> +                                 PlatformDevtreeData *data)
>>> +{
>>> +    char *name;
>>
>>Use g_autofree
>
>Yes, good idea.
>
>>> +    uint64_t num_blocks = object_property_get_uint(OBJECT(sbdev),
>>> +                                                   "num-blocks",
>>> +                                                   &error_fatal);
>>> +    uint64_t sector_length = object_property_get_uint(OBJECT(sbdev),
>>> +                                                      "sector-length",
>>> +                                                      &error_fatal);
>>> +    uint64_t bank_width = object_property_get_uint(OBJECT(sbdev),
>>> +                                                   "width",
>>> +                                                   &error_fatal);
>>> +    hwaddr flashbase = 0;
>>> +    hwaddr flashsize = num_blocks * sector_length;
>>> +    void *fdt = data->fdt;
>>> +
>>> +    name = g_strdup_printf("%s/nor@%" PRIx64, data->node, flashbase);
>>> +    qemu_fdt_add_subnode(fdt, name);
>>> +    qemu_fdt_setprop_cell(fdt, name, "#address-cells", 1);
>>> +    qemu_fdt_setprop_cell(fdt, name, "#size-cells", 1);
>>
>>#address-cells and #size-cells are not needed.
>
>Will remove.
>
>>> +    qemu_fdt_setprop_string(fdt, name, "compatible", "cfi-flash");
>>> +    qemu_fdt_setprop_sized_cells(fdt, name, "reg",
>>> +                                 1, flashbase, 1, flashsize);
>>> +    qemu_fdt_setprop_cell(fdt, name, "bank-width", bank_width);
>>> +    g_free(name);
>>> +}
>>> +
>>>  static void platform_bus_create_devtree(PPCE500MachineState *pms,
>>>                                          void *fdt, const char *mpic)
>>>  {
>>> @@ -276,6 +306,8 @@ static void 
>>> platform_bus_create_devtree(PPCE500MachineState *pms,
>>>      uint64_t addr = pmc->platform_bus_base;
>>>      uint64_t size = pmc->platform_bus_size;
>>>      int irq_start = pmc->platform_bus_first_irq;
>>> +    SysBusDevice *sbdev;
>>> +    bool ambiguous;
>>>
>>>      /* Create a /platform node that we can put all devices into */
>>>
>>> @@ -302,6 +334,13 @@ static void 
>>> platform_bus_create_devtree(PPCE500MachineState *pms,
>>>      /* Loop through all dynamic sysbus devices and create nodes for them */
>>>      foreach_dynamic_sysbus_device(sysbus_device_create_devtree, &data);
>>>
>>> +    sbdev = SYS_BUS_DEVICE(object_resolve_path_type("", TYPE_PFLASH_CFI01,
>>> +                                                    &ambiguous));
>>
>>Can this be moved into sysbus_device_create_devtree(), and use the
>>same logic as the eTSEC device?
>
>I've tried that, but the logic for eTSEC seems to get triggered for 
>user-created devices only. Since TYPE_PFLASH_CFI01 isn't user-created we're 
>not triggered I guess.
>
>I think that the eTSEC handling could be moved into sysbus-fdt.c but I'm not 
>sure whether this is allowed due to poisoning.
>
>>> +    if (sbdev) {
>>> +        assert(!ambiguous);
>>> +        create_devtree_flash(sbdev, &data);
>>> +    }
>>> +
>>>      g_free(node);
>>>  }
>>>
>>> @@ -856,6 +895,7 @@ void ppce500_init(MachineState *machine)
>>>      unsigned int pci_irq_nrs[PCI_NUM_PINS] = {1, 2, 3, 4};
>>>      IrqLines *irqs;
>>>      DeviceState *dev, *mpicdev;
>>> +    DriveInfo *dinfo;
>>>      CPUPPCState *firstenv = NULL;
>>>      MemoryRegion *ccsr_addr_space;
>>>      SysBusDevice *s;
>>> @@ -1024,6 +1064,20 @@ void ppce500_init(MachineState *machine)
>>>                                  pmc->platform_bus_base,
>>>                                  sysbus_mmio_get_region(s, 0));
>>>
>>> +    dinfo = drive_get(IF_PFLASH, 0, 0);
>>> +    if (dinfo) {
>>> +        BlockBackend *blk = blk_by_legacy_dinfo(dinfo);
>>> +        BlockDriverState *bs = blk_bs(blk);
>>> +        uint64_t size = bdrv_getlength(bs);
>>> +        if (ctpop64(size) != 1) {
>>> +            error_report("Size of pflash file must be a power of two.");
>>> +            exit(1);
>>> +        }
>>
>>I think we should also check whether the flash size plus the eTSEC
>>size exceeds the platform bus mmio window size otherwise it won't work
>>for both devices present, no?
>
>I could check that the flash fits inside the eLBC memory window.
>
>For user-created devices such as eTSEC, however, I'd like to rely on other 
>parts of QEMU to check this. First, I don't know how to get access to all 
>relevant devices and their memory windows, and second, catching all possible 
>(future) cases here seems a bit ad-hoc and fragile to me.

As it turns out, platform_bus_link_device() already aborts with an error if an 
eTSEC device doesn't fit in the remaining space. So only the pflash size 
remains to be checked.
>
>Best regards,
>Bernhard
>>
>>> +        pflash_cfi01_register(pmc->platform_bus_base, "e500.flash",
>>> +                              size, blk,
>>> +                              64 * KiB, 2, 0x89, 0x18, 0x0000, 0x0, 1);
>>> +    }
>>> +
>>>      /*
>>>       * Smart firmware defaults ahead!
>>>       *
>>
>>Regards,
>>Bin
>