| Message ID | 20200508113414.3091532-2-jiaxun.yang@flygoat.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v8,1/5] PCI: Don't disable decoding when mmio_always_on is set | expand |
On Fri, May 08, 2020 at 07:34:02PM +0800, Jiaxun Yang wrote: > This controller can be found on Loongson-2K SoC, Loongson-3 > systems with RS780E/LS7A PCH. > > The RS780E part of code was previously located at > arch/mips/pci/ops-loongson3.c and now it can use generic PCI > driver implementation. > > Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com> > Reviewed-by: Rob Herring <robh@kernel.org> > +static void system_bus_quirk(struct pci_dev *pdev) > +{ > + u16 tmp; > + > + /* > + * System buses on Loongson system contain garbage in BARs > + * but their decoding need to be enabled to ensure devices > + * under system buses are reachable. In most cases it should > + * be done by the firmware. This isn't a very satisfying explanation because devices that have decoding enabled can interfere with other devices in the system, and I can't tell whether that's a problem here. What happens when you turn on MEM/IO decoding below? Does the device decode any address space? How do we know what it is? Is it related to the BAR contents? I'm a little dubious about the need for the PCI_COMMAND write because the previous version didn't do it (since it incorrectly wrote to PCI_STATUS), and I assume that version worked. > + pdev->mmio_always_on = 1; > + pdev->non_compliant_bars = 1; > + /* Enable MEM & IO Decoding */ > + pci_read_config_word(pdev, PCI_COMMAND, &tmp); > + tmp |= PCI_COMMAND_IO | PCI_COMMAND_MEMORY; > + pci_write_config_word(pdev, PCI_COMMAND, tmp); > +} > + Omit this blank line. > +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON, > + DEV_LS2K_APB, system_bus_quirk); > +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON, > + DEV_LS7A_CONF, system_bus_quirk); > +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON, > + DEV_LS7A_LPC, system_bus_quirk); > + > +static void loongson_mrrs_quirk(struct pci_dev *dev) > +{ > + struct pci_bus *bus = dev->bus; > + struct pci_dev *bridge; > + static const struct pci_device_id bridge_devids[] = { > + { PCI_VDEVICE(LOONGSON, DEV_PCIE_PORT_0) }, > + { PCI_VDEVICE(LOONGSON, DEV_PCIE_PORT_1) }, > + { PCI_VDEVICE(LOONGSON, DEV_PCIE_PORT_2) }, > + { 0, }, > + }; > + > + Remove one of these blank lines. > + /* look for the matching bridge */ > + while (!pci_is_root_bus(bus)) { > + bridge = bus->self; > + bus = bus->parent; > + /* > + * Some Loongson PCIe ports have a h/w limitation of > + * 256 bytes maximum read request size. They can't handle > + * anything larger than this. So force this limit on > + * any devices attached under these ports. > + */ > + if (pci_match_id(bridge_devids, bridge)) { > + if (pcie_get_readrq(dev) > 256) { > + pci_info(dev, "limiting MRRS to 256\n"); > + pcie_set_readrq(dev, 256); > + } > + break; > + } > + } > +} > +DECLARE_PCI_FIXUP_ENABLE(PCI_ANY_ID, PCI_ANY_ID, loongson_mrrs_quirk); > +void __iomem *pci_loongson_map_bus(struct pci_bus *bus, unsigned int devfn, > + int where) > +{ > + unsigned char busnum = bus->number; > + struct pci_host_bridge *bridge = pci_find_host_bridge(bus); > + struct loongson_pci *priv = pci_host_bridge_priv(bridge); > + > + /* > + * Do not read more than one device on the bus other than > + * the host bridge. s/host bridge/root bus/ ? IIUC, the test below assumes the root bus is bus 0, which is not necessarily the case. Many other .*_map_bus() implementations have similar tests for devices on the root bus: al_pcie_map_bus(...) { if (bus->number == cfg->busr.start) { > + if (priv->flags & FLAG_DEV_FIX && bus->primary != 0 && > + PCI_SLOT(devfn) > 0) > + return NULL;
于 2020年5月9日 GMT+08:00 上午1:17:30, Bjorn Helgaas <helgaas@kernel.org> 写到: >On Fri, May 08, 2020 at 07:34:02PM +0800, Jiaxun Yang wrote: >> This controller can be found on Loongson-2K SoC, Loongson-3 >> systems with RS780E/LS7A PCH. >> >> The RS780E part of code was previously located at >> arch/mips/pci/ops-loongson3.c and now it can use generic PCI >> driver implementation. >> >> Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com> >> Reviewed-by: Rob Herring <robh@kernel.org> > >> +static void system_bus_quirk(struct pci_dev *pdev) >> +{ >> + u16 tmp; >> + >> + /* >> + * System buses on Loongson system contain garbage in BARs >> + * but their decoding need to be enabled to ensure devices >> + * under system buses are reachable. In most cases it should >> + * be done by the firmware. > >This isn't a very satisfying explanation because devices that have >decoding enabled can interfere with other devices in the system, and I >can't tell whether that's a problem here. > >What happens when you turn on MEM/IO decoding below? Does the device >decode any address space? How do we know what it is? Is it related >to the BAR contents? > >I'm a little dubious about the need for the PCI_COMMAND write because >the previous version didn't do it (since it incorrectly wrote to >PCI_STATUS), and I assume that version worked. Hi, Sorry, but that's all I can tell from the chips manual as I'm not a employee of the vendor. My assumption is these BAR contains the address of those system components that already configured by firmware and we shouldn't touch it. In fact according to my tests if we let Kernel probe these BAR then the system will hang immediately. Chip manual suggested OS to ensure decoding is enabled so I'm doing like this. But without this system can also work. Do you think I should drop it until figure out what was it actually doing? > >> + pdev->mmio_always_on = 1; >> + pdev->non_compliant_bars = 1; >> + /* Enable MEM & IO Decoding */ >> + pci_read_config_word(pdev, PCI_COMMAND, &tmp); >> + tmp |= PCI_COMMAND_IO | PCI_COMMAND_MEMORY; >> + pci_write_config_word(pdev, PCI_COMMAND, tmp); > > >> +} >> + > >Omit this blank line. Ack > >> +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON, >> + DEV_LS2K_APB, system_bus_quirk); >> +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON, >> + DEV_LS7A_CONF, system_bus_quirk); >> +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON, >> + DEV_LS7A_LPC, system_bus_quirk); >> + >> +static void loongson_mrrs_quirk(struct pci_dev *dev) >> +{ >> + struct pci_bus *bus = dev->bus; >> + struct pci_dev *bridge; >> + static const struct pci_device_id bridge_devids[] = { >> + { PCI_VDEVICE(LOONGSON, DEV_PCIE_PORT_0) }, >> + { PCI_VDEVICE(LOONGSON, DEV_PCIE_PORT_1) }, >> + { PCI_VDEVICE(LOONGSON, DEV_PCIE_PORT_2) }, >> + { 0, }, >> + }; >> + >> + > >Remove one of these blank lines. Ack > >> + /* look for the matching bridge */ >> + while (!pci_is_root_bus(bus)) { >> + bridge = bus->self; >> + bus = bus->parent; >> + /* >> + * Some Loongson PCIe ports have a h/w limitation of >> + * 256 bytes maximum read request size. They can't handle >> + * anything larger than this. So force this limit on >> + * any devices attached under these ports. >> + */ >> + if (pci_match_id(bridge_devids, bridge)) { >> + if (pcie_get_readrq(dev) > 256) { >> + pci_info(dev, "limiting MRRS to 256\n"); >> + pcie_set_readrq(dev, 256); >> + } >> + break; >> + } >> + } >> +} >> +DECLARE_PCI_FIXUP_ENABLE(PCI_ANY_ID, PCI_ANY_ID, loongson_mrrs_quirk); > >> +void __iomem *pci_loongson_map_bus(struct pci_bus *bus, unsigned int devfn, >> + int where) >> +{ >> + unsigned char busnum = bus->number; >> + struct pci_host_bridge *bridge = pci_find_host_bridge(bus); >> + struct loongson_pci *priv = pci_host_bridge_priv(bridge); >> + >> + /* >> + * Do not read more than one device on the bus other than >> + * the host bridge. > >s/host bridge/root bus/ ? > >IIUC, the test below assumes the root bus is bus 0, which is not >necessarily the case. Many other .*_map_bus() implementations have >similar tests for devices on the root bus: Ack > > al_pcie_map_bus(...) > { > if (bus->number == cfg->busr.start) { > >> + if (priv->flags & FLAG_DEV_FIX && bus->primary != 0 && >> + PCI_SLOT(devfn) > 0) >> + return NULL; Thanks!
On Sat, May 09, 2020 at 01:28:24AM +0800, Jiaxun Yang wrote: > 于 2020年5月9日 GMT+08:00 上午1:17:30, Bjorn Helgaas <helgaas@kernel.org> 写到: > >On Fri, May 08, 2020 at 07:34:02PM +0800, Jiaxun Yang wrote: > >> This controller can be found on Loongson-2K SoC, Loongson-3 > >> systems with RS780E/LS7A PCH. > >> > >> The RS780E part of code was previously located at > >> arch/mips/pci/ops-loongson3.c and now it can use generic PCI > >> driver implementation. > >> > >> Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com> > >> Reviewed-by: Rob Herring <robh@kernel.org> > > > >> +static void system_bus_quirk(struct pci_dev *pdev) > >> +{ > >> + u16 tmp; > >> + > >> + /* > >> + * System buses on Loongson system contain garbage in BARs > >> + * but their decoding need to be enabled to ensure devices > >> + * under system buses are reachable. In most cases it should > >> + * be done by the firmware. > > > >This isn't a very satisfying explanation because devices that have > >decoding enabled can interfere with other devices in the system, and I > >can't tell whether that's a problem here. > > > >What happens when you turn on MEM/IO decoding below? Does the device > >decode any address space? How do we know what it is? Is it related > >to the BAR contents? > > > >I'm a little dubious about the need for the PCI_COMMAND write because > >the previous version didn't do it (since it incorrectly wrote to > >PCI_STATUS), and I assume that version worked. > > Sorry, but that's all I can tell from the chips manual as I'm not a > employee of the vendor. > > My assumption is these BAR contains the address of those system > components that already configured by firmware and we shouldn't > touch it. What are the values in the BARs? Do they look like addresses? Would they make sense in the iomem_resource, i.e., in /proc/iomem? If the BARs contain addresses of devices, the kernel needs to avoid that address space when allocating space for other devices. But without probing the BARs, the kernel has no idea what the *size* of the regions is. Does the manual say anything about that? Can you tell if there's anything at all Linux could do with these devices? If they don't have BARs and they don't document any device-specific registers in config space, there's not much value in treating them like PCI devices at all. I wonder if we should just make a way to completely ignore them, e.g., a way for pci_setup_device() to return an error. I guess we *could* do that already by making your early fixup set dev->hdr_type to 0xff or something. > In fact according to my tests if we let Kernel probe these BAR then > the system will hang immediately. > > Chip manual suggested OS to ensure decoding is enabled so I'm doing > like this. But without this system can also work. > > Do you think I should drop it until figure out what was it actually > doing?
diff --git a/drivers/pci/controller/Kconfig b/drivers/pci/controller/Kconfig index 91bfdb784829..ae36edb1d7db 100644 --- a/drivers/pci/controller/Kconfig +++ b/drivers/pci/controller/Kconfig @@ -258,6 +258,16 @@ config PCI_HYPERV_INTERFACE The Hyper-V PCI Interface is a helper driver allows other drivers to have a common interface with the Hyper-V PCI frontend driver. +config PCI_LOONGSON + bool "LOONGSON PCI Controller" + depends on MACH_LOONGSON64 || COMPILE_TEST + depends on OF + depends on PCI_QUIRKS + default MACH_LOONGSON64 + help + Say Y here if you want to enable PCI controller support on + Loongson systems. + source "drivers/pci/controller/dwc/Kconfig" source "drivers/pci/controller/mobiveil/Kconfig" source "drivers/pci/controller/cadence/Kconfig" diff --git a/drivers/pci/controller/Makefile b/drivers/pci/controller/Makefile index 158c59771824..fbac4b0190a0 100644 --- a/drivers/pci/controller/Makefile +++ b/drivers/pci/controller/Makefile @@ -28,6 +28,7 @@ obj-$(CONFIG_PCIE_MEDIATEK) += pcie-mediatek.o obj-$(CONFIG_PCIE_TANGO_SMP8759) += pcie-tango.o obj-$(CONFIG_VMD) += vmd.o obj-$(CONFIG_PCIE_BRCMSTB) += pcie-brcmstb.o +obj-$(CONFIG_PCI_LOONGSON) += pci-loongson.o # pcie-hisi.o quirks are needed even without CONFIG_PCIE_DW obj-y += dwc/ obj-y += mobiveil/ diff --git a/drivers/pci/controller/pci-loongson.c b/drivers/pci/controller/pci-loongson.c new file mode 100644 index 000000000000..76442f44a41e --- /dev/null +++ b/drivers/pci/controller/pci-loongson.c @@ -0,0 +1,257 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Loongson PCI Host Controller Driver + * + * Copyright (C) 2020 Jiaxun Yang <jiaxun.yang@flygoat.com> + */ + +#include <linux/of_device.h> +#include <linux/of_pci.h> +#include <linux/pci.h> +#include <linux/pci_ids.h> + +#include "../pci.h" + +/* Device IDs */ +#define DEV_PCIE_PORT_0 0x7a09 +#define DEV_PCIE_PORT_1 0x7a19 +#define DEV_PCIE_PORT_2 0x7a29 + +#define DEV_LS2K_APB 0x7a02 +#define DEV_LS7A_CONF 0x7a10 +#define DEV_LS7A_LPC 0x7a0c + +#define FLAG_CFG0 BIT(0) +#define FLAG_CFG1 BIT(1) +#define FLAG_DEV_FIX BIT(2) + +struct loongson_pci { + void __iomem *cfg0_base; + void __iomem *cfg1_base; + struct platform_device *pdev; + u32 flags; +}; + +/* Fixup wrong class code in PCIe bridges */ +static void bridge_class_quirk(struct pci_dev *dev) +{ + dev->class = PCI_CLASS_BRIDGE_PCI << 8; +} +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_LOONGSON, + DEV_PCIE_PORT_0, bridge_class_quirk); +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_LOONGSON, + DEV_PCIE_PORT_1, bridge_class_quirk); +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_LOONGSON, + DEV_PCIE_PORT_2, bridge_class_quirk); + +static void system_bus_quirk(struct pci_dev *pdev) +{ + u16 tmp; + + /* + * System buses on Loongson system contain garbage in BARs + * but their decoding need to be enabled to ensure devices + * under system buses are reachable. In most cases it should + * be done by the firmware. + */ + pdev->mmio_always_on = 1; + pdev->non_compliant_bars = 1; + /* Enable MEM & IO Decoding */ + pci_read_config_word(pdev, PCI_COMMAND, &tmp); + tmp |= PCI_COMMAND_IO | PCI_COMMAND_MEMORY; + pci_write_config_word(pdev, PCI_COMMAND, tmp); +} + +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON, + DEV_LS2K_APB, system_bus_quirk); +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON, + DEV_LS7A_CONF, system_bus_quirk); +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON, + DEV_LS7A_LPC, system_bus_quirk); + +static void loongson_mrrs_quirk(struct pci_dev *dev) +{ + struct pci_bus *bus = dev->bus; + struct pci_dev *bridge; + static const struct pci_device_id bridge_devids[] = { + { PCI_VDEVICE(LOONGSON, DEV_PCIE_PORT_0) }, + { PCI_VDEVICE(LOONGSON, DEV_PCIE_PORT_1) }, + { PCI_VDEVICE(LOONGSON, DEV_PCIE_PORT_2) }, + { 0, }, + }; + + + /* look for the matching bridge */ + while (!pci_is_root_bus(bus)) { + bridge = bus->self; + bus = bus->parent; + /* + * Some Loongson PCIe ports have a h/w limitation of + * 256 bytes maximum read request size. They can't handle + * anything larger than this. So force this limit on + * any devices attached under these ports. + */ + if (pci_match_id(bridge_devids, bridge)) { + if (pcie_get_readrq(dev) > 256) { + pci_info(dev, "limiting MRRS to 256\n"); + pcie_set_readrq(dev, 256); + } + break; + } + } +} +DECLARE_PCI_FIXUP_ENABLE(PCI_ANY_ID, PCI_ANY_ID, loongson_mrrs_quirk); + +static void __iomem *cfg1_map(struct loongson_pci *priv, int bus, + unsigned int devfn, int where) +{ + unsigned long addroff = 0x0; + + if (bus != 0) + addroff |= BIT(28); /* Type 1 Access */ + addroff |= (where & 0xff) | ((where & 0xf00) << 16); + addroff |= (bus << 16) | (devfn << 8); + return priv->cfg1_base + addroff; +} + +static void __iomem *cfg0_map(struct loongson_pci *priv, int bus, + unsigned int devfn, int where) +{ + unsigned long addroff = 0x0; + + if (bus != 0) + addroff |= BIT(24); /* Type 1 Access */ + addroff |= (bus << 16) | (devfn << 8) | where; + return priv->cfg0_base + addroff; +} + +void __iomem *pci_loongson_map_bus(struct pci_bus *bus, unsigned int devfn, + int where) +{ + unsigned char busnum = bus->number; + struct pci_host_bridge *bridge = pci_find_host_bridge(bus); + struct loongson_pci *priv = pci_host_bridge_priv(bridge); + + /* + * Do not read more than one device on the bus other than + * the host bridge. + */ + if (priv->flags & FLAG_DEV_FIX && bus->primary != 0 && + PCI_SLOT(devfn) > 0) + return NULL; + + /* CFG0 can only access standard space */ + if (where < PCI_CFG_SPACE_SIZE && priv->cfg0_base) + return cfg0_map(priv, busnum, devfn, where); + + /* CFG1 can access extended space */ + if (where < PCI_CFG_SPACE_EXP_SIZE && priv->cfg1_base) + return cfg1_map(priv, busnum, devfn, where); + + return NULL; +} + +static int loongson_map_irq(const struct pci_dev *dev, u8 slot, u8 pin) +{ + int irq; + u8 val; + + irq = of_irq_parse_and_map_pci(dev, slot, pin); + if (irq > 0) + return irq; + + /* Care i8259 legacy systems */ + pci_read_config_byte(dev, PCI_INTERRUPT_LINE, &val); + /* i8259 only have 15 IRQs */ + if (val > 15) + return 0; + + return val; +} + +/* H/w only accept 32-bit PCI operations */ +static struct pci_ops loongson_pci_ops = { + .map_bus = pci_loongson_map_bus, + .read = pci_generic_config_read32, + .write = pci_generic_config_write32, +}; + +static const struct of_device_id loongson_pci_of_match[] = { + { .compatible = "loongson,ls2k-pci", + .data = (void *)(FLAG_CFG0 | FLAG_CFG1 | FLAG_DEV_FIX), }, + { .compatible = "loongson,ls7a-pci", + .data = (void *)(FLAG_CFG0 | FLAG_CFG1 | FLAG_DEV_FIX), }, + { .compatible = "loongson,rs780e-pci", + .data = (void *)(FLAG_CFG0), }, + {} +}; + +static int loongson_pci_probe(struct platform_device *pdev) +{ + struct loongson_pci *priv; + struct device *dev = &pdev->dev; + struct device_node *node = dev->of_node; + struct pci_host_bridge *bridge; + struct resource *regs; + int err; + + if (!node) + return -ENODEV; + + bridge = devm_pci_alloc_host_bridge(dev, sizeof(*priv)); + if (!bridge) + return -ENODEV; + + priv = pci_host_bridge_priv(bridge); + priv->pdev = pdev; + priv->flags = (unsigned long)of_device_get_match_data(dev); + + regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!regs) { + dev_err(dev, "missing mem resources for cfg0\n"); + return -EINVAL; + } + + priv->cfg0_base = devm_pci_remap_cfg_resource(dev, regs); + if (IS_ERR(priv->cfg0_base)) + return PTR_ERR(priv->cfg0_base); + + /* CFG1 is optional */ + if (priv->flags & FLAG_CFG1) { + regs = platform_get_resource(pdev, IORESOURCE_MEM, 1); + if (!regs) + dev_info(dev, "missing mem resource for cfg1\n"); + else { + priv->cfg1_base = devm_pci_remap_cfg_resource(dev, regs); + if (IS_ERR(priv->cfg1_base)) + priv->cfg1_base = NULL; + } + } + + err = pci_parse_request_of_pci_ranges(dev, &bridge->windows, + &bridge->dma_ranges, NULL); + if (err) { + dev_err(dev, "failed to get bridge resources\n"); + return err; + } + + bridge->dev.parent = dev; + bridge->sysdata = priv; + bridge->ops = &loongson_pci_ops; + bridge->map_irq = loongson_map_irq; + + err = pci_host_probe(bridge); + if (err) + return err; + + return 0; +} + +static struct platform_driver loongson_pci_driver = { + .driver = { + .name = "loongson-pci", + .of_match_table = loongson_pci_of_match, + }, + .probe = loongson_pci_probe, +}; +builtin_platform_driver(loongson_pci_driver);