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 X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0AF5EC43331 for ; Wed, 1 Apr 2020 16:52:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C9AE92063A for ; Wed, 1 Apr 2020 16:52:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388665AbgDAQec convert rfc822-to-8bit (ORCPT ); Wed, 1 Apr 2020 12:34:32 -0400 Received: from gloria.sntech.de ([185.11.138.130]:40862 "EHLO gloria.sntech.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732532AbgDAQe3 (ORCPT ); Wed, 1 Apr 2020 12:34:29 -0400 Received: from ip5f5aa64a.dynamic.kabel-deutschland.de ([95.90.166.74] helo=diego.localnet) by gloria.sntech.de with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1jJgJl-0003TS-Fj; Wed, 01 Apr 2020 18:34:17 +0200 From: Heiko =?ISO-8859-1?Q?St=FCbner?= To: =?ISO-8859-1?Q?Myl=E8ne?= Josserand Cc: linux-arm-kernel@lists.infradead.org, mturquette@baylibre.com, sboyd@kernel.org, linux-kernel@vger.kernel.org, linux-rockchip@lists.infradead.org, linux-clk@vger.kernel.org, kernel@collabora.com, kever.yang@rock-chips.com, geert@linux-m68k.org Subject: Re: [PATCH v2 1/2] soc: rockchip: Register a soc_device to retrieve revision Date: Wed, 01 Apr 2020 18:34:16 +0200 Message-ID: <5143930.cPWVAAQKI9@diego> In-Reply-To: <20200401153513.423683-2-mylene.josserand@collabora.com> References: <20200401153513.423683-1-mylene.josserand@collabora.com> <20200401153513.423683-2-mylene.josserand@collabora.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8BIT Content-Type: text/plain; charset="iso-8859-1" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Mylène, Am Mittwoch, 1. April 2020, 17:35:12 CEST schrieb Mylène Josserand: > Determine which revision of rk3288 by checking the HDMI version. > According to the Rockchip BSP kernel/u-boot, on rk3288w, the HDMI > revision equals 0x1A which is not the case for the rk3288. > > As these SOC have some differences, this driver will help us > to know on which revision we are by using 'soc_device' registration > to be able to use 'soc_device_match' to detect rk3288/rk3288w. > > Signed-off-by: Mylène Josserand I like your new approach quite a lot :-) There are some things we need to take into account though, see below. > --- > drivers/soc/rockchip/Makefile | 1 + > drivers/soc/rockchip/rk3288.c | 125 ++++++++++++++++++++++++++++++++++ > 2 files changed, 126 insertions(+) > create mode 100644 drivers/soc/rockchip/rk3288.c > > diff --git a/drivers/soc/rockchip/Makefile b/drivers/soc/rockchip/Makefile > index afca0a4c4b72..9dbf12913512 100644 > --- a/drivers/soc/rockchip/Makefile > +++ b/drivers/soc/rockchip/Makefile > @@ -2,5 +2,6 @@ > # > # Rockchip Soc drivers > # > +obj-$(CONFIG_ARCH_ROCKCHIP) += rk3288.o > obj-$(CONFIG_ROCKCHIP_GRF) += grf.o > obj-$(CONFIG_ROCKCHIP_PM_DOMAINS) += pm_domains.o > diff --git a/drivers/soc/rockchip/rk3288.c b/drivers/soc/rockchip/rk3288.c I'd really like this to be a soc.c instead of rk3288.c ;-) > new file mode 100644 > index 000000000000..83379ba2b31b > --- /dev/null > +++ b/drivers/soc/rockchip/rk3288.c > @@ -0,0 +1,125 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Copyright 2020 Collabora Ltd > + * Author: Mylene Josserand > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#define RK3288_HDMI_REV_REG 0x04 > +#define RK3288W_HDMI_REV 0x1A > + > +enum rk3288_soc_rev { > + RK3288_SOC_REV_NOT_DETECT, > + RK3288_SOC_REV_RK3288, > + RK3288_SOC_REV_RK3288W, > +}; > + > +static int rk3288_revision(void) > +{ > + static int revision = RK3288_SOC_REV_NOT_DETECT; > + struct device_node *dn; > + void __iomem *hdmi_base; > + > + if (revision != RK3288_SOC_REV_NOT_DETECT) > + return revision; > + > + dn = of_find_compatible_node(NULL, NULL, "rockchip,rk3288-dw-hdmi"); > + if (!dn) { > + pr_err("%s: Couldn't find HDMI node\n", __func__); > + return -EINVAL; > + } > + > + hdmi_base = of_iomap(dn, 0); > + of_node_put(dn); > + > + if (!hdmi_base) { > + pr_err("%s: Couldn't map %pOF regs\n", __func__, > + hdmi_base); > + return -ENXIO; > + } The possible problem I see here is clocking and power-domain of the hdmi controller in corner-cases. In the past we already had a lot of fun with kexec, which also indicates that people actually use kexec productively. So while all clocks are ungated and all power-domains are powered on first boot, on a system without graphics the pclk+power-domain could be off when doing a kexec into a second kernel, which then would probably hang here. Of course with the hdmi-pclk being sourced from hclk_vio we run into a chicken-egg-problem, as we need pclk_hdmi_ctrl to register hclk_vio at all. So I guess one way out of this could be to - amend rk3288_clk_shutdown() to also ungate the hdmi-pclk on shutdown - add a shutdown mechanism to the power-domain driver so that it can enable PD_VIO on shutdown > + > + if (readl_relaxed(hdmi_base + RK3288_HDMI_REV_REG) > + == RK3288W_HDMI_REV) nit: a nicer look would be something like val = readl_relaxed(hdmi_base + RK3288_HDMI_REV_REG); if (val == RK3288W_HDMI_REV) > + revision = RK3288_SOC_REV_RK3288W; > + else > + revision = RK3288_SOC_REV_RK3288; > + > + iounmap(hdmi_base); > + > + return revision; > +} > + > +static const char *rk3288_socinfo_revision(u32 rev) > +{ > + const char *soc_rev; > + > + switch (rev) { > + case RK3288_SOC_REV_RK3288: > + soc_rev = "RK3288"; > + break; > + > + case RK3288_SOC_REV_RK3288W: > + soc_rev = "RK3288w"; can we maybe use lower-case letters for all here? > + break; > + > + case RK3288_SOC_REV_NOT_DETECT: > + soc_rev = ""; > + break; > + > + default: > + soc_rev = "unknown"; > + break; > + } > + > + return kstrdup_const(soc_rev, GFP_KERNEL); > +} > + > +static const struct of_device_id rk3288_soc_match[] = { > + { .compatible = "rockchip,rk3288", }, > + { } > +}; > + > +static int __init rk3288_soc_init(void) as noted at the top, I'd really like to see this more generalized so that other socs can just hook in there with a revision callback in a rockchip_soc_data struct. > +{ > + struct soc_device_attribute *soc_dev_attr; > + struct soc_device *soc_dev; > + struct device_node *np; > + > + np = of_find_matching_node(NULL, rk3288_soc_match); > + if (!np) > + return -ENODEV; > + > + soc_dev_attr = kzalloc(sizeof(*soc_dev_attr), GFP_KERNEL); > + if (!soc_dev_attr) > + return -ENOMEM; > + > + soc_dev_attr->family = "Rockchip"; > + soc_dev_attr->soc_id = "RK32xx"; nit: rk3288 instead of "32xx" please > + > + np = of_find_node_by_path("/"); > + of_property_read_string(np, "model", &soc_dev_attr->machine); > + of_node_put(np); > + > + soc_dev_attr->revision = rk3288_socinfo_revision(rk3288_revision()); > + > + soc_dev = soc_device_register(soc_dev_attr); > + if (IS_ERR(soc_dev)) { > + kfree_const(soc_dev_attr->revision); > + kfree_const(soc_dev_attr->soc_id); > + kfree(soc_dev_attr); > + return PTR_ERR(soc_dev); > + } > + > + dev_info(soc_device_to_device(soc_dev), "Rockchip %s %s detected\n", > + soc_dev_attr->soc_id, soc_dev_attr->revision); nit: dev_dbg should be enough, that information doesn't really matter for most people, as it's only relevant to clock internals. Heiko