Amazon's Annapurna Labs DT-based PCIe host controller driver

This series adds support for Amazon's Annapurna Labs DT-based PCIe host controller driver.
Additionally, it adds 3 quirks (ACS, VPD and MSI-X) and 2 generic DWC patches.

Changes since v5:
- Modified commit subject of PATCH 6/7
- Removed timestamps from commit message of PATCH 4/7
- Modified ACS quirk according to Bjorn's comments

Changes since v4:
- Moved the HEADER_TYPE validations to after pp->ops->host_init() and ep->ops->ep_init()
- Changed to dw_pcie_rd_own_conf() instead of dw_pcie_readb_dbi() for reading the HEADER_TYPE
- Used existing quirk_blacklist_vpd() instead of quirk_al_vpd_release()
- Added a newline in ACS quirk comment

Changes since v3:
- Removed PATCH 8/8 since the usage of the PCI flags will be discussed in the upcoming LPC
- Align commit subject with the folder convention
- Added explanation regarding ECAM "overload" mechanism
- Switched to read/write{_relaxed} APIs
- Modified a dev_err to dev_dbg
- Removed unnecessary variable
- Removed driver details from dt-binding description
- Changed to SoC specific compatibles
- Fixed typo in a commit message
- Added comment regarding MSI in the MSI-X quirk

Changes since v2:
- Added al_pcie_controller_readl/writel() wrappers
- Reorganized local vars in several functions according to reverse tree structure
- Removed unnecessary check of ret value
- Changed return type of al_pcie_config_prepare() from int to void
- Removed check if link is up from probe() [done internally in dw_pcie_rd/wr_conf()]

Changes since v1:
- Added comment regarding 0x0031 being used as a dev_id for non root-port devices as well
- Fixed different message/comment/print wordings
- Added panic stacktrace to commit message of MSI-x quirk patch
- Changed to pci_warn() instead of dev_warn()
- Added unit_address after node_name in dt-binding
- Updated Kconfig help description
- Used GENMASK and FIELD_PREP/GET where appropriate
- Removed leftover field from struct al_pcie and moved all ptrs to
the beginning
- Re-wrapped function definitions and invocations to use fewer lines
- Change %p to %px in dbg prints in rd/wr_conf() functions
- Removed validation that the port is configured to RC mode (as this is added generically in PATCH 7/8)
- Removed unnecessary variable initializations
- Switched to %pR for printing resources

Ali Saidi (1):
PCI: Add ACS quirk for Amazon Annapurna Labs root ports

Jonathan Chocron (6):
PCI: Add Amazon's Annapurna Labs vendor ID
PCI/VPD: Prevent VPD access for Amazon's Annapurna Labs Root Port
PCI: Add quirk to disable MSI-X support for Amazon's Annapurna Labs
Root Port
dt-bindings: PCI: Add Amazon's Annapurna Labs PCIe host bridge binding
PCI: dwc: al: Add Amazon Annapurna Labs PCIe controller driver
PCI: dwc: Add validation that PCIe core is set to correct mode

 .../devicetree/bindings/pci/pcie-al.txt       |  46 +++
 MAINTAINERS                                   |   3 +-
 drivers/pci/controller/dwc/Kconfig            |  12 +
 drivers/pci/controller/dwc/pcie-al.c          | 365 ++++++++++++++++++
 .../pci/controller/dwc/pcie-designware-ep.c   |   8 +
 .../pci/controller/dwc/pcie-designware-host.c |  16 +
 drivers/pci/quirks.c                          |  38 ++
 drivers/pci/vpd.c                             |   6 +
 include/linux/pci_ids.h                       |   2 +
 9 files changed, 495 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/devicetree/bindings/pci/pcie-al.txt

2.17.1

Add Amazon's Annapurna Labs vendor ID to pci_ids.h.

---
 include/linux/pci_ids.h | 2 ++
 1 file changed, 2 insertions(+)

index f59a6f98900c..f3130542c752 100644
@@ -2571,6 +2571,8 @@
 
 #define PCI_VENDOR_ID_ASMEDIA		0x1b21
 
+#define PCI_VENDOR_ID_AMAZON_ANNAPURNA_LABS	0x1c36
+
 #define PCI_VENDOR_ID_CIRCUITCO		0x1cc8
 #define PCI_SUBSYSTEM_ID_CIRCUITCO_MINNOWBOARD	0x0001
 

2.17.1

From: Ali Saidi <[email protected]>

The Amazon's Annapurna Labs root ports don't advertise an ACS capability, but they don't allow peer-to-peer transactions and do validate bus numbers through the SMMU. Additionally, it's not possible for one RP to pass traffic to another RP.

---
 drivers/pci/quirks.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

index ded60757a573..2e983f2a0ee9 100644
@@ -4418,6 +4418,24 @@ static int pci_quirk_qcom_rp_acs(struct pci_dev *dev, u16 acs_flags)
 	return ret;
 }
 
+static int pci_quirk_al_acs(struct pci_dev *dev, u16 acs_flags)
+{
+	if (pci_pcie_type(dev) != PCI_EXP_TYPE_ROOT_PORT)
+		return -ENOTTY;
+
+	/*
+	 * Amazon's Annapurna Labs root ports don't include an ACS capability,
+	 * but do include ACS-like functionality. The hardware doesn't support
+	 * peer-to-peer transactions via the root port and each has a unique
+	 * segment number.
+	 *
+	 * Additionally, the root ports cannot send traffic to each other.
+	 */
+	acs_flags &= ~(PCI_ACS_SV | PCI_ACS_RR | PCI_ACS_CR | PCI_ACS_UF);
+
+	return acs_flags ? 0 : 1;
+}
+
 /*
  * Sunrise Point PCH root ports implement ACS, but unfortunately as shown in
  * the datasheet (Intel 100 Series Chipset Family PCH Datasheet, Vol. 2,

@@ -4611,6 +4629,8 @@ static const struct pci_dev_acs_enabled {
 	{ PCI_VENDOR_ID_AMPERE, 0xE00A, pci_quirk_xgene_acs },
 	{ PCI_VENDOR_ID_AMPERE, 0xE00B, pci_quirk_xgene_acs },
 	{ PCI_VENDOR_ID_AMPERE, 0xE00C, pci_quirk_xgene_acs },
+	/* Amazon Annapurna Labs */
+	{ PCI_VENDOR_ID_AMAZON_ANNAPURNA_LABS, 0x0031, pci_quirk_al_acs },
 	{ 0 }
 };
 

2.17.1

The Amazon Annapurna Labs PCIe Root Port exposes the VPD capability, but there is no actual support for it.

Trying to access the VPD (for example, as part of lspci -vv or when reading the vpd sysfs file), results in the following warning print:

pcieport 0001:00:00.0: VPD access failed. This is likely a firmware bug on this device. Contact the card vendor for a firmware update

---
 drivers/pci/vpd.c | 6 ++++++
 1 file changed, 6 insertions(+)

index 4963c2e2bd4c..7915d10f9aa1 100644
@@ -571,6 +571,12 @@ DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LSI_LOGIC, 0x005f, quirk_blacklist_vpd);
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATTANSIC, PCI_ANY_ID,
 		quirk_blacklist_vpd);
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_QLOGIC, 0x2261, quirk_blacklist_vpd);
+/*
+ * The Amazon Annapurna Labs 0x0031 device id is reused for other non Root Port
+ * device types, so the quirk is registered for the PCI_CLASS_BRIDGE_PCI class.
+ */
+DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_AMAZON_ANNAPURNA_LABS, 0x0031,
+			      PCI_CLASS_BRIDGE_PCI, 8, quirk_blacklist_vpd);
 
 /*
  * For Broadcom 5706, 5708, 5709 rev. A nics, any read beyond the

2.17.1

The Root Port (identified by [1c36:0031]) doesn't support MSI-X. On some platforms it is configured to not advertise the capability at all, while on others it (mistakenly) does. This causes a panic during initialization by the pcieport driver, since it tries to configure the MSI-X capability. Specifically, when trying to access the MSI-X table a "non-existing addr" exception occurs.

Example stacktrace snippet:

SError Interrupt on CPU2, code 0xbf000000 -- SError

  CPU: 2 PID: 1 Comm: swapper/0 Not tainted 5.2.0-rc1-Jonny-14847-ge76f1d4a1828-dirty #33
  Hardware name: Annapurna Labs Alpine V3 EVP (DT)
  pstate: 80000005 (Nzcv daif -PAN -UAO)
  pc : __pci_enable_msix_range+0x4e4/0x608
  lr : __pci_enable_msix_range+0x498/0x608
  sp : ffffff80117db700
  x29: ffffff80117db700 x28: 0000000000000001
  x27: 0000000000000001 x26: 0000000000000000
  x25: ffffffd3e9d8c0b0 x24: 0000000000000000
  x23: 0000000000000000 x22: 0000000000000000
  x21: 0000000000000001 x20: 0000000000000000
  x19: ffffffd3e9d8c000 x18: ffffffffffffffff
  x17: 0000000000000000 x16: 0000000000000000
  x15: ffffff80116496c8 x14: ffffffd3e9844503
  x13: ffffffd3e9844502 x12: 0000000000000038
  x11: ffffffffffffff00 x10: 0000000000000040
  x9 : ffffff801165e270 x8 : ffffff801165e268
  x7 : 0000000000000002 x6 : 00000000000000b2
  x5 : ffffffd3e9d8c2c0 x4 : 0000000000000000
  x3 : 0000000000000000 x2 : 0000000000000000
  x1 : 0000000000000000 x0 : ffffffd3e9844680
  Kernel panic - not syncing: Asynchronous SError Interrupt
  CPU: 2 PID: 1 Comm: swapper/0 Not tainted 5.2.0-rc1-Jonny-14847-ge76f1d4a1828-dirty #33
  Hardware name: Annapurna Labs Alpine V3 EVP (DT)
  Call trace:
   dump_backtrace+0x0/0x140
   show_stack+0x14/0x20
   dump_stack+0xa8/0xcc
   panic+0x140/0x334
   nmi_panic+0x6c/0x70
   arm64_serror_panic+0x74/0x88
   __pte_error+0x0/0x28
   el1_error+0x84/0xf8
   __pci_enable_msix_range+0x4e4/0x608
   pci_alloc_irq_vectors_affinity+0xdc/0x150
   pcie_port_device_register+0x2b8/0x4e0
   pcie_portdrv_probe+0x34/0xf0

Notice that this quirk also disables MSI (which may work, but hasn't been tested nor has a current use case), since currently there is no standard way to disable only MSI-X.

---
 drivers/pci/quirks.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

index 2e983f2a0ee9..c1077e806291 100644
@@ -2977,6 +2977,24 @@ DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATTANSIC, 0x10a1,
 			quirk_msi_intx_disable_qca_bug);
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATTANSIC, 0xe091,
 			quirk_msi_intx_disable_qca_bug);
+
+/*
+ * Amazon's Annapurna Labs 1c36:0031 Root Ports don't support MSI-X, so it
+ * should be disabled on platforms where the device (mistakenly) advertises it.
+ *
+ * Notice that this quirk also disables MSI (which may work, but hasn't been
+ * tested), since currently there is no standard way to disable only MSI-X.
+ *
+ * The 0031 device id is reused for other non Root Port device types,
+ * therefore the quirk is registered for the PCI_CLASS_BRIDGE_PCI class.
+ */
+static void quirk_al_msi_disable(struct pci_dev *dev)
+{
+	dev->no_msi = 1;
+	pci_warn(dev, "Disabling MSI/MSI-X\n");
+}
+DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_AMAZON_ANNAPURNA_LABS, 0x0031,
+			      PCI_CLASS_BRIDGE_PCI, 8, quirk_al_msi_disable);
 #endif /* CONFIG_PCI_MSI */
 
 /*

2.17.1

I will prepare this series for upstream but I would like to have Bjorn's ACK before pushing it out since you updated this patch following his review.

Thanks,
Lorenzo

Document Amazon's Annapurna Labs PCIe host bridge.

---
 .../devicetree/bindings/pci/pcie-al.txt       | 46 +++++++++++++++++++
 MAINTAINERS                                   |  3 +-
 2 files changed, 48 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/devicetree/bindings/pci/pcie-al.txt

new file mode 100644
index 000000000000..557a5089229d
@@ -0,0 +1,46 @@
+* Amazon Annapurna Labs PCIe host bridge
+
+Amazon's Annapurna Labs PCIe Host Controller is based on the Synopsys DesignWare
+PCI core. It inherits common properties defined in
+Documentation/devicetree/bindings/pci/designware-pcie.txt.
+
+Properties of the host controller node that differ from it are:
+
+- compatible:
+	Usage: required
+	Value type: <stringlist>
+	Definition: Value should contain
+			- "amazon,al-alpine-v2-pcie" for alpine_v2
+			- "amazon,al-alpine-v3-pcie" for alpine_v3
+
+- reg:
+	Usage: required
+	Value type: <prop-encoded-array>
+	Definition: Register ranges as listed in the reg-names property
+
+- reg-names:
+	Usage: required
+	Value type: <stringlist>
+	Definition: Must include the following entries
+			- "config"	PCIe ECAM space
+			- "controller"	AL proprietary registers
+			- "dbi"		Designware PCIe registers
+
+Example:
+
+	pcie-external0: pcie@fb600000 {
+		compatible = "amazon,al-alpine-v3-pcie";
+		reg = <0x0 0xfb600000 0x0 0x00100000
+		       0x0 0xfd800000 0x0 0x00010000
+		       0x0 0xfd810000 0x0 0x00001000>;
+		reg-names = "config", "controller", "dbi";
+		bus-range = <0 255>;
+		device_type = "pci";
+		#address-cells = <3>;
+		#size-cells = <2>;
+		#interrupt-cells = <1>;
+		interrupts = <GIC_SPI 49 IRQ_TYPE_LEVEL_HIGH>;
+		interrupt-map-mask = <0x00 0 0 7>;
+		interrupt-map = <0x0000 0 0 1 &gic GIC_SPI 41 IRQ_TYPE_LEVEL_HIGH>; /* INTa */
+		ranges = <0x02000000 0x0 0xc0010000 0x0 0xc0010000 0x0 0x07ff0000>;
+	};

index 783569e3c4b4..d200b16fa95c 100644
@@ -12448,10 +12448,11 @@ T:	git git://git.kernel.org/pub/scm/linux/kernel/git/lpieralisi/pci.git/
 S:	Supported
 F:	drivers/pci/controller/
 
-PCIE DRIVER FOR ANNAPURNA LABS
+PCIE DRIVER FOR AMAZON ANNAPURNA LABS
 M:	Jonathan Chocron <[email protected]>
 L:	[email protected]
 S:	Maintained
+F:	Documentation/devicetree/bindings/pci/pcie-al.txt
 F:	drivers/pci/controller/dwc/pcie-al.c
 
 PCIE DRIVER FOR AMLOGIC MESON

2.17.1

This driver is DT based and utilizes the DesignWare APIs.

It allows using a smaller ECAM range for a larger bus range - usually an entire bus uses 1MB of address space, but the driver can use it for a larger number of buses. This is achieved by using a HW mechanism which allows changing the BUS part of the "final" outgoing config transaction. There are 2 HW regs, one which is basically a bitmask determining which bits to take from the AXI transaction itself and another which holds the complementary part programmed by the driver.

All link initializations are handled by the boot FW.

---
 drivers/pci/controller/dwc/Kconfig   |  12 +
 drivers/pci/controller/dwc/pcie-al.c | 365 +++++++++++++++++++++++++++
 2 files changed, 377 insertions(+)

index 4fada2e93285..0ba988b5b5bc 100644
@@ -256,4 +256,16 @@ config PCIE_UNIPHIER
 	  Say Y here if you want PCIe controller support on UniPhier SoCs.
 	  This driver supports LD20 and PXs3 SoCs.
 
+config PCIE_AL
+	bool "Amazon Annapurna Labs PCIe controller"
+	depends on OF && (ARM64 || COMPILE_TEST)
+	depends on PCI_MSI_IRQ_DOMAIN
+	select PCIE_DW_HOST
+	help
+	  Say Y here to enable support of the Amazon's Annapurna Labs PCIe
+	  controller IP on Amazon SoCs. The PCIe controller uses the DesignWare
+	  core plus Annapurna Labs proprietary hardware wrappers. This is
+	  required only for DT-based platforms. ACPI platforms with the
+	  Annapurna Labs PCIe controller don't need to enable this.
+
 endmenu

2.17.1

Some PCIe controllers can be set to either Host or EP according to some early boot FW. To make sure there is no discrepancy (e.g. FW configured the port to EP mode while the DT specifies it as a host bridge or vice versa), a check has been added for each mode.

---
 drivers/pci/controller/dwc/pcie-designware-ep.c  |  8 ++++++++
 .../pci/controller/dwc/pcie-designware-host.c    | 16 ++++++++++++++++
 2 files changed, 24 insertions(+)

index 65f479250087..3dd2e2697294 100644
@@ -498,6 +498,7 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
 	int ret;
 	u32 reg;
 	void *addr;
+	u8 hdr_type;
 	unsigned int nbars;
 	unsigned int offset;
 	struct pci_epc *epc;

@@ -562,6 +563,13 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
 	if (ep->ops->ep_init)
 		ep->ops->ep_init(ep);
 
+	hdr_type = dw_pcie_readb_dbi(pci, PCI_HEADER_TYPE);
+	if (hdr_type != PCI_HEADER_TYPE_NORMAL) {
+		dev_err(pci->dev, "PCIe controller is not set to EP mode (hdr_type:0x%x)!\n",
+			hdr_type);
+		return -EIO;
+	}
+
 	ret = of_property_read_u8(np, "max-functions", &epc->max_functions);
 	if (ret < 0)
 		epc->max_functions = 1;

index d3156446ff27..0f36a926059a 100644
@@ -323,6 +323,7 @@ int dw_pcie_host_init(struct pcie_port *pp)
 	struct pci_bus *child;
 	struct pci_host_bridge *bridge;
 	struct resource *cfg_res;
+	u32 hdr_type;
 	int ret;
 
 	raw_spin_lock_init(&pci->pp.lock);

@@ -464,6 +465,21 @@ int dw_pcie_host_init(struct pcie_port *pp)
 			goto err_free_msi;
 	}
 
+	ret = dw_pcie_rd_own_conf(pp, PCI_HEADER_TYPE, 1, &hdr_type);
+	if (ret != PCIBIOS_SUCCESSFUL) {
+		dev_err(pci->dev, "Failed reading PCI_HEADER_TYPE cfg space reg (ret: 0x%x)\n",
+			ret);
+		ret = pcibios_err_to_errno(ret);
+		goto err_free_msi;
+	}
+	if (hdr_type != PCI_HEADER_TYPE_BRIDGE) {
+		dev_err(pci->dev,
+			"PCIe controller is not set to bridge type (hdr_type: 0x%x)!\n",
+			hdr_type);
+		ret = -EIO;
+		goto err_free_msi;
+	}
+
 	pp->root_bus_nr = pp->busn->start;
 
 	bridge->dev.parent = dev;

2.17.1