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Commit bddc8027 authored by Guilherme G. Piccoli's avatar Guilherme G. Piccoli Committed by Greg Kroah-Hartman
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nvme/quirk: Add a delay before checking for adapter readiness 



commit 54adc01055b75ec8769c5a36574c7a0895c0c0b2 upstream.

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: default avatarGuilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
[mauricfo: backport to v4.4.70 without nvme quirk handling & nvme_ctrl]
Signed-off-by: default avatarMauricio Faria de Oliveira <mauricfo@linux.vnet.ibm.com>
Tested-by: default avatarNarasimhan Vaidyanathan <vnarasimhan@in.ibm.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent e5f87c73

drivers/nvme/host/nvme.h

+7 −0
Original line number Diff line number Diff line
@@ -27,6 +27,13 @@ enum { 
	NVME_NS_LIGHTNVM	= 1,

};



/* 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



/*

 * Represents an NVM Express device.  Each nvme_dev is a PCI function.

 */

drivers/nvme/host/pci.c

+10 −0
Original line number Diff line number Diff line
@@ -1633,10 +1633,20 @@ static int nvme_wait_ready(struct nvme_dev *dev, u64 cap, bool enabled) 
 */

static int nvme_disable_ctrl(struct nvme_dev *dev, u64 cap)

{

	struct pci_dev *pdev = to_pci_dev(dev->dev);



	dev->ctrl_config &= ~NVME_CC_SHN_MASK;

	dev->ctrl_config &= ~NVME_CC_ENABLE;

	writel(dev->ctrl_config, &dev->bar->cc);



	/* Checking for dev->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 (pdev->vendor == 0x1c58 && pdev->device == 0x0003 && dev->tagset)

		msleep(NVME_QUIRK_DELAY_AMOUNT);



	return nvme_wait_ready(dev, cap, false);

}