linux/arch/powerpc/kernel/io-workarounds.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Support PCI IO workaround
 *
 *  Copyright (C) 2006 Benjamin Herrenschmidt <benh@kernel.crashing.org>
 *		       IBM, Corp.
 *  (C) Copyright 2007-2008 TOSHIBA CORPORATION
 */
#undef DEBUG

#include <linux/kernel.h>
#include <linux/sched/mm.h>	/* for init_mm */

#include <asm/io.h>
#include <asm/machdep.h>
#include <linux/pgtable.h>
#include <asm/ppc-pci.h>
#include <asm/io-workarounds.h>
#include <asm/pte-walk.h>


#define IOWA_MAX_BUS	8

static struct iowa_bus iowa_busses[IOWA_MAX_BUS];
static unsigned int iowa_bus_count;

static struct iowa_bus *iowa_pci_find(unsigned long vaddr, unsigned long paddr)
{
	int i, j;
	struct resource *res;
	unsigned long vstart, vend;

	for (i = 0; i < iowa_bus_count; i++) {
		struct iowa_bus *bus = &iowa_busses[i];
		struct pci_controller *phb = bus->phb;

		if (vaddr) {
			vstart = (unsigned long)phb->io_base_virt;
			vend = vstart + phb->pci_io_size - 1;
			if ((vaddr >= vstart) && (vaddr <= vend))
				return bus;
		}

		if (paddr)
			for (j = 0; j < 3; j++) {
				res = &phb->mem_resources[j];
				if (paddr >= res->start && paddr <= res->end)
					return bus;
			}
	}

	return NULL;
}

#ifdef CONFIG_PPC_INDIRECT_MMIO
struct iowa_bus *iowa_mem_find_bus(const PCI_IO_ADDR addr)
{
	unsigned hugepage_shift;
	struct iowa_bus *bus;
	int token;

	token = PCI_GET_ADDR_TOKEN(addr);

	if (token && token <= iowa_bus_count)
		bus = &iowa_busses[token - 1];
	else {
		unsigned long vaddr, paddr;
		pte_t *ptep;

		vaddr = (unsigned long)PCI_FIX_ADDR(addr);
		if (vaddr < PHB_IO_BASE || vaddr >= PHB_IO_END)
			return NULL;
		/*
		 * We won't find huge pages here (iomem). Also can't hit
		 * a page table free due to init_mm
		 */
		ptep = find_init_mm_pte(vaddr, &hugepage_shift);
		if (ptep == NULL)
			paddr = 0;
		else {
			WARN_ON(hugepage_shift);
			paddr = pte_pfn(*ptep) << PAGE_SHIFT;
		}
		bus = iowa_pci_find(vaddr, paddr);

		if (bus == NULL)
			return NULL;
	}

	return bus;
}
#else /* CONFIG_PPC_INDIRECT_MMIO */
struct iowa_bus *iowa_mem_find_bus(const PCI_IO_ADDR addr)
{
	return NULL;
}
#endif /* !CONFIG_PPC_INDIRECT_MMIO */

#ifdef CONFIG_PPC_INDIRECT_PIO
struct iowa_bus *iowa_pio_find_bus(unsigned long port)
{
	unsigned long vaddr = (unsigned long)pci_io_base + port;
	return iowa_pci_find(vaddr, 0);
}
#else
struct iowa_bus *iowa_pio_find_bus(unsigned long port)
{
	return NULL;
}
#endif

#define DEF_PCI_AC_RET(name, ret, at, al, space, aa)		\
static ret iowa_##name at					\
{								\
	struct iowa_bus *bus;					\
	bus = iowa_##space##_find_bus(aa);			\
	if (bus && bus->ops && bus->ops->name)			\
		return bus->ops->name al;			\
	return __do_##name al;					\
}

#define DEF_PCI_AC_NORET(name, at, al, space, aa)		\
static void iowa_##name at					\
{								\
	struct iowa_bus *bus;					\
	bus = iowa_##space##_find_bus(aa);			\
	if (bus && bus->ops && bus->ops->name) {		\
		bus->ops->name al;				\
		return;						\
	}							\
	__do_##name al;						\
}

#include <asm/io-defs.h>

#undef DEF_PCI_AC_RET
#undef DEF_PCI_AC_NORET

static const struct ppc_pci_io iowa_pci_io = {

#define DEF_PCI_AC_RET(name, ret, at, al, space, aa)	.name = iowa_##name,
#define DEF_PCI_AC_NORET(name, at, al, space, aa)	.name = iowa_##name,

#include <asm/io-defs.h>

#undef DEF_PCI_AC_RET
#undef DEF_PCI_AC_NORET

};

#ifdef CONFIG_PPC_INDIRECT_MMIO
void __iomem *iowa_ioremap(phys_addr_t addr, unsigned long size,
			   pgprot_t prot, void *caller)
{
	struct iowa_bus *bus;
	void __iomem *res = __ioremap_caller(addr, size, prot, caller);
	int busno;

	bus = iowa_pci_find(0, (unsigned long)addr);
	if (bus != NULL) {
		busno = bus - iowa_busses;
		PCI_SET_ADDR_TOKEN(res, busno + 1);
	}
	return res;
}
#endif /* !CONFIG_PPC_INDIRECT_MMIO */

bool io_workaround_inited;

/* Enable IO workaround */
static void io_workaround_init(void)
{
	if (io_workaround_inited)
		return;
	ppc_pci_io = iowa_pci_io;
	io_workaround_inited = true;
}

/* Register new bus to support workaround */
void iowa_register_bus(struct pci_controller *phb, struct ppc_pci_io *ops,
		       int (*initfunc)(struct iowa_bus *, void *), void *data)
{
	struct iowa_bus *bus;
	struct device_node *np = phb->dn;

	io_workaround_init();

	if (iowa_bus_count >= IOWA_MAX_BUS) {
		pr_err("IOWA:Too many pci bridges, "
		       "workarounds disabled for %pOF\n", np);
		return;
	}

	bus = &iowa_busses[iowa_bus_count];
	bus->phb = phb;
	bus->ops = ops;
	bus->private = data;

	if (initfunc)
		if ((*initfunc)(bus, data))
			return;

	iowa_bus_count++;

	pr_debug("IOWA:[%d]Add bus, %pOF.\n", iowa_bus_count-1, np);
}