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

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Message-ID: <20230420111324.GA970483@google.com>
Date:   Thu, 20 Apr 2023 12:13:24 +0100
From:   Lee Jones <lee@...nel.org>
To:     Xu Yilun <yilun.xu@...el.com>
Cc:     Ilpo Järvinen <ilpo.jarvinen@...ux.intel.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 Fri, 21 Apr 2023, Xu Yilun wrote:

> On 2023-04-17 at 12:26:53 +0300, 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>
> 
> Reviewed-by: Xu Yilun <yilun.xu@...el.com>
> 
> Hi Lee:
> 
> Could the fpga part also been applied to mfd tree when everyone is good?

Yes, with an Acked-by it can.

-- 
Lee Jones [李琼斯]