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Date:   Mon, 16 Oct 2023 18:28:15 +0200
From:   Andrew Lunn <andrew@lunn.ch>
To:     MD Danish Anwar <danishanwar@ti.com>
Cc:     Jacob Keller <jacob.e.keller@intel.com>,
        Paolo Abeni <pabeni@redhat.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Eric Dumazet <edumazet@google.com>,
        "David S. Miller" <davem@davemloft.net>,
        linux-kernel@vger.kernel.org, netdev@vger.kernel.org, srk@ti.com,
        Vignesh Raghavendra <vigneshr@ti.com>, r-gunasekaran@ti.com,
        Roger Quadros <rogerq@kernel.org>
Subject: Re: [PATCH net v2] net: ti: icssg-prueth: Fix r30 CMDs bitmasks
Message-ID: <11109e7d-139b-4c8c-beaa-e1e89e355b1b@lunn.ch>
References: <20231016161525.1695795-1-danishanwar@ti.com>
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On Mon, Oct 16, 2023 at 09:45:25PM +0530, MD Danish Anwar wrote:
> The bitmask for EMAC_PORT_DISABLE and EMAC_PORT_FORWARD has been changed
> in the ICSSG firmware REL.PRU-ICSS-ETHERNET-SWITCH_02.02.12.05.
> 
> The current bitmasks are wrong and as a result EMAC_PORT_DISABLE and
> EMAC_PORT_FORWARD commands doesn not work.
> Update r30 commands to use the same bitmask as used by the ICSSG firmware
> REL.PRU-ICSS-ETHERNET-SWITCH_02.02.12.05.
> 
> These bitmasks are not backwards compatible. This will work with
> firmware version REL.PRU-ICSS-ETHERNET-SWITCH_02.02.12.05 and above but
> not with lower firmware versions.

Breaking backwards compatibility is generally not allowed.

As far as i understand the driver, it loads whatever version of
firmware is available. It does not ask for a specific version. So you
should ask the firmware what version it is, and then handle the
bitmask as appropriate.

How many different versions of REL.PRU-ICSS-ETHERNET-SWITCH have been
released? They don't appear to be part of linux-firmware.git :-(

    Andrew

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