[PATCH] nvme: Quirks for PM1725 controllers

[Martin K. Petersen]

PM1725 controllers have a couple of quirks that need to be handled in
the driver:

 - I/O queue depth must be limited to 64 entries on controllers that do
   not report MQES.

 - The host interface registers go offline briefly while resetting the
   chip. Thus a delay is needed before checking whether the controller
   is ready.

Note that the admin queue depth is also limited to 64 on older versions
of this board. Since our NVME_AQ_DEPTH is now 32 that is no longer an
issue.

Signed-off-by: Martin K. Petersen <martin.petersen at oracle.com>
---
 drivers/nvme/host/pci.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 32a98e2740ad..343263bcb49a 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -1908,6 +1908,12 @@ static int nvme_pci_enable(struct nvme_dev *dev)
 		dev_warn(dev->ctrl.device, "detected Apple NVMe controller, "
 			"set queue depth=%u to work around controller resets\n",
 			dev->q_depth);
+	} else if (pdev->vendor == PCI_VENDOR_ID_SAMSUNG &&
+		   (pdev->device == 0xa821 || pdev->device == 0xa822) &&
+		   NVME_CAP_MQES(cap) == 0) {
+		dev->q_depth = 64;
+		dev_err(dev->ctrl.device, "detected PM1725 NVMe controller, "
+                        "set queue depth=%u\n", dev->q_depth);
 	}
 
 	/*
@@ -2454,6 +2460,10 @@ static const struct pci_device_id nvme_id_table[] = {
 		.driver_data = NVME_QUIRK_DELAY_BEFORE_CHK_RDY, },
 	{ PCI_DEVICE(0x1c5f, 0x0540),	/* Memblaze Pblaze4 adapter */
 		.driver_data = NVME_QUIRK_DELAY_BEFORE_CHK_RDY, },
+	{ PCI_DEVICE(0x144d, 0xa821),   /* Samsung PM1725 */
+		.driver_data = NVME_QUIRK_DELAY_BEFORE_CHK_RDY, },
+	{ PCI_DEVICE(0x144d, 0xa822),   /* Samsung PM1725a */
+		.driver_data = NVME_QUIRK_DELAY_BEFORE_CHK_RDY, },
 	{ PCI_DEVICE_CLASS(PCI_CLASS_STORAGE_EXPRESS, 0xffffff) },
 	{ PCI_DEVICE(PCI_VENDOR_ID_APPLE, 0x2001) },
 	{ PCI_DEVICE(PCI_VENDOR_ID_APPLE, 0x2003) },
-- 
2.13.0