Re: [PATCH 2/2] ArmVirtPkg/NorFlashQemuLib: discover NOR flash banks dynamically

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

On Mon, 19 Nov 2018 at 11:10, Leif Lindholm <leif.lindholm@linaro.org> wrote:
>
> On Fri, Nov 16, 2018 at 05:29:05PM -0800, Ard Biesheuvel wrote:
> > On Fri, 16 Nov 2018 at 16:45, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
> > >
> > > NorFlashQemuLib is one of the last remaining drivers in ArmVirtPkg
> > > that are not based on the device tree received from QEMU.
> > >
> > > For ArmVirtQemu, this does not really matter, given that the NOR
> > > flash banks are always the same: the PEI code is linked to execute
> > > in place from flash bank #0, and the fixed varstore PCDs refer to
> > > flash bank #1 directly.
> > >
> > > However, ArmVirtQemuKernel can execute at any offset, and flash bank
> >
> > #0 is configured as secure-only when running with support for EL3 enabled.
>
> Never gets old :)
>

No this is entirely reasonable: it makes perfect sense for a NOR flash
at address 0x0 to be secure only on a system that implements EL3,
since mach-virt's default reset vector is 0x0.

> > > In this case, NorFlashQemuLib should not expose the first flash bank
> > > at all.
> > >
> > > To prevent introducing too much internal knowledge about which flash
> > > bank is accessible under which circumstances, let's switch to using
> > > the DTB to decide which flash banks to expose to the NOR flash driver.
>
> Does this mean we as a side effect get rid of the limitation that the
> pflash image needs to be exactly 64MB. Or does that require further
> changes on the QEMU side?
>

No that is a QEMU thing.

> If it does, please add a comment to the commit message.
> Either way:
> Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
>

Thanks

> > >
> > > Contributed-under: TianoCore Contribution Agreement 1.1
> > > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> > > ---
> > >  ArmVirtPkg/Library/NorFlashQemuLib/NorFlashQemuLib.c   | 84 +++++++++++++++-----
> > >  ArmVirtPkg/Library/NorFlashQemuLib/NorFlashQemuLib.inf | 12 +++
> > >  2 files changed, 75 insertions(+), 21 deletions(-)
> > >
> > > diff --git a/ArmVirtPkg/Library/NorFlashQemuLib/NorFlashQemuLib.c b/ArmVirtPkg/Library/NorFlashQemuLib/NorFlashQemuLib.c
> > > index e3bbae5b06c5..dc0a15e77170 100644
> > > --- a/ArmVirtPkg/Library/NorFlashQemuLib/NorFlashQemuLib.c
> > > +++ b/ArmVirtPkg/Library/NorFlashQemuLib/NorFlashQemuLib.c
> > > @@ -1,6 +1,6 @@
> > >  /** @file
> > >
> > > - Copyright (c) 2014, Linaro Ltd. All rights reserved.<BR>
> > > + Copyright (c) 2014-2018, Linaro Ltd. All rights reserved.<BR>
> > >
> > >   This program and the accompanying materials
> > >   are licensed and made available under the terms and conditions of the BSD License
> > > @@ -12,13 +12,16 @@
> > >
> > >   **/
> > >
> > > +#include <Library/BaseLib.h>
> > > +#include <Library/DebugLib.h>
> > >  #include <Library/NorFlashPlatformLib.h>
> > > +#include <Library/UefiBootServicesTableLib.h>
> > > +
> > > +#include <Protocol/FdtClient.h>
> > >
> > >  #define QEMU_NOR_BLOCK_SIZE    SIZE_256KB
> > > -#define QEMU_NOR0_BASE         0x0
> > > -#define QEMU_NOR0_SIZE         SIZE_64MB
> > > -#define QEMU_NOR1_BASE         0x04000000
> > > -#define QEMU_NOR1_SIZE         SIZE_64MB
> > > +
> > > +#define MAX_FLASH_BANKS        4
> > >
> > >  EFI_STATUS
> > >  NorFlashPlatformInitialization (
> > > @@ -28,21 +31,7 @@ NorFlashPlatformInitialization (
> > >    return EFI_SUCCESS;
> > >  }
> > >
> > > -NOR_FLASH_DESCRIPTION mNorFlashDevices[] = {
> > > -  {
> > > -    QEMU_NOR0_BASE,
> > > -    QEMU_NOR0_BASE,
> > > -    QEMU_NOR0_SIZE,
> > > -    QEMU_NOR_BLOCK_SIZE,
> > > -    {0xF9B94AE2, 0x8BA6, 0x409B, {0x9D, 0x56, 0xB9, 0xB4, 0x17, 0xF5, 0x3C, 0xB3}}
> > > -  }, {
> > > -    QEMU_NOR1_BASE,
> > > -    QEMU_NOR1_BASE,
> > > -    QEMU_NOR1_SIZE,
> > > -    QEMU_NOR_BLOCK_SIZE,
> > > -    {0x8047DB4B, 0x7E9C, 0x4C0C, {0x8E, 0xBC, 0xDF, 0xBB, 0xAA, 0xCA, 0xCE, 0x8F}}
> > > -  }
> > > -};
> > > +NOR_FLASH_DESCRIPTION mNorFlashDevices[MAX_FLASH_BANKS];
> > >
> > >  EFI_STATUS
> > >  NorFlashPlatformGetDevices (
> > > @@ -50,7 +39,60 @@ NorFlashPlatformGetDevices (
> > >    OUT UINT32                  *Count
> > >    )
> > >  {
> > > +  FDT_CLIENT_PROTOCOL         *FdtClient;
> > > +  INT32                       Node;
> > > +  EFI_STATUS                  Status;
> > > +  EFI_STATUS                  FindNodeStatus;
> > > +  CONST UINT64                *Reg;
> > > +  UINT32                      RegSize;
> > > +  CONST CHAR8                 *NodeStatus;
> > > +  UINTN                       Num;
> > > +
> > > +  Status = gBS->LocateProtocol (&gFdtClientProtocolGuid, NULL,
> > > +                  (VOID **)&FdtClient);
> > > +  ASSERT_EFI_ERROR (Status);
> > > +
> > > +  Num = 0;
> > > +  for (FindNodeStatus = FdtClient->FindCompatibleNode (FdtClient,
> > > +                                     "cfi-flash", &Node);
> > > +       !EFI_ERROR (FindNodeStatus);
> > > +       FindNodeStatus = FdtClient->FindNextCompatibleNode (FdtClient,
> > > +                                     "cfi-flash", Node, &Node)) {
> > > +
> > > +    Status = FdtClient->GetNodeProperty (FdtClient, Node, "status",
> > > +                          (CONST VOID **)&NodeStatus, NULL);
> > > +    if (!EFI_ERROR (Status) && AsciiStrnCmp (NodeStatus, "ok", 2) != 0) {
> > > +      continue;
> > > +    }
> > > +
> > > +    Status = FdtClient->GetNodeProperty (FdtClient, Node, "reg",
> > > +                          (CONST VOID **)&Reg, &RegSize);
> > > +    if (EFI_ERROR (Status)) {
> > > +      DEBUG ((EFI_D_ERROR, "%a: GetNodeProperty () failed (Status == %r)\n",
> > > +        __FUNCTION__, Status));
> > > +      continue;
> > > +    }
> > > +
> > > +    ASSERT ((RegSize % (2 * sizeof(UINT64))) == 0);
> > > +
> > > +    while (RegSize > 0) {
> > > +      mNorFlashDevices[Num].DeviceBaseAddress = (UINTN)SwapBytes64 (Reg[0]);
> > > +      mNorFlashDevices[Num].RegionBaseAddress = (UINTN)SwapBytes64 (Reg[0]);
> > > +      mNorFlashDevices[Num].Size              = (UINTN)SwapBytes64 (Reg[1]);
> > > +      mNorFlashDevices[Num].BlockSize         = QEMU_NOR_BLOCK_SIZE;
> > > +
> > > +      Num++;
> > > +      Reg += 2;
> > > +      RegSize -= 2 * sizeof(UINT64);
> > > +
> > > +      if (Num >= MAX_FLASH_BANKS) {
> > > +        goto Finished;
> > > +      }
> > > +    }
> > > +  }
> > > +
> > > +Finished:
> > >    *NorFlashDescriptions = mNorFlashDevices;
> > > -  *Count = ARRAY_SIZE (mNorFlashDevices);
> > > +  *Count = Num;
> > >    return EFI_SUCCESS;
> > >  }
> > > diff --git a/ArmVirtPkg/Library/NorFlashQemuLib/NorFlashQemuLib.inf b/ArmVirtPkg/Library/NorFlashQemuLib/NorFlashQemuLib.inf
> > > index 126d1671f544..d86ff36dbd58 100644
> > > --- a/ArmVirtPkg/Library/NorFlashQemuLib/NorFlashQemuLib.inf
> > > +++ b/ArmVirtPkg/Library/NorFlashQemuLib/NorFlashQemuLib.inf
> > > @@ -28,3 +28,15 @@
> > >  [Packages]
> > >    MdePkg/MdePkg.dec
> > >    ArmPlatformPkg/ArmPlatformPkg.dec
> > > +  ArmVirtPkg/ArmVirtPkg.dec
> > > +
> > > +[LibraryClasses]
> > > +  BaseLib
> > > +  DebugLib
> > > +  UefiBootServicesTableLib
> > > +
> > > +[Protocols]
> > > +  gFdtClientProtocolGuid          ## CONSUMES
> > > +
> > > +[Depex]
> > > +  gFdtClientProtocolGuid
> > > --
> > > 2.17.1
> > >