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From: Arnd Bergmann <arnd@arndb.de>
To: Alex Elder <elder@linaro.org>
Cc: David Miller <davem@davemloft.net>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Ilias Apalodimas <ilias.apalodimas@linaro.org>,
	Networking <netdev@vger.kernel.org>,
	DTML <devicetree@vger.kernel.org>,
	linux-arm-msm@vger.kernel.org, linux-soc@vger.kernel.org,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	syadagir@codeaurora.org, mjavid@codeaurora.org,
	Rob Herring <robh+dt@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>
Subject: Re: [RFC PATCH 07/12] soc: qcom: ipa: IPA register abstraction
Date: Wed, 7 Nov 2018 16:00:58 +0100
Message-ID: <CAK8P3a2FsgR=SYAWsgFURVni1ReiCugKs1iUAfQzZhPkbW8aOA@mail.gmail.com> (raw)
In-Reply-To: <20181107003250.5832-8-elder@linaro.org>

On Wed, Nov 7, 2018 at 1:33 AM Alex Elder <elder@linaro.org> wrote:
> diff --git a/drivers/net/ipa/ipa_reg.c b/drivers/net/ipa/ipa_reg.c
> new file mode 100644
> index 000000000000..5e0aa6163235
> --- /dev/null
> +++ b/drivers/net/ipa/ipa_reg.c
> @@ -0,0 +1,972 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +/* Copyright (c) 2012-2018, The Linux Foundation. All rights reserved.
> + * Copyright (C) 2018 Linaro Ltd.
> + */
> +
> +#include <linux/types.h>
> +#include <linux/io.h>
> +#include <linux/bitfield.h>
> +
> +#include "ipa_reg.h"
> +
> +/* I/O remapped base address of IPA register space */
> +static void __iomem *ipa_reg_virt;

This should of course be part of the device structure.

> +/* struct ipa_reg_desc - descriptor for an abstracted hardware register
> + *
> + * @construct - fn to construct the register value from its field structure
> + * @parse - function to parse register field values into its field structure
> + * @offset - register offset relative to base address
> + * @n_ofst - size multiplier for "N-parameterized" registers
> + */
> +struct ipa_reg_desc {
> +       u32 (*construct)(enum ipa_reg reg, const void *fields);
> +       void (*parse)(enum ipa_reg reg, void *fields, u32 val);
> +       u32 offset;
> +       u16 n_ofst;
> +};

Indirect function pointers can be a bit expensive in the post-spectre
days. It's probably not overly important if these are always part of
an MMIO access function, but you should be careful about using
these in the data path.

How many different versions do we have to support in practice?

       Arnd

  reply index

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-07  0:32 [RFC PATCH 00/12] net: introduce Qualcomm IPA driver Alex Elder
2018-11-07  0:32 ` [RFC PATCH 01/12] dt-bindings: soc: qcom: add IPA bindings Alex Elder
2018-11-07 11:50   ` Arnd Bergmann
2018-11-09 22:38     ` Alex Elder
2018-11-07 14:59   ` Rob Herring
2018-11-09 22:38     ` Alex Elder
2018-11-11  1:40       ` Rob Herring
2018-11-13 16:28     ` Alex Elder
2018-11-07  0:32 ` [RFC PATCH 02/12] soc: qcom: ipa: DMA helpers Alex Elder
2018-11-07 12:17   ` Arnd Bergmann
2018-11-13 16:33     ` Alex Elder
2018-11-07  0:32 ` [RFC PATCH 03/12] soc: qcom: ipa: generic software interface Alex Elder
2018-11-07  0:32 ` [RFC PATCH 04/12] soc: qcom: ipa: immediate commands Alex Elder
2018-11-07 14:36   ` Arnd Bergmann
2018-11-13 16:58     ` Alex Elder
2018-11-07  0:32 ` [RFC PATCH 05/12] soc: qcom: ipa: IPA interrupts and the microcontroller Alex Elder
2018-11-07  0:32 ` [RFC PATCH 06/12] soc: qcom: ipa: QMI modem communication Alex Elder
2018-11-07  0:32 ` [RFC PATCH 07/12] soc: qcom: ipa: IPA register abstraction Alex Elder
2018-11-07 15:00   ` Arnd Bergmann [this message]
2018-11-15  2:48     ` Alex Elder
2018-11-15 14:42       ` Arnd Bergmann
2018-11-07  0:32 ` [RFC PATCH 08/12] soc: qcom: ipa: utility functions Alex Elder
2018-11-07  0:32 ` [RFC PATCH 09/12] soc: qcom: ipa: main IPA source file Alex Elder
2018-11-07 14:08   ` Arnd Bergmann
2018-11-15  3:11     ` Alex Elder
2018-11-07  0:32 ` [RFC PATCH 10/12] soc: qcom: ipa: data path Alex Elder
2018-11-07 14:55   ` Arnd Bergmann
2018-11-15  3:31     ` Alex Elder
2018-11-15 14:48       ` Arnd Bergmann
2018-11-07  0:32 ` [RFC PATCH 11/12] soc: qcom: ipa: IPA rmnet interface Alex Elder
2018-11-07 13:30   ` Arnd Bergmann
2018-11-07 15:26   ` Dan Williams
2018-11-07  0:32 ` [RFC PATCH 12/12] soc: qcom: ipa: build and "ipa_i.h" Alex Elder
2018-11-07  0:40   ` Randy Dunlap
2018-11-08 16:22     ` Alex Elder
2018-11-07 12:34   ` Arnd Bergmann
2018-11-07 15:46 ` [RFC PATCH 00/12] net: introduce Qualcomm IPA driver Arnd Bergmann

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