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 CC38BC433F5 for ; Mon, 17 Jan 2022 13:18:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240179AbiAQNSZ (ORCPT ); Mon, 17 Jan 2022 08:18:25 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50336 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229591AbiAQNSY (ORCPT ); Mon, 17 Jan 2022 08:18:24 -0500 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CF549C061574 for ; Mon, 17 Jan 2022 05:18:23 -0800 (PST) Received: from dude02.hi.pengutronix.de ([2001:67c:670:100:1d::28]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1n9Rtu-0004nS-9h; Mon, 17 Jan 2022 14:18:22 +0100 Received: from sha by dude02.hi.pengutronix.de with local (Exim 4.94.2) (envelope-from ) id 1n9Rtt-00APAa-61; Mon, 17 Jan 2022 14:18:21 +0100 Date: Mon, 17 Jan 2022 14:18:21 +0100 To: Dario Binacchi Cc: linux-kernel@vger.kernel.org, Michael Trimarchi , Han Xu , Miquel Raynal , Richard Weinberger , Vignesh Raghavendra , linux-mtd@lists.infradead.org Subject: Re: [RFC PATCH v2 3/5] mtd: rawnand: gpmi: use a table to get EDO mode setup Message-ID: References: <20220117111829.1811997-1-dario.binacchi@amarulasolutions.com> <20220117111829.1811997-4-dario.binacchi@amarulasolutions.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220117111829.1811997-4-dario.binacchi@amarulasolutions.com> X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-IRC: #ptxdist @freenode X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-Uptime: 13:56:46 up 110 days, 1:53, 80 users, load average: 20.96, 15.71, 15.82 From: Sascha Hauer X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::28 X-SA-Exim-Mail-From: sha@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Dario, On Mon, Jan 17, 2022 at 12:18:27PM +0100, Dario Binacchi wrote: > +struct edo_mode { > + u32 tRC_min; > + long clk_rate; > + u8 wrn_dly_sel; > +}; > + > +static const struct edo_mode edo_modes[] = { > + {.tRC_min = 30000, .clk_rate = 22000000, > + .wrn_dly_sel = BV_GPMI_CTRL1_WRN_DLY_SEL_4_TO_8NS}, > + {.tRC_min = 30000, .clk_rate = 22000000, > + .wrn_dly_sel = BV_GPMI_CTRL1_WRN_DLY_SEL_4_TO_8NS}, > + {.tRC_min = 30000, .clk_rate = 22000000, > + .wrn_dly_sel = BV_GPMI_CTRL1_WRN_DLY_SEL_4_TO_8NS}, > + {.tRC_min = 30000, .clk_rate = 22000000, > + .wrn_dly_sel = BV_GPMI_CTRL1_WRN_DLY_SEL_4_TO_8NS}, > + {.tRC_min = 25000, .clk_rate = 80000000, > + .wrn_dly_sel = BV_GPMI_CTRL1_WRN_DLY_SEL_NO_DELAY}, > + {.tRC_min = 20000, .clk_rate = 100000000, > + .wrn_dly_sel = BV_GPMI_CTRL1_WRN_DLY_SEL_NO_DELAY}, > +}; > + > /* > * <1> Firstly, we should know what's the GPMI-clock means. > * The GPMI-clock is the internal clock in the gpmi nand controller. > @@ -657,22 +678,18 @@ static void gpmi_nfc_compute_timings(struct gpmi_nand_data *this, > int sample_delay_ps, sample_delay_factor; > u16 busy_timeout_cycles; > u8 wrn_dly_sel; > + int i, emode = ARRAY_SIZE(edo_modes) - 1; > > - if (sdr->tRC_min >= 30000) { > - /* ONFI non-EDO modes [0-3] */ > - hw->clk_rate = 22000000; > - wrn_dly_sel = BV_GPMI_CTRL1_WRN_DLY_SEL_4_TO_8NS; > - } else if (sdr->tRC_min >= 25000) { > - /* ONFI EDO mode 4 */ > - hw->clk_rate = 80000000; > - wrn_dly_sel = BV_GPMI_CTRL1_WRN_DLY_SEL_NO_DELAY; > - } else { > - /* ONFI EDO mode 5 */ > - hw->clk_rate = 100000000; > - wrn_dly_sel = BV_GPMI_CTRL1_WRN_DLY_SEL_NO_DELAY; > + /* Search the required EDO mode */ > + for (i = 0; i < ARRAY_SIZE(edo_modes); i++) { > + if (sdr->tRC_min >= edo_modes[i].tRC_min) { > + emode = i; > + break; > + } The first four entries of edo_modes[] all have the same value, so this loop will never end on the second, third or fourth element. These elements are just there to match 'emode' with the existing ONFI mode numbers, but then 'emode' is never used as an ONFI mode number, instead it's only used as an index to the array. You could equally well remove the second till fourth array entries. Then with only three entries left in the array I wonder if you're not better off with the original code and change it to something like: if (sdr->tRC_min >= 30000) { /* ONFI non-EDO modes [0-3] */ hw->clk_rate = 22000000; min_rate = 0; wrn_dly_sel = BV_GPMI_CTRL1_WRN_DLY_SEL_4_TO_8NS; } else if (sdr->tRC_min >= 25000) { /* ONFI EDO mode 4 */ hw->clk_rate = 80000000; min_rate = 22000000; wrn_dly_sel = BV_GPMI_CTRL1_WRN_DLY_SEL_NO_DELAY; } else { /* ONFI EDO mode 5 */ hw->clk_rate = 100000000; min_rate = 80000000; wrn_dly_sel = BV_GPMI_CTRL1_WRN_DLY_SEL_NO_DELAY; } hw->clk_rate = clk_round_rate(r->clock[0], hw->clk_rate); if (hw->clk_rate < min_rate) return -EINVAL; I think this would be easier to follow. Sascha -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |