Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Tue, 14 Jan 2020 16:41:10 +0530
From:   Viresh Kumar <viresh.kumar@linaro.org>
To:     Arnd Bergmann <arnd@arndb.de>
Cc:     Sudeep Holla <sudeep.holla@arm.com>,
        Jassi Brar <jassisinghbrar@gmail.com>,
        cristian.marussi@arm.com, peng.fan@nxp.com,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH V2] firmware: arm_scmi: Make scmi core independent of
 transport type
Message-ID: <20200114111110.jhkj2y47ncp5233r@vireshk-i7>
References: <3f5567ec928e20963d729350e6d674c4acb0c7a0.1578648530.git.viresh.kumar@linaro.org>
 <CAK8P3a1MLyP4ooyEDiBF1fE0BJGocgDmO1f5Qrvn_W5eqahz8g@mail.gmail.com>
 <20200113064156.lt3xxpzygattz3he@vireshk-i7>
 <CAK8P3a2u6s4MAM_9bOqSt5NwVc4XrXs9W36tp-7rWWTXx0+pRg@mail.gmail.com>
 <20200114092615.nvj6mkwkplub5ul7@vireshk-i7>
 <CAK8P3a0jXyJArzQFd+u68iRvXNnXb_oHbWF9-abvvFuqhpi-NA@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CAK8P3a0jXyJArzQFd+u68iRvXNnXb_oHbWF9-abvvFuqhpi-NA@mail.gmail.com>
User-Agent: NeoMutt/20180716-391-311a52
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 14-01-20, 10:56, Arnd Bergmann wrote:
> My point was that you cannot mix __iomem accesses with pointer
> accesses. As I understood it, the current version uses a pointer to a

The current version is stupid as I misunderstood the whole __iomem
thing and just dropped it :)

> hardware mailbox with structured data, so you have to use ioremap()
> to get a token you can pass into ioread(), but (some of) the new
> transport types would just be backed by regular RAM, on which this
> is not a well-defined operation and you have to use memremap()
> and memcpy() instead.

Okay, I think I understand that a bit now. So here are the things
which I may need to do now:

- Maybe move payload to struct scmi_mailbox structure, as that is the
  transport dependent structure..

- Do ioremap, etc in mailbox.c only instead of driver.c

- Provide more ops in struct scmi_transport_ops to provide read/write
  helpers to the payload and implement the ones based on
  ioread/iowrite in mailbox.c ..

Am I thinking in the right direction now ?

-- 
viresh