linux-kernel - [PATCH 0/4] spi: axi-spi-engine: offload instruction optimization

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20250428-adi-main-v1-0-4b8a1b88a212@baylibre.com>
Date: Mon, 28 Apr 2025 15:58:55 -0500
From: David Lechner <dlechner@...libre.com>
To: Michael Hennerich <michael.hennerich@...log.com>, 
 Nuno Sá <nuno.sa@...log.com>, 
 Mark Brown <broonie@...nel.org>
Cc: linux-spi@...r.kernel.org, linux-kernel@...r.kernel.org, 
 David Lechner <dlechner@...libre.com>
Subject: [PATCH 0/4] spi: axi-spi-engine: offload instruction optimization

In order to achieve a 4 MSPS rate on a 16-bit ADC with a 80 MHz SCLK
using the SPI offload feature of the AXI SPI Engine, we need to shave
off some time that is spent executing unnecessary instructions. There
are a few one-time setup instructions that can be moved so that they
execute only once when the SPI offload trigger is enabled rather than
repeating each time the offload is triggered. Additionally, a recent
change to the IP block allows dropping the SYNC instruction completely.
With these changes, we are left with only the 3 instructions that are
needed to to assert CS, transfer the data, and deassert CS. This makes
3 + 16 * 12.5 ns = 237.5 ns < 250 ns which is comfortably within the
available time period.

Signed-off-by: David Lechner <dlechner@...libre.com>
---
David Lechner (4):
      spi: axi-spi-engine: wait for completion in setup
      spi: axi-spi-engine: don't repeat mode config for offload
      spi: axi-spi-engine: optimize bits_per_word for offload
      spi: axi-spi-engine: omit SYNC from offload instructions

 drivers/spi/spi-axi-spi-engine.c | 91 +++++++++++++++++++++++++++++++++++++---
 1 file changed, 85 insertions(+), 6 deletions(-)
---
base-commit: aba9c2fee9598d797034ffd289b0da770d9119e8
change-id: 20250331-adi-main-46863acfc540

Best regards,
-- 
David Lechner <dlechner@...libre.com>