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| author | Laszlo Ersek <lersek@redhat.com> | 2017-01-27 05:49:03 +0100 |
|---|---|---|
| committer | Laszlo Ersek <lersek@redhat.com> | 2017-01-31 00:14:12 +0100 |
| commit | d055601ea7dc7cc09338445188ba18482365c2a1 (patch) | |
| tree | b69f4ac6bc8d3f65dc7e7e928556f6e0e883a311 /OvmfPkg/Library/QemuFwCfgLib | |
| parent | 465663e9f128428323e6c6e4431dd15ac287a24c (diff) | |
| download | edk2-d055601ea7dc7cc09338445188ba18482365c2a1.tar.gz edk2-d055601ea7dc7cc09338445188ba18482365c2a1.tar.bz2 edk2-d055601ea7dc7cc09338445188ba18482365c2a1.zip | |
OvmfPkg/QemuFwCfgLib: generalize InternalQemuFwCfgDmaBytes() to SKIP op
The fw_cfg DMA interface provides a simple method to skip over bytes in an
fw_cfg blob before reading or writing more bytes.
InternalQemuFwCfgDmaBytes() can support it easily, we just have to expose
the Control parameter more flexibly than the current "Write" BOOLEAN.
Cc: Jordan Justen <jordan.l.justen@intel.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=359
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Diffstat (limited to 'OvmfPkg/Library/QemuFwCfgLib')
| -rw-r--r-- | OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c | 31 |
1 files changed, 19 insertions, 12 deletions
diff --git a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c index a228c029df..6b6b2c7726 100644 --- a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c +++ b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c @@ -47,32 +47,39 @@ QemuFwCfgSelectItem ( /**
- Transfer an array of bytes using the DMA interface.
+ Transfer an array of bytes, or skip a number of bytes, using the DMA
+ interface.
- @param[in] Size Size in bytes to transfer.
- @param[in,out] Buffer Buffer to read data into or write data from. May be
- NULL if Size is zero.
- @param[in] Write TRUE if writing to fw_cfg from Buffer, FALSE if
- reading from fw_cfg into Buffer.
+ @param[in] Size Size in bytes to transfer or skip.
+
+ @param[in,out] Buffer Buffer to read data into or write data from. Ignored,
+ and may be NULL, if Size is zero, or Control is
+ FW_CFG_DMA_CTL_SKIP.
+
+ @param[in] Control One of the following:
+ FW_CFG_DMA_CTL_WRITE - write to fw_cfg from Buffer.
+ FW_CFG_DMA_CTL_READ - read from fw_cfg into Buffer.
+ FW_CFG_DMA_CTL_SKIP - skip bytes in fw_cfg.
**/
VOID
InternalQemuFwCfgDmaBytes (
IN UINT32 Size,
IN OUT VOID *Buffer OPTIONAL,
- IN BOOLEAN Write
+ IN UINT32 Control
)
{
volatile FW_CFG_DMA_ACCESS Access;
UINT32 AccessHigh, AccessLow;
UINT32 Status;
+ ASSERT (Control == FW_CFG_DMA_CTL_WRITE || Control == FW_CFG_DMA_CTL_READ ||
+ Control == FW_CFG_DMA_CTL_SKIP);
+
if (Size == 0) {
return;
}
- Access.Control = SwapBytes32 (
- Write ? FW_CFG_DMA_CTL_WRITE : FW_CFG_DMA_CTL_READ
- );
+ Access.Control = SwapBytes32 (Control);
Access.Length = SwapBytes32 (Size);
Access.Address = SwapBytes64 ((UINTN)Buffer);
@@ -125,7 +132,7 @@ InternalQemuFwCfgReadBytes ( )
{
if (InternalQemuFwCfgDmaIsAvailable () && Size <= MAX_UINT32) {
- InternalQemuFwCfgDmaBytes ((UINT32)Size, Buffer, FALSE);
+ InternalQemuFwCfgDmaBytes ((UINT32)Size, Buffer, FW_CFG_DMA_CTL_READ);
return;
}
IoReadFifo8 (0x511, Size, Buffer);
@@ -177,7 +184,7 @@ QemuFwCfgWriteBytes ( {
if (InternalQemuFwCfgIsAvailable ()) {
if (InternalQemuFwCfgDmaIsAvailable () && Size <= MAX_UINT32) {
- InternalQemuFwCfgDmaBytes ((UINT32)Size, Buffer, TRUE);
+ InternalQemuFwCfgDmaBytes ((UINT32)Size, Buffer, FW_CFG_DMA_CTL_WRITE);
return;
}
IoWriteFifo8 (0x511, Size, Buffer);
|