// SPDX-License-Identifier: GPL-2.0-or-later
/*
* arch/powerpc/sysdev/dart_iommu.c
*
* Copyright (C) 2004 Olof Johansson <[email protected]>, IBM Corporation
* Copyright (C) 2005 Benjamin Herrenschmidt <[email protected]>,
* IBM Corporation
*
* Based on pSeries_iommu.c:
* Copyright (C) 2001 Mike Corrigan & Dave Engebretsen, IBM Corporation
* Copyright (C) 2004 Olof Johansson <[email protected]>, IBM Corporation
*
* Dynamic DMA mapping support, Apple U3, U4 & IBM CPC925 "DART" iommu.
*/
#include <linux/init.h>
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/pci.h>
#include <linux/dma-mapping.h>
#include <linux/vmalloc.h>
#include <linux/suspend.h>
#include <linux/memblock.h>
#include <linux/gfp.h>
#include <linux/of_address.h>
#include <asm/io.h>
#include <asm/iommu.h>
#include <asm/pci-bridge.h>
#include <asm/machdep.h>
#include <asm/cacheflush.h>
#include <asm/ppc-pci.h>
#include "dart.h"
/* DART table address and size */
static u32 *dart_tablebase;
static unsigned long dart_tablesize;
/* Mapped base address for the dart */
static unsigned int __iomem *dart;
/* Dummy val that entries are set to when unused */
static unsigned int dart_emptyval;
static struct iommu_table iommu_table_dart;
static int iommu_table_dart_inited;
static int dart_dirty;
static int dart_is_u4;
#define DART_U4_BYPASS_BASE 0x8000000000ull
#define DBG(...)
static DEFINE_SPINLOCK(invalidate_lock);
static inline void dart_tlb_invalidate_all(void)
{
unsigned long l = 0;
unsigned int reg, inv_bit;
unsigned long limit;
unsigned long flags;
spin_lock_irqsave(&invalidate_lock, flags);
DBG("dart: flush\n");
/* To invalidate the DART, set the DARTCNTL_FLUSHTLB bit in the
* control register and wait for it to clear.
*
* Gotcha: Sometimes, the DART won't detect that the bit gets
* set. If so, clear it and set it again.
*/
limit = 0;
inv_bit = dart_is_u4 ? DART_CNTL_U4_FLUSHTLB : DART_CNTL_U3_FLUSHTLB;
retry:
l = 0;
reg = DART_IN(DART_CNTL);
reg |= inv_bit;
DART_OUT(DART_CNTL, reg);
while ((DART_IN(DART_CNTL) & inv_bit) && l < (1L << limit))
l++;
if (l == (1L << limit)) {
if (limit < 4) {
limit++;
reg = DART_IN(DART_CNTL);
reg &= ~inv_bit;
DART_OUT(DART_CNTL, reg);
goto retry;
} else
panic("DART: TLB did not flush after waiting a long "
"time. Buggy U3 ?");
}
spin_unlock_irqrestore(&invalidate_lock, flags);
}
static inline void dart_tlb_invalidate_one(unsigned long bus_rpn)
{
unsigned int reg;
unsigned int l, limit;
unsigned long flags;
spin_lock_irqsave(&invalidate_lock, flags);
reg = DART_CNTL_U4_ENABLE | DART_CNTL_U4_IONE |
(bus_rpn & DART_CNTL_U4_IONE_MASK);
DART_OUT(DART_CNTL, reg);
limit = 0;
wait_more:
l = 0;
while ((DART_IN(DART_CNTL) & DART_CNTL_U4_IONE) && l < (1L << limit)) {
rmb();
l++;
}
if (l == (1L << limit)) {
if (limit < 4) {
limit++;
goto wait_more;
} else
panic("DART: TLB did not flush after waiting a long "
"time. Buggy U4 ?");
}
spin_unlock_irqrestore(&invalidate_lock, flags);
}
static void dart_cache_sync(unsigned int *base, unsigned int count)
{
/*
* We add 1 to the number of entries to flush, following a
* comment in Darwin indicating that the memory controller
* can prefetch unmapped memory under some circumstances.
*/
unsigned long start = (unsigned long)base;
unsigned long end = start + (count + 1) * sizeof(unsigned int);
unsigned int tmp;
/* Perform a standard cache flush */
flush_dcache_range(start, end);
/*
* Perform the sequence described in the CPC925 manual to
* ensure all the data gets to a point the cache incoherent
* DART hardware will see.
*/
asm volatile(" sync;"
" isync;"
" dcbf 0,%1;"
" sync;"
" isync;"
" lwz %0,0(%1);"
" isync" : "=r" (tmp) : "r" (end) : "memory");
}
static void dart_flush(struct iommu_table *tbl)
{
mb();
if (dart_dirty) {
dart_tlb_invalidate_all();
dart_dirty = 0;
}
}
static int dart_build(struct iommu_table *tbl, long index,
long npages, unsigned long uaddr,
enum dma_data_direction direction,
unsigned long attrs)
{
unsigned int *dp, *orig_dp;
unsigned int rpn;
long l;
DBG("dart: build at: %lx, %lx, addr: %x\n", index, npages, uaddr);
orig_dp = dp = ((unsigned int*)tbl->it_base) + index;
/* On U3, all memory is contiguous, so we can move this
* out of the loop.
*/
l = npages;
while (l--) {
rpn = __pa(uaddr) >> DART_PAGE_SHIFT;
*(dp++) = DARTMAP_VALID | (rpn & DARTMAP_RPNMASK);
uaddr += DART_PAGE_SIZE;
}
dart_cache_sync(orig_dp, npages);
if (dart_is_u4) {
rpn = index;
while (npages--)
dart_tlb_invalidate_one(rpn++);
} else {
dart_dirty = 1;
}
return 0;
}
static void dart_free(struct iommu_table *tbl, long index, long npages)
{
unsigned int *dp, *orig_dp;
long orig_npages = npages;
/* We don't worry about flushing the TLB cache. The only drawback of
* not doing it is that we won't catch buggy device drivers doing
* bad DMAs, but then no 32-bit architecture ever does either.
*/
DBG("dart: free at: %lx, %lx\n", index, npages);
orig_dp = dp = ((unsigned int *)tbl->it_base) + index;
while (npages--)
*(dp++) = dart_emptyval;
dart_cache_sync(orig_dp, orig_npages);
}
static void __init allocate_dart(void)
{
unsigned long tmp;
/* 512 pages (2MB) is max DART tablesize. */
dart_tablesize = 1UL << 21;
/*
* 16MB (1 << 24) alignment. We allocate a full 16Mb chuck since we
* will blow up an entire large page anyway in the kernel mapping.
*/
dart_tablebase = memblock_alloc_try_nid_raw(SZ_16M, SZ_16M,
MEMBLOCK_LOW_LIMIT, SZ_2G,
NUMA_NO_NODE);
if (!dart_tablebase)
panic("Failed to allocate 16MB below 2GB for DART table\n");
/* Allocate a spare page to map all invalid DART pages. We need to do
* that to work around what looks like a problem with the HT bridge
* prefetching into invalid pages and corrupting data
*/
tmp = memblock_phys_alloc(DART_PAGE_SIZE, DART_PAGE_SIZE);
if (!tmp)
panic("DART: table allocation failed\n");
dart_emptyval = DARTMAP_VALID | ((tmp >> DART_PAGE_SHIFT) &
DARTMAP_RPNMASK);
printk(KERN_INFO "DART table allocated at: %p\n", dart_tablebase);
}
static int __init dart_init(struct device_node *dart_node)
{
unsigned int i;
unsigned long base, size;
struct resource r;
/* IOMMU disabled by the user ? bail out */
if (iommu_is_off)
return -ENODEV;
/*
* Only use the DART if the machine has more than 1GB of RAM
* or if requested with iommu=on on cmdline.
*
* 1GB of RAM is picked as limit because some default devices
* (i.e. Airport Extreme) have 30 bit address range limits.
*/
if (!iommu_force_on && memblock_end_of_DRAM() <= 0x40000000ull)
return -ENODEV;
/* Get DART registers */
if (of_address_to_resource(dart_node, 0, &r))
panic("DART: can't get register base ! ");
/* Map in DART registers */
dart = ioremap(r.start, resource_size(&r));
if (dart == NULL)
panic("DART: Cannot map registers!");
/* Allocate the DART and dummy page */
allocate_dart();
/* Fill initial table */
for (i = 0; i < dart_tablesize/4; i++)
dart_tablebase[i] = dart_emptyval;
/* Push to memory */
dart_cache_sync(dart_tablebase, dart_tablesize / sizeof(u32));
/* Initialize DART with table base and enable it. */
base = ((unsigned long)dart_tablebase) >> DART_PAGE_SHIFT;
size = dart_tablesize >> DART_PAGE_SHIFT;
if (dart_is_u4) {
size &= DART_SIZE_U4_SIZE_MASK;
DART_OUT(DART_BASE_U4, base);
DART_OUT(DART_SIZE_U4, size);
DART_OUT(DART_CNTL, DART_CNTL_U4_ENABLE);
} else {
size &= DART_CNTL_U3_SIZE_MASK;
DART_OUT(DART_CNTL,
DART_CNTL_U3_ENABLE |
(base << DART_CNTL_U3_BASE_SHIFT) |
(size << DART_CNTL_U3_SIZE_SHIFT));
}
/* Invalidate DART to get rid of possible stale TLBs */
dart_tlb_invalidate_all();
printk(KERN_INFO "DART IOMMU initialized for %s type chipset\n",
dart_is_u4 ? "U4" : "U3");
return 0;
}
static struct iommu_table_ops iommu_dart_ops = {
.set = dart_build,
.clear = dart_free,
.flush = dart_flush,
};
static void iommu_table_dart_setup(void)
{
iommu_table_dart.it_busno = 0;
iommu_table_dart.it_offset = 0;
/* it_size is in number of entries */
iommu_table_dart.it_size = dart_tablesize / sizeof(u32);
iommu_table_dart.it_page_shift = IOMMU_PAGE_SHIFT_4K;
/* Initialize the common IOMMU code */
iommu_table_dart.it_base = (unsigned long)dart_tablebase;
iommu_table_dart.it_index = 0;
iommu_table_dart.it_blocksize = 1;
iommu_table_dart.it_ops = &iommu_dart_ops;
if (!iommu_init_table(&iommu_table_dart, -1, 0, 0))
panic("Failed to initialize iommu table");
/* Reserve the last page of the DART to avoid possible prefetch
* past the DART mapped area
*/
set_bit(iommu_table_dart.it_size - 1, iommu_table_dart.it_map);
}
static void pci_dma_bus_setup_dart(struct pci_bus *bus)
{
if (!iommu_table_dart_inited) {
iommu_table_dart_inited = 1;
iommu_table_dart_setup();
}
}
static bool dart_device_on_pcie(struct device *dev)
{
struct device_node *np = of_node_get(dev->of_node);
while(np) {
if (of_device_is_compatible(np, "U4-pcie") ||
of_device_is_compatible(np, "u4-pcie")) {
of_node_put(np);
return true;
}
np = of_get_next_parent(np);
}
return false;
}
static void pci_dma_dev_setup_dart(struct pci_dev *dev)
{
if (dart_is_u4 && dart_device_on_pcie(&dev->dev))
dev->dev.archdata.dma_offset = DART_U4_BYPASS_BASE;
set_iommu_table_base(&dev->dev, &iommu_table_dart);
}
static bool iommu_bypass_supported_dart(struct pci_dev *dev, u64 mask)
{
return dart_is_u4 &&
dart_device_on_pcie(&dev->dev) &&
mask >= DMA_BIT_MASK(40);
}
void __init iommu_init_early_dart(struct pci_controller_ops *controller_ops)
{
struct device_node *dn;
/* Find the DART in the device-tree */
dn = of_find_compatible_node(NULL, "dart", "u3-dart");
if (dn == NULL) {
dn = of_find_compatible_node(NULL, "dart", "u4-dart");
if (dn == NULL)
return; /* use default direct_dma_ops */
dart_is_u4 = 1;
}
/* Initialize the DART HW */
if (dart_init(dn) != 0) {
of_node_put(dn);
return;
}
/*
* U4 supports a DART bypass, we use it for 64-bit capable devices to
* improve performance. However, that only works for devices connected
* to the U4 own PCIe interface, not bridged through hypertransport.
* We need the device to support at least 40 bits of addresses.
*/
controller_ops->dma_dev_setup = pci_dma_dev_setup_dart;
controller_ops->dma_bus_setup = pci_dma_bus_setup_dart;
controller_ops->iommu_bypass_supported = iommu_bypass_supported_dart;
/* Setup pci_dma ops */
set_pci_dma_ops(&dma_iommu_ops);
of_node_put(dn);
}
#ifdef CONFIG_PM
static void iommu_dart_restore(void)
{
dart_cache_sync(dart_tablebase, dart_tablesize / sizeof(u32));
dart_tlb_invalidate_all();
}
static int __init iommu_init_late_dart(void)
{
if (!dart_tablebase)
return 0;
ppc_md.iommu_restore = iommu_dart_restore;
return 0;
}
late_initcall(iommu_init_late_dart);
#endif /* CONFIG_PM */
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