From: Alexander Graf <agraf@suse.de>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH 03/11] riscv: generic: Ensure that U-Boot runs within 4GB for 64bit systems
Date: Thu, 17 Jan 2019 19:06:21 +0100 [thread overview]
Message-ID: <d9efdfcf-7ed3-aef3-90b2-21805f338843@suse.de> (raw)
In-Reply-To: <20190117103748.36613-4-anup.patel@wdc.com>
On 01/17/2019 11:38 AM, Anup Patel wrote:
> On 64bit systems, the DRAM top can be easily beyond 4GB and U-Boot
> DMA mapping APIs will generate DMA addresses beyond 4GB. This
> breaks DMA programming in 32bit DMA capable devices (such as
> Cadence MACB ethernet). For example, If DRAM is more then 2GB
> on QEMU sifive_u machine then Cadence MACB ethernet stops working
> for U-Boot because it is a 32bit DMA capable device.
>
> To handle 32bit DMA capable devices on 64bit systems, we provide
> custom implementation of board_get_usable_ram_top() which ensures
> that usable ram top is not more then 4GB. This in-turn ensures
> that U-Boot always runs within 4GB hence DMA addresses generated
> by DMA mapping APIs will be within 4GB too.
>
> Signed-off-by: Anup Patel <anup.patel@wdc.com>
> Signed-off-by: Atish Patra <atish.patra@wdc.com>
You could probably write that with MIN() more easily, but this way works
fine too.
Reviewed-by: Alexander Graf <agraf@suse.de>
Alex
next prev parent reply other threads:[~2019-01-17 18:06 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-17 10:38 [U-Boot] [PATCH 00/11] SiFive FU540 Support Anup Patel
2019-01-17 10:38 ` [U-Boot] [PATCH 01/11] riscv: Rename cpu/qemu to cpu/generic Anup Patel
2019-01-17 18:04 ` Alexander Graf
2019-01-17 10:38 ` [U-Boot] [PATCH 02/11] riscv: Add asm/dma-mapping.h for DMA mappings Anup Patel
2019-01-17 18:05 ` Alexander Graf
2019-01-17 10:38 ` [U-Boot] [PATCH 03/11] riscv: generic: Ensure that U-Boot runs within 4GB for 64bit systems Anup Patel
2019-01-17 18:06 ` Alexander Graf [this message]
2019-01-17 10:38 ` [U-Boot] [PATCH 04/11] net: macb: Fix clk API usage for RISC-V systems Anup Patel
2019-01-17 18:07 ` Alexander Graf
2019-01-18 6:05 ` Anup Patel
2019-01-18 11:35 ` Alexander Graf
2019-01-18 13:28 ` Anup Patel
2019-01-18 13:35 ` Alexander Graf
2019-01-31 10:04 ` Simon Glass
2019-02-05 11:17 ` Anup Patel
2019-01-17 10:38 ` [U-Boot] [PATCH 05/11] net: macb: Fix GEM hardware detection Anup Patel
2019-01-17 18:12 ` Alexander Graf
2019-01-17 10:39 ` [U-Boot] [PATCH 06/11] clk: Add SiFive FU540 PRCI clock driver Anup Patel
2019-01-17 18:17 ` Alexander Graf
2019-01-17 10:39 ` [U-Boot] [PATCH 07/11] clk: Add fixed-factor " Anup Patel
2019-01-17 18:20 ` Alexander Graf
2019-01-18 6:14 ` Anup Patel
2019-01-21 14:19 ` Alexander Graf
2019-01-22 12:35 ` Anup Patel
2019-01-17 10:39 ` [U-Boot] [PATCH 08/11] drivers: serial_sifive: Fix baud rate calculation Anup Patel
2019-01-17 18:22 ` Alexander Graf
2019-01-17 10:39 ` [U-Boot] [PATCH 09/11] drivers: serial: serial_sifive: Skip baudrate config if no input clock Anup Patel
2019-01-17 18:25 ` Alexander Graf
2019-01-17 10:39 ` [U-Boot] [PATCH 10/11] cpu: Bind timer driver for boot hart Anup Patel
2019-01-17 18:26 ` Alexander Graf
2019-01-17 10:39 ` [U-Boot] [PATCH 11/11] riscv: Add SiFive FU540 board support Anup Patel
2019-01-17 16:55 ` Troy Benjegerdes
2019-01-17 18:20 ` Atish Patra
2019-01-17 23:05 ` Alexander Graf
2019-01-17 23:09 ` [U-Boot] [PATCH 00/11] SiFive FU540 Support Alexander Graf
2019-01-18 5:53 ` Anup Patel
-- strict thread matches above, loose matches on Subject: below --
2019-01-17 11:03 Anup Patel
2019-01-17 11:03 ` [U-Boot] [PATCH 03/11] riscv: generic: Ensure that U-Boot runs within 4GB for 64bit systems Anup Patel
2019-01-17 10:34 [U-Boot] [PATCH 00/11] SiFive FU540 Support Anup Patel
2019-01-17 10:35 ` [U-Boot] [PATCH 03/11] riscv: generic: Ensure that U-Boot runs within 4GB for 64bit systems Anup Patel
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