1// SPDX-License-Identifier: GPL-2.0
  2#include <linux/kernel.h>
  3#include <linux/pci.h>
  4#include <asm/bootinfo.h>
  5
  6#include <asm/lasat/lasat.h>
  7#include <asm/nile4.h>
  8
  9#define PCI_ACCESS_READ	 0
 10#define PCI_ACCESS_WRITE 1
 11
 12#define LO(reg) (reg / 4)
 13#define HI(reg) (reg / 4 + 1)
 14
 15volatile unsigned long *const vrc_pciregs = (void *) Vrc5074_BASE;
 16
 17static int nile4_pcibios_config_access(unsigned char access_type,
 18	struct pci_bus *bus, unsigned int devfn, int where, u32 *val)
 19{
 20	unsigned char busnum = bus->number;
 21	u32 adr, mask, err;
 22
 23	if ((busnum == 0) && (PCI_SLOT(devfn) > 8))
 24		/* The addressing scheme chosen leaves room for just
 25		 * 8 devices on the first busnum (besides the PCI
 26		 * controller itself) */
 27		return PCIBIOS_DEVICE_NOT_FOUND;
 28
 29	if ((busnum == 0) && (devfn == PCI_DEVFN(0, 0))) {
 30		/* Access controller registers directly */
 31		if (access_type == PCI_ACCESS_WRITE) {
 32			vrc_pciregs[(0x200 + where) >> 2] = *val;
 33		} else {
 34			*val = vrc_pciregs[(0x200 + where) >> 2];
 35		}
 36		return PCIBIOS_SUCCESSFUL;
 37	}
 38
 39	/* Temporarily map PCI Window 1 to config space */
 40	mask = vrc_pciregs[LO(NILE4_PCIINIT1)];
 41	vrc_pciregs[LO(NILE4_PCIINIT1)] = 0x0000001a | (busnum ? 0x200 : 0);
 42
 43	/* Clear PCI Error register. This also clears the Error Type
 44	 * bits in the Control register */
 45	vrc_pciregs[LO(NILE4_PCIERR)] = 0;
 46	vrc_pciregs[HI(NILE4_PCIERR)] = 0;
 47
 48	/* Setup address */
 49	if (busnum == 0)
 50		adr =
 51		    KSEG1ADDR(PCI_WINDOW1) +
 52		    ((1 << (PCI_SLOT(devfn) + 15)) | (PCI_FUNC(devfn) << 8)
 53		     | (where & ~3));
 54	else
 55		adr = KSEG1ADDR(PCI_WINDOW1) | (busnum << 16) | (devfn << 8) |
 56		      (where & ~3);
 57
 58	if (access_type == PCI_ACCESS_WRITE)
 59		*(u32 *) adr = *val;
 60	else
 61		*val = *(u32 *) adr;
 62
 63	/* Check for master or target abort */
 64	err = (vrc_pciregs[HI(NILE4_PCICTRL)] >> 5) & 0x7;
 65
 66	/* Restore PCI Window 1 */
 67	vrc_pciregs[LO(NILE4_PCIINIT1)] = mask;
 68
 69	if (err)
 70		return PCIBIOS_DEVICE_NOT_FOUND;
 71
 72	return PCIBIOS_SUCCESSFUL;
 73}
 74
 75static int nile4_pcibios_read(struct pci_bus *bus, unsigned int devfn,
 76	int where, int size, u32 *val)
 77{
 78	u32 data = 0;
 79	int err;
 80
 81	if ((size == 2) && (where & 1))
 82		return PCIBIOS_BAD_REGISTER_NUMBER;
 83	else if ((size == 4) && (where & 3))
 84		return PCIBIOS_BAD_REGISTER_NUMBER;
 85
 86	err = nile4_pcibios_config_access(PCI_ACCESS_READ, bus, devfn, where,
 87					  &data);
 88	if (err)
 89		return err;
 90
 91	if (size == 1)
 92		*val = (data >> ((where & 3) << 3)) & 0xff;
 93	else if (size == 2)
 94		*val = (data >> ((where & 3) << 3)) & 0xffff;
 95	else
 96		*val = data;
 97
 98	return PCIBIOS_SUCCESSFUL;
 99}
100
101static int nile4_pcibios_write(struct pci_bus *bus, unsigned int devfn,
102	int where, int size, u32 val)
103{
104	u32 data = 0;
105	int err;
106
107	if ((size == 2) && (where & 1))
108		return PCIBIOS_BAD_REGISTER_NUMBER;
109	else if ((size == 4) && (where & 3))
110		return PCIBIOS_BAD_REGISTER_NUMBER;
111
112	err = nile4_pcibios_config_access(PCI_ACCESS_READ, bus, devfn, where,
113					  &data);
114	if (err)
115		return err;
116
117	if (size == 1)
118		data = (data & ~(0xff << ((where & 3) << 3))) |
119		    (val << ((where & 3) << 3));
120	else if (size == 2)
121		data = (data & ~(0xffff << ((where & 3) << 3))) |
122		    (val << ((where & 3) << 3));
123	else
124		data = val;
125
126	if (nile4_pcibios_config_access
127	    (PCI_ACCESS_WRITE, bus, devfn, where, &data))
128		return -1;
129
130	return PCIBIOS_SUCCESSFUL;
131}
132
133struct pci_ops nile4_pci_ops = {
134	.read = nile4_pcibios_read,
135	.write = nile4_pcibios_write,
136};