From 63cb77136e04ff24ca520e46f5ff57d351dadbdb Mon Sep 17 00:00:00 2001 From: Serge Semin Date: Tue, 26 May 2020 15:59:26 +0300 Subject: bus: Add Baikal-T1 AXI-bus driver 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. [arnd: fix build warnings for missing includes and wrong return types] Link: https://lore.kernel.org/r/20200526125928.17096-5-Sergey.Semin@baikalelectronics.ru Signed-off-by: Serge Semin Cc: Alexey Malahov Cc: Paul Burton Cc: Olof Johansson Cc: Rob Herring Cc: linux-mips@vger.kernel.org Cc: soc@kernel.org Cc: devicetree@vger.kernel.org Reported-by: kbuild test robot Reported-by: kbuild test robot Signed-off-by: Arnd Bergmann --- drivers/bus/Kconfig | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'drivers/bus/Kconfig') diff --git a/drivers/bus/Kconfig b/drivers/bus/Kconfig index 6d4e4497b59b..1080dd26e268 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 || 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 -- cgit v1.2.3 From 8f93662d8324940e8925a0e492c587dbcf7c7fee Mon Sep 17 00:00:00 2001 From: Serge Semin Date: Tue, 26 May 2020 15:59:27 +0300 Subject: bus: Add Baikal-T1 APB-bus driver 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. [arnd: fix build warnings for missing includes and wrong return types] Link: https://lore.kernel.org/r/20200526125928.17096-6-Sergey.Semin@baikalelectronics.ru Signed-off-by: Serge Semin Cc: Alexey Malahov Cc: Paul Burton Cc: Olof Johansson Cc: Rob Herring Cc: linux-mips@vger.kernel.org Cc: soc@kernel.org Cc: devicetree@vger.kernel.org Reported-by: kbuild test robot Reported-by: kbuild test robot Signed-off-by: Arnd Bergmann --- drivers/bus/Kconfig | 15 ++ drivers/bus/Makefile | 1 + drivers/bus/bt1-apb.c | 422 ++++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 438 insertions(+) create mode 100644 drivers/bus/bt1-apb.c (limited to 'drivers/bus/Kconfig') diff --git a/drivers/bus/Kconfig b/drivers/bus/Kconfig index 1080dd26e268..030f0e59f193 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 || 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 || 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..abccd1dfc544 --- /dev/null +++ b/drivers/bus/bt1-apb.c @@ -0,0 +1,422 @@ +// 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 +#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 ssize_t inject_error_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + return scnprintf(buf, PAGE_SIZE, "Error injection: nodev irq\n"); +} + +static ssize_t 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"); -- cgit v1.2.3 From dc20e93b935e43e9315128626f20962039fda7d9 Mon Sep 17 00:00:00 2001 From: Serge Semin Date: Thu, 28 May 2020 22:31:12 +0300 Subject: bus: bt1-apb: Build the driver into the kernel Seeing trigger_all_cpu_backtrace() isn't exported from the kernel and since calling it is a very important part of driver, which may provide a better description of a possible cause of the error, let's disable the ability to build the driver as a loadable kernel module. Link: https://lore.kernel.org/r/20200528193113.17372-1-Sergey.Semin@baikalelectronics.ru Signed-off-by: Serge Semin Cc: Alexey Malahov Cc: Olof Johansson Cc: soc@kernel.org Signed-off-by: Arnd Bergmann --- drivers/bus/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/bus/Kconfig') diff --git a/drivers/bus/Kconfig b/drivers/bus/Kconfig index 030f0e59f193..18858f560d1f 100644 --- a/drivers/bus/Kconfig +++ b/drivers/bus/Kconfig @@ -30,7 +30,7 @@ config BRCMSTB_GISB_ARB and internal bus master decoding. config BT1_APB - tristate "Baikal-T1 APB-bus driver" + bool "Baikal-T1 APB-bus driver" depends on MIPS_BAIKAL_T1 || COMPILE_TEST select REGMAP_MMIO help -- cgit v1.2.3 From 22e795b470aebef4c01346e3b43e0af49c7638be Mon Sep 17 00:00:00 2001 From: Serge Semin Date: Thu, 28 May 2020 22:31:13 +0300 Subject: bus: bt1-axi: Build the driver into the kernel Alas the method trigger_all_cpu_backtrace() isn't exported by the kernel, but we need to have it called in case of the bus errors detected to get a better description of a possible cause of the error. Let's disable the ability to build the driver as a loadable kernel module then. Note In future the driver will support the AXI-bus interconnect capability, so we'd have to make it built into the kernel anyway. Link: https://lore.kernel.org/r/20200528193113.17372-2-Sergey.Semin@baikalelectronics.ru Signed-off-by: Serge Semin Cc: Alexey Malahov Cc: Olof Johansson Cc: soc@kernel.org Signed-off-by: Arnd Bergmann --- drivers/bus/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/bus/Kconfig') diff --git a/drivers/bus/Kconfig b/drivers/bus/Kconfig index 18858f560d1f..4be793c5ab4d 100644 --- a/drivers/bus/Kconfig +++ b/drivers/bus/Kconfig @@ -45,7 +45,7 @@ config BT1_APB accessed via corresponding sysfs nodes. config BT1_AXI - tristate "Baikal-T1 AXI-bus driver" + bool "Baikal-T1 AXI-bus driver" depends on MIPS_BAIKAL_T1 || COMPILE_TEST select MFD_SYSCON help -- cgit v1.2.3