From patchwork Thu May 7 22:41:14 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Serge Semin X-Patchwork-Id: 11535043 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6A94E1392 for ; Thu, 7 May 2020 22:41:46 +0000 (UTC) Received: by mail.kernel.org (Postfix) id 654A720CC7; Thu, 7 May 2020 22:41:46 +0000 (UTC) Delivered-To: soc@kernel.org Received: from mail.baikalelectronics.ru (mail.baikalelectronics.com [87.245.175.226]) by mail.kernel.org (Postfix) with ESMTP id EEA2F21473; Thu, 7 May 2020 22:41:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EEA2F21473 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=baikalelectronics.ru Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=Sergey.Semin@baikalelectronics.ru Received: from localhost (unknown [127.0.0.1]) by mail.baikalelectronics.ru (Postfix) with ESMTP id 4376580307C2; Thu, 7 May 2020 22:41:45 +0000 (UTC) X-Virus-Scanned: amavisd-new at baikalelectronics.ru Received: from mail.baikalelectronics.ru ([127.0.0.1]) by localhost (mail.baikalelectronics.ru [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id t8s8ukNo7Mpq; Fri, 8 May 2020 01:41:43 +0300 (MSK) From: Serge Semin To: Thomas Bogendoerfer , Greg Kroah-Hartman , Arnd Bergmann , Rob Herring List-Id: CC: Serge Semin , Serge Semin , Alexey Malahov , Paul Burton , Ralf Baechle , Tony Lindgren , Tero Kristo , Manivannan Sadhasivam , Jeffrey Hugo , Linus Walleij , Olof Johansson , , , , Subject: [PATCH v2 2/4] dt-bindings: bus: Add Baikal-T1 APB-bus binding Date: Fri, 8 May 2020 01:41:14 +0300 Message-ID: <20200507224116.1523-3-Sergey.Semin@baikalelectronics.ru> In-Reply-To: <20200507224116.1523-1-Sergey.Semin@baikalelectronics.ru> References: <20200306130731.938808030702@mail.baikalelectronics.ru> <20200507224116.1523-1-Sergey.Semin@baikalelectronics.ru> MIME-Version: 1.0 X-ClientProxiedBy: MAIL.baikal.int (192.168.51.25) To mail (192.168.51.25) Baikal-T1 CPU or DMAC MMIO requests are handled by the AMBA 3 AXI Interconnect which routes them to the AXI-APB bridge, which in turn serializes accesses and routes them to the corresponding APB slave device. This binding describes the AXI-APB bridge considered as the APB-bus. It is supposed to be compatible with "be,bt1-apb" and "simple-bus" drivers, should be equipped with EHB MMIO region and a region with no slave device mapped, interrupts line number, APB reference clock and domain reset line. Signed-off-by: Serge Semin Cc: Alexey Malahov Cc: Paul Burton Cc: Ralf Baechle Cc: Tony Lindgren Cc: Tero Kristo Cc: Manivannan Sadhasivam Cc: Jeffrey Hugo Cc: Linus Walleij Cc: Olof Johansson Cc: linux-mips@vger.kernel.org Cc: soc@kernel.org Reviewed-by: Rob Herring --- Rob, I had to remove your Reviewed-by tag, since new changes had been introduced. Changelog v2: - Move driver to the bus subsystem. - Don't use a multi-arg clock phandle reference in the examples dt-bindings property. Thus redundant include statement can be removed. - Use dual GPL/BSD license. - Use single lined copyright header. - Lowercase the unit-address. - Convert a dedicated EHB block binding to the Baikal-T1 APB-bus one. - Add APB reference clock and reset support. - Replace "additionalProperties: false" property with "unevaluatedProperties: false". - Add reg-names property. --- .../bindings/bus/baikal,bt1-apb.yaml | 90 +++++++++++++++++++ 1 file changed, 90 insertions(+) create mode 100644 Documentation/devicetree/bindings/bus/baikal,bt1-apb.yaml diff --git a/Documentation/devicetree/bindings/bus/baikal,bt1-apb.yaml b/Documentation/devicetree/bindings/bus/baikal,bt1-apb.yaml new file mode 100644 index 000000000000..d6a3b71ea835 --- /dev/null +++ b/Documentation/devicetree/bindings/bus/baikal,bt1-apb.yaml @@ -0,0 +1,90 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +# Copyright (C) 2020 BAIKAL ELECTRONICS, JSC +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/bus/baikal,bt1-apb.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Baikal-T1 APB-bus + +maintainers: + - Serge Semin + +description: | + Baikal-T1 CPU or DMAC MMIO requests are handled by the AMBA 3 AXI Interconnect + which routes them to the AXI-APB bridge. This interface is a single master + multiple slaves bus in turn serializing IO accesses and routing them to the + addressed APB slave devices. In case of any APB protocol collisions, slave + device not responding on timeout an IRQ is raised with an erroneous address + reported to the APB terminator (APB Errors Handler Block). + +allOf: + - $ref: /schemas/simple-bus.yaml# + +properties: + compatible: + contains: + const: baikal,bt1-apb + + reg: + items: + - description: APB EHB MMIO registers + - description: APB MMIO region with no any device mapped + + reg-names: + items: + - const: ehb + - const: nodev + + interrupts: + maxItems: 1 + + clocks: + items: + - description: APB reference clock + + clock-names: + items: + - const: pclk + + resets: + items: + - description: APB domain reset line + + reset-names: + items: + - const: prst + +unevaluatedProperties: false + +required: + - compatible + - reg + - reg-names + - interrupts + - clocks + - clock-names + +examples: + - | + #include + + bus@1f059000 { + compatible = "baikal,bt1-apb", "simple-bus"; + reg = <0 0x1f059000 0 0x1000>, + <0 0x1d000000 0 0x2040000>; + reg-names = "ehb", "nodev"; + #address-cells = <1>; + #size-cells = <1>; + + ranges; + + interrupts = ; + + clocks = <&ccu_sys 1>; + clock-names = "pclk"; + + resets = <&ccu_sys 1>; + reset-names = "prst"; + }; +... From patchwork Thu May 7 22:41:15 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Serge Semin X-Patchwork-Id: 11535049 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C4E061392 for ; Thu, 7 May 2020 22:41:54 +0000 (UTC) Received: by mail.kernel.org (Postfix) id C0FDE20870; Thu, 7 May 2020 22:41:54 +0000 (UTC) Delivered-To: soc@kernel.org Received: from mail.baikalelectronics.ru (mail.baikalelectronics.com [87.245.175.226]) by mail.kernel.org (Postfix) with ESMTP id 5BBD2208CA; Thu, 7 May 2020 22:41:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5BBD2208CA Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=baikalelectronics.ru Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=Sergey.Semin@baikalelectronics.ru Received: from localhost (unknown [127.0.0.1]) by mail.baikalelectronics.ru (Postfix) with ESMTP id B3E9280307C7; Thu, 7 May 2020 22:41:53 +0000 (UTC) X-Virus-Scanned: amavisd-new at baikalelectronics.ru Received: from mail.baikalelectronics.ru ([127.0.0.1]) by localhost (mail.baikalelectronics.ru [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id gbs-BpSY03B9; Fri, 8 May 2020 01:41:52 +0300 (MSK) From: Serge Semin To: Thomas Bogendoerfer , Greg Kroah-Hartman , Arnd Bergmann List-Id: CC: Serge Semin , Serge Semin , Alexey Malahov , Paul Burton , Ralf Baechle , Tony Lindgren , Tero Kristo , Manivannan Sadhasivam , Jeffrey Hugo , Linus Walleij , Olof Johansson , Rob Herring , , , , David Lechner , Jonathan Cameron , Sameer Pujar , John Garry , =?utf-8?q?Marek_Beh=C3=BAn?= , Subject: [PATCH v2 3/4] bus: Add Baikal-T1 AXI-bus driver Date: Fri, 8 May 2020 01:41:15 +0300 Message-ID: <20200507224116.1523-4-Sergey.Semin@baikalelectronics.ru> In-Reply-To: <20200507224116.1523-1-Sergey.Semin@baikalelectronics.ru> References: <20200306130731.938808030702@mail.baikalelectronics.ru> <20200507224116.1523-1-Sergey.Semin@baikalelectronics.ru> MIME-Version: 1.0 X-ClientProxiedBy: MAIL.baikal.int (192.168.51.25) To mail (192.168.51.25) AXI3-bus is the main communication bus connecting all high-speed peripheral IP-cores with RAM controller and MIPS P5600 cores on Baikal-T1 SoC. Bus traffic arbitration is done by means of DW AMBA 3 AXI Interconnect (so called AXI Main Interconnect) routing IO requests from one SoC block to another. This driver provides a way to detect any bus protocol errors and device not responding situations by means of an embedded on top of the interconnect errors handler block (EHB). AXI Interconnect QoS arbitration tuning is currently unsupported. The bus doesn't provide a way to detect the interconnected devices, so they are supposed to be statically defined like by means of the simple-bus sub-nodes. Signed-off-by: Serge Semin Cc: Alexey Malahov Cc: Paul Burton Cc: Ralf Baechle Cc: Tony Lindgren Cc: Tero Kristo Cc: Manivannan Sadhasivam Cc: Jeffrey Hugo Cc: Linus Walleij Cc: Olof Johansson Cc: Rob Herring Cc: linux-mips@vger.kernel.org Cc: soc@kernel.org Cc: devicetree@vger.kernel.org --- Changelog v2: - Fix commit message and Kconfig help text spelling. - Move driver from soc to the bus subsystem. - Convert a simple EHB driver to the Baikal-T1 AXI-bus one. - Use syscon regmap to access the AXI-bus erroneous address. - Add interconnect reset line support. - Remove probe-status info string printout. - Use generic FIELD_{GET,PREP} macros instead of handwritten ones. - Since the driver depends on the OF config we can remove of_match_ptr() macro utilization. - Don't print error-message if no platform IRQ found. Just return an error. - Select MFD_SYSCON config. --- drivers/bus/Kconfig | 15 ++ drivers/bus/Makefile | 1 + drivers/bus/bt1-axi.c | 318 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 334 insertions(+) create mode 100644 drivers/bus/bt1-axi.c diff --git a/drivers/bus/Kconfig b/drivers/bus/Kconfig index 6d4e4497b59b..4139e2408937 100644 --- a/drivers/bus/Kconfig +++ b/drivers/bus/Kconfig @@ -29,6 +29,21 @@ config BRCMSTB_GISB_ARB arbiter. This driver provides timeout and target abort error handling and internal bus master decoding. +config BT1_AXI + tristate "Baikal-T1 AXI-bus driver" + depends on (MIPS_BAIKAL_T1 && OF) || COMPILE_TEST + select MFD_SYSCON + help + AXI3-bus is the main communication bus connecting all high-speed + peripheral IP-cores with RAM controller and with MIPS P5600 cores on + Baikal-T1 SoC. Traffic arbitration is done by means of DW AMBA 3 AXI + Interconnect (so called AXI Main Interconnect) routing IO requests + from one SoC block to another. This driver provides a way to detect + any bus protocol errors and device not responding situations by + means of an embedded on top of the interconnect errors handler + block (EHB). AXI Interconnect QoS arbitration tuning is currently + unsupported. + config MOXTET tristate "CZ.NIC Turris Mox module configuration bus" depends on SPI_MASTER && OF diff --git a/drivers/bus/Makefile b/drivers/bus/Makefile index 05f32cd694a4..eaa25d171ebd 100644 --- a/drivers/bus/Makefile +++ b/drivers/bus/Makefile @@ -13,6 +13,7 @@ obj-$(CONFIG_MOXTET) += moxtet.o # DPAA2 fsl-mc bus obj-$(CONFIG_FSL_MC_BUS) += fsl-mc/ +obj-$(CONFIG_BT1_AXI) += bt1-axi.o obj-$(CONFIG_IMX_WEIM) += imx-weim.o obj-$(CONFIG_MIPS_CDMM) += mips_cdmm.o obj-$(CONFIG_MVEBU_MBUS) += mvebu-mbus.o diff --git a/drivers/bus/bt1-axi.c b/drivers/bus/bt1-axi.c new file mode 100644 index 000000000000..5d288aa6da31 --- /dev/null +++ b/drivers/bus/bt1-axi.c @@ -0,0 +1,318 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2020 BAIKAL ELECTRONICS, JSC + * + * Authors: + * Serge Semin + * + * Baikal-T1 AXI-bus driver + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define BT1_AXI_WERRL 0x110 +#define BT1_AXI_WERRH 0x114 +#define BT1_AXI_WERRH_TYPE BIT(23) +#define BT1_AXI_WERRH_ADDR_FLD 24 +#define BT1_AXI_WERRH_ADDR_MASK GENMASK(31, BT1_AXI_WERRH_ADDR_FLD) + +/* + * struct bt1_axi - Baikal-T1 AXI-bus private data + * @dev: Pointer to the device structure. + * @qos_regs: AXI Interconnect QoS tuning registers. + * @sys_regs: Baikal-T1 System Controller registers map. + * @irq: Errors IRQ number. + * @aclk: AXI reference clock. + * @arst: AXI Interconnect reset line. + * @count: Number of errors detected. + */ +struct bt1_axi { + struct device *dev; + + void __iomem *qos_regs; + struct regmap *sys_regs; + int irq; + + struct clk *aclk; + + struct reset_control *arst; + + atomic_t count; +}; + +static irqreturn_t bt1_axi_isr(int irq, void *data) +{ + struct bt1_axi *axi = data; + u32 low = 0, high = 0; + + regmap_read(axi->sys_regs, BT1_AXI_WERRL, &low); + regmap_read(axi->sys_regs, BT1_AXI_WERRH, &high); + + dev_crit_ratelimited(axi->dev, + "AXI-bus fault %d: %s at 0x%x%08x\n", + atomic_inc_return(&axi->count), + high & BT1_AXI_WERRH_TYPE ? "no slave" : "slave protocol error", + high, low); + + /* + * Print backtrace on each CPU. This might be pointless if the fault + * has happened on the same CPU as the IRQ handler is executed or + * the other core proceeded further execution despite the error. + * But if it's not, by looking at the trace we would get straight to + * the cause of the problem. + */ + trigger_all_cpu_backtrace(); + + return IRQ_HANDLED; +} + +static void bt1_axi_clear_data(void *data) +{ + struct bt1_axi *axi = data; + struct platform_device *pdev = to_platform_device(axi->dev); + + platform_set_drvdata(pdev, NULL); +} + +static struct bt1_axi *bt1_axi_create_data(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct bt1_axi *axi; + int ret; + + axi = devm_kzalloc(dev, sizeof(*axi), GFP_KERNEL); + if (!axi) + return ERR_PTR(-ENOMEM); + + ret = devm_add_action(dev, bt1_axi_clear_data, axi); + if (ret) { + dev_err(dev, "Can't add AXI EHB data clear action\n"); + return ERR_PTR(ret); + } + + axi->dev = dev; + atomic_set(&axi->count, 0); + platform_set_drvdata(pdev, axi); + + return axi; +} + +static int bt1_axi_request_regs(struct bt1_axi *axi) +{ + struct platform_device *pdev = to_platform_device(axi->dev); + struct device *dev = axi->dev; + + axi->sys_regs = syscon_regmap_lookup_by_phandle(dev->of_node, "syscon"); + if (IS_ERR(axi->sys_regs)) { + dev_err(dev, "Couldn't find syscon registers\n"); + return PTR_ERR(axi->sys_regs); + } + + axi->qos_regs = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(axi->qos_regs)) { + dev_err(dev, "Couldn't map AXI-bus QoS registers\n"); + return PTR_ERR(axi->qos_regs); + } + + return 0; +} + +static int bt1_axi_request_rst(struct bt1_axi *axi) +{ + int ret; + + axi->arst = devm_reset_control_get_optional_exclusive(axi->dev, "arst"); + if (IS_ERR(axi->arst)) { + dev_warn(axi->dev, "Couldn't get reset control line\n"); + return PTR_ERR(axi->arst); + } + + ret = reset_control_deassert(axi->arst); + if (ret) + dev_err(axi->dev, "Failed to deassert the reset line\n"); + + return ret; +} + +static void bt1_axi_disable_clk(void *data) +{ + struct bt1_axi *axi = data; + + clk_disable_unprepare(axi->aclk); +} + +static int bt1_axi_request_clk(struct bt1_axi *axi) +{ + int ret; + + axi->aclk = devm_clk_get(axi->dev, "aclk"); + if (IS_ERR(axi->aclk)) { + dev_err(axi->dev, "Couldn't get AXI Interconnect clock\n"); + return PTR_ERR(axi->aclk); + } + + ret = clk_prepare_enable(axi->aclk); + if (ret) { + dev_err(axi->dev, "Couldn't enable the AXI clock\n"); + return ret; + } + + ret = devm_add_action_or_reset(axi->dev, bt1_axi_disable_clk, axi); + if (ret) { + dev_err(axi->dev, "Can't add AXI clock disable action\n"); + return ret; + } + + return 0; +} + +static int bt1_axi_request_irq(struct bt1_axi *axi) +{ + struct platform_device *pdev = to_platform_device(axi->dev); + int ret; + + axi->irq = platform_get_irq(pdev, 0); + if (axi->irq < 0) + return axi->irq; + + ret = devm_request_irq(axi->dev, axi->irq, bt1_axi_isr, IRQF_SHARED, + "bt1-axi", axi); + if (ret) { + dev_err(axi->dev, "Couldn't request AXI EHB IRQ\n"); + return ret; + } + + return 0; +} + +static ssize_t count_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct bt1_axi *axi = dev_get_drvdata(dev); + + return scnprintf(buf, PAGE_SIZE, "%d\n", atomic_read(&axi->count)); +} +static DEVICE_ATTR_RO(count); + +static int inject_error_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + return scnprintf(buf, PAGE_SIZE, "Error injection: bus unaligned\n"); +} + +static int inject_error_store(struct device *dev, + struct device_attribute *attr, + const char *data, size_t count) +{ + struct bt1_axi *axi = dev_get_drvdata(dev); + + /* + * Performing unaligned read from the memory will cause the CM2 bus + * error while unaligned writing - the AXI bus write error handled + * by this driver. + */ + if (!strncmp(data, "bus", 3)) + readb(axi->qos_regs); + else if (!strncmp(data, "unaligned", 9)) + writeb(0, axi->qos_regs); + else + return -EINVAL; + + return count; +} +static DEVICE_ATTR_RW(inject_error); + +static struct attribute *bt1_axi_sysfs_attrs[] = { + &dev_attr_count.attr, + &dev_attr_inject_error.attr, + NULL +}; +ATTRIBUTE_GROUPS(bt1_axi_sysfs); + +static void bt1_axi_remove_sysfs(void *data) +{ + struct bt1_axi *axi = data; + + device_remove_groups(axi->dev, bt1_axi_sysfs_groups); +} + +static int bt1_axi_init_sysfs(struct bt1_axi *axi) +{ + int ret; + + ret = device_add_groups(axi->dev, bt1_axi_sysfs_groups); + if (ret) { + dev_err(axi->dev, "Failed to add sysfs files group\n"); + return ret; + } + + ret = devm_add_action_or_reset(axi->dev, bt1_axi_remove_sysfs, axi); + if (ret) + dev_err(axi->dev, "Can't add AXI EHB sysfs remove action\n"); + + return ret; +} + +static int bt1_axi_probe(struct platform_device *pdev) +{ + struct bt1_axi *axi; + int ret; + + axi = bt1_axi_create_data(pdev); + if (IS_ERR(axi)) + return PTR_ERR(axi); + + ret = bt1_axi_request_regs(axi); + if (ret) + return ret; + + ret = bt1_axi_request_rst(axi); + if (ret) + return ret; + + ret = bt1_axi_request_clk(axi); + if (ret) + return ret; + + ret = bt1_axi_request_irq(axi); + if (ret) + return ret; + + ret = bt1_axi_init_sysfs(axi); + if (ret) + return ret; + + return 0; +} + +static const struct of_device_id bt1_axi_of_match[] = { + { .compatible = "baikal,bt1-axi" }, + { } +}; +MODULE_DEVICE_TABLE(of, bt1_axi_of_match); + +static struct platform_driver bt1_axi_driver = { + .probe = bt1_axi_probe, + .driver = { + .name = "bt1-axi", + .of_match_table = bt1_axi_of_match + } +}; +module_platform_driver(bt1_axi_driver); + +MODULE_AUTHOR("Serge Semin "); +MODULE_DESCRIPTION("Baikal-T1 AXI-bus driver"); +MODULE_LICENSE("GPL v2"); From patchwork Thu May 7 22:41:16 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Serge Semin X-Patchwork-Id: 11535053 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 0E86C139F for ; Thu, 7 May 2020 22:42:06 +0000 (UTC) Received: by mail.kernel.org (Postfix) id 0A48021473; Thu, 7 May 2020 22:42:06 +0000 (UTC) Delivered-To: soc@kernel.org Received: from mail.baikalelectronics.ru (mail.baikalelectronics.com [87.245.175.226]) by mail.kernel.org (Postfix) with ESMTP id 9659220870; Thu, 7 May 2020 22:42:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9659220870 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=baikalelectronics.ru Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=Sergey.Semin@baikalelectronics.ru Received: from localhost (unknown [127.0.0.1]) by mail.baikalelectronics.ru (Postfix) with ESMTP id DCF9C803087B; Thu, 7 May 2020 22:42:04 +0000 (UTC) X-Virus-Scanned: amavisd-new at baikalelectronics.ru Received: from mail.baikalelectronics.ru ([127.0.0.1]) by localhost (mail.baikalelectronics.ru [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Qi2xCxMi0Egw; Fri, 8 May 2020 01:42:03 +0300 (MSK) From: Serge Semin To: Thomas Bogendoerfer , Greg Kroah-Hartman , Arnd Bergmann List-Id: CC: Serge Semin , Serge Semin , Alexey Malahov , Paul Burton , Ralf Baechle , Tony Lindgren , Tero Kristo , Manivannan Sadhasivam , Jeffrey Hugo , Linus Walleij , Olof Johansson , Rob Herring , , , , David Lechner , Jonathan Cameron , Thierry Reding , John Garry , =?utf-8?q?Marek_Beh=C3=BAn?= , Sameer Pujar , Sujeev Dias , Siddartha Mohanadoss , Subject: [PATCH v2 4/4] bus: Add Baikal-T1 APB-bus driver Date: Fri, 8 May 2020 01:41:16 +0300 Message-ID: <20200507224116.1523-5-Sergey.Semin@baikalelectronics.ru> In-Reply-To: <20200507224116.1523-1-Sergey.Semin@baikalelectronics.ru> References: <20200306130731.938808030702@mail.baikalelectronics.ru> <20200507224116.1523-1-Sergey.Semin@baikalelectronics.ru> MIME-Version: 1.0 X-ClientProxiedBy: MAIL.baikal.int (192.168.51.25) To mail (192.168.51.25) Baikal-T1 AXI-APB bridge is used to access the SoC subsystem CSRs. IO requests are routed to this bus by means of the DW AMBA 3 AXI Interconnect. In case if an attempted APB transaction stays with no response for a pre-defined time an interrupt occurs and the bus gets freed for a next operation. This driver provides the interrupt handler to detect the erroneous address, prints an error message about the address fault, updates an errors counter. The counter and the APB-bus operations timeout can be accessed via corresponding sysfs nodes. A dedicated sysfs-node can be also used to artificially cause the bus errors described above. Signed-off-by: Serge Semin Cc: Alexey Malahov Cc: Paul Burton Cc: Ralf Baechle Cc: Tony Lindgren Cc: Tero Kristo Cc: Manivannan Sadhasivam Cc: Jeffrey Hugo Cc: Linus Walleij Cc: Olof Johansson Cc: Rob Herring Cc: linux-mips@vger.kernel.org Cc: soc@kernel.org Cc: devicetree@vger.kernel.org --- Changelog v2: - Fix commit message and Kconfig help text spelling. - Move driver from soc to the bus subsystem. - Convert a simple EHB driver to the Baikal-T1 AXI-bus one. - Convert registers MMIO to the regmap. - Add reset line support. - Remove probe-status info string printout. - Since the driver depends on the OF config we can remove of_match_ptr() macro utilization. - Don't print error-message if no platform IRQ found. Just return an error. --- drivers/bus/Kconfig | 15 ++ drivers/bus/Makefile | 1 + drivers/bus/bt1-apb.c | 421 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 437 insertions(+) create mode 100644 drivers/bus/bt1-apb.c diff --git a/drivers/bus/Kconfig b/drivers/bus/Kconfig index 4139e2408937..5f491040c9d8 100644 --- a/drivers/bus/Kconfig +++ b/drivers/bus/Kconfig @@ -29,6 +29,21 @@ config BRCMSTB_GISB_ARB arbiter. This driver provides timeout and target abort error handling and internal bus master decoding. +config BT1_APB + tristate "Baikal-T1 APB-bus driver" + depends on (MIPS_BAIKAL_T1 && OF) || COMPILE_TEST + select REGMAP_MMIO + help + Baikal-T1 AXI-APB bridge is used to access the SoC subsystem CSRs. + IO requests are routed to this bus by means of the DW AMBA 3 AXI + Interconnect. In case of any APB protocol collisions, slave device + not responding on timeout an IRQ is raised with an erroneous address + reported to the APB terminator (APB Errors Handler Block). This + driver provides the interrupt handler to detect the erroneous + address, prints an error message about the address fault, updates an + errors counter. The counter and the APB-bus operations timeout can be + accessed via corresponding sysfs nodes. + config BT1_AXI tristate "Baikal-T1 AXI-bus driver" depends on (MIPS_BAIKAL_T1 && OF) || COMPILE_TEST diff --git a/drivers/bus/Makefile b/drivers/bus/Makefile index eaa25d171ebd..08ccbfaf7705 100644 --- a/drivers/bus/Makefile +++ b/drivers/bus/Makefile @@ -13,6 +13,7 @@ obj-$(CONFIG_MOXTET) += moxtet.o # DPAA2 fsl-mc bus obj-$(CONFIG_FSL_MC_BUS) += fsl-mc/ +obj-$(CONFIG_BT1_APB) += bt1-apb.o obj-$(CONFIG_BT1_AXI) += bt1-axi.o obj-$(CONFIG_IMX_WEIM) += imx-weim.o obj-$(CONFIG_MIPS_CDMM) += mips_cdmm.o diff --git a/drivers/bus/bt1-apb.c b/drivers/bus/bt1-apb.c new file mode 100644 index 000000000000..295cfa83aa23 --- /dev/null +++ b/drivers/bus/bt1-apb.c @@ -0,0 +1,421 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2020 BAIKAL ELECTRONICS, JSC + * + * Authors: + * Serge Semin + * + * Baikal-T1 APB-bus driver + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define APB_EHB_ISR 0x00 +#define APB_EHB_ISR_PENDING BIT(0) +#define APB_EHB_ISR_MASK BIT(1) +#define APB_EHB_ADDR 0x04 +#define APB_EHB_TIMEOUT 0x08 + +#define APB_EHB_TIMEOUT_MIN 0x000003FFU +#define APB_EHB_TIMEOUT_MAX 0xFFFFFFFFU + +/* + * struct bt1_apb - Baikal-T1 APB EHB private data + * @dev: Pointer to the device structure. + * @regs: APB EHB registers map. + * @res: No-device error injection memory region. + * @irq: Errors IRQ number. + * @rate: APB-bus reference clock rate. + * @pclk: APB-reference clock. + * @prst: APB domain reset line. + * @count: Number of errors detected. + */ +struct bt1_apb { + struct device *dev; + + struct regmap *regs; + void __iomem *res; + int irq; + + unsigned long rate; + struct clk *pclk; + + struct reset_control *prst; + + atomic_t count; +}; + +static const struct regmap_config bt1_apb_regmap_cfg = { + .reg_bits = 32, + .val_bits = 32, + .reg_stride = 4, + .max_register = APB_EHB_TIMEOUT, + .fast_io = true +}; + +static inline unsigned long bt1_apb_n_to_timeout_us(struct bt1_apb *apb, u32 n) +{ + u64 timeout = (u64)n * USEC_PER_SEC; + + do_div(timeout, apb->rate); + + return timeout; + +} + +static inline unsigned long bt1_apb_timeout_to_n_us(struct bt1_apb *apb, + unsigned long timeout) +{ + u64 n = (u64)timeout * apb->rate; + + do_div(n, USEC_PER_SEC); + + return n; + +} + +static irqreturn_t bt1_apb_isr(int irq, void *data) +{ + struct bt1_apb *apb = data; + u32 addr = 0; + + regmap_read(apb->regs, APB_EHB_ADDR, &addr); + + dev_crit_ratelimited(apb->dev, + "APB-bus fault %d: Slave access timeout at 0x%08x\n", + atomic_inc_return(&apb->count), + addr); + + /* + * Print backtrace on each CPU. This might be pointless if the fault + * has happened on the same CPU as the IRQ handler is executed or + * the other core proceeded further execution despite the error. + * But if it's not, by looking at the trace we would get straight to + * the cause of the problem. + */ + trigger_all_cpu_backtrace(); + + regmap_update_bits(apb->regs, APB_EHB_ISR, APB_EHB_ISR_PENDING, 0); + + return IRQ_HANDLED; +} + +static void bt1_apb_clear_data(void *data) +{ + struct bt1_apb *apb = data; + struct platform_device *pdev = to_platform_device(apb->dev); + + platform_set_drvdata(pdev, NULL); +} + +static struct bt1_apb *bt1_apb_create_data(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct bt1_apb *apb; + int ret; + + apb = devm_kzalloc(dev, sizeof(*apb), GFP_KERNEL); + if (!apb) + return ERR_PTR(-ENOMEM); + + ret = devm_add_action(dev, bt1_apb_clear_data, apb); + if (ret) { + dev_err(dev, "Can't add APB EHB data clear action\n"); + return ERR_PTR(ret); + } + + apb->dev = dev; + atomic_set(&apb->count, 0); + platform_set_drvdata(pdev, apb); + + return apb; +} + +static int bt1_apb_request_regs(struct bt1_apb *apb) +{ + struct platform_device *pdev = to_platform_device(apb->dev); + void __iomem *regs; + + regs = devm_platform_ioremap_resource_byname(pdev, "ehb"); + if (IS_ERR(regs)) { + dev_err(apb->dev, "Couldn't map APB EHB registers\n"); + return PTR_ERR(regs); + } + + apb->regs = devm_regmap_init_mmio(apb->dev, regs, &bt1_apb_regmap_cfg); + if (IS_ERR(apb->regs)) { + dev_err(apb->dev, "Couldn't create APB EHB regmap\n"); + return PTR_ERR(apb->regs); + } + + apb->res = devm_platform_ioremap_resource_byname(pdev, "nodev"); + if (IS_ERR(apb->res)) { + dev_err(apb->dev, "Couldn't map reserved region\n"); + return PTR_ERR(apb->res); + } + + return 0; +} + +static int bt1_apb_request_rst(struct bt1_apb *apb) +{ + int ret; + + apb->prst = devm_reset_control_get_optional_exclusive(apb->dev, "prst"); + if (IS_ERR(apb->prst)) { + dev_warn(apb->dev, "Couldn't get reset control line\n"); + return PTR_ERR(apb->prst); + } + + ret = reset_control_deassert(apb->prst); + if (ret) + dev_err(apb->dev, "Failed to deassert the reset line\n"); + + return ret; +} + +static void bt1_apb_disable_clk(void *data) +{ + struct bt1_apb *apb = data; + + clk_disable_unprepare(apb->pclk); +} + +static int bt1_apb_request_clk(struct bt1_apb *apb) +{ + int ret; + + apb->pclk = devm_clk_get(apb->dev, "pclk"); + if (IS_ERR(apb->pclk)) { + dev_err(apb->dev, "Couldn't get APB clock descriptor\n"); + return PTR_ERR(apb->pclk); + } + + ret = clk_prepare_enable(apb->pclk); + if (ret) { + dev_err(apb->dev, "Couldn't enable the APB clock\n"); + return ret; + } + + ret = devm_add_action_or_reset(apb->dev, bt1_apb_disable_clk, apb); + if (ret) { + dev_err(apb->dev, "Can't add APB EHB clocks disable action\n"); + return ret; + } + + apb->rate = clk_get_rate(apb->pclk); + if (!apb->rate) { + dev_err(apb->dev, "Invalid clock rate\n"); + return -EINVAL; + } + + return 0; +} + +static void bt1_apb_clear_irq(void *data) +{ + struct bt1_apb *apb = data; + + regmap_update_bits(apb->regs, APB_EHB_ISR, APB_EHB_ISR_MASK, 0); +} + +static int bt1_apb_request_irq(struct bt1_apb *apb) +{ + struct platform_device *pdev = to_platform_device(apb->dev); + int ret; + + apb->irq = platform_get_irq(pdev, 0); + if (apb->irq < 0) + return apb->irq; + + ret = devm_request_irq(apb->dev, apb->irq, bt1_apb_isr, IRQF_SHARED, + "bt1-apb", apb); + if (ret) { + dev_err(apb->dev, "Couldn't request APB EHB IRQ\n"); + return ret; + } + + ret = devm_add_action(apb->dev, bt1_apb_clear_irq, apb); + if (ret) { + dev_err(apb->dev, "Can't add APB EHB IRQs clear action\n"); + return ret; + } + + /* Unmask IRQ and clear it' pending flag. */ + regmap_update_bits(apb->regs, APB_EHB_ISR, + APB_EHB_ISR_PENDING | APB_EHB_ISR_MASK, + APB_EHB_ISR_MASK); + + return 0; +} + +static ssize_t count_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct bt1_apb *apb = dev_get_drvdata(dev); + + return scnprintf(buf, PAGE_SIZE, "%d\n", atomic_read(&apb->count)); +} +static DEVICE_ATTR_RO(count); + +static ssize_t timeout_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct bt1_apb *apb = dev_get_drvdata(dev); + unsigned long timeout; + int ret; + u32 n; + + ret = regmap_read(apb->regs, APB_EHB_TIMEOUT, &n); + if (ret) + return ret; + + timeout = bt1_apb_n_to_timeout_us(apb, n); + + return scnprintf(buf, PAGE_SIZE, "%lu\n", timeout); +} + +static ssize_t timeout_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct bt1_apb *apb = dev_get_drvdata(dev); + unsigned long timeout; + int ret; + u32 n; + + if (kstrtoul(buf, 0, &timeout) < 0) + return -EINVAL; + + n = bt1_apb_timeout_to_n_us(apb, timeout); + n = clamp(n, APB_EHB_TIMEOUT_MIN, APB_EHB_TIMEOUT_MAX); + + ret = regmap_write(apb->regs, APB_EHB_TIMEOUT, n); + + return ret ?: count; +} +static DEVICE_ATTR_RW(timeout); + +static int inject_error_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + return scnprintf(buf, PAGE_SIZE, "Error injection: nodev irq\n"); +} + +static int inject_error_store(struct device *dev, + struct device_attribute *attr, + const char *data, size_t count) +{ + struct bt1_apb *apb = dev_get_drvdata(dev); + + /* + * Either dummy read from the unmapped address in the APB IO area + * or manually set the IRQ status. + */ + if (!strncmp(data, "nodev", 5)) + readl(apb->res); + else if (!strncmp(data, "irq", 3)) + regmap_update_bits(apb->regs, APB_EHB_ISR, APB_EHB_ISR_PENDING, + APB_EHB_ISR_PENDING); + else + return -EINVAL; + + return count; +} +static DEVICE_ATTR_RW(inject_error); + +static struct attribute *bt1_apb_sysfs_attrs[] = { + &dev_attr_count.attr, + &dev_attr_timeout.attr, + &dev_attr_inject_error.attr, + NULL +}; +ATTRIBUTE_GROUPS(bt1_apb_sysfs); + +static void bt1_apb_remove_sysfs(void *data) +{ + struct bt1_apb *apb = data; + + device_remove_groups(apb->dev, bt1_apb_sysfs_groups); +} + +static int bt1_apb_init_sysfs(struct bt1_apb *apb) +{ + int ret; + + ret = device_add_groups(apb->dev, bt1_apb_sysfs_groups); + if (ret) { + dev_err(apb->dev, "Failed to create EHB APB sysfs nodes\n"); + return ret; + } + + ret = devm_add_action_or_reset(apb->dev, bt1_apb_remove_sysfs, apb); + if (ret) + dev_err(apb->dev, "Can't add APB EHB sysfs remove action\n"); + + return ret; +} + +static int bt1_apb_probe(struct platform_device *pdev) +{ + struct bt1_apb *apb; + int ret; + + apb = bt1_apb_create_data(pdev); + if (IS_ERR(apb)) + return PTR_ERR(apb); + + ret = bt1_apb_request_regs(apb); + if (ret) + return ret; + + ret = bt1_apb_request_rst(apb); + if (ret) + return ret; + + ret = bt1_apb_request_clk(apb); + if (ret) + return ret; + + ret = bt1_apb_request_irq(apb); + if (ret) + return ret; + + ret = bt1_apb_init_sysfs(apb); + if (ret) + return ret; + + return 0; +} + +static const struct of_device_id bt1_apb_of_match[] = { + { .compatible = "baikal,bt1-apb" }, + { } +}; +MODULE_DEVICE_TABLE(of, bt1_apb_of_match); + +static struct platform_driver bt1_apb_driver = { + .probe = bt1_apb_probe, + .driver = { + .name = "bt1-apb", + .of_match_table = bt1_apb_of_match + } +}; +module_platform_driver(bt1_apb_driver); + +MODULE_AUTHOR("Serge Semin "); +MODULE_DESCRIPTION("Baikal-T1 APB-bus driver"); +MODULE_LICENSE("GPL v2");