From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7D9BDC433EF for ; Tue, 4 Jan 2022 08:58:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229584AbiADI6A convert rfc822-to-8bit (ORCPT ); Tue, 4 Jan 2022 03:58:00 -0500 Received: from relay4-d.mail.gandi.net ([217.70.183.196]:56207 "EHLO relay4-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229472AbiADI6A (ORCPT ); Tue, 4 Jan 2022 03:58:00 -0500 Received: (Authenticated sender: miquel.raynal@bootlin.com) by relay4-d.mail.gandi.net (Postfix) with ESMTPSA id 22E05E000C; Tue, 4 Jan 2022 08:57:57 +0000 (UTC) Date: Tue, 4 Jan 2022 09:57:55 +0100 From: Miquel Raynal To: Florian Fainelli Cc: linux-mtd@lists.infradead.org, =?UTF-8?B?UmFmYcWCIE1pxYJlY2tp?= , Richard Weinberger , Vignesh Raghavendra , Brian Norris , Kamal Dasu , Arnd Bergmann , Cai Huoqing , Colin Ian King , open list , "open list:BROADCOM SPECIFIC AMBA DRIVER (BCMA)" , "open list:BROADCOM STB NAND FLASH DRIVER" Subject: Re: [PATCH 1/9] mtd: rawnand: brcmnand: Allow SoC to provide I/O operations Message-ID: <20220104095755.46858287@xps13> In-Reply-To: <20220104093221.6414aab9@xps13> References: <20211223002225.3738385-1-f.fainelli@gmail.com> <20211223002225.3738385-2-f.fainelli@gmail.com> <20220103174953.40d7fa52@xps13> <299bf6ed-80e6-ad15-8dc7-5ededaca15c5@gmail.com> <20220104093221.6414aab9@xps13> Organization: Bootlin X-Mailer: Claws Mail 3.17.7 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org Hi Miquel, miquel.raynal@bootlin.com wrote on Tue, 4 Jan 2022 09:32:21 +0100: > Hi Florian, > > f.fainelli@gmail.com wrote on Mon, 3 Jan 2022 09:24:26 -0800: > > > On 1/3/2022 8:49 AM, Miquel Raynal wrote: > > > Hi Florian, > > > > > > f.fainelli@gmail.com wrote on Wed, 22 Dec 2021 16:22:17 -0800: > > > > > >> Allow a brcmnand_soc instance to provide a custom set of I/O operations > > >> which we will require when using this driver on a BCMA bus which is not > > >> directly memory mapped I/O. Update the nand_{read,write}_reg accordingly > > >> to use the SoC operations if provided. > > >> > > >> Signed-off-by: Florian Fainelli > > >> --- > > >> drivers/mtd/nand/raw/brcmnand/brcmnand.c | 14 ++++++++++++-- > > >> drivers/mtd/nand/raw/brcmnand/brcmnand.h | 23 +++++++++++++++++++++++ > > >> 2 files changed, 35 insertions(+), 2 deletions(-) > > >> > > >> diff --git a/drivers/mtd/nand/raw/brcmnand/brcmnand.c b/drivers/mtd/nand/raw/brcmnand/brcmnand.c > > >> index f75929783b94..7a1673b1b1af 100644 > > >> --- a/drivers/mtd/nand/raw/brcmnand/brcmnand.c > > >> +++ b/drivers/mtd/nand/raw/brcmnand/brcmnand.c > > >> @@ -594,13 +594,18 @@ enum { > > >> >> static inline u32 nand_readreg(struct brcmnand_controller *ctrl, u32 offs) > > >> { > > >> + if (brcmnand_soc_has_ops(ctrl->soc)) > > >> + return brcmnand_soc_read(ctrl->soc, offs); > > >> return brcmnand_readl(ctrl->nand_base + offs); > > >> } > > >> >> static inline void nand_writereg(struct brcmnand_controller *ctrl, u32 offs, > > >> u32 val) > > >> { > > >> - brcmnand_writel(val, ctrl->nand_base + offs); > > >> + if (brcmnand_soc_has_ops(ctrl->soc)) > > >> + brcmnand_soc_write(ctrl->soc, val, offs); > > >> + else > > >> + brcmnand_writel(val, ctrl->nand_base + offs); > > >> } > > >> >> static int brcmnand_revision_init(struct brcmnand_controller *ctrl) > > >> @@ -766,13 +771,18 @@ static inline void brcmnand_rmw_reg(struct brcmnand_controller *ctrl, > > >> >> static inline u32 brcmnand_read_fc(struct brcmnand_controller *ctrl, int word) > > >> { > > >> + if (brcmnand_soc_has_ops(ctrl->soc)) > > >> + return brcmnand_soc_read(ctrl->soc, ~0); > > >> return __raw_readl(ctrl->nand_fc + word * 4); > > >> } > > >> >> static inline void brcmnand_write_fc(struct brcmnand_controller *ctrl, > > >> int word, u32 val) > > >> { > > >> - __raw_writel(val, ctrl->nand_fc + word * 4); > > >> + if (brcmnand_soc_has_ops(ctrl->soc)) > > >> + brcmnand_soc_write(ctrl->soc, val, ~0); > > >> + else > > >> + __raw_writel(val, ctrl->nand_fc + word * 4); > > >> } > > >> >> static inline void edu_writel(struct brcmnand_controller *ctrl, > > >> diff --git a/drivers/mtd/nand/raw/brcmnand/brcmnand.h b/drivers/mtd/nand/raw/brcmnand/brcmnand.h > > >> index eb498fbe505e..a3f2ad5f6572 100644 > > >> --- a/drivers/mtd/nand/raw/brcmnand/brcmnand.h > > >> +++ b/drivers/mtd/nand/raw/brcmnand/brcmnand.h > > >> @@ -11,12 +11,19 @@ > > >> >> struct platform_device; > > >> struct dev_pm_ops; > > >> +struct brcmnand_io_ops; > > >> >> struct brcmnand_soc { > > >> bool (*ctlrdy_ack)(struct brcmnand_soc *soc); > > >> void (*ctlrdy_set_enabled)(struct brcmnand_soc *soc, bool en); > > >> void (*prepare_data_bus)(struct brcmnand_soc *soc, bool prepare, > > >> bool is_param); > > >> + const struct brcmnand_io_ops *ops; > > >> +}; > > >> + > > >> +struct brcmnand_io_ops { > > >> + u32 (*read_reg)(struct brcmnand_soc *soc, u32 offset); > > >> + void (*write_reg)(struct brcmnand_soc *soc, u32 val, u32 offset); > > >> }; > > >> >> static inline void brcmnand_soc_data_bus_prepare(struct brcmnand_soc *soc, > > >> @@ -58,6 +65,22 @@ static inline void brcmnand_writel(u32 val, void __iomem *addr) > > >> writel_relaxed(val, addr); > > >> } > > >> >> +static inline bool brcmnand_soc_has_ops(struct brcmnand_soc *soc) > > >> +{ > > >> + return soc && soc->ops && soc->ops->read_reg && soc->ops->write_reg; > > >> +} > > >> + > > >> +static inline u32 brcmnand_soc_read(struct brcmnand_soc *soc, u32 offset) > > >> +{ > > >> + return soc->ops->read_reg(soc, offset); > > >> +} > > >> + > > >> +static inline void brcmnand_soc_write(struct brcmnand_soc *soc, u32 val, > > >> + u32 offset) > > >> +{ > > >> + soc->ops->write_reg(soc, val, offset); > > >> +} > > >> + > > > > > > It might be worth looking into more optimized ways to do these checks, > > > in particular the read/write_reg ones because you're checking against > > > some static data which cannot be optimized out by the compiler but > > > won't change in the lifetime of the kernel. > > > > I suppose I could add an addition if IS_ENABLED(CONFIG_MTD_NAND_BRCMNAND_BCMA) at the front of brcmnand_soc_has_ops(), would that address your concern or you have something else in mind? > > I don't like much the #ifdef solution, instead you might think of > static keys, or even better using a regmap. Regmap implementation is > free, you can use either one way or the other and for almost no > overhead compared to the bunch of functions you have here. Maybe regmaps will actually be slower than these regular if's. Perhaps static keys are the best option? Cheers, Miquèl