Re: [Qemu-devel] [patch 1/2] Add Flash support to the Versatile PB platform

["Cedric Hombourger" <chombourger@gmail.com>]

Hi Thomas,

Well done! I have had a modified qemu for sometime now to do this as
well but never got to the point where the Linux kernel could mount the
root file-system from flash. I quickly gave a try to your patch using
the latest svn and it seems to be the same (i.e. u-boot ok, kernel
gets loaded from flash to memory and then boots but it fails to mount
a root file-system). I have started to look into this but not yet deep
enough to understand what is going on.... my kernel seems to be
reading zeros instead of the cramfs magic number while the address
that I am reading from seems to be correct. Is this something that you
have tested and works for you? I will be happy to help if you also
have issues.

Cedric

2008/10/13 Thomas Petazzoni <thomas.petazzoni@free-electrons.com>:
> This patch adds the emulation of the 64 MB Intel Flash present at
> address 0x34000000 on the ARM Versatile PB platform, with a 256 KB
> sector size. This flash emulation is enabled using the -pflash
> option.
>
> If a -pflash option is present but no -kernel option has been
> specified, Qemu starts execution at the flash starting address. If a
> -kernel option has been specified together with a -pflash option, then
> Qemu normally boots from the kernel (but the flash is still emulated,
> of course).
>
> The case where neither -kernel nor -pflash have been specified is
> already catched by the Qemu main function :
>
>    if (!linux_boot && net_boot == 0 &&
>        !machine->nodisk_ok && nb_drives_opt == 0)
>        help(1);
>
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
> ---
>  hw/versatilepb.c |   43 ++++++++++++++++++++++++++++++++++++-------
>  1 file changed, 36 insertions(+), 7 deletions(-)
>
> Index: qemu/hw/versatilepb.c
> ===================================================================
> --- qemu.orig/hw/versatilepb.c
> +++ qemu/hw/versatilepb.c
> @@ -15,6 +15,7 @@
>  #include "sysemu.h"
>  #include "pci.h"
>  #include "boards.h"
> +#include "flash.h"
>
>  /* Primary interrupt controller.  */
>
> @@ -159,6 +160,10 @@
>
>  static struct arm_boot_info versatile_binfo;
>
> +#define VERSATILE_FLASH_ADDR      0x34000000
> +#define VERSATILE_FLASH_SIZE      (64 * 1024 * 1024)
> +#define VERSATILE_FLASH_SECT_SIZE (256 * 1024)
> +
>  static void versatile_init(ram_addr_t ram_size, int vga_ram_size,
>                      const char *boot_device, DisplayState *ds,
>                      const char *kernel_filename, const char *kernel_cmdline,
> @@ -174,6 +179,7 @@
>     int n;
>     int done_smc = 0;
>     int index;
> +    int hasflash = 0;
>
>     if (!cpu_model)
>         cpu_model = "arm926";
> @@ -184,7 +190,8 @@
>     }
>     /* ??? RAM should repeat to fill physical memory space.  */
>     /* SDRAM at address zero.  */
> -    cpu_register_physical_memory(0, ram_size, IO_MEM_RAM);
> +    cpu_register_physical_memory(0, ram_size,
> +                                qemu_ram_alloc(ram_size) | IO_MEM_RAM);
>
>     arm_sysctl_init(0x10000000, 0x41007004);
>     pic = arm_pic_init_cpu(env);
> @@ -249,6 +256,21 @@
>     /* Add PL031 Real Time Clock. */
>     pl031_init(0x101e8000,pic[10]);
>
> +    index = drive_get_index(IF_PFLASH, 0, 0);
> +    if (index != -1) {
> +      if (!pflash_cfi01_register(VERSATILE_FLASH_ADDR,
> +                                qemu_ram_alloc(VERSATILE_FLASH_SIZE),
> +                                drives_table[index].bdrv,
> +                                VERSATILE_FLASH_SECT_SIZE,
> +                                VERSATILE_FLASH_SIZE / VERSATILE_FLASH_SECT_SIZE,
> +                                4, 0, 0, 0, 0)) {
> +       fprintf(stderr, "qemu: error registering flash memory.\n");
> +       exit(1);
> +      }
> +
> +      hasflash = 1;
> +    }
> +
>     /* Memory map for Versatile/PB:  */
>     /* 0x10000000 System registers.  */
>     /* 0x10001000 PCI controller config registers.  */
> @@ -285,12 +307,17 @@
>     /*  0x101f3000 UART2.  */
>     /* 0x101f4000 SSPI.  */
>
> -    versatile_binfo.ram_size = ram_size;
> -    versatile_binfo.kernel_filename = kernel_filename;
> -    versatile_binfo.kernel_cmdline = kernel_cmdline;
> -    versatile_binfo.initrd_filename = initrd_filename;
> -    versatile_binfo.board_id = board_id;
> -    arm_load_kernel(env, &versatile_binfo);
> +    if (kernel_filename) {
> +      versatile_binfo.ram_size = ram_size;
> +      versatile_binfo.kernel_filename = kernel_filename;
> +      versatile_binfo.kernel_cmdline = kernel_cmdline;
> +      versatile_binfo.initrd_filename = initrd_filename;
> +      versatile_binfo.board_id = board_id;
> +      arm_load_kernel(env, &versatile_binfo);
> +    }
> +    else if (hasflash) {
> +      env->regs[15] = VERSATILE_FLASH_ADDR;
> +    }
>  }
>
>  static void vpb_init(ram_addr_t ram_size, int vga_ram_size,
> @@ -321,6 +348,7 @@
>     .init = vpb_init,
>     .use_scsi = 1,
>     .max_cpus = 1,
> +    .ram_require = VERSATILE_FLASH_SIZE,
>  };
>
>  QEMUMachine versatileab_machine = {
> @@ -329,4 +357,5 @@
>     .init = vab_init,
>     .use_scsi = 1,
>     .max_cpus = 1,
> +    .ram_require = VERSATILE_FLASH_SIZE,
>  };
>
> --
> Thomas Petazzoni, Free Electrons
> Kernel, drivers and embedded Linux development,
> consulting, training and support.
> http://free-electrons.com
>
>
>