[RFC PATCH] PCI/pci-host-generic: Add support for Cavium Thunder fixed BARs.

David Daney ddaney.cavm at gmail.com
Mon Sep 28 17:56:24 PDT 2015


From: David Daney <david.daney at cavium.com>

Early versions of the Cavium Thunder CN88XX processor are missing
Enhanced Allocation (EA) capabilities for the fixed BAR addresses used
by the on-SoC hardware blocks.

Add config access functions that synthesize the missing EA
capabilities for versions that are missing that information.  Since
this is a little hacky, gate the inclusion of the code with a new
Kconfig variable.

Signed-off-by: David Daney <david.daney at cavium.com>
---

As suggested by Bjorn Helgaas...  It is RFC at this point, but this is
working well for me.

Depends on:

https://lkml.org/lkml/2015/9/28/796

 drivers/pci/host/Kconfig                  |   9 +
 drivers/pci/host/Makefile                 |   1 +
 drivers/pci/host/pci-host-generic.c       |  22 ++-
 drivers/pci/host/thunder_ecam_config_io.c | 273 ++++++++++++++++++++++++++++++
 4 files changed, 304 insertions(+), 1 deletion(-)
 create mode 100644 drivers/pci/host/thunder_ecam_config_io.c

diff --git a/drivers/pci/host/Kconfig b/drivers/pci/host/Kconfig
index d5e58ba..9f3a9cd 100644
--- a/drivers/pci/host/Kconfig
+++ b/drivers/pci/host/Kconfig
@@ -58,6 +58,15 @@ config PCI_HOST_GENERIC
 	  Say Y here if you want to support a simple generic PCI host
 	  controller, such as the one emulated by kvmtool.
 
+config PCI_HOST_THUNDER
+	bool "Extensions to Generic PCI host controller for Cavium Thunder"
+	depends on PCI_HOST_GENERIC && ARM64
+	help
+	  Say Y here to enable PCI config access methods needed by
+	  CN88XX Cavium Thunder SoCs.  The access is standard ECAM,
+	  but Enhanced Allocation (EA) capability structures are
+	  synthesized for on-SoC devices with fixed BARs.
+
 config PCIE_SPEAR13XX
 	bool "STMicroelectronics SPEAr PCIe controller"
 	depends on ARCH_SPEAR13XX
diff --git a/drivers/pci/host/Makefile b/drivers/pci/host/Makefile
index 140d66f..8b77d62 100644
--- a/drivers/pci/host/Makefile
+++ b/drivers/pci/host/Makefile
@@ -7,6 +7,7 @@ obj-$(CONFIG_PCI_TEGRA) += pci-tegra.o
 obj-$(CONFIG_PCI_RCAR_GEN2) += pci-rcar-gen2.o
 obj-$(CONFIG_PCI_RCAR_GEN2_PCIE) += pcie-rcar.o
 obj-$(CONFIG_PCI_HOST_GENERIC) += pci-host-generic.o
+obj-$(CONFIG_PCI_HOST_THUNDER) += thunder_ecam_config_io.o
 obj-$(CONFIG_PCIE_SPEAR13XX) += pcie-spear13xx.o
 obj-$(CONFIG_PCI_KEYSTONE) += pci-keystone-dw.o pci-keystone.o
 obj-$(CONFIG_PCIE_XILINX) += pcie-xilinx.o
diff --git a/drivers/pci/host/pci-host-generic.c b/drivers/pci/host/pci-host-generic.c
index 6f12830..64558e5 100644
--- a/drivers/pci/host/pci-host-generic.c
+++ b/drivers/pci/host/pci-host-generic.c
@@ -91,6 +91,21 @@ static struct gen_pci_cfg_bus_ops gen_pci_cfg_ecam_bus_ops = {
 	}
 };
 
+#ifdef CONFIG_PCI_HOST_THUNDER
+int thunder_ecam_config_read(struct pci_bus *bus, unsigned int devfn,
+			     int where, int size, u32 *val);
+int thunder_ecam_config_write(struct pci_bus *bus, unsigned int devfn,
+			     int where, int size, u32 val);
+static struct gen_pci_cfg_bus_ops gen_pci_cfg_thunder_ecam_bus_ops = {
+	.bus_shift	= 20,
+	.ops		= {
+		.map_bus	= gen_pci_map_cfg_bus_ecam,
+		.read		= thunder_ecam_config_read,
+		.write		= thunder_ecam_config_write,
+	}
+};
+#endif
+
 static void __iomem *gen_pci_map_cfg_bus_thunder_pem(struct pci_bus *bus,
 						     unsigned int devfn,
 						     int where)
@@ -108,6 +123,7 @@ static void __iomem *gen_pci_map_cfg_bus_thunder_pem(struct pci_bus *bus,
 	return pci->cfg.win[idx] + ((devfn << 16) | where);
 }
 
+#ifdef CONFIG_PCI_HOST_THUNDER
 static struct gen_pci_cfg_bus_ops gen_pci_cfg_thunder_pem_bus_ops = {
 	.bus_shift	= 24,
 	.ops		= {
@@ -116,6 +132,7 @@ static struct gen_pci_cfg_bus_ops gen_pci_cfg_thunder_pem_bus_ops = {
 		.write		= pci_generic_config_write,
 	}
 };
+#endif
 
 static const struct of_device_id gen_pci_of_match[] = {
 	{ .compatible = "pci-host-cam-generic",
@@ -126,7 +143,10 @@ static const struct of_device_id gen_pci_of_match[] = {
 
 	{ .compatible = "cavium,pci-host-thunder-pem",
 	  .data = &gen_pci_cfg_thunder_pem_bus_ops },
-
+#ifdef CONFIG_PCI_HOST_THUNDER
+	{ .compatible = "cavium,pci-host-thunder-ecam",
+	  .data = &gen_pci_cfg_thunder_ecam_bus_ops },
+#endif
 	{ },
 };
 MODULE_DEVICE_TABLE(of, gen_pci_of_match);
diff --git a/drivers/pci/host/thunder_ecam_config_io.c b/drivers/pci/host/thunder_ecam_config_io.c
new file mode 100644
index 0000000..58c3109
--- /dev/null
+++ b/drivers/pci/host/thunder_ecam_config_io.c
@@ -0,0 +1,273 @@
+/*
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2015 Cavium, Inc.
+ *
+ */
+
+#include <linux/pci.h>
+#include <linux/ioport.h>
+#include <linux/printk.h>
+
+static void set_val(u32 v, int where, int size, u32 *val)
+{
+	int shift = (where & 3) * 8;
+
+	pr_debug("set_val %04x: %08x\n", (unsigned)(where & ~3), v);
+	v >>= shift;
+	if (size == 1)
+		v &= 0xff;
+	else if (size == 2)
+		v &= 0xffff;
+	*val = v;
+}
+
+static int handle_ea_bar(u32 e0, int bar, struct pci_bus *bus,
+			 unsigned int devfn, int where, int size, u32 *val)
+{
+	void __iomem *addr;
+	u32 v;
+	/*
+	 * Each entry is 16-byte aligned bits[2,3] select which word
+	 * in the entry
+	 */
+	int where_a = where & 0xc;
+
+	if (where_a == 0) {
+		set_val(e0, where, size, val);
+		return PCIBIOS_SUCCESSFUL;
+	}
+	if (where_a == 0x4) {
+		addr = bus->ops->map_bus(bus, devfn, bar); /* BAR 0 */
+		if (!addr) {
+			*val = ~0;
+			return PCIBIOS_DEVICE_NOT_FOUND;
+		}
+		v = readl(addr);
+		v &= ~0xf;
+		v |= 2; /* EA entry-1. Base-L */
+		set_val(v, where, size, val);
+		return PCIBIOS_SUCCESSFUL;
+	}
+	if (where_a == 0x8) {
+		u32 barl_orig;
+		u32 barl_rb;
+
+		addr = bus->ops->map_bus(bus, devfn, bar); /* BAR 0 */
+		if (!addr) {
+			*val = ~0;
+			return PCIBIOS_DEVICE_NOT_FOUND;
+		}
+		barl_orig = readl(addr + 0);
+		writel(0xffffffff, addr + 0);
+		barl_rb = readl(addr + 0);
+		writel(barl_orig, addr + 0);
+		/* zeros in unsettable bits. */
+		v = ~barl_rb & ~3;
+		v |= 0xc; /* EA entry-2. Offset-L */
+		set_val(v, where, size, val);
+		return PCIBIOS_SUCCESSFUL;
+	}
+	if (where_a == 0xc) {
+		addr = bus->ops->map_bus(bus, devfn, bar + 4); /* BAR 1 */
+		if (!addr) {
+			*val = ~0;
+			return PCIBIOS_DEVICE_NOT_FOUND;
+		}
+		v = readl(addr); /* EA entry-3. Base-H */
+		set_val(v, where, size, val);
+		return PCIBIOS_SUCCESSFUL;
+	}
+	return PCIBIOS_DEVICE_NOT_FOUND;
+}
+int thunder_ecam_config_write(struct pci_bus *bus, unsigned int devfn,
+			      int where, int size, u32 val)
+{
+	/*
+	 * All BARs have fixed addresses, ignore BAR writes so they
+	 * don't get corrupted.
+	 */
+	if ((where >= 0x10 && where < 0x2c) || (where >= 0x1a4 && where < 0x1bc))
+		/* BAR or SRIOV BAR */
+		return PCIBIOS_SUCCESSFUL;
+
+	return pci_generic_config_write(bus, devfn, where, size, val);
+}
+
+int thunder_ecam_config_read(struct pci_bus *bus, unsigned int devfn,
+			     int where, int size, u32 *val)
+{
+	u32 v;
+	u32 vendor_device;
+	void __iomem *addr;
+	int cfg_type;
+	int where_a = where & ~3;
+
+	/*
+	 * All BARs have fixed addresses specified by the EA
+	 * capability, they must return zero on read.
+	 */
+	if ((where >= 0x10 && where < 0x2c) || (where >= 0x1a4 && where < 0x1bc)) {
+		/* BAR or SRIOV BAR */
+		*val = 0;
+		return PCIBIOS_SUCCESSFUL;
+	}
+
+	addr = bus->ops->map_bus(bus, devfn, 0);
+	if (!addr) {
+		*val = ~0;
+		return PCIBIOS_DEVICE_NOT_FOUND;
+	}
+
+	vendor_device = readl(addr);
+	if (vendor_device == 0xffffffff)
+		goto no_emulation;
+
+	addr = bus->ops->map_bus(bus, devfn, 8);
+	if (!addr) {
+		*val = ~0;
+		return PCIBIOS_DEVICE_NOT_FOUND;
+	}
+
+	v = readl(addr);
+	if (v == 0xffffffff)
+		goto no_emulation;
+
+	if ((v & 0xff) < 8) {
+		pr_debug("%04x:%04x - Fix pass#: %08x, where: %03x, devfn: %03x\n",
+			 vendor_device & 0xffff, vendor_device >> 16, v, (unsigned) where, devfn);
+		/* pass 1.x*/
+	} else {
+		pr_debug("%04x:%04x - OK pass#: %08x, devfn: %03x\n",
+			 vendor_device & 0xffff, vendor_device >> 16, v, devfn);
+		goto no_emulation;
+	}
+
+	addr = bus->ops->map_bus(bus, devfn, 0xc);
+	if (!addr) {
+		*val = ~0;
+		return PCIBIOS_DEVICE_NOT_FOUND;
+	}
+
+	v = readl(addr);
+	/* Check for non type-00 header. */
+	cfg_type = (v >> 16) & 0x7f;
+	if (cfg_type == 0) {
+		bool has_msix;
+		bool is_nic = (vendor_device == 0xa01e177d);
+		bool is_tns = (vendor_device == 0xa01f177d);
+
+		addr = bus->ops->map_bus(bus, devfn, 0x70);
+		if (!addr) {
+			*val = ~0;
+			return PCIBIOS_DEVICE_NOT_FOUND;
+		}
+		/* E_CAP */
+		v = readl(addr);
+		has_msix = (v & 0xff00) != 0;
+
+		if (!has_msix && where_a == 0x70) {
+			v |= 0xbc00; /* next capability is EA at 0xbc */
+			set_val(v, where, size, val);
+			return PCIBIOS_SUCCESSFUL;
+		}
+		if (where_a == 0xb0) {
+			addr = bus->ops->map_bus(bus, devfn, where_a);
+			if (!addr) {
+				*val = ~0;
+				return PCIBIOS_DEVICE_NOT_FOUND;
+			}
+			v = readl(addr);
+			if (v & 0xff00)
+				pr_err("Bad MSIX cap header: %08x\n", v);
+			v |= 0xbc00; /* next capability is EA at 0xbc */
+			set_val(v, where, size, val);
+			return PCIBIOS_SUCCESSFUL;
+		}
+		if (where_a == 0xbc) {
+			if (is_nic)
+				v = 0x40014; /* EA last in chain, 4 entries. */
+			else if (is_tns)
+				v = 0x40014; /* EA last in chain, 3 entries. */
+			else if (has_msix)
+				v = 0x20014; /* EA last in chain, 2 entries. */
+			else
+				v = 0x10014; /* EA last in chain, 1 entry. */
+			set_val(v, where, size, val);
+			return PCIBIOS_SUCCESSFUL;
+		}
+		if (where_a >= 0xc0 && where_a < 0xd0)
+			return handle_ea_bar(0x80ff0003, /* EA entry-0. PP=0, BAR0 Size:3 */
+					     0x10, bus, devfn, where, size, val);
+		if (where_a >= 0xd0 && where_a < 0xe0 && has_msix)
+			return handle_ea_bar(0x80ff0043, /* EA entry-1. PP=0, BAR4 Size:3 */
+					     0x20, bus, devfn, where, size, val);
+		if (where_a >= 0xe0 && where_a < 0xf0 && is_tns)
+			return handle_ea_bar(0x80ff0023, /* EA entry-2. PP=0, BAR2, Size:3 */
+					     0x18, bus, devfn, where, size, val);
+		if (where_a >= 0xe0 && where_a < 0xf0 && is_nic)
+			return handle_ea_bar(0x80ff0493, /* EA entry-2. PP=4, VF_BAR0 (9), Size:3 */
+					     0x1a4, bus, devfn, where, size, val);
+		if (where_a >= 0xf0 && where_a < 0x100 && is_nic)
+			return handle_ea_bar(0x80ff04d3, /* EA entry-3. PP=4, VF_BAR4 (d), Size:3 */
+					     0x1b4, bus, devfn, where, size, val);
+	} else if (cfg_type == 1) {
+		if (where_a == 0x70) {
+			addr = bus->ops->map_bus(bus, devfn, where_a);
+			if (!addr) {
+				*val = ~0;
+				return PCIBIOS_DEVICE_NOT_FOUND;
+			}
+			v = readl(addr);
+			if (v & 0xff00)
+				pr_err("Bad PCIe cap header: %08x\n", v);
+			v |= 0xbc00; /* next capability is EA at 0xbc */
+			set_val(v, where, size, val);
+			return PCIBIOS_SUCCESSFUL;
+		}
+		if (where_a == 0xbc) {
+			v = 0x10014; /* EA last in chain, 1 entry. */
+			set_val(v, where, size, val);
+			return PCIBIOS_SUCCESSFUL;
+		}
+		if (where_a == 0xc0) {
+			v = 0x0101; /* subordinate:secondary = 1:1 */
+			set_val(v, where, size, val);
+			return PCIBIOS_SUCCESSFUL;
+		}
+		if (where_a == 0xc4) {
+			v = 0x80ff0564; /* Enabled, not-Write, SP=ff, PP=05, BEI=6, ES=4 */
+			set_val(v, where, size, val);
+			return PCIBIOS_SUCCESSFUL;
+		}
+		if (where_a == 0xc8) {
+			v = 0x00000002; /* Base-L 64-bit */
+			set_val(v, where, size, val);
+			return PCIBIOS_SUCCESSFUL;
+		}
+		if (where_a == 0xcc) {
+			v = 0xfffffffe; /* MaxOffset-L 64-bit */
+			set_val(v, where, size, val);
+			return PCIBIOS_SUCCESSFUL;
+		}
+		if (where_a == 0xd0) {
+			if (devfn == 8)
+				v = 0x000087e0; /* RSL Base-H */
+			else
+				v = 0x00008430; /* NIC Base-H */
+			set_val(v, where, size, val);
+			return PCIBIOS_SUCCESSFUL;
+		}
+		if (where_a == 0xd4) {
+			v = 0x0000000f; /* MaxOffset-H */
+			set_val(v, where, size, val);
+			return PCIBIOS_SUCCESSFUL;
+		}
+
+	}
+no_emulation:
+	return pci_generic_config_read(bus, devfn, where, size, val);
+}
-- 
1.9.1




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