diff options
Diffstat (limited to 'drivers/ata/libahci.c')
| -rw-r--r-- | drivers/ata/libahci.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c index 38e1b4e9ecf..3f586ec84a3 100644 --- a/drivers/ata/libahci.c +++ b/drivers/ata/libahci.c @@ -437,11 +437,29 @@ static int ahci_scr_write(struct ata_link *link, unsigned int sc_reg, u32 val) return -EINVAL; } +static int ahci_is_device_present(void __iomem *port_mmio) +{ + u8 status = readl(port_mmio + PORT_TFDATA) & 0xff; + + /* Make sure PxTFD.STS.BSY and PxTFD.STS.DRQ are 0 */ + if (status & (ATA_BUSY | ATA_DRQ)) + return 0; + + /* Make sure PxSSTS.DET is 3h */ + status = readl(port_mmio + PORT_SCR_STAT) & 0xf; + if (status != 3) + return 0; + return 1; +} + void ahci_start_engine(struct ata_port *ap) { void __iomem *port_mmio = ahci_port_base(ap); u32 tmp; + if (!ahci_is_device_present(port_mmio)) + return; + /* start DMA */ tmp = readl(port_mmio + PORT_CMD); tmp |= PORT_CMD_START; |