While most hardware will simply ignore a write to a read-only register, some hardware will signal an abort if this occurs.
This commit introduces the flag AHCI_HFLAG_NO_WRITE_TO_RO to prevent the AHCI library from attempting to write to the HOST_CAP, HOST_CAP2, and HOST_PORTS_IMPL registers which may be read-only. Signed-off-by: Doug Berger <[email protected]> --- drivers/ata/ahci.h | 2 ++ drivers/ata/libahci.c | 3 ++- 2 files changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/ata/ahci.h b/drivers/ata/ahci.h index ee176e4af97a..8b61123d2c3c 100644 --- a/drivers/ata/ahci.h +++ b/drivers/ata/ahci.h @@ -249,6 +249,8 @@ enum { #endif AHCI_HFLAG_WAKE_BEFORE_STOP = (1 << 22), /* wake before DMA stop */ AHCI_HFLAG_YES_ALPM = (1 << 23), /* force ALPM cap on */ + AHCI_HFLAG_NO_WRITE_TO_RO = (1 << 24), /* don't write to read + only registers */ /* ap->flags bits */ diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c index 4462f8a8cf2c..3e286d86ab42 100644 --- a/drivers/ata/libahci.c +++ b/drivers/ata/libahci.c @@ -945,7 +945,8 @@ int ahci_reset_controller(struct ata_host *host) /* Some registers might be cleared on reset. Restore * initial values. */ - ahci_restore_initial_config(host); + if (!(hpriv->flags & AHCI_HFLAG_NO_WRITE_TO_RO)) + ahci_restore_initial_config(host); } else dev_info(host->dev, "skipping global host reset\n"); -- 2.13.0
