[PATCH v7 2/3] pci, pci-thunder-pem: Add PCIe host driver for ThunderX processors.
From: Yury Norov <hidden>
Date: 2016-03-05 15:54:57
Also in:
linux-devicetree, linux-pci, lkml
Hi David, On Fri, Mar 04, 2016 at 02:31:47PM -0800, David Daney wrote:
quoted hunk ↗ jump to hunk
From: David Daney <redacted> The root complexes used to access off-chip PCIe devices (called PEM units in the hardware manuals) on some Cavium ThunderX processors require quirky access methods for the config space of the PCIe bridge. Add a driver to provide these config space accessor functions. The pci-host-common code is used to configure the PCI machinery. Signed-off-by: David Daney <redacted> Acked-by: Rob Herring <robh@kernel.org> Acked-by: Arnd Bergmann <arnd@arndb.de> --- .../devicetree/bindings/pci/pci-thunder-pem.txt | 43 +++ MAINTAINERS | 8 + drivers/pci/host/Kconfig | 7 + drivers/pci/host/Makefile | 1 + drivers/pci/host/pci-thunder-pem.c | 347 +++++++++++++++++++++ 5 files changed, 406 insertions(+) create mode 100644 Documentation/devicetree/bindings/pci/pci-thunder-pem.txt create mode 100644 drivers/pci/host/pci-thunder-pem.cdiff --git a/Documentation/devicetree/bindings/pci/pci-thunder-pem.txt b/Documentation/devicetree/bindings/pci/pci-thunder-pem.txt new file mode 100644 index 0000000..f131fae --- /dev/null +++ b/Documentation/devicetree/bindings/pci/pci-thunder-pem.txt@@ -0,0 +1,43 @@ +* ThunderX PEM PCIe host controller + +Firmware-initialized PCI host controller found on some Cavium +ThunderX processors. + +The properties and their meanings are identical to those described in +host-generic-pci.txt except as listed below. + +Properties of the host controller node that differ from +host-generic-pci.txt: + +- compatible : Must be "cavium,pci-host-thunder-pem" + +- reg : Two entries: First the configuration space for down + stream devices base address and size, as accessed + from the parent bus. Second, the register bank of + the PEM device PCIe bridge. + +Example: + + pci at 87e0,c2000000 { + compatible = "cavium,pci-host-thunder-pem"; + device_type = "pci"; + msi-parent = <&its>; + msi-map = <0 &its 0x10000 0x10000>; + bus-range = <0x8f 0xc7>; + #size-cells = <2>; + #address-cells = <3>; + + reg = <0x8880 0x8f000000 0x0 0x39000000>, /* Configuration space */ + <0x87e0 0xc2000000 0x0 0x00010000>; /* PEM space */ + ranges = <0x01000000 0x00 0x00020000 0x88b0 0x00020000 0x00 0x00010000>, /* I/O */ + <0x03000000 0x00 0x10000000 0x8890 0x10000000 0x0f 0xf0000000>, /* mem64 */ + <0x43000000 0x10 0x00000000 0x88a0 0x00000000 0x10 0x00000000>, /* mem64-pref */ + <0x03000000 0x87e0 0xc2f00000 0x87e0 0xc2000000 0x00 0x00100000>; /* mem64 PEM BAR4 */ + + #interrupt-cells = <1>; + interrupt-map-mask = <0 0 0 7>; + interrupt-map = <0 0 0 1 &gic0 0 0 0 24 4>, /* INTA */ + <0 0 0 2 &gic0 0 0 0 25 4>, /* INTB */ + <0 0 0 3 &gic0 0 0 0 26 4>, /* INTC */ + <0 0 0 4 &gic0 0 0 0 27 4>; /* INTD */ + };diff --git a/MAINTAINERS b/MAINTAINERS index 370b3cb..cef8dda 100644 --- a/MAINTAINERS +++ b/MAINTAINERS@@ -8407,6 +8407,14 @@ L: linux-arm-msm at vger.kernel.org S: Maintained F: drivers/pci/host/*qcom* +PCIE DRIVER FOR CAVIUM THUNDERX +M: David Daney <david.daney@cavium.com> +L: linux-pci at vger.kernel.org +L: linux-arm-kernel at lists.infradead.org (moderated for non-subscribers) +S: Supported +F: Documentation/devicetree/bindings/pci/pci-thunder-* +F: drivers/pci/host/pci-thunder-* + PCMCIA SUBSYSTEM P: Linux PCMCIA Team L: linux-pcmcia at lists.infradead.orgdiff --git a/drivers/pci/host/Kconfig b/drivers/pci/host/Kconfig index cd5dfbb..c642797 100644 --- a/drivers/pci/host/Kconfig +++ b/drivers/pci/host/Kconfig@@ -196,4 +196,11 @@ config PCIE_QCOM PCIe controller uses the Designware core plus Qualcomm-specific hardware wrappers. +config PCI_HOST_THUNDER_PEM + bool "Cavium Thunder PCIe controller to off-chip devices" + depends on OF && ARM64 + select PCI_HOST_COMMON + help + Say Y here if you want PCIe support for CN88XX Cavium Thunder SoCs. + endmenudiff --git a/drivers/pci/host/Makefile b/drivers/pci/host/Makefile index 3b24af8..8903172 100644 --- a/drivers/pci/host/Makefile +++ b/drivers/pci/host/Makefile@@ -23,3 +23,4 @@ obj-$(CONFIG_PCIE_ALTERA) += pcie-altera.o obj-$(CONFIG_PCIE_ALTERA_MSI) += pcie-altera-msi.o obj-$(CONFIG_PCI_HISI) += pcie-hisi.o obj-$(CONFIG_PCIE_QCOM) += pcie-qcom.o +obj-$(CONFIG_PCI_HOST_THUNDER_PEM) += pci-thunder-pem.odiff --git a/drivers/pci/host/pci-thunder-pem.c b/drivers/pci/host/pci-thunder-pem.c new file mode 100644 index 0000000..4b939c7 --- /dev/null +++ b/drivers/pci/host/pci-thunder-pem.c@@ -0,0 +1,347 @@ +/* + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + * + * Copyright (C) 2015 - 2016 Cavium, Inc. + * + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of_address.h> +#include <linux/of_pci.h> +#include <linux/platform_device.h> + +#include "pci-host-common.h" + +#define PEM_CFG_WR 0x28 +#define PEM_CFG_RD 0x30 + +struct thunder_pem_pci { + struct gen_pci gen_pci; + u32 ea_entry[3]; + void __iomem *pem_reg_base; +}; + +static void __iomem *thunder_pem_map_bus(struct pci_bus *bus, + unsigned int devfn, int where) +{ + struct gen_pci *pci = bus->sysdata; + resource_size_t idx = bus->number - pci->cfg.bus_range->start; + + return pci->cfg.win[idx] + ((devfn << 16) | where); +} + +static int thunder_pem_bridge_read(struct pci_bus *bus, unsigned int devfn, + int where, int size, u32 *val) +{ + u64 read_val; + struct thunder_pem_pci *pem_pci; + struct gen_pci *pci = bus->sysdata; + + pem_pci = container_of(pci, struct thunder_pem_pci, gen_pci); + + if (devfn != 0 || where >= 2048) { + *val = ~0; + return PCIBIOS_DEVICE_NOT_FOUND; + } + + /* + * 32-bit accesses only. Write the address to the low order + * bits of PEM_CFG_RD, then trigger the read by reading back. + * The config data lands in the upper 32-bits of PEM_CFG_RD. + */ + read_val = where & ~3ull; + writeq(read_val, pem_pci->pem_reg_base + PEM_CFG_RD); + read_val = readq(pem_pci->pem_reg_base + PEM_CFG_RD); + read_val >>= 32; + + /* + * The config space contains some garbage, fix it up. Also + * synthesize an EA capability for the BAR used by MSI-X. + */ + switch (where & ~3) { + case 0x40: + read_val &= 0xffff00ff; + read_val |= 0x00007000; /* Skip MSI CAP */ + break; + case 0x70: /* Express Cap */ + /* PME interrupt on vector 2*/ + read_val |= (2u << 25); + break; + case 0xb0: /* MSI-X Cap */ + /* TableSize=4, Next Cap is EA */ + read_val &= 0xc00000ff; + read_val |= 0x0003bc00; + break; + case 0xb4: + /* Table offset=0, BIR=0 */ + read_val = 0x00000000; + break; + case 0xb8: + /* BPA offset=0xf0000, BIR=0 */ + read_val = 0x000f0000; + break; + case 0xbc: + /* EA, 1 entry, no next Cap */ + read_val = 0x00010014; + break; + case 0xc0: + /* DW2 for type-1 */ + read_val = 0x00000000; + break; + case 0xc4: + /* Entry BEI=0, PP=0x00, SP=0xff, ES=3 */ + read_val = 0x80ff0003; + break; + case 0xc8: + read_val = pem_pci->ea_entry[0]; + break; + case 0xcc: + read_val = pem_pci->ea_entry[1]; + break; + case 0xd0: + read_val = pem_pci->ea_entry[2]; + break; + default: + break; + } + read_val >>= (8 * (where & 3)); + switch (size) { + case 1: + read_val &= 0xff; + break; + case 2: + read_val &= 0xffff; + break; + default: + break; + } + *val = read_val; + return PCIBIOS_SUCCESSFUL; +} + +static int thunder_pem_config_read(struct pci_bus *bus, unsigned int devfn, + int where, int size, u32 *val) +{ + struct gen_pci *pci = bus->sysdata; + + if (bus->number < pci->cfg.bus_range->start || + bus->number > pci->cfg.bus_range->end) + return PCIBIOS_DEVICE_NOT_FOUND; + + /* + * The first device on the bus is the PEM PCIe bridge. + * Special case its config access. + */ + if (bus->number == pci->cfg.bus_range->start) + return thunder_pem_bridge_read(bus, devfn, where, size, val); + + return pci_generic_config_read(bus, devfn, where, size, val); +} + +/* + * Some of the w1c_bits below also include read-only or non-writable + * reserved bits, this makes the code simpler and is OK as the bits + * are not affected by writing zeros to them. + */ +static u32 thunder_pem_bridge_w1c_bits(int where) +{ + u32 w1c_bits = 0; + + switch (where & ~3) { + case 0x04: /* Command/Status */ + case 0x1c: /* Base and I/O Limit/Secondary Status */ + w1c_bits = 0xff000000; + break; + case 0x44: /* Power Management Control and Status */ + w1c_bits = 0xfffffe00; + break; + case 0x78: /* Device Control/Device Status */ + case 0x80: /* Link Control/Link Status */ + case 0x88: /* Slot Control/Slot Status */ + case 0x90: /* Root Status */ + case 0xa0: /* Link Control 2 Registers/Link Status 2 */ + w1c_bits = 0xffff0000; + break; + case 0x104: /* Uncorrectable Error Status */ + case 0x110: /* Correctable Error Status */ + case 0x130: /* Error Status */ + case 0x160: /* Link Control 4 */
This patchset is full of magic numbers. For better readability and portability, it's better to declare all that as macro: #define LINK_CONTROL_4 0x160 If there's some specific reason to use numbers, I think, it should be explained.
+ w1c_bits = 0xffffffff;
+ break;
+ default:
+ break;
+ }
+ return w1c_bits;
+}
+
+static int thunder_pem_bridge_write(struct pci_bus *bus, unsigned int devfn,
+ int where, int size, u32 val)
+{
+ struct gen_pci *pci = bus->sysdata;
+ struct thunder_pem_pci *pem_pci;
+ u64 write_val, read_val;
+ u32 mask = 0;
+
+ pem_pci = container_of(pci, struct thunder_pem_pci, gen_pci);
+
+ if (devfn != 0 || where >= 2048)
+ return PCIBIOS_DEVICE_NOT_FOUND;
+
+ /*
+ * 32-bit accesses only. If the write is for a size smaller
+ * than 32-bits, we must first read the 32-bit value and merge
+ * in the desired bits and then write the whole 32-bits back
+ * out.
+ */
+ switch (size) {
+ case 1:
+ read_val = where & ~3ull;
+ writeq(read_val, pem_pci->pem_reg_base + PEM_CFG_RD);
+ read_val = readq(pem_pci->pem_reg_base + PEM_CFG_RD);
+ read_val >>= 32;
+ mask = ~(0xff << (8 * (where & 3)));I'm pretty sure, there's no any rocket science, but it's hard to understand what happens here. What is 8? Bits in byte? Bytes in word? Anything PCI-specific? Moreover, you repeat this line several times here (though little modified). Maybe it deserves to be wrapped by some explaining macro?
+ read_val &= mask; + val = (val & 0xff) << (8 * (where & 3)); + val |= (u32)read_val; + break; + case 2:
Case 1 and 2 are looking very similar. Is it possible to wrap them? For now it looks like code duplication.
+ read_val = where & ~3ull;
+ writeq(read_val, pem_pci->pem_reg_base + PEM_CFG_RD);
+ read_val = readq(pem_pci->pem_reg_base + PEM_CFG_RD);
+ read_val >>= 32;
+ mask = ~(0xffff << (8 * (where & 3)));
+ read_val &= mask;
+ val = (val & 0xffff) << (8 * (where & 3));
+ val |= (u32)read_val;
+ break;
+ default:
+ break;
+ }
+
+ /*
+ * By expanding the write width to 32 bits, we may
+ * inadvertently hit some W1C bits that were not intended to
+ * be written. Calculate the mask that must be applied to the
+ * data to be written to avoid these cases.
+ */
+ if (mask) {
+ u32 w1c_bits = thunder_pem_bridge_w1c_bits(where);
+
+ if (w1c_bits) {
+ mask &= w1c_bits;
+ val &= ~mask;
+ }
+ }
+
+ /*
+ * Low order bits are the config address, the high order 32
+ * bits are the data to be written.
+ */
+ write_val = where & ~3ull;
+ write_val |= (((u64)val) << 32);
+ writeq(write_val, pem_pci->pem_reg_base + PEM_CFG_WR);
+ return PCIBIOS_SUCCESSFUL;
+}
+
+static int thunder_pem_config_write(struct pci_bus *bus, unsigned int devfn,
+ int where, int size, u32 val)
+{
+ struct gen_pci *pci = bus->sysdata;
+
+ if (bus->number < pci->cfg.bus_range->start ||
+ bus->number > pci->cfg.bus_range->end)
+ return PCIBIOS_DEVICE_NOT_FOUND;
+ /*
+ * The first device on the bus is the PEM PCIe bridge.
+ * Special case its config access.
+ */
+ if (bus->number == pci->cfg.bus_range->start)
+ return thunder_pem_bridge_write(bus, devfn, where, size, val);
+
+
+ return pci_generic_config_write(bus, devfn, where, size, val);
+}
+
+static struct gen_pci_cfg_bus_ops thunder_pem_bus_ops = {
+ .bus_shift = 24,
+ .ops = {
+ .map_bus = thunder_pem_map_bus,
+ .read = thunder_pem_config_read,
+ .write = thunder_pem_config_write,
+ }
+};
+
+static const struct of_device_id thunder_pem_of_match[] = {
+ { .compatible = "cavium,pci-host-thunder-pem",
+ .data = &thunder_pem_bus_ops },
+
+ { },
+};
+MODULE_DEVICE_TABLE(of, thunder_pem_of_match);
+
+static int thunder_pem_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ const struct of_device_id *of_id;
+ resource_size_t bar4_start;
+ struct resource *res_pem;
+ struct thunder_pem_pci *pem_pci;
+
+ pem_pci = devm_kzalloc(dev, sizeof(*pem_pci), GFP_KERNEL);
+ if (!pem_pci)
+ return -ENOMEM;
+
+ of_id = of_match_node(thunder_pem_of_match, dev->of_node);
+ pem_pci->gen_pci.cfg.ops = (struct gen_pci_cfg_bus_ops *)of_id->data;
+
+ /*
+ * The second register range is the PEM bridge to the PCIe
+ * bus. It has a different config access method than those
+ * devices behind the bridge.
+ */
+ res_pem = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+ if (!res_pem) {
+ dev_err(dev, "missing \"reg[1]\"property\n");
+ return -EINVAL;
+ }
+
+ pem_pci->pem_reg_base = devm_ioremap(dev, res_pem->start, 0x10000);
+ if (!pem_pci->pem_reg_base)
+ return -ENOMEM;
+
+ /*
+ * The MSI-X BAR for the PEM and AER interrupts is located at
+ * a fixed offset from the PEM register base. Generate a
+ * fragment of the synthesized Enhanced Allocation capability
+ * structure here for the BAR.
+ */
+ bar4_start = res_pem->start + 0xf00000;
+ pem_pci->ea_entry[0] = (u32)bar4_start | 2;
+ pem_pci->ea_entry[1] = (u32)(res_pem->end - bar4_start) & ~3u;
+ pem_pci->ea_entry[2] = (u32)(bar4_start >> 32);
+
+ return pci_host_common_probe(pdev, &pem_pci->gen_pci);
+}
+
+static struct platform_driver thunder_pem_driver = {
+ .driver = {
+ .name = KBUILD_MODNAME,
+ .of_match_table = thunder_pem_of_match,
+ },
+ .probe = thunder_pem_probe,
+};
+module_platform_driver(thunder_pem_driver);
+
+MODULE_DESCRIPTION("Thunder PEM PCIe host driver");
+MODULE_LICENSE("GPL v2");
--
1.8.3.1
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