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linux-next/drivers/of/of_reserved_mem.c
Stewart Smith 22f8cc6e33 drivers: of: increase MAX_RESERVED_REGIONS to 32
There are two types of memory reservations firmware can ask the kernel
to make in the device tree: static and dynamic.
See Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt

If you have greater than 16 entries in /reserved-memory (as we do on
POWER9 systems) you would get this scary looking error message:
 [    0.000000] OF: reserved mem: not enough space all defined regions.

This is harmless if all your reservations are static (which with OPAL on
POWER9, they are).

It is not harmless if you have any dynamic reservations after the 16th.

In the first pass over the fdt to find reservations, the child nodes of
/reserved-memory are added to a static array in of_reserved_mem.c so that
memory can be reserved in a 2nd pass. The array has 16 entries. This is why,
on my dual socket POWER9 system, I get that error 4 times with 20 static
reservations.

We don't have a problem on ppc though, as in arch/powerpc/kernel/prom.c
we look at the new style /reserved-ranges property to do reservations,
and this logic was introduced in 0962e8004e (well before any powernv
system shipped).

A Google search shows up no occurances of that exact error message, so we're
probably safe in that no machine that people use has memory not being reserved
when it should be.

The simple fix is to bump the length of the array to 32 which "should be
enough for everyone(TM)". The simple fix of not recording static allocations
in the array would cause problems for devices with "memory-region" properties.
A more future-proof fix is likely possible, although more invasive and this
simple fix is perfectly suitable in the meantime while a more future-proof
fix is developed.

Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>
Tested-by: Mauricio Faria de Oliveira <mauricfo@linux.vnet.ibm.com>
Signed-off-by: Rob Herring <robh@kernel.org>
2017-10-12 12:23:45 -05:00

400 lines
10 KiB
C

/*
* Device tree based initialization code for reserved memory.
*
* Copyright (c) 2013, 2015 The Linux Foundation. All Rights Reserved.
* Copyright (c) 2013,2014 Samsung Electronics Co., Ltd.
* http://www.samsung.com
* Author: Marek Szyprowski <m.szyprowski@samsung.com>
* Author: Josh Cartwright <joshc@codeaurora.org>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License or (at your optional) any later version of the license.
*/
#define pr_fmt(fmt) "OF: reserved mem: " fmt
#include <linux/err.h>
#include <linux/of.h>
#include <linux/of_fdt.h>
#include <linux/of_platform.h>
#include <linux/mm.h>
#include <linux/sizes.h>
#include <linux/of_reserved_mem.h>
#include <linux/sort.h>
#include <linux/slab.h>
#define MAX_RESERVED_REGIONS 32
static struct reserved_mem reserved_mem[MAX_RESERVED_REGIONS];
static int reserved_mem_count;
#if defined(CONFIG_HAVE_MEMBLOCK)
#include <linux/memblock.h>
int __init __weak early_init_dt_alloc_reserved_memory_arch(phys_addr_t size,
phys_addr_t align, phys_addr_t start, phys_addr_t end, bool nomap,
phys_addr_t *res_base)
{
phys_addr_t base;
/*
* We use __memblock_alloc_base() because memblock_alloc_base()
* panic()s on allocation failure.
*/
end = !end ? MEMBLOCK_ALLOC_ANYWHERE : end;
base = __memblock_alloc_base(size, align, end);
if (!base)
return -ENOMEM;
/*
* Check if the allocated region fits in to start..end window
*/
if (base < start) {
memblock_free(base, size);
return -ENOMEM;
}
*res_base = base;
if (nomap)
return memblock_remove(base, size);
return 0;
}
#else
int __init __weak early_init_dt_alloc_reserved_memory_arch(phys_addr_t size,
phys_addr_t align, phys_addr_t start, phys_addr_t end, bool nomap,
phys_addr_t *res_base)
{
pr_err("Reserved memory not supported, ignoring region 0x%llx%s\n",
size, nomap ? " (nomap)" : "");
return -ENOSYS;
}
#endif
/**
* res_mem_save_node() - save fdt node for second pass initialization
*/
void __init fdt_reserved_mem_save_node(unsigned long node, const char *uname,
phys_addr_t base, phys_addr_t size)
{
struct reserved_mem *rmem = &reserved_mem[reserved_mem_count];
if (reserved_mem_count == ARRAY_SIZE(reserved_mem)) {
pr_err("not enough space all defined regions.\n");
return;
}
rmem->fdt_node = node;
rmem->name = uname;
rmem->base = base;
rmem->size = size;
reserved_mem_count++;
return;
}
/**
* res_mem_alloc_size() - allocate reserved memory described by 'size', 'align'
* and 'alloc-ranges' properties
*/
static int __init __reserved_mem_alloc_size(unsigned long node,
const char *uname, phys_addr_t *res_base, phys_addr_t *res_size)
{
int t_len = (dt_root_addr_cells + dt_root_size_cells) * sizeof(__be32);
phys_addr_t start = 0, end = 0;
phys_addr_t base = 0, align = 0, size;
int len;
const __be32 *prop;
int nomap;
int ret;
prop = of_get_flat_dt_prop(node, "size", &len);
if (!prop)
return -EINVAL;
if (len != dt_root_size_cells * sizeof(__be32)) {
pr_err("invalid size property in '%s' node.\n", uname);
return -EINVAL;
}
size = dt_mem_next_cell(dt_root_size_cells, &prop);
nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;
prop = of_get_flat_dt_prop(node, "alignment", &len);
if (prop) {
if (len != dt_root_addr_cells * sizeof(__be32)) {
pr_err("invalid alignment property in '%s' node.\n",
uname);
return -EINVAL;
}
align = dt_mem_next_cell(dt_root_addr_cells, &prop);
}
/* Need adjust the alignment to satisfy the CMA requirement */
if (IS_ENABLED(CONFIG_CMA)
&& of_flat_dt_is_compatible(node, "shared-dma-pool")
&& of_get_flat_dt_prop(node, "reusable", NULL)
&& !of_get_flat_dt_prop(node, "no-map", NULL)) {
unsigned long order =
max_t(unsigned long, MAX_ORDER - 1, pageblock_order);
align = max(align, (phys_addr_t)PAGE_SIZE << order);
}
prop = of_get_flat_dt_prop(node, "alloc-ranges", &len);
if (prop) {
if (len % t_len != 0) {
pr_err("invalid alloc-ranges property in '%s', skipping node.\n",
uname);
return -EINVAL;
}
base = 0;
while (len > 0) {
start = dt_mem_next_cell(dt_root_addr_cells, &prop);
end = start + dt_mem_next_cell(dt_root_size_cells,
&prop);
ret = early_init_dt_alloc_reserved_memory_arch(size,
align, start, end, nomap, &base);
if (ret == 0) {
pr_debug("allocated memory for '%s' node: base %pa, size %ld MiB\n",
uname, &base,
(unsigned long)size / SZ_1M);
break;
}
len -= t_len;
}
} else {
ret = early_init_dt_alloc_reserved_memory_arch(size, align,
0, 0, nomap, &base);
if (ret == 0)
pr_debug("allocated memory for '%s' node: base %pa, size %ld MiB\n",
uname, &base, (unsigned long)size / SZ_1M);
}
if (base == 0) {
pr_info("failed to allocate memory for node '%s'\n", uname);
return -ENOMEM;
}
*res_base = base;
*res_size = size;
return 0;
}
static const struct of_device_id __rmem_of_table_sentinel
__used __section(__reservedmem_of_table_end);
/**
* res_mem_init_node() - call region specific reserved memory init code
*/
static int __init __reserved_mem_init_node(struct reserved_mem *rmem)
{
extern const struct of_device_id __reservedmem_of_table[];
const struct of_device_id *i;
for (i = __reservedmem_of_table; i < &__rmem_of_table_sentinel; i++) {
reservedmem_of_init_fn initfn = i->data;
const char *compat = i->compatible;
if (!of_flat_dt_is_compatible(rmem->fdt_node, compat))
continue;
if (initfn(rmem) == 0) {
pr_info("initialized node %s, compatible id %s\n",
rmem->name, compat);
return 0;
}
}
return -ENOENT;
}
static int __init __rmem_cmp(const void *a, const void *b)
{
const struct reserved_mem *ra = a, *rb = b;
if (ra->base < rb->base)
return -1;
if (ra->base > rb->base)
return 1;
return 0;
}
static void __init __rmem_check_for_overlap(void)
{
int i;
if (reserved_mem_count < 2)
return;
sort(reserved_mem, reserved_mem_count, sizeof(reserved_mem[0]),
__rmem_cmp, NULL);
for (i = 0; i < reserved_mem_count - 1; i++) {
struct reserved_mem *this, *next;
this = &reserved_mem[i];
next = &reserved_mem[i + 1];
if (!(this->base && next->base))
continue;
if (this->base + this->size > next->base) {
phys_addr_t this_end, next_end;
this_end = this->base + this->size;
next_end = next->base + next->size;
pr_err("OVERLAP DETECTED!\n%s (%pa--%pa) overlaps with %s (%pa--%pa)\n",
this->name, &this->base, &this_end,
next->name, &next->base, &next_end);
}
}
}
/**
* fdt_init_reserved_mem - allocate and init all saved reserved memory regions
*/
void __init fdt_init_reserved_mem(void)
{
int i;
/* check for overlapping reserved regions */
__rmem_check_for_overlap();
for (i = 0; i < reserved_mem_count; i++) {
struct reserved_mem *rmem = &reserved_mem[i];
unsigned long node = rmem->fdt_node;
int len;
const __be32 *prop;
int err = 0;
prop = of_get_flat_dt_prop(node, "phandle", &len);
if (!prop)
prop = of_get_flat_dt_prop(node, "linux,phandle", &len);
if (prop)
rmem->phandle = of_read_number(prop, len/4);
if (rmem->size == 0)
err = __reserved_mem_alloc_size(node, rmem->name,
&rmem->base, &rmem->size);
if (err == 0)
__reserved_mem_init_node(rmem);
}
}
static inline struct reserved_mem *__find_rmem(struct device_node *node)
{
unsigned int i;
if (!node->phandle)
return NULL;
for (i = 0; i < reserved_mem_count; i++)
if (reserved_mem[i].phandle == node->phandle)
return &reserved_mem[i];
return NULL;
}
struct rmem_assigned_device {
struct device *dev;
struct reserved_mem *rmem;
struct list_head list;
};
static LIST_HEAD(of_rmem_assigned_device_list);
static DEFINE_MUTEX(of_rmem_assigned_device_mutex);
/**
* of_reserved_mem_device_init_by_idx() - assign reserved memory region to
* given device
* @dev: Pointer to the device to configure
* @np: Pointer to the device_node with 'reserved-memory' property
* @idx: Index of selected region
*
* This function assigns respective DMA-mapping operations based on reserved
* memory region specified by 'memory-region' property in @np node to the @dev
* device. When driver needs to use more than one reserved memory region, it
* should allocate child devices and initialize regions by name for each of
* child device.
*
* Returns error code or zero on success.
*/
int of_reserved_mem_device_init_by_idx(struct device *dev,
struct device_node *np, int idx)
{
struct rmem_assigned_device *rd;
struct device_node *target;
struct reserved_mem *rmem;
int ret;
if (!np || !dev)
return -EINVAL;
target = of_parse_phandle(np, "memory-region", idx);
if (!target)
return -ENODEV;
rmem = __find_rmem(target);
of_node_put(target);
if (!rmem || !rmem->ops || !rmem->ops->device_init)
return -EINVAL;
rd = kmalloc(sizeof(struct rmem_assigned_device), GFP_KERNEL);
if (!rd)
return -ENOMEM;
ret = rmem->ops->device_init(rmem, dev);
if (ret == 0) {
rd->dev = dev;
rd->rmem = rmem;
mutex_lock(&of_rmem_assigned_device_mutex);
list_add(&rd->list, &of_rmem_assigned_device_list);
mutex_unlock(&of_rmem_assigned_device_mutex);
/* ensure that dma_ops is set for virtual devices
* using reserved memory
*/
of_dma_configure(dev, np);
dev_info(dev, "assigned reserved memory node %s\n", rmem->name);
} else {
kfree(rd);
}
return ret;
}
EXPORT_SYMBOL_GPL(of_reserved_mem_device_init_by_idx);
/**
* of_reserved_mem_device_release() - release reserved memory device structures
* @dev: Pointer to the device to deconfigure
*
* This function releases structures allocated for memory region handling for
* the given device.
*/
void of_reserved_mem_device_release(struct device *dev)
{
struct rmem_assigned_device *rd;
struct reserved_mem *rmem = NULL;
mutex_lock(&of_rmem_assigned_device_mutex);
list_for_each_entry(rd, &of_rmem_assigned_device_list, list) {
if (rd->dev == dev) {
rmem = rd->rmem;
list_del(&rd->list);
kfree(rd);
break;
}
}
mutex_unlock(&of_rmem_assigned_device_mutex);
if (!rmem || !rmem->ops || !rmem->ops->device_release)
return;
rmem->ops->device_release(rmem, dev);
}
EXPORT_SYMBOL_GPL(of_reserved_mem_device_release);