Re: [PATCH v4 5/7] hw/ppc/e500: Implement pflash handling

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

On 18/10/22 23:01, Bernhard Beschow wrote:
> Allows e500 boards to have their root file system reside on flash using
> only builtin devices located in the eLBC memory region.
> 
> 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 | 16 ++++++++
>   hw/ppc/Kconfig              |  1 +
>   hw/ppc/e500.c               | 79 +++++++++++++++++++++++++++++++++++++
>   3 files changed, 96 insertions(+)

> @@ -1024,6 +1061,48 @@ void ppce500_init(MachineState *machine)
>                                   pmc->platform_bus_base,
>                                   &pms->pbus_dev->mmio);
>   
> +    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);
> +        uint64_t mmio_size = pms->pbus_dev->mmio.size;
> +        uint32_t sector_len = 64 * KiB;
> +
> +        if (!is_power_of_2(size)) {
> +            error_report("Size of pflash file must be a power of two.");
> +            exit(1);
> +        }
> +
> +        if (size > mmio_size) {
> +            error_report("Size of pflash file must not be bigger than %" PRIu64
> +                         " bytes.", mmio_size);
> +            exit(1);
> +        }
> +
> +        if (!QEMU_IS_ALIGNED(size, sector_len)) {
> +            error_report("Size of pflash file must be a multiple of %" PRIu32
> +                         ".", sector_len);
> +            exit(1);
> +        }

Again, this check is unrelated to the board code and belong to the flash 
device (the board has no idea of the underlying flash restrictions).

(see below)

> +        dev = qdev_new(TYPE_PFLASH_CFI01);
> +        qdev_prop_set_drive(dev, "drive", blk);
> +        qdev_prop_set_uint32(dev, "num-blocks", size / sector_len);
> +        qdev_prop_set_uint64(dev, "sector-length", sector_len);
> +        qdev_prop_set_uint8(dev, "width", 2);
> +        qdev_prop_set_bit(dev, "big-endian", true);
> +        qdev_prop_set_uint16(dev, "id0", 0x89);
> +        qdev_prop_set_uint16(dev, "id1", 0x18);
> +        qdev_prop_set_uint16(dev, "id2", 0x0000);
> +        qdev_prop_set_uint16(dev, "id3", 0x0);
> +        qdev_prop_set_string(dev, "name", "e500.flash");
> +        sysbus_realize_and_unref(SYS_BUS_DEVICE(dev), &error_fatal);

If you want to report the error differently, you can use a local Error*
and display it with error_report_err() before exiting.

Anyhow can be cleaned later, so:
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>

> +        memory_region_add_subregion(&pms->pbus_dev->mmio, 0,
> +                                    pflash_cfi01_get_memory(PFLASH_CFI01(dev)));
> +    }