plat: marvell: armada: a3k: improve 4GB DRAM usage from 3.375 GB to 3.75 GB
The current configuration of CPU windows on Armada 37x0 with 4 GB DRAM
can only utilize 3.375 GB of memory. This is because there are only 5
configuration windows, configured as such (in hexadecimal, also showing
ranges not configurable by CPU windows):
0 - 80000000 | 2 GB | DDR | CPU window 0
80000000 - C0000000 | 1 GB | DDR | CPU window 1
C0000000 - D0000000 | 256 MB | DDR | CPU window 2
D0000000 - D2000000 | 32 MB | | Internal regs
empty space | | |
D8000000 - D8010000 | 64 KB | | CCI regs
empty space | | |
E0000000 - E8000000 | 128 MB | DDR | CPU window 3
E8000000 - F0000000 | 128 MB | PCIe | CPU window 4
empty space | | |
FFF00000 - end | 64 KB | | Boot ROM
This can be improved by taking into account that:
- CCI window can be moved (the base address is only hardcoded in TF-A;
U-Boot and Linux will not break with changing of this address)
- PCIe window can be moved (upstream U-Boot can change device-tree
ranges of PCIe if PCIe window is moved)
Change the layout after the Internal regs as such:
D2000000 - F2000000 | 512 MB | DDR | CPU window 3
F2000000 - FA000000 | 128 MB | PCIe | CPU window 4
empty space | | |
FE000000 - FE010000 | 64 KB | | CCI regs
empty space | | |
FFF00000 - end | 64 KB | | Boot ROM
(Note that CCI regs base address is moved from D8000000 to FE000000 in
all cases, not only for the configuration with 4 GB of DRAM. This is
because TF-A is built with this address as a constant, so we cannot
change this address at runtime only on some boards.)
This yields 3.75 GB of usable RAM.
Moreover U-Boot can theoretically reconfigure the PCIe window to DDR if
it discovers that no PCIe card is connected. This can add another 128 MB
of DRAM (resulting only in 128 MB of DRAM not being used).
Signed-off-by: Marek Behún <marek.behun@nic.cz>
Change-Id: I4ca1999f852f90055fac8b2c4f7e80275a13ad7e
diff --git a/plat/marvell/armada/a3k/common/dram_win.c b/plat/marvell/armada/a3k/common/dram_win.c
index 694f6d4..e89f295 100644
--- a/plat/marvell/armada/a3k/common/dram_win.c
+++ b/plat/marvell/armada/a3k/common/dram_win.c
@@ -1,5 +1,5 @@
/*
- * Copyright (C) 2018 Marvell International Ltd.
+ * Copyright (C) 2018-2021 Marvell International Ltd.
*
* SPDX-License-Identifier: BSD-3-Clause
* https://spdx.org/licenses
@@ -92,33 +92,35 @@
},
/*
- * If total dram size is more than 2GB, now there is only one case - 4GB
- * dram; we will use below cpu windows configurations:
- * - Internal Regs, CCI-400, Boot Rom and PCIe windows are kept as
- * default;
- * - Use 4 CPU decode windows for DRAM, which cover 3.375GB DRAM;
- * DDR window 0 is configured in tim header with 2GB size, no need to
- * configure it again here;
+ * If total DRAM size is more than 2GB, now there is only one case:
+ * 4GB of DRAM; to better utilize address space (for maximization of
+ * DRAM usage), we will use the configuration of CPU windows below:
+ * - Internal Regs and Boot ROM windows are kept as default;
+ * - CCI-400 is moved from its default address to another address
+ * (this is actually done even if DRAM size is not more than 2 GB,
+ * because the firmware is compiled with that address as a
+ * constant);
+ * - PCIe window is moved to another address;
+ * - Use 4 CPU decode windows for DRAM, which cover 3.75GB DRAM;
+ * DDR window 0 is configured in tim header with 2G B size, no need
+ * to configure it again here;
*
- * 0xFFFFFFFF ---> |-----------------------|
- * | Boot ROM | 64KB
+ * 0xFFFFFFFF ---> +-----------------------+
+ * | Boot ROM | 64 KB
* 0xFFF00000 ---> +-----------------------+
* : :
- * 0xF0000000 ---> |-----------------------|
- * | PCIE | 128 MB
- * 0xE8000000 ---> |-----------------------|
- * | DDR window 3 | 128 MB
- * 0xE0000000 ---> +-----------------------+
+ * 0xFE010000 ---> +-----------------------+
+ * | CCI Regs | 64 KB
+ * 0xFE000000 ---> +-----------------------+
* : :
- * 0xD8010000 ---> |-----------------------|
- * | CCI Regs | 64 KB
- * 0xD8000000 ---> +-----------------------+
- * : :
- * : :
+ * 0xFA000000 ---> +-----------------------+
+ * | PCIE | 128 MB
+ * 0xF2000000 ---> +-----------------------+
+ * | DDR window 3 | 512 MB
* 0xD2000000 ---> +-----------------------+
- * | Internal Regs | 32MB
+ * | Internal Regs | 32 MB
* 0xD0000000 ---> |-----------------------|
- * | DDR window 2 | 256 MB
+ * | DDR window 2 | 256 MB
* 0xC0000000 ---> |-----------------------|
* | |
* | DDR window 1 | 1 GB
@@ -155,14 +157,14 @@
0xc0000000},
{CPU_WIN_ENABLED,
CPU_WIN_TARGET_DRAM,
- 0xe0000000,
- 0x08000000,
- 0xe0000000},
+ 0xd2000000,
+ 0x20000000,
+ 0xd2000000},
{CPU_WIN_ENABLED,
CPU_WIN_TARGET_PCIE,
- 0xe8000000,
+ 0xf2000000,
0x08000000,
- 0xe8000000},
+ 0xf2000000},
},
};