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Add support for AHCI BIOS/OS Handoff.

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This allows clean handoff from BIOS implementing some asynchronous I/O to
the OS AHCI driver.  During attach driver declares OS ownership request
and waits from 25ms to 2s for BIOS to complete operation and release the
hardware.

MFC after:	2 weeks
This commit is contained in:
Alexander Motin 2020-04-01 03:27:47 +00:00
parent 16b766eed4
commit 274328a4ef
2 changed files with 27 additions and 0 deletions
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20
sys/dev/ahci/ahci.c
View File

@ -141,8 +141,28 @@ int
ahci_ctlr_reset(device_t dev)
{
struct ahci_controller *ctlr = device_get_softc(dev);
uint32_t v;
int timeout;
/* BIOS/OS Handoff */
if ((ATA_INL(ctlr->r_mem, AHCI_VS) >= 0x00010200) &&
(ATA_INL(ctlr->r_mem, AHCI_CAP2) & AHCI_CAP2_BOH) &&
((v = ATA_INL(ctlr->r_mem, AHCI_BOHC)) & AHCI_BOHC_OOS) == 0) {
/* Request OS ownership. */
ATA_OUTL(ctlr->r_mem, AHCI_BOHC, v | AHCI_BOHC_OOS);
/* Wait up to 2s for BIOS ownership release. */
for (timeout = 0; timeout < 80; timeout++) {
DELAY(25000);
v = ATA_INL(ctlr->r_mem, AHCI_BOHC);
if ((v & AHCI_BOHC_BOS) == 0)
break;
if ((v & AHCI_BOHC_BB) == 0)
break;
}
}
/* Enable AHCI mode */
ATA_OUTL(ctlr->r_mem, AHCI_GHC, AHCI_GHC_AE);
/* Reset AHCI controller */

7
sys/dev/ahci/ahci.h
View File

@ -214,6 +214,13 @@
#define AHCI_CAP2_SADM 0x00000010
#define AHCI_CAP2_DESO 0x00000020
#define AHCI_BOHC 0x28
#define AHCI_BOHC_BOS 0x00000001
#define AHCI_BOHC_OOS 0x00000002
#define AHCI_BOHC_SOOE 0x00000004
#define AHCI_BOHC_OOC 0x00000008
#define AHCI_BOHC_BB 0x00000010
#define AHCI_VSCAP 0xa4
#define AHCI_OFFSET 0x100
#define AHCI_STEP 0x80