soc/tegra: cbb: Changes for v6.1-rc1

This introduces the CBB driver that is used to provide (a lot of)
 information about SErrors when things go wrong, instead of the kernel
 just crashing or hanging.
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Merge tag 'tegra-for-6.1-cbb' of git://git.kernel.org/pub/scm/linux/kernel/git/tegra/linux into arm/drivers

soc/tegra: cbb: Changes for v6.1-rc1

This introduces the CBB driver that is used to provide (a lot of)
information about SErrors when things go wrong, instead of the kernel
just crashing or hanging.

* tag 'tegra-for-6.1-cbb' of git://git.kernel.org/pub/scm/linux/kernel/git/tegra/linux:
  soc/tegra: cbb: Add support for Tegra241 (Grace)
  soc/tegra: cbb: Add driver for Tegra234 CBB 2.0
  soc/tegra: cbb: Add CBB 1.0 driver for Tegra194
  soc/tegra: Set ERD bit to mask inband errors

Link: https://lore.kernel.org/r/20220916101957.1635854-2-thierry.reding@gmail.com
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

drivers/soc/tegra/Kconfig

@@ -161,3 +161,12 @@ config SOC_TEGRA30_VOLTAGE_COUPLER
 	bool "Voltage scaling support for Tegra30 SoCs"
 	depends on ARCH_TEGRA_3x_SOC || COMPILE_TEST
 	depends on REGULATOR
+
+config SOC_TEGRA_CBB
+	tristate "Tegra driver to handle error from CBB"
+	depends on ARCH_TEGRA_194_SOC || ARCH_TEGRA_234_SOC
+	default y
+	help
+	  Support for handling error from Tegra Control Backbone(CBB).
+	  This driver handles the errors from CBB and prints debug
+	  information about the failed transactions.

drivers/soc/tegra/Makefile

@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 obj-y += fuse/
+obj-y += cbb/
 
 obj-y += common.o
 obj-$(CONFIG_SOC_TEGRA_FLOWCTRL) += flowctrl.o

drivers/soc/tegra/cbb/Makefile

@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Control Backbone Driver code.
+#
+ifdef CONFIG_SOC_TEGRA_CBB
+obj-y += tegra-cbb.o
+obj-$(CONFIG_ARCH_TEGRA_194_SOC) += tegra194-cbb.o
+obj-$(CONFIG_ARCH_TEGRA_234_SOC) += tegra234-cbb.o
+endif

drivers/soc/tegra/cbb/tegra-cbb.c

@@ -0,0 +1,190 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2021-2022, NVIDIA CORPORATION. All rights reserved
+ */
+
+#include <linux/clk.h>
+#include <linux/cpufeature.h>
+#include <linux/debugfs.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/of_irq.h>
+#include <linux/of_address.h>
+#include <linux/interrupt.h>
+#include <linux/ioport.h>
+#include <linux/version.h>
+#include <soc/tegra/fuse.h>
+#include <soc/tegra/tegra-cbb.h>
+
+void tegra_cbb_print_err(struct seq_file *file, const char *fmt, ...)
+{
+	struct va_format vaf;
+	va_list args;
+
+	va_start(args, fmt);
+
+	if (file) {
+		seq_vprintf(file, fmt, args);
+	} else {
+		vaf.fmt = fmt;
+		vaf.va = &args;
+		pr_crit("%pV", &vaf);
+	}
+
+	va_end(args);
+}
+
+void tegra_cbb_print_cache(struct seq_file *file, u32 cache)
+{
+	const char *buff_str, *mod_str, *rd_str, *wr_str;
+
+	buff_str = (cache & BIT(0)) ? "Bufferable " : "";
+	mod_str = (cache & BIT(1)) ? "Modifiable " : "";
+	rd_str = (cache & BIT(2)) ? "Read-Allocate " : "";
+	wr_str = (cache & BIT(3)) ? "Write-Allocate" : "";
+
+	if (cache == 0x0)
+		buff_str = "Device Non-Bufferable";
+
+	tegra_cbb_print_err(file, "\t  Cache\t\t\t: 0x%x -- %s%s%s%s\n",
+			    cache, buff_str, mod_str, rd_str, wr_str);
+}
+
+void tegra_cbb_print_prot(struct seq_file *file, u32 prot)
+{
+	const char *data_str, *secure_str, *priv_str;
+
+	data_str = (prot & 0x4) ? "Instruction" : "Data";
+	secure_str = (prot & 0x2) ? "Non-Secure" : "Secure";
+	priv_str = (prot & 0x1) ? "Privileged" : "Unprivileged";
+
+	tegra_cbb_print_err(file, "\t  Protection\t\t: 0x%x -- %s, %s, %s Access\n",
+			    prot, priv_str, secure_str, data_str);
+}
+
+static int tegra_cbb_err_show(struct seq_file *file, void *data)
+{
+	struct tegra_cbb *cbb = file->private;
+
+	return cbb->ops->debugfs_show(cbb, file, data);
+}
+
+static int tegra_cbb_err_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, tegra_cbb_err_show, inode->i_private);
+}
+
+static const struct file_operations tegra_cbb_err_fops = {
+	.open = tegra_cbb_err_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = single_release
+};
+
+static int tegra_cbb_err_debugfs_init(struct tegra_cbb *cbb)
+{
+	static struct dentry *root;
+
+	if (!root) {
+		root = debugfs_create_file("tegra_cbb_err", 0444, NULL, cbb, &tegra_cbb_err_fops);
+		if (IS_ERR_OR_NULL(root)) {
+			pr_err("%s(): could not create debugfs node\n", __func__);
+			return PTR_ERR(root);
+		}
+	}
+
+	return 0;
+}
+
+void tegra_cbb_stall_enable(struct tegra_cbb *cbb)
+{
+	if (cbb->ops->stall_enable)
+		cbb->ops->stall_enable(cbb);
+}
+
+void tegra_cbb_fault_enable(struct tegra_cbb *cbb)
+{
+	if (cbb->ops->fault_enable)
+		cbb->ops->fault_enable(cbb);
+}
+
+void tegra_cbb_error_clear(struct tegra_cbb *cbb)
+{
+	if (cbb->ops->error_clear)
+		cbb->ops->error_clear(cbb);
+}
+
+u32 tegra_cbb_get_status(struct tegra_cbb *cbb)
+{
+	if (cbb->ops->get_status)
+		return cbb->ops->get_status(cbb);
+
+	return 0;
+}
+
+int tegra_cbb_get_irq(struct platform_device *pdev, unsigned int *nonsec_irq,
+		      unsigned int *sec_irq)
+{
+	unsigned int index = 0;
+	int num_intr = 0, irq;
+
+	num_intr = platform_irq_count(pdev);
+	if (!num_intr)
+		return -EINVAL;
+
+	if (num_intr == 2) {
+		irq = platform_get_irq(pdev, index);
+		if (irq <= 0) {
+			dev_err(&pdev->dev, "failed to get non-secure IRQ: %d\n", irq);
+			return -ENOENT;
+		}
+
+		*nonsec_irq = irq;
+		index++;
+	}
+
+	irq = platform_get_irq(pdev, index);
+	if (irq <= 0) {
+		dev_err(&pdev->dev, "failed to get secure IRQ: %d\n", irq);
+		return -ENOENT;
+	}
+
+	*sec_irq = irq;
+
+	if (num_intr == 1)
+		dev_dbg(&pdev->dev, "secure IRQ: %u\n", *sec_irq);
+
+	if (num_intr == 2)
+		dev_dbg(&pdev->dev, "secure IRQ: %u, non-secure IRQ: %u\n", *sec_irq, *nonsec_irq);
+
+	return 0;
+}
+
+int tegra_cbb_register(struct tegra_cbb *cbb)
+{
+	int ret;
+
+	if (IS_ENABLED(CONFIG_DEBUG_FS)) {
+		ret = tegra_cbb_err_debugfs_init(cbb);
+		if (ret) {
+			dev_err(cbb->dev, "failed to create debugfs\n");
+			return ret;
+		}
+	}
+
+	/* register interrupt handler for errors due to different initiators */
+	ret = cbb->ops->interrupt_enable(cbb);
+	if (ret < 0) {
+		dev_err(cbb->dev, "Failed to register CBB Interrupt ISR");
+		return ret;
+	}
+
+	cbb->ops->error_enable(cbb);
+	dsb(sy);
+
+	return 0;
+}

drivers/soc/tegra/fuse/tegra-apbmisc.c

@@ -16,12 +16,16 @@
 
 #define FUSE_SKU_INFO	0x10
 
+#define ERD_ERR_CONFIG 0x120c
+#define ERD_MASK_INBAND_ERR 0x1
+
 #define PMC_STRAPPING_OPT_A_RAM_CODE_SHIFT	4
 #define PMC_STRAPPING_OPT_A_RAM_CODE_MASK_LONG	\
 	(0xf << PMC_STRAPPING_OPT_A_RAM_CODE_SHIFT)
 #define PMC_STRAPPING_OPT_A_RAM_CODE_MASK_SHORT	\
 	(0x3 << PMC_STRAPPING_OPT_A_RAM_CODE_SHIFT)
 
+static void __iomem *apbmisc_base;
 static bool long_ram_code;
 static u32 strapping;
 static u32 chipid;
@@ -93,6 +97,28 @@ u32 tegra_read_ram_code(void)
 }
 EXPORT_SYMBOL_GPL(tegra_read_ram_code);
 
+/*
+ * The function sets ERD(Error Response Disable) bit.
+ * This allows to mask inband errors and always send an
+ * OKAY response from CBB to the master which caused error.
+ */
+int tegra194_miscreg_mask_serror(void)
+{
+	if (!apbmisc_base)
+		return -EPROBE_DEFER;
+
+	if (!of_machine_is_compatible("nvidia,tegra194")) {
+		WARN(1, "Only supported for Tegra194 devices!\n");
+		return -EOPNOTSUPP;
+	}
+
+	writel_relaxed(ERD_MASK_INBAND_ERR,
+		       apbmisc_base + ERD_ERR_CONFIG);
+
+	return 0;
+}
+EXPORT_SYMBOL(tegra194_miscreg_mask_serror);
+
 static const struct of_device_id apbmisc_match[] __initconst = {
 	{ .compatible = "nvidia,tegra20-apbmisc", },
 	{ .compatible = "nvidia,tegra186-misc", },
@@ -134,7 +160,7 @@ void __init tegra_init_revision(void)
 
 void __init tegra_init_apbmisc(void)
 {
-	void __iomem *apbmisc_base, *strapping_base;
+	void __iomem *strapping_base;
 	struct resource apbmisc, straps;
 	struct device_node *np;
 
@@ -196,7 +222,6 @@ void __init tegra_init_apbmisc(void)
 		pr_err("failed to map APBMISC registers\n");
 	} else {
 		chipid = readl_relaxed(apbmisc_base + 4);
-		iounmap(apbmisc_base);
 	}
 
 	strapping_base = ioremap(straps.start, resource_size(&straps));

include/soc/tegra/fuse.h

@@ -58,6 +58,7 @@ u32 tegra_read_chipid(void);
 u8 tegra_get_chip_id(void);
 u8 tegra_get_platform(void);
 bool tegra_is_silicon(void);
+int tegra194_miscreg_mask_serror(void);
 #else
 static struct tegra_sku_info tegra_sku_info __maybe_unused;
 
@@ -95,6 +96,11 @@ static inline bool tegra_is_silicon(void)
 {
 	return false;
 }
+
+static inline int tegra194_miscreg_mask_serror(void)
+{
+	return false;
+}
 #endif
 
 struct device *tegra_soc_device_register(void);

include/soc/tegra/tegra-cbb.h

@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2021-2022, NVIDIA CORPORATION. All rights reserved
+ */
+
+#ifndef TEGRA_CBB_H
+#define TEGRA_CBB_H
+
+#include <linux/list.h>
+
+struct tegra_cbb_error {
+	const char *code;
+	const char *source;
+	const char *desc;
+};
+
+struct tegra_cbb {
+	struct device *dev;
+	const struct tegra_cbb_ops *ops;
+	struct list_head node;
+};
+
+struct tegra_cbb_ops {
+	int (*debugfs_show)(struct tegra_cbb *cbb, struct seq_file *s, void *v);
+	int (*interrupt_enable)(struct tegra_cbb *cbb);
+	void (*error_enable)(struct tegra_cbb *cbb);
+	void (*fault_enable)(struct tegra_cbb *cbb);
+	void (*stall_enable)(struct tegra_cbb *cbb);
+	void (*error_clear)(struct tegra_cbb *cbb);
+	u32 (*get_status)(struct tegra_cbb *cbb);
+};
+
+int tegra_cbb_get_irq(struct platform_device *pdev, unsigned int *nonsec_irq,
+		      unsigned int *sec_irq);
+__printf(2, 3)
+void tegra_cbb_print_err(struct seq_file *file, const char *fmt, ...);
+
+void tegra_cbb_print_cache(struct seq_file *file, u32 cache);
+void tegra_cbb_print_prot(struct seq_file *file, u32 prot);
+int tegra_cbb_register(struct tegra_cbb *cbb);
+
+void tegra_cbb_fault_enable(struct tegra_cbb *cbb);
+void tegra_cbb_stall_enable(struct tegra_cbb *cbb);
+void tegra_cbb_error_clear(struct tegra_cbb *cbb);
+u32 tegra_cbb_get_status(struct tegra_cbb *cbb);
+
+#endif /* TEGRA_CBB_H */