From dfc229f6a67b03e3c47b67b92982a100cfef738a Mon Sep 17 00:00:00 2001 From: Laszlo Ersek Date: Tue, 19 Jan 2016 10:46:34 +0000 Subject: [PATCH] MdeModulePkg/.../IdeMode: actualize DRQReady*() comment blocks The DRQReady() and DRQReady2() functions only differ in that they poll different status registers for BSY, ERR, and DRQ: the former looks at the Status Register (clearing interrupt status), while the latter looks at the Alternate Status Register (not clearing interrupt status). They both correctly return a unique status code, EFI_NOT_READY, for the BSY==0 && ERR==0 && DRQ==0 case; that is, when the device reports "command complete". However, the functions' leading comments don't explain this case, so it's easy to miss in callers. Update the comments. Cc: Feng Tian Cc: Star Zeng Cc: John Snow Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Laszlo Ersek Reviewed-by: Feng Tian git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@19684 6f19259b-4bc3-4df7-8a09-765794883524 --- .../Bus/Ata/AtaAtapiPassThru/IdeMode.c | 31 +++++++++++++++---- 1 file changed, 25 insertions(+), 6 deletions(-) diff --git a/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/IdeMode.c b/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/IdeMode.c index f74e5ca373..b06f9889ed 100644 --- a/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/IdeMode.c +++ b/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/IdeMode.c @@ -467,9 +467,18 @@ DRQClear2 ( @param IdeRegisters A pointer to EFI_IDE_REGISTERS data structure. @param Timeout The time to complete the command, uses 100ns as a unit. - @retval EFI_SUCCESS DRQ bit set within the time out. - @retval EFI_TIMEOUT DRQ bit not set within the time out. - @retval EFI_ABORTED DRQ bit not set caused by the command abort. + @retval EFI_SUCCESS BSY bit cleared and DRQ bit set within the + timeout. + + @retval EFI_TIMEOUT BSY bit not cleared within the timeout. + + @retval EFI_ABORTED Polling abandoned due to command abort. + + @retval EFI_DEVICE_ERROR Polling abandoned due to a non-abort error. + + @retval EFI_NOT_READY BSY bit cleared within timeout, and device + reported "command complete" by clearing DRQ + bit. @note Read Status Register will clear interrupt status. @@ -542,9 +551,19 @@ DRQReady ( @param IdeRegisters A pointer to EFI_IDE_REGISTERS data structure. @param Timeout The time to complete the command, uses 100ns as a unit. - @retval EFI_SUCCESS DRQ bit set within the time out. - @retval EFI_TIMEOUT DRQ bit not set within the time out. - @retval EFI_ABORTED DRQ bit not set caused by the command abort. + @retval EFI_SUCCESS BSY bit cleared and DRQ bit set within the + timeout. + + @retval EFI_TIMEOUT BSY bit not cleared within the timeout. + + @retval EFI_ABORTED Polling abandoned due to command abort. + + @retval EFI_DEVICE_ERROR Polling abandoned due to a non-abort error. + + @retval EFI_NOT_READY BSY bit cleared within timeout, and device + reported "command complete" by clearing DRQ + bit. + @note Read Alternate Status Register will not clear interrupt status. **/