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nvme/quirk: Add a delay before checking for adapter readiness 

When disabling the controller, the specification says the register
NVME_REG_CC should be written and then driver needs to wait the
adapter to be ready, which is checked by reading another register
bit (NVME_CSTS_RDY). There's a timeout validation in this checking,
so in case this timeout is reached the driver gives up and removes
the adapter from the system.

After a firmware activation procedure, the PCI_DEVICE(0x1c58, 0x0003)
(HGST adapter) end up being removed if we issue a reset_controller,
because driver keeps verifying the NVME_REG_CSTS until the timeout is
reached. This patch adds a necessary quirk for this adapter, by
introducing a delay before nvme_wait_ready(), so the reset procedure
is able to be completed. This quirk is needed because just increasing
the timeout is not enough in case of this adapter - the driver must
wait before start reading NVME_REG_CSTS register on this specific
device.

Signed-off-by: Guilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Guilherme G. Piccoli 2016-06-14 18:22:41 -03:00 committed by Jens Axboe
parent 41d512e51b
commit 54adc01055
3 changed files with 24 additions and 0 deletions
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9
drivers/nvme/host/core.c
View File

@ -1109,6 +1109,15 @@ int nvme_disable_ctrl(struct nvme_ctrl *ctrl, u64 cap)
ret = ctrl->ops->reg_write32(ctrl, NVME_REG_CC, ctrl->ctrl_config);
if (ret)
return ret;
/* Checking for ctrl->tagset is a trick to avoid sleeping on module
* load, since we only need the quirk on reset_controller. Notice
* that the HGST device needs this delay only in firmware activation
* procedure; unfortunately we have no (easy) way to verify this.
*/
if ((ctrl->quirks & NVME_QUIRK_DELAY_BEFORE_CHK_RDY) && ctrl->tagset)
msleep(NVME_QUIRK_DELAY_AMOUNT);
return nvme_wait_ready(ctrl, cap, false);
}
EXPORT_SYMBOL_GPL(nvme_disable_ctrl);

13
drivers/nvme/host/nvme.h
View File

@ -68,8 +68,21 @@ enum nvme_quirks {
* logical blocks.
*/
NVME_QUIRK_DISCARD_ZEROES = (1 << 2),
/*
* The controller needs a delay before starts checking the device
* readiness, which is done by reading the NVME_CSTS_RDY bit.
*/
NVME_QUIRK_DELAY_BEFORE_CHK_RDY = (1 << 3),
};
/* The below value is the specific amount of delay needed before checking
* readiness in case of the PCI_DEVICE(0x1c58, 0x0003), which needs the
* NVME_QUIRK_DELAY_BEFORE_CHK_RDY quirk enabled. The value (in ms) was
* found empirically.
*/
#define NVME_QUIRK_DELAY_AMOUNT 2000
enum nvme_ctrl_state {
NVME_CTRL_NEW,
NVME_CTRL_LIVE,

2
drivers/nvme/host/pci.c
View File

@ -2094,6 +2094,8 @@ static const struct pci_device_id nvme_id_table[] = {
NVME_QUIRK_DISCARD_ZEROES, },
{ PCI_VDEVICE(INTEL, 0x5845), /* Qemu emulated controller */
.driver_data = NVME_QUIRK_IDENTIFY_CNS, },
{ PCI_DEVICE(0x1c58, 0x0003), /* HGST adapter */
.driver_data = NVME_QUIRK_DELAY_BEFORE_CHK_RDY, },
{ PCI_DEVICE_CLASS(PCI_CLASS_STORAGE_EXPRESS, 0xffffff) },
{ PCI_DEVICE(PCI_VENDOR_ID_APPLE, 0x2001) },
{ 0, }