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From:   Filippo Sironi <sironi@amazon.de>
To:     <serebrin@amazon.com>, <dwmw@amazon.co.uk>, <kbusch@kernel.org>,
        <axboe@fb.com>, <hch@lst.de>, <sagi@grimberg.me>,
        <linux-nvme@lists.infradead.org>, <linux-kernel@vger.kernel.org>
CC:     Filippo Sironi <sironi@amazon.de>
Subject: [PATCH] nvme: Add 48-bit DMA address quirk
Date:   Wed, 3 Feb 2021 10:43:38 +0100
Message-ID: <20210203094338.19473-1-sironi@amazon.de>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

Certain NVMe controllers don't support 64-bit DMA addresses.  Instead,
they are limited to 48-bit DMA addresses.  Let's add a quirk to use them
properly.

Signed-off-by: Filippo Sironi <sironi@amazon.de>
---
 drivers/nvme/host/nvme.h |  5 +++++
 drivers/nvme/host/pci.c  | 12 +++++++++++-
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index 88a6b97247f5..dae747b4ac35 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -144,6 +144,11 @@ enum nvme_quirks {
 	 * NVMe 1.3 compliance.
 	 */
 	NVME_QUIRK_NO_NS_DESC_LIST		= (1 << 15),
+
+	/*
+	 * The controller supports up to 48-bit DMA address.
+	 */
+	NVME_QUIRK_DMA_ADDRESS_BITS_48		= (1 << 16),
 };
 
 /*
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 81e6389b2042..5716ae16c7a7 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -2362,13 +2362,16 @@ static int nvme_pci_enable(struct nvme_dev *dev)
 {
 	int result = -ENOMEM;
 	struct pci_dev *pdev = to_pci_dev(dev->dev);
+	int dma_address_bits = 64;
 
 	if (pci_enable_device_mem(pdev))
 		return result;
 
 	pci_set_master(pdev);
 
-	if (dma_set_mask_and_coherent(dev->dev, DMA_BIT_MASK(64)))
+	if (dev->ctrl.quirks & NVME_QUIRK_DMA_ADDRESS_BITS_48)
+		dma_address_bits = 48;
+	if (dma_set_mask_and_coherent(dev->dev, DMA_BIT_MASK(dma_address_bits)))
 		goto disable;
 
 	if (readl(dev->bar + NVME_REG_CSTS) == -1) {
@@ -3259,6 +3262,13 @@ static const struct pci_device_id nvme_id_table[] = {
 		.driver_data = NVME_QUIRK_DISABLE_WRITE_ZEROES, },
 	{ PCI_DEVICE(0x1d97, 0x2263),   /* SPCC */
 		.driver_data = NVME_QUIRK_DISABLE_WRITE_ZEROES, },
+	{ .vendor = PCI_VENDOR_ID_AMAZON,
+	  .device = PCI_ANY_ID,
+	  .subvendor = PCI_ANY_ID,
+	  .subdevice = PCI_ANY_ID,
+	  .class = PCI_CLASS_STORAGE_EXPRESS,
+	  .class_mask = 0xffffff,
+	  .driver_data = NVME_QUIRK_DMA_ADDRESS_BITS_48 },
 	{ PCI_DEVICE(PCI_VENDOR_ID_APPLE, 0x2001),
 		.driver_data = NVME_QUIRK_SINGLE_VECTOR },
 	{ PCI_DEVICE(PCI_VENDOR_ID_APPLE, 0x2003) },
-- 
2.17.1


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