From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Tue, 18 Mar 2025 09:25:40 +0100 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by lore.white.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1tuSGb-000xpW-1f for lore@lore.pengutronix.de; Tue, 18 Mar 2025 09:25:40 +0100 Received: from bombadil.infradead.org ([2607:7c80:54:3::133]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1tuSGa-0004gc-AA for lore@pengutronix.de; Tue, 18 Mar 2025 09:25:40 +0100 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=GCtRbAQphZf8G8G2YA5AFWgQTcYiYKRlbVYTamDK41c=; b=BjXlbgmWkqcLUDkdh++HELGqTd MLuTRly0vqJBQ+b7dRjpkzPoP4SPoj1sIVlaOzlS+zW+xhJI5Viooq3ZZ+rskaXkAi28+Fk6Xkwha BOENJUdSNc5qPMU9BUFfEZX9QbSzizHdejpuDgRaGay8SZGkSeaY8tMi7GkD3HDApnkW8EnNbcTnT ajK31JSbKqcd7elX9UH1Ik5m/7mwJXutI5IGicW7TW2kS1PyiXWIXsTDfFz8bA4xCG7x3LJRBq82z fgYIbqgtSGEw+XOjm+jHdFzS+odonsatKPZcKghSdHbVIFuMewYUVLbjToFU30uf7uHR2hrUIgmOc 5v1QVaww==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tuSG9-000000059yq-2TgL; Tue, 18 Mar 2025 08:25:13 +0000 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tuSG6-000000059x1-0Y0P for barebox@lists.infradead.org; Tue, 18 Mar 2025 08:25:12 +0000 Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1tuSG4-0004Q6-PX; Tue, 18 Mar 2025 09:25:08 +0100 Received: from dude05.red.stw.pengutronix.de ([2a0a:edc0:0:1101:1d::54]) by drehscheibe.grey.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1tuSG4-000OTX-0L; Tue, 18 Mar 2025 09:25:08 +0100 Received: from localhost ([::1] helo=dude05.red.stw.pengutronix.de) by dude05.red.stw.pengutronix.de with esmtp (Exim 4.96) (envelope-from ) id 1tuSG4-001lFs-1Q; Tue, 18 Mar 2025 09:25:08 +0100 From: Ahmad Fatoum To: barebox@lists.infradead.org Cc: Ahmad Fatoum Date: Tue, 18 Mar 2025 09:25:06 +0100 Message-Id: <20250318082507.419785-3-a.fatoum@pengutronix.de> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250318082507.419785-1-a.fatoum@pengutronix.de> References: <20250318082507.419785-1-a.fatoum@pengutronix.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250318_012510_173549_F71AE861 X-CRM114-Status: GOOD ( 21.05 ) X-BeenThere: barebox@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "barebox" X-SA-Exim-Connect-IP: 2607:7c80:54:3::133 X-SA-Exim-Mail-From: barebox-bounces+lore=pengutronix.de@lists.infradead.org X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on metis.whiteo.stw.pengutronix.de X-Spam-Level: X-Spam-Status: No, score=-5.4 required=4.0 tests=AWL,BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_NONE autolearn=unavailable autolearn_force=no version=3.4.2 Subject: [PATCH 3/4] amba: support masking data abort during identification X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on metis.whiteo.stw.pengutronix.de) Registration of an AMBA device requires reading its pid and cid registers after turning on the device. This is the first I/O done to the device and may end up crashing if the device tree doesn't describe the correct clock and power domains or if a previous boot stage should've enabled them, but didn't. This is not a likely issue, but when it happens it crashes the system annoyingly early during device tree populating. Add a symbol that masks the data abort exception around the identification code to turn the crash into an error message instead. Signed-off-by: Ahmad Fatoum --- drivers/amba/Kconfig | 19 +++++++++++++++++++ drivers/amba/bus.c | 12 +++++++++++- 2 files changed, 30 insertions(+), 1 deletion(-) diff --git a/drivers/amba/Kconfig b/drivers/amba/Kconfig index 444d4ce7435c..be5e053f4b84 100644 --- a/drivers/amba/Kconfig +++ b/drivers/amba/Kconfig @@ -1,3 +1,22 @@ # SPDX-License-Identifier: GPL-2.0-only config ARM_AMBA bool + +config ARM_AMBA_DABT_MASK + bool + prompt "Mask data abort while identifying AMBA devices" if COMPILE_TEST + depends on ARM_AMBA && ARCH_HAS_DATA_ABORT_MASK + help + Registration of an AMBA device requires reading its pid and cid + registers after turning on the device, which can involve enabling + clocks, deasserting resets and powering on power domains. + In some cases, these resources are not available to barebox running + in the normal world and thus need to be setup by a previous + stage bootloader running in the secure world. + If such setup doesn't happen, accessing devices may lead to + a data abort or complete system hang. + + As a workaround for the former case, this option can be enabled + to gracefully handle data aborts during readout of the PID/CID + registers. The proper solution is fixing your first stage + bootloader or allow barebox access to the missing resources. diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c index 6463366fafc5..5ed8336e6124 100644 --- a/drivers/amba/bus.c +++ b/drivers/amba/bus.c @@ -10,6 +10,7 @@ #include #include #include +#include #define to_amba_driver(d) container_of(d, struct amba_driver, drv) @@ -132,6 +133,9 @@ int amba_device_add(struct amba_device *dev) if (ret == 0) { u32 pid, cid; + if (IS_ENABLED(CONFIG_ARM_AMBA_DABT_MASK)) + data_abort_mask(); + /* * Read pid and cid based on size of resource * they are located at end of region @@ -139,8 +143,14 @@ int amba_device_add(struct amba_device *dev) pid = amba_device_get_pid(tmp, size); cid = amba_device_get_cid(tmp, size); - if (cid == AMBA_CID) + if (IS_ENABLED(CONFIG_ARM_AMBA_DABT_MASK) && data_abort_unmask()) { + dev_err(amba_bustype.dev, + "data abort during MMIO read of PID/CID for %pOF\n", + dev->dev.of_node); + ret = -EFAULT; + } else if (cid == AMBA_CID) { dev->periphid = pid; + } if (!dev->periphid) ret = -ENODEV; -- 2.39.5