diff options
Diffstat (limited to 'drivers/pci/pci-bridge-emul.c')
| -rw-r--r-- | drivers/pci/pci-bridge-emul.c | 492 |
1 files changed, 492 insertions, 0 deletions
diff --git a/drivers/pci/pci-bridge-emul.c b/drivers/pci/pci-bridge-emul.c new file mode 100644 index 000000000..37504c2cc --- /dev/null +++ b/drivers/pci/pci-bridge-emul.c @@ -0,0 +1,492 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2018 Marvell + * + * Author: Thomas Petazzoni <thomas.petazzoni@bootlin.com> + * + * This file helps PCI controller drivers implement a fake root port + * PCI bridge when the HW doesn't provide such a root port PCI + * bridge. + * + * It emulates a PCI bridge by providing a fake PCI configuration + * space (and optionally a PCIe capability configuration space) in + * memory. By default the read/write operations simply read and update + * this fake configuration space in memory. However, PCI controller + * drivers can provide through the 'struct pci_sw_bridge_ops' + * structure a set of operations to override or complement this + * default behavior. + */ + +#include <linux/pci.h> +#include "pci-bridge-emul.h" + +#define PCI_BRIDGE_CONF_END PCI_STD_HEADER_SIZEOF +#define PCI_CAP_PCIE_SIZEOF (PCI_EXP_SLTSTA2 + 2) +#define PCI_CAP_PCIE_START PCI_BRIDGE_CONF_END +#define PCI_CAP_PCIE_END (PCI_CAP_PCIE_START + PCI_CAP_PCIE_SIZEOF) + +/** + * struct pci_bridge_reg_behavior - register bits behaviors + * @ro: Read-Only bits + * @rw: Read-Write bits + * @w1c: Write-1-to-Clear bits + * + * Reads and Writes will be filtered by specified behavior. All other bits not + * declared are assumed 'Reserved' and will return 0 on reads, per PCIe 5.0: + * "Reserved register fields must be read only and must return 0 (all 0's for + * multi-bit fields) when read". + */ +struct pci_bridge_reg_behavior { + /* Read-only bits */ + u32 ro; + + /* Read-write bits */ + u32 rw; + + /* Write-1-to-clear bits */ + u32 w1c; +}; + +static const +struct pci_bridge_reg_behavior pci_regs_behavior[PCI_STD_HEADER_SIZEOF / 4] = { + [PCI_VENDOR_ID / 4] = { .ro = ~0 }, + [PCI_COMMAND / 4] = { + .rw = (PCI_COMMAND_IO | PCI_COMMAND_MEMORY | + PCI_COMMAND_MASTER | PCI_COMMAND_PARITY | + PCI_COMMAND_SERR), + .ro = ((PCI_COMMAND_SPECIAL | PCI_COMMAND_INVALIDATE | + PCI_COMMAND_VGA_PALETTE | PCI_COMMAND_WAIT | + PCI_COMMAND_FAST_BACK) | + (PCI_STATUS_CAP_LIST | PCI_STATUS_66MHZ | + PCI_STATUS_FAST_BACK | PCI_STATUS_DEVSEL_MASK) << 16), + .w1c = PCI_STATUS_ERROR_BITS << 16, + }, + [PCI_CLASS_REVISION / 4] = { .ro = ~0 }, + + /* + * Cache Line Size register: implement as read-only, we do not + * pretend implementing "Memory Write and Invalidate" + * transactions" + * + * Latency Timer Register: implemented as read-only, as "A + * bridge that is not capable of a burst transfer of more than + * two data phases on its primary interface is permitted to + * hardwire the Latency Timer to a value of 16 or less" + * + * Header Type: always read-only + * + * BIST register: implemented as read-only, as "A bridge that + * does not support BIST must implement this register as a + * read-only register that returns 0 when read" + */ + [PCI_CACHE_LINE_SIZE / 4] = { .ro = ~0 }, + + /* + * Base Address registers not used must be implemented as + * read-only registers that return 0 when read. + */ + [PCI_BASE_ADDRESS_0 / 4] = { .ro = ~0 }, + [PCI_BASE_ADDRESS_1 / 4] = { .ro = ~0 }, + + [PCI_PRIMARY_BUS / 4] = { + /* Primary, secondary and subordinate bus are RW */ + .rw = GENMASK(24, 0), + /* Secondary latency is read-only */ + .ro = GENMASK(31, 24), + }, + + [PCI_IO_BASE / 4] = { + /* The high four bits of I/O base/limit are RW */ + .rw = (GENMASK(15, 12) | GENMASK(7, 4)), + + /* The low four bits of I/O base/limit are RO */ + .ro = (((PCI_STATUS_66MHZ | PCI_STATUS_FAST_BACK | + PCI_STATUS_DEVSEL_MASK) << 16) | + GENMASK(11, 8) | GENMASK(3, 0)), + + .w1c = PCI_STATUS_ERROR_BITS << 16, + }, + + [PCI_MEMORY_BASE / 4] = { + /* The high 12-bits of mem base/limit are RW */ + .rw = GENMASK(31, 20) | GENMASK(15, 4), + + /* The low four bits of mem base/limit are RO */ + .ro = GENMASK(19, 16) | GENMASK(3, 0), + }, + + [PCI_PREF_MEMORY_BASE / 4] = { + /* The high 12-bits of pref mem base/limit are RW */ + .rw = GENMASK(31, 20) | GENMASK(15, 4), + + /* The low four bits of pref mem base/limit are RO */ + .ro = GENMASK(19, 16) | GENMASK(3, 0), + }, + + [PCI_PREF_BASE_UPPER32 / 4] = { + .rw = ~0, + }, + + [PCI_PREF_LIMIT_UPPER32 / 4] = { + .rw = ~0, + }, + + [PCI_IO_BASE_UPPER16 / 4] = { + .rw = ~0, + }, + + [PCI_CAPABILITY_LIST / 4] = { + .ro = GENMASK(7, 0), + }, + + /* + * If expansion ROM is unsupported then ROM Base Address register must + * be implemented as read-only register that return 0 when read, same + * as for unused Base Address registers. + */ + [PCI_ROM_ADDRESS1 / 4] = { + .ro = ~0, + }, + + /* + * Interrupt line (bits 7:0) are RW, interrupt pin (bits 15:8) + * are RO, and bridge control (31:16) are a mix of RW, RO, + * reserved and W1C bits + */ + [PCI_INTERRUPT_LINE / 4] = { + /* Interrupt line is RW */ + .rw = (GENMASK(7, 0) | + ((PCI_BRIDGE_CTL_PARITY | + PCI_BRIDGE_CTL_SERR | + PCI_BRIDGE_CTL_ISA | + PCI_BRIDGE_CTL_VGA | + PCI_BRIDGE_CTL_MASTER_ABORT | + PCI_BRIDGE_CTL_BUS_RESET | + BIT(8) | BIT(9) | BIT(11)) << 16)), + + /* Interrupt pin is RO */ + .ro = (GENMASK(15, 8) | ((PCI_BRIDGE_CTL_FAST_BACK) << 16)), + + .w1c = BIT(10) << 16, + }, +}; + +static const +struct pci_bridge_reg_behavior pcie_cap_regs_behavior[PCI_CAP_PCIE_SIZEOF / 4] = { + [PCI_CAP_LIST_ID / 4] = { + /* + * Capability ID, Next Capability Pointer and + * bits [14:0] of Capabilities register are all read-only. + * Bit 15 of Capabilities register is reserved. + */ + .ro = GENMASK(30, 0), + }, + + [PCI_EXP_DEVCAP / 4] = { + /* + * Bits [31:29] and [17:16] are reserved. + * Bits [27:18] are reserved for non-upstream ports. + * Bits 28 and [14:6] are reserved for non-endpoint devices. + * Other bits are read-only. + */ + .ro = BIT(15) | GENMASK(5, 0), + }, + + [PCI_EXP_DEVCTL / 4] = { + /* + * Device control register is RW, except bit 15 which is + * reserved for non-endpoints or non-PCIe-to-PCI/X bridges. + */ + .rw = GENMASK(14, 0), + + /* + * Device status register has bits 6 and [3:0] W1C, [5:4] RO, + * the rest is reserved. Also bit 6 is reserved for non-upstream + * ports. + */ + .w1c = GENMASK(3, 0) << 16, + .ro = GENMASK(5, 4) << 16, + }, + + [PCI_EXP_LNKCAP / 4] = { + /* + * All bits are RO, except bit 23 which is reserved and + * bit 18 which is reserved for non-upstream ports. + */ + .ro = lower_32_bits(~(BIT(23) | PCI_EXP_LNKCAP_CLKPM)), + }, + + [PCI_EXP_LNKCTL / 4] = { + /* + * Link control has bits [15:14], [11:3] and [1:0] RW, the + * rest is reserved. Bit 8 is reserved for non-upstream ports. + * + * Link status has bits [13:0] RO, and bits [15:14] + * W1C. + */ + .rw = GENMASK(15, 14) | GENMASK(11, 9) | GENMASK(7, 3) | GENMASK(1, 0), + .ro = GENMASK(13, 0) << 16, + .w1c = GENMASK(15, 14) << 16, + }, + + [PCI_EXP_SLTCAP / 4] = { + .ro = ~0, + }, + + [PCI_EXP_SLTCTL / 4] = { + /* + * Slot control has bits [14:0] RW, the rest is + * reserved. + * + * Slot status has bits 8 and [4:0] W1C, bits [7:5] RO, the + * rest is reserved. + */ + .rw = GENMASK(14, 0), + .w1c = (PCI_EXP_SLTSTA_ABP | PCI_EXP_SLTSTA_PFD | + PCI_EXP_SLTSTA_MRLSC | PCI_EXP_SLTSTA_PDC | + PCI_EXP_SLTSTA_CC | PCI_EXP_SLTSTA_DLLSC) << 16, + .ro = (PCI_EXP_SLTSTA_MRLSS | PCI_EXP_SLTSTA_PDS | + PCI_EXP_SLTSTA_EIS) << 16, + }, + + [PCI_EXP_RTCTL / 4] = { + /* + * Root control has bits [4:0] RW, the rest is + * reserved. + * + * Root capabilities has bit 0 RO, the rest is reserved. + */ + .rw = (PCI_EXP_RTCTL_SECEE | PCI_EXP_RTCTL_SENFEE | + PCI_EXP_RTCTL_SEFEE | PCI_EXP_RTCTL_PMEIE | + PCI_EXP_RTCTL_CRSSVE), + .ro = PCI_EXP_RTCAP_CRSVIS << 16, + }, + + [PCI_EXP_RTSTA / 4] = { + /* + * Root status has bits 17 and [15:0] RO, bit 16 W1C, the rest + * is reserved. + */ + .ro = GENMASK(15, 0) | PCI_EXP_RTSTA_PENDING, + .w1c = PCI_EXP_RTSTA_PME, + }, +}; + +/* + * Initialize a pci_bridge_emul structure to represent a fake PCI + * bridge configuration space. The caller needs to have initialized + * the PCI configuration space with whatever values make sense + * (typically at least vendor, device, revision), the ->ops pointer, + * and optionally ->data and ->has_pcie. + */ +int pci_bridge_emul_init(struct pci_bridge_emul *bridge, + unsigned int flags) +{ + BUILD_BUG_ON(sizeof(bridge->conf) != PCI_BRIDGE_CONF_END); + + bridge->conf.class_revision |= cpu_to_le32(PCI_CLASS_BRIDGE_PCI << 16); + bridge->conf.header_type = PCI_HEADER_TYPE_BRIDGE; + bridge->conf.cache_line_size = 0x10; + bridge->conf.status = cpu_to_le16(PCI_STATUS_CAP_LIST); + bridge->pci_regs_behavior = kmemdup(pci_regs_behavior, + sizeof(pci_regs_behavior), + GFP_KERNEL); + if (!bridge->pci_regs_behavior) + return -ENOMEM; + + if (bridge->has_pcie) { + bridge->conf.capabilities_pointer = PCI_CAP_PCIE_START; + bridge->conf.status |= cpu_to_le16(PCI_STATUS_CAP_LIST); + bridge->pcie_conf.cap_id = PCI_CAP_ID_EXP; + bridge->pcie_conf.cap |= cpu_to_le16(PCI_EXP_TYPE_ROOT_PORT << 4); + bridge->pcie_cap_regs_behavior = + kmemdup(pcie_cap_regs_behavior, + sizeof(pcie_cap_regs_behavior), + GFP_KERNEL); + if (!bridge->pcie_cap_regs_behavior) { + kfree(bridge->pci_regs_behavior); + return -ENOMEM; + } + /* These bits are applicable only for PCI and reserved on PCIe */ + bridge->pci_regs_behavior[PCI_CACHE_LINE_SIZE / 4].ro &= + ~GENMASK(15, 8); + bridge->pci_regs_behavior[PCI_COMMAND / 4].ro &= + ~((PCI_COMMAND_SPECIAL | PCI_COMMAND_INVALIDATE | + PCI_COMMAND_VGA_PALETTE | PCI_COMMAND_WAIT | + PCI_COMMAND_FAST_BACK) | + (PCI_STATUS_66MHZ | PCI_STATUS_FAST_BACK | + PCI_STATUS_DEVSEL_MASK) << 16); + bridge->pci_regs_behavior[PCI_PRIMARY_BUS / 4].ro &= + ~GENMASK(31, 24); + bridge->pci_regs_behavior[PCI_IO_BASE / 4].ro &= + ~((PCI_STATUS_66MHZ | PCI_STATUS_FAST_BACK | + PCI_STATUS_DEVSEL_MASK) << 16); + bridge->pci_regs_behavior[PCI_INTERRUPT_LINE / 4].rw &= + ~((PCI_BRIDGE_CTL_MASTER_ABORT | + BIT(8) | BIT(9) | BIT(11)) << 16); + bridge->pci_regs_behavior[PCI_INTERRUPT_LINE / 4].ro &= + ~((PCI_BRIDGE_CTL_FAST_BACK) << 16); + bridge->pci_regs_behavior[PCI_INTERRUPT_LINE / 4].w1c &= + ~(BIT(10) << 16); + } + + if (flags & PCI_BRIDGE_EMUL_NO_PREFETCHABLE_BAR) { + bridge->pci_regs_behavior[PCI_PREF_MEMORY_BASE / 4].ro = ~0; + bridge->pci_regs_behavior[PCI_PREF_MEMORY_BASE / 4].rw = 0; + } + + return 0; +} +EXPORT_SYMBOL_GPL(pci_bridge_emul_init); + +/* + * Cleanup a pci_bridge_emul structure that was previously initialized + * using pci_bridge_emul_init(). + */ +void pci_bridge_emul_cleanup(struct pci_bridge_emul *bridge) +{ + if (bridge->has_pcie) + kfree(bridge->pcie_cap_regs_behavior); + kfree(bridge->pci_regs_behavior); +} +EXPORT_SYMBOL_GPL(pci_bridge_emul_cleanup); + +/* + * Should be called by the PCI controller driver when reading the PCI + * configuration space of the fake bridge. It will call back the + * ->ops->read_base or ->ops->read_pcie operations. + */ +int pci_bridge_emul_conf_read(struct pci_bridge_emul *bridge, int where, + int size, u32 *value) +{ + int ret; + int reg = where & ~3; + pci_bridge_emul_read_status_t (*read_op)(struct pci_bridge_emul *bridge, + int reg, u32 *value); + __le32 *cfgspace; + const struct pci_bridge_reg_behavior *behavior; + + if (bridge->has_pcie && reg >= PCI_CAP_PCIE_END) { + *value = 0; + return PCIBIOS_SUCCESSFUL; + } + + if (!bridge->has_pcie && reg >= PCI_BRIDGE_CONF_END) { + *value = 0; + return PCIBIOS_SUCCESSFUL; + } + + if (bridge->has_pcie && reg >= PCI_CAP_PCIE_START) { + reg -= PCI_CAP_PCIE_START; + read_op = bridge->ops->read_pcie; + cfgspace = (__le32 *) &bridge->pcie_conf; + behavior = bridge->pcie_cap_regs_behavior; + } else { + read_op = bridge->ops->read_base; + cfgspace = (__le32 *) &bridge->conf; + behavior = bridge->pci_regs_behavior; + } + + if (read_op) + ret = read_op(bridge, reg, value); + else + ret = PCI_BRIDGE_EMUL_NOT_HANDLED; + + if (ret == PCI_BRIDGE_EMUL_NOT_HANDLED) + *value = le32_to_cpu(cfgspace[reg / 4]); + + /* + * Make sure we never return any reserved bit with a value + * different from 0. + */ + *value &= behavior[reg / 4].ro | behavior[reg / 4].rw | + behavior[reg / 4].w1c; + + if (size == 1) + *value = (*value >> (8 * (where & 3))) & 0xff; + else if (size == 2) + *value = (*value >> (8 * (where & 3))) & 0xffff; + else if (size != 4) + return PCIBIOS_BAD_REGISTER_NUMBER; + + return PCIBIOS_SUCCESSFUL; +} +EXPORT_SYMBOL_GPL(pci_bridge_emul_conf_read); + +/* + * Should be called by the PCI controller driver when writing the PCI + * configuration space of the fake bridge. It will call back the + * ->ops->write_base or ->ops->write_pcie operations. + */ +int pci_bridge_emul_conf_write(struct pci_bridge_emul *bridge, int where, + int size, u32 value) +{ + int reg = where & ~3; + int mask, ret, old, new, shift; + void (*write_op)(struct pci_bridge_emul *bridge, int reg, + u32 old, u32 new, u32 mask); + __le32 *cfgspace; + const struct pci_bridge_reg_behavior *behavior; + + if (bridge->has_pcie && reg >= PCI_CAP_PCIE_END) + return PCIBIOS_SUCCESSFUL; + + if (!bridge->has_pcie && reg >= PCI_BRIDGE_CONF_END) + return PCIBIOS_SUCCESSFUL; + + shift = (where & 0x3) * 8; + + if (size == 4) + mask = 0xffffffff; + else if (size == 2) + mask = 0xffff << shift; + else if (size == 1) + mask = 0xff << shift; + else + return PCIBIOS_BAD_REGISTER_NUMBER; + + ret = pci_bridge_emul_conf_read(bridge, reg, 4, &old); + if (ret != PCIBIOS_SUCCESSFUL) + return ret; + + if (bridge->has_pcie && reg >= PCI_CAP_PCIE_START) { + reg -= PCI_CAP_PCIE_START; + write_op = bridge->ops->write_pcie; + cfgspace = (__le32 *) &bridge->pcie_conf; + behavior = bridge->pcie_cap_regs_behavior; + } else { + write_op = bridge->ops->write_base; + cfgspace = (__le32 *) &bridge->conf; + behavior = bridge->pci_regs_behavior; + } + + /* Keep all bits, except the RW bits */ + new = old & (~mask | ~behavior[reg / 4].rw); + + /* Update the value of the RW bits */ + new |= (value << shift) & (behavior[reg / 4].rw & mask); + + /* Clear the W1C bits */ + new &= ~((value << shift) & (behavior[reg / 4].w1c & mask)); + + /* Save the new value with the cleared W1C bits into the cfgspace */ + cfgspace[reg / 4] = cpu_to_le32(new); + + /* + * Clear the W1C bits not specified by the write mask, so that the + * write_op() does not clear them. + */ + new &= ~(behavior[reg / 4].w1c & ~mask); + + /* + * Set the W1C bits specified by the write mask, so that write_op() + * knows about that they are to be cleared. + */ + new |= (value << shift) & (behavior[reg / 4].w1c & mask); + + if (write_op) + write_op(bridge, reg, old, new, mask); + + return PCIBIOS_SUCCESSFUL; +} +EXPORT_SYMBOL_GPL(pci_bridge_emul_conf_write); |