Commit bfa1ce5f authored by Thomas Petazzoni's avatar Thomas Petazzoni Committed by Gregory CLEMENT
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bus: mvebu-mbus: add mv_mbus_dram_info_nooverlap()

This commit introduces a variant of the mv_mbus_dram_info() function
called mv_mbus_dram_info_nooverlap(). Both functions are used by
Marvell drivers supporting devices doing DMA, and provide them a
description the DRAM ranges that they need to configure their DRAM

The ranges provided by the mv_mbus_dram_info() function may overlap
with the I/O windows if there is a lot (>= 4 GB) of RAM
installed. This is not a problem for most of the DMA masters, except
for the upcoming new CESA crypto driver because it does DMA to the
SRAM, which is mapped through an I/O window. For this unit, we need to
have DRAM ranges that do not overlap with the I/O windows.

A first implementation done in commit 1737cac6

 ("bus: mvebu-mbus:
make sure SDRAM CS for DMA don't overlap the MBus bridge window"),
changed the information returned by mv_mbus_dram_info() to match this
requirement. However, it broke the requirement of the other DMA
masters than the DRAM ranges should have power of two sizes.

To solve this situation, this commit introduces a new
mv_mbus_dram_info_nooverlap() function, which returns the same
information as mv_mbus_dram_info(), but guaranteed to not overlap with
the I/O windows.

In the end, it gives us two variants of the mv_mbus_dram_info*()

 - The normal one, mv_mbus_dram_info(), which has been around for many
   years. This function returns the raw DRAM ranges, which are
   guaranteed to use power of two sizes, but will overlap with I/O
   windows. This function will therefore be used by all DMA masters
   (SATA, XOR, Ethernet, etc.) except the CESA crypto driver.

 - The new 'nooverlap' variant, mv_mbus_dram_info_nooverlap(). This
   function returns DRAM ranges after they have been "tweaked" to make
   sure they don't overlap with I/O windows. By doing this tweaking,
   we remove the power of two size guarantee. This variant will be
   used by the new CESA crypto driver.
Signed-off-by: default avatarThomas Petazzoni <>
Signed-off-by: default avatarGregory CLEMENT <>
parent 885dbd15
......@@ -57,6 +57,7 @@
#include <linux/of_address.h>
#include <linux/debugfs.h>
#include <linux/log2.h>
#include <linux/memblock.h>
#include <linux/syscore_ops.h>
......@@ -152,13 +153,39 @@ struct mvebu_mbus_state {
static struct mvebu_mbus_state mbus_state;
* We provide two variants of the mv_mbus_dram_info() function:
* - The normal one, where the described DRAM ranges may overlap with
* the I/O windows, but for which the DRAM ranges are guaranteed to
* have a power of two size. Such ranges are suitable for the DMA
* masters that only DMA between the RAM and the device, which is
* actually all devices except the crypto engines.
* - The 'nooverlap' one, where the described DRAM ranges are
* guaranteed to not overlap with the I/O windows, but for which the
* DRAM ranges will not have power of two sizes. They will only be
* aligned on a 64 KB boundary, and have a size multiple of 64
* KB. Such ranges are suitable for the DMA masters that DMA between
* the crypto SRAM (which is mapped through an I/O window) and a
* device. This is the case for the crypto engines.
static struct mbus_dram_target_info mvebu_mbus_dram_info;
static struct mbus_dram_target_info mvebu_mbus_dram_info_nooverlap;
const struct mbus_dram_target_info *mv_mbus_dram_info(void)
return &mvebu_mbus_dram_info;
const struct mbus_dram_target_info *mv_mbus_dram_info_nooverlap(void)
return &mvebu_mbus_dram_info_nooverlap;
/* Checks whether the given window has remap capability */
static bool mvebu_mbus_window_is_remappable(struct mvebu_mbus_state *mbus,
const int win)
......@@ -576,6 +603,95 @@ static unsigned int armada_xp_mbus_win_remap_offset(int win)
* Use the memblock information to find the MBus bridge hole in the
* physical address space.
static void __init
mvebu_mbus_find_bridge_hole(uint64_t *start, uint64_t *end)
struct memblock_region *r;
uint64_t s = 0;
for_each_memblock(memory, r) {
* This part of the memory is above 4 GB, so we don't
* care for the MBus bridge hole.
if (r->base >= 0x100000000ULL)
* The MBus bridge hole is at the end of the RAM under
* the 4 GB limit.
if (r->base + r->size > s)
s = r->base + r->size;
*start = s;
*end = 0x100000000ULL;
* This function fills in the mvebu_mbus_dram_info_nooverlap data
* structure, by looking at the mvebu_mbus_dram_info data, and
* removing the parts of it that overlap with I/O windows.
static void __init
mvebu_mbus_setup_cpu_target_nooverlap(struct mvebu_mbus_state *mbus)
uint64_t mbus_bridge_base, mbus_bridge_end;
int cs_nooverlap = 0;
int i;
mvebu_mbus_find_bridge_hole(&mbus_bridge_base, &mbus_bridge_end);
for (i = 0; i < mvebu_mbus_dram_info.num_cs; i++) {
struct mbus_dram_window *w;
u64 base, size, end;
w = &mvebu_mbus_dram_info.cs[i];
base = w->base;
size = w->size;
end = base + size;
* The CS is fully enclosed inside the MBus bridge
* area, so ignore it.
if (base >= mbus_bridge_base && end <= mbus_bridge_end)
* Beginning of CS overlaps with end of MBus, raise CS
* base address, and shrink its size.
if (base >= mbus_bridge_base && end > mbus_bridge_end) {
size -= mbus_bridge_end - base;
base = mbus_bridge_end;
* End of CS overlaps with beginning of MBus, shrink
* CS size.
if (base < mbus_bridge_base && end > mbus_bridge_base)
size -= end - mbus_bridge_base;
w = &mvebu_mbus_dram_info_nooverlap.cs[cs_nooverlap++];
w->cs_index = i;
w->mbus_attr = 0xf & ~(1 << i);
if (mbus->hw_io_coherency)
w->mbus_attr |= ATTR_HW_COHERENCY;
w->base = base;
w->size = size;
mvebu_mbus_dram_info_nooverlap.mbus_dram_target_id = TARGET_DDR;
mvebu_mbus_dram_info_nooverlap.num_cs = cs_nooverlap;
static void __init
mvebu_mbus_default_setup_cpu_target(struct mvebu_mbus_state *mbus)
......@@ -964,6 +1080,7 @@ static int __init mvebu_mbus_common_init(struct mvebu_mbus_state *mbus,
mvebu_mbus_disable_window(mbus, win);
if (is_coherent)
......@@ -54,11 +54,16 @@ struct mbus_dram_target_info
extern const struct mbus_dram_target_info *mv_mbus_dram_info(void);
extern const struct mbus_dram_target_info *mv_mbus_dram_info_nooverlap(void);
static inline const struct mbus_dram_target_info *mv_mbus_dram_info(void)
return NULL;
static inline const struct mbus_dram_target_info *mv_mbus_dram_info_nooverlap(void)
return NULL;
int mvebu_mbus_save_cpu_target(u32 *store_addr);
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