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// SPDX-License-Identifier: GPL-2.0
/*
* Generic SH7786 PCI-Express operations.
*
* Copyright (C) 2009 - 2010 Paul Mundt
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/pci.h>
#include <linux/io.h>
#include <linux/spinlock.h>
#include "pcie-sh7786.h"
enum {
PCI_ACCESS_READ,
PCI_ACCESS_WRITE,
};
static int sh7786_pcie_config_access(unsigned char access_type,
struct pci_bus *bus, unsigned int devfn, int where, u32 *data)
{
struct pci_channel *chan = bus->sysdata;
int dev, func, type, reg;
dev = PCI_SLOT(devfn);
func = PCI_FUNC(devfn);
type = !!bus->parent;
reg = where & ~3;
if (bus->number > 255 || dev > 31 || func > 7)
return PCIBIOS_FUNC_NOT_SUPPORTED;
/*
* While each channel has its own memory-mapped extended config
* space, it's generally only accessible when in endpoint mode.
* When in root complex mode, the controller is unable to target
* itself with either type 0 or type 1 accesses, and indeed, any
* controller initiated target transfer to its own config space
* result in a completer abort.
*
* Each channel effectively only supports a single device, but as
* the same channel <-> device access works for any PCI_SLOT()
* value, we cheat a bit here and bind the controller's config
* space to devfn 0 in order to enable self-enumeration. In this
* case the regular PAR/PDR path is sidelined and the mangled
* config access itself is initiated as a SuperHyway transaction.
*/
if (pci_is_root_bus(bus)) {
if (dev == 0) {
if (access_type == PCI_ACCESS_READ)
*data = pci_read_reg(chan, PCI_REG(reg));
else
pci_write_reg(chan, *data, PCI_REG(reg));
return PCIBIOS_SUCCESSFUL;
} else if (dev > 1)
return PCIBIOS_DEVICE_NOT_FOUND;
}
/* Clear errors */
pci_write_reg(chan, pci_read_reg(chan, SH4A_PCIEERRFR), SH4A_PCIEERRFR);
/* Set the PIO address */
pci_write_reg(chan, (bus->number << 24) | (dev << 19) |
(func << 16) | reg, SH4A_PCIEPAR);
/* Enable the configuration access */
pci_write_reg(chan, (1 << 31) | (type << 8), SH4A_PCIEPCTLR);
/* Check for errors */
if (pci_read_reg(chan, SH4A_PCIEERRFR) & 0x10)
return PCIBIOS_DEVICE_NOT_FOUND;
/* Check for master and target aborts */
if (pci_read_reg(chan, SH4A_PCIEPCICONF1) & ((1 << 29) | (1 << 28)))
return PCIBIOS_DEVICE_NOT_FOUND;
if (access_type == PCI_ACCESS_READ)
*data = pci_read_reg(chan, SH4A_PCIEPDR);
else
pci_write_reg(chan, *data, SH4A_PCIEPDR);
/* Disable the configuration access */
pci_write_reg(chan, 0, SH4A_PCIEPCTLR);
return PCIBIOS_SUCCESSFUL;
}
static int sh7786_pcie_read(struct pci_bus *bus, unsigned int devfn,
int where, int size, u32 *val)
{
unsigned long flags;
int ret;
u32 data;
if ((size == 2) && (where & 1))
return PCIBIOS_BAD_REGISTER_NUMBER;
else if ((size == 4) && (where & 3))
return PCIBIOS_BAD_REGISTER_NUMBER;
raw_spin_lock_irqsave(&pci_config_lock, flags);
ret = sh7786_pcie_config_access(PCI_ACCESS_READ, bus,
devfn, where, &data);
if (ret != PCIBIOS_SUCCESSFUL) {
*val = 0xffffffff;
goto out;
}
if (size == 1)
*val = (data >> ((where & 3) << 3)) & 0xff;
else if (size == 2)
*val = (data >> ((where & 2) << 3)) & 0xffff;
else
*val = data;
dev_dbg(&bus->dev, "pcie-config-read: bus=%3d devfn=0x%04x "
"where=0x%04x size=%d val=0x%08lx\n", bus->number,
devfn, where, size, (unsigned long)*val);
out:
raw_spin_unlock_irqrestore(&pci_config_lock, flags);
return ret;
}
static int sh7786_pcie_write(struct pci_bus *bus, unsigned int devfn,
int where, int size, u32 val)
{
unsigned long flags;
int shift, ret;
u32 data;
if ((size == 2) && (where & 1))
return PCIBIOS_BAD_REGISTER_NUMBER;
else if ((size == 4) && (where & 3))
return PCIBIOS_BAD_REGISTER_NUMBER;
raw_spin_lock_irqsave(&pci_config_lock, flags);
ret = sh7786_pcie_config_access(PCI_ACCESS_READ, bus,
devfn, where, &data);
if (ret != PCIBIOS_SUCCESSFUL)
goto out;
dev_dbg(&bus->dev, "pcie-config-write: bus=%3d devfn=0x%04x "
"where=0x%04x size=%d val=%08lx\n", bus->number,
devfn, where, size, (unsigned long)val);
if (size == 1) {
shift = (where & 3) << 3;
data &= ~(0xff << shift);
data |= ((val & 0xff) << shift);
} else if (size == 2) {
shift = (where & 2) << 3;
data &= ~(0xffff << shift);
data |= ((val & 0xffff) << shift);
} else
data = val;
ret = sh7786_pcie_config_access(PCI_ACCESS_WRITE, bus,
devfn, where, &data);
out:
raw_spin_unlock_irqrestore(&pci_config_lock, flags);
return ret;
}
struct pci_ops sh7786_pci_ops = {
.read = sh7786_pcie_read,
.write = sh7786_pcie_write,
};
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