PMP registers used to be accessed with dedicated accessors ->pmp_read
and ->pmp_write. During reset, those callbacks are called with the
port frozen so they should be able to run without depending on
interrupt delivery. To achieve this, they were implemented polling.
However, as resetting the host port makes the PMP to isolate fan-out
ports until SError.X is cleared, resetting fan-out ports while port is
frozen doesn't buy much additional safety.
This patch updates libata PMP support such that PMP registers are
accessed using regular ata_exec_internal() mechanism and kills
->pmp_read/write() callbacks. The following changes are made.
* PMP access helpers - sata_pmp_read_init_tf(), sata_pmp_read_val(),
sata_pmp_write_init_tf() are folded into sata_pmp_read/write() which
are now standalone PMP register access functions.
* sata_pmp_read/write() returns err_mask instead of rc. This is
consistent with other functions which issue internal commands and
allows more detailed error reporting.
* ahci interrupt handler is modified to ignore BAD_PMP and
spurious/illegal completion IRQs while reset is in progress. These
conditions are expected during reset.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Extend ata_acpi_associate_sata_port() such that it can handle PMP and
call it when PMP is attached and detached.
Build breakage when !CONFIG_ATA_ACPI was spotted and fixed by Petr
Vandrovec.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Petr Vandrovec <petr@vandrovec.name>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Implement Port Multiplier support. To support PMP, a LLDD has to
supply ops->pmp_read() and pmp_write(). If non-null, ->pmp_attach and
->pmp_detach are called on PMP attach and detach, respectively.
->pmp_read/write() can be called while the port is frozen, so they
must be implemented by polling. This patch supplies several helpers
to ease ->pmp_read/write() implementation.
Also, irq_handler and error_handler must be PMP aware. Most of PMP
aware EH can be done by calling ata_pmp_do_eh() with appropriate
methods. PMP EH uses separate set of reset methods and this patch
implements standard prereset, hardreset and postreset methods.
This patch only implements PMP support. The next patch will integrate
PMP into the reset of libata and thus enable PMP support.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Tejun Heo