linux-kernel - Re: [PATCH v3 4/4] mfd: intel-m10-bmc: Manage access to MAX 10 fw handshake registers

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Date:   Thu, 27 Apr 2023 16:07:12 +0100
From:   Lee Jones <lee@...nel.org>
To:     Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Cc:     Xu Yilun <yilun.xu@...el.com>, Wu Hao <hao.wu@...el.com>,
        Tom Rix <trix@...hat.com>, Moritz Fischer <mdf@...nel.org>,
        linux-fpga@...r.kernel.org, Jean Delvare <jdelvare@...e.com>,
        Guenter Roeck <linux@...ck-us.net>,
        Russ Weight <russell.h.weight@...el.com>,
        linux-kernel@...r.kernel.org, linux-hwmon@...r.kernel.org
Subject: Re: [PATCH v3 4/4] mfd: intel-m10-bmc: Manage access to MAX 10 fw
 handshake registers

On Mon, 17 Apr 2023, Ilpo Järvinen wrote:

> On some MAX 10 cards, the BMC firmware is not available to service
> handshake registers during secure update erase and write phases at
> normal speeds. This problem affects at least hwmon driver. When the MAX
> 10 hwmon driver tries to read the sensor values during a secure update,
> the reads are slowed down (e.g., reading all D5005 sensors takes ~24s
> which is magnitudes worse than the normal <0.02s).
> 
> Manage access to the handshake registers using a rw semaphore and a FW
> state variable to prevent accesses during those secure update phases
> and return -EBUSY instead.
> 
> If handshake_sys_reg_nranges == 0, don't update bwcfw_state as it is not
> used. This avoids the locking cost.
> 
> Co-developed-by: Russ Weight <russell.h.weight@...el.com>
> Signed-off-by: Russ Weight <russell.h.weight@...el.com>
> Co-developed-by: Xu Yilun <yilun.xu@...el.com>
> Signed-off-by: Xu Yilun <yilun.xu@...el.com>
> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
> ---
>  drivers/fpga/intel-m10-bmc-sec-update.c | 17 +++++--
>  drivers/mfd/intel-m10-bmc-core.c        | 67 ++++++++++++++++++++++++-
>  drivers/mfd/intel-m10-bmc-spi.c         | 14 ++++++
>  include/linux/mfd/intel-m10-bmc.h       | 28 +++++++++++
>  4 files changed, 121 insertions(+), 5 deletions(-)

Applied, thanks

-- 
Lee Jones [李琼斯]