[PATCH v4 3/4] nvme-pci: Add support for Apple 2018+ models

[Benjamin Herrenschmidt]

Based on reverse engineering and original patch by

Paul Pawlowski <paul@xxxxxxxx>

This adds support for Apple weird implementation of NVME in their
2018 or later machines. It accounts for the twice-as-big SQ entries
for the IO queues, and the fact that only interrupt vector 0 appears
to function properly.

Signed-off-by: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Reviewed-by: Minwoo Im <minwoo.im.dev@xxxxxxxxx>
---
 drivers/nvme/host/nvme.h | 10 ++++++++++
 drivers/nvme/host/pci.c  | 21 ++++++++++++++++++++-
 2 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index 8dc010ca30e5..0925f7fc13ff 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -92,6 +92,16 @@ enum nvme_quirks {
 	 * Broken Write Zeroes.
 	 */
 	NVME_QUIRK_DISABLE_WRITE_ZEROES		= (1 << 9),
+
+	/*
+	 * Use only one interrupt vector for all queues
+	 */
+	NVME_QUIRK_SINGLE_VECTOR		= (1 << 10),
+
+	/*
+	 * Use non-standard 128 bytes SQEs.
+	 */
+	NVME_QUIRK_128_BYTES_SQES		= (1 << 11),
 };
 
 /*
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 78a660e229d9..c683263cdf60 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -2081,6 +2081,13 @@ static int nvme_setup_irqs(struct nvme_dev *dev, unsigned int nr_io_queues)
 	dev->io_queues[HCTX_TYPE_DEFAULT] = 1;
 	dev->io_queues[HCTX_TYPE_READ] = 0;
 
+	/*
+	 * Some Apple controllers require all queues to use the
+	 * first vector.
+	 */
+	if (dev->ctrl.quirks & NVME_QUIRK_SINGLE_VECTOR)
+		irq_queues = 1;
+
 	return pci_alloc_irq_vectors_affinity(pdev, 1, irq_queues,
 			      PCI_IRQ_ALL_TYPES | PCI_IRQ_AFFINITY, &affd);
 }
@@ -2321,7 +2328,16 @@ static int nvme_pci_enable(struct nvme_dev *dev)
 	dev->ctrl.sqsize = dev->q_depth - 1; /* 0's based queue depth */
 	dev->db_stride = 1 << NVME_CAP_STRIDE(dev->ctrl.cap);
 	dev->dbs = dev->bar + 4096;
-	dev->io_sqes = NVME_NVM_IOSQES;
+
+	/*
+	 * Some Apple controllers require a non-standard SQE size.
+	 * Interestingly they also seem to ignore the CC:IOSQES register
+	 * so we don't bother updating it here.
+	 */
+	if (dev->ctrl.quirks & NVME_QUIRK_128_BYTES_SQES)
+		dev->io_sqes = 7;
+	else
+		dev->io_sqes = NVME_NVM_IOSQES;
 
 	/*
 	 * Temporary fix for the Apple controller found in the MacBook8,1 and
@@ -3039,6 +3055,9 @@ static const struct pci_device_id nvme_id_table[] = {
 	{ PCI_DEVICE_CLASS(PCI_CLASS_STORAGE_EXPRESS, 0xffffff) },
 	{ PCI_DEVICE(PCI_VENDOR_ID_APPLE, 0x2001) },
 	{ PCI_DEVICE(PCI_VENDOR_ID_APPLE, 0x2003) },
+	{ PCI_DEVICE(PCI_VENDOR_ID_APPLE, 0x2005),
+		.driver_data = NVME_QUIRK_SINGLE_VECTOR |
+				NVME_QUIRK_128_BYTES_SQES },
 	{ 0, }
 };
 MODULE_DEVICE_TABLE(pci, nvme_id_table);
-- 
2.17.1