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MdeModulePkg/AtaAtapiPassThru: don't write read-only AHCI MMIO register

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Per AHCI 1.1 spec, AE bit of GHC register is read-only if CAP.SAM is 1

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Feng Tian <feng.tian@intel.com>
Reviewed-by: Star Zeng <star.zeng@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@16321 6f19259b-4bc3-4df7-8a09-765794883524
This commit is contained in:
Feng Tian
2014-11-10 05:46:21 +00:00
committed by erictian
parent 33985e3b52
commit 1ff1dd0ff9
2 changed files with 23 additions and 9 deletions
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29
MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AhciMode.c
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@@ -1440,8 +1440,19 @@ AhciReset (
{
UINT64 Delay;
UINT32 Value;
UINT32 Capability;
AhciOrReg (PciIo, EFI_AHCI_GHC_OFFSET, EFI_AHCI_GHC_ENABLE);
//
// Collect AHCI controller information
//
Capability = AhciReadReg (PciIo, EFI_AHCI_CAPABILITY_OFFSET);
//
// Enable AE before accessing any AHCI registers if Supports AHCI Mode Only is not set
//
if ((Capability & EFI_AHCI_CAP_SAM) == 0) {
AhciOrReg (PciIo, EFI_AHCI_GHC_OFFSET, EFI_AHCI_GHC_ENABLE);
}
AhciOrReg (PciIo, EFI_AHCI_GHC_OFFSET, EFI_AHCI_GHC_RESET);
@@ -2244,16 +2255,18 @@ AhciModeInitialization (
return EFI_DEVICE_ERROR;
}
//
// Enable AE before accessing any AHCI registers
//
AhciOrReg (PciIo, EFI_AHCI_GHC_OFFSET, EFI_AHCI_GHC_ENABLE);
//
// Collect AHCI controller information
//
Capability = AhciReadReg(PciIo, EFI_AHCI_CAPABILITY_OFFSET);
Capability = AhciReadReg (PciIo, EFI_AHCI_CAPABILITY_OFFSET);
//
// Enable AE before accessing any AHCI registers if Supports AHCI Mode Only is not set
//
if ((Capability & EFI_AHCI_CAP_SAM) == 0) {
AhciOrReg (PciIo, EFI_AHCI_GHC_OFFSET, EFI_AHCI_GHC_ENABLE);
}
//
// Get the number of command slots per port supported by this HBA.
//