Merge tag 'for-linus' of git://github.com/openrisc/linux

Pull OpenRISC updates from Stafford Horne:

 - Update for Litex SoC controller to support wider width registers as
   well as reset.

 - Refactor SMP code to use device tree to define possible cpus.

 - Update build including generating vmlinux.bin

* tag 'for-linus' of git://github.com/openrisc/linux:
  openrisc: Use devicetree to determine present cpus
  drivers/soc/litex: Add restart handler
  openrisc: add arch/openrisc/Kbuild
  drivers/soc/litex: make 'litex_[set|get]_reg()' methods private
  drivers/soc/litex: support 32-bit subregisters, 64-bit CPUs
  drivers/soc/litex: s/LITEX_REG_SIZE/LITEX_SUBREG_ALIGN/g
  drivers/soc/litex: separate MMIO from subregister offset calculation
  drivers/soc/litex: move generic accessors to litex.h
  openrisc: restart: Call common handlers before hanging
  openrisc: Add vmlinux.bin target

arch/openrisc/Kbuild

@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-y += lib/ kernel/ mm/
+obj-y += boot/dts/

arch/openrisc/Makefile

@@ -24,6 +24,10 @@ LIBGCC 		:= $(shell $(CC) $(KBUILD_CFLAGS) -print-libgcc-file-name)
 
 KBUILD_CFLAGS	+= -pipe -ffixed-r10 -D__linux__
 
+all: vmlinux.bin
+
+boot := arch/$(ARCH)/boot
+
 ifeq ($(CONFIG_OPENRISC_HAVE_INST_MUL),y)
 	KBUILD_CFLAGS += $(call cc-option,-mhard-mul)
 else
@@ -38,14 +42,13 @@ endif
 
 head-y 		:= arch/openrisc/kernel/head.o
 
-core-y		+= arch/openrisc/lib/ \
+core-y		+= arch/openrisc/
-		   arch/openrisc/kernel/ \
-		   arch/openrisc/mm/
 libs-y		+= $(LIBGCC)
 
-ifneq '$(CONFIG_OPENRISC_BUILTIN_DTB)' '""'
+PHONY += vmlinux.bin
-BUILTIN_DTB := y
+
-else
+vmlinux.bin: vmlinux
-BUILTIN_DTB := n
+	$(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
-endif
+
-core-$(BUILTIN_DTB) += arch/openrisc/boot/dts/
+archclean:
+	$(Q)$(MAKE) $(clean)=$(boot)

arch/openrisc/boot/.gitignore

@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0
+vmlinux.bin

arch/openrisc/boot/Makefile

@@ -0,0 +1,10 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for bootable kernel images
+#
+
+targets += vmlinux.bin
+
+OBJCOPYFLAGS_vmlinux.bin := -O binary
+$(obj)/vmlinux.bin: vmlinux FORCE
+	$(call if_changed,objcopy)

arch/openrisc/kernel/process.c

@@ -34,6 +34,7 @@
 #include <linux/init_task.h>
 #include <linux/mqueue.h>
 #include <linux/fs.h>
+#include <linux/reboot.h>
 
 #include <linux/uaccess.h>
 #include <asm/io.h>
@@ -49,10 +50,16 @@
  */
 struct thread_info *current_thread_info_set[NR_CPUS] = { &init_thread_info, };
 
-void machine_restart(void)
+void machine_restart(char *cmd)
 {
-	printk(KERN_INFO "*** MACHINE RESTART ***\n");
+	do_kernel_restart(cmd);
-	__asm__("l.nop 1");
+
+	/* Give a grace period for failure to restart of 1s */
+	mdelay(1000);
+
+	/* Whoops - the platform was unable to reboot. Tell the user! */
+	pr_emerg("Reboot failed -- System halted\n");
+	while (1);
 }
 
 /*

arch/openrisc/kernel/smp.c

@@ -16,6 +16,7 @@
 #include <linux/sched.h>
 #include <linux/sched/mm.h>
 #include <linux/irq.h>
+#include <linux/of.h>
 #include <asm/cpuinfo.h>
 #include <asm/mmu_context.h>
 #include <asm/tlbflush.h>
@@ -60,22 +61,32 @@ void __init smp_prepare_boot_cpu(void)
 
 void __init smp_init_cpus(void)
 {
-	int i;
+	struct device_node *cpu;
+	u32 cpu_id;
 
-	for (i = 0; i < NR_CPUS; i++)
+	for_each_of_cpu_node(cpu) {
-		set_cpu_possible(i, true);
+		if (of_property_read_u32(cpu, "reg", &cpu_id)) {
+			pr_warn("%s missing reg property", cpu->full_name);
+			continue;
+		}
+
+		if (cpu_id < NR_CPUS)
+			set_cpu_possible(cpu_id, true);
+	}
 }
 
 void __init smp_prepare_cpus(unsigned int max_cpus)
 {
-	int i;
+	unsigned int cpu;
 
 	/*
 	 * Initialise the present map, which describes the set of CPUs
 	 * actually populated at the present time.
 	 */
-	for (i = 0; i < max_cpus; i++)
+	for_each_possible_cpu(cpu) {
-		set_cpu_present(i, true);
+		if (cpu < max_cpus)
+			set_cpu_present(cpu, true);
+	}
 }
 
 void __init smp_cpus_done(unsigned int max_cpus)

drivers/soc/litex/Kconfig

@@ -12,9 +12,21 @@ config LITEX_SOC_CONTROLLER
 	select LITEX
 	help
 	  This option enables the SoC Controller Driver which verifies
-	  LiteX CSR access and provides common litex_get_reg/litex_set_reg
+	  LiteX CSR access and provides common litex_[read|write]*
 	  accessors.
 	  All drivers that use functions from litex.h must depend on
 	  LITEX.
 
+config LITEX_SUBREG_SIZE
+	int "Size of a LiteX CSR subregister, in bytes"
+	depends on LITEX
+	range 1 4
+	default 4
+	help
+	LiteX MMIO registers (referred to as Configuration and Status
+	registers, or CSRs) are spread across adjacent 8- or 32-bit
+	subregisters, located at 32-bit aligned MMIO addresses. Use
+	this to select the appropriate size (1 or 4 bytes) matching
+	your particular LiteX build.
+
 endmenu

drivers/soc/litex/litex_soc_ctrl.c

@@ -15,79 +15,11 @@
 #include <linux/module.h>
 #include <linux/errno.h>
 #include <linux/io.h>
+#include <linux/reboot.h>
 
-/*
+/* reset register located at the base address */
- * LiteX SoC Generator, depending on the configuration, can split a single
+#define RESET_REG_OFF           0x00
- * logical CSR (Control&Status Register) into a series of consecutive physical
+#define RESET_REG_VALUE         0x00000001
- * registers.
- *
- * For example, in the configuration with 8-bit CSR Bus, 32-bit aligned (the
- * default one for 32-bit CPUs) a 32-bit logical CSR will be generated as four
- * 32-bit physical registers, each one containing one byte of meaningful data.
- *
- * For details see: https://github.com/enjoy-digital/litex/wiki/CSR-Bus
- *
- * The purpose of `litex_set_reg`/`litex_get_reg` is to implement the logic
- * of writing to/reading from the LiteX CSR in a single place that can be
- * then reused by all LiteX drivers.
- */
-
-/**
- * litex_set_reg() - Writes the value to the LiteX CSR (Control&Status Register)
- * @reg: Address of the CSR
- * @reg_size: The width of the CSR expressed in the number of bytes
- * @val: Value to be written to the CSR
- *
- * In the currently supported LiteX configuration (8-bit CSR Bus, 32-bit aligned),
- * a 32-bit LiteX CSR is generated as 4 consecutive 32-bit physical registers,
- * each one containing one byte of meaningful data.
- *
- * This function splits a single possibly multi-byte write into a series of
- * single-byte writes with a proper offset.
- */
-void litex_set_reg(void __iomem *reg, unsigned long reg_size,
-		    unsigned long val)
-{
-	unsigned long shifted_data, shift, i;
-
-	for (i = 0; i < reg_size; ++i) {
-		shift = ((reg_size - i - 1) * LITEX_SUBREG_SIZE_BIT);
-		shifted_data = val >> shift;
-
-		WRITE_LITEX_SUBREGISTER(shifted_data, reg, i);
-	}
-}
-EXPORT_SYMBOL_GPL(litex_set_reg);
-
-/**
- * litex_get_reg() - Reads the value of the LiteX CSR (Control&Status Register)
- * @reg: Address of the CSR
- * @reg_size: The width of the CSR expressed in the number of bytes
- *
- * Return: Value read from the CSR
- *
- * In the currently supported LiteX configuration (8-bit CSR Bus, 32-bit aligned),
- * a 32-bit LiteX CSR is generated as 4 consecutive 32-bit physical registers,
- * each one containing one byte of meaningful data.
- *
- * This function generates a series of single-byte reads with a proper offset
- * and joins their results into a single multi-byte value.
- */
-unsigned long litex_get_reg(void __iomem *reg, unsigned long reg_size)
-{
-	unsigned long shifted_data, shift, i;
-	unsigned long result = 0;
-
-	for (i = 0; i < reg_size; ++i) {
-		shifted_data = READ_LITEX_SUBREGISTER(reg, i);
-
-		shift = ((reg_size - i - 1) * LITEX_SUBREG_SIZE_BIT);
-		result |= (shifted_data << shift);
-	}
-
-	return result;
-}
-EXPORT_SYMBOL_GPL(litex_get_reg);
 
 #define SCRATCH_REG_OFF         0x04
 #define SCRATCH_REG_VALUE       0x12345678
@@ -131,15 +63,27 @@ static int litex_check_csr_access(void __iomem *reg_addr)
 	/* restore original value of the SCRATCH register */
 	litex_write32(reg_addr + SCRATCH_REG_OFF, SCRATCH_REG_VALUE);
 
-	pr_info("LiteX SoC Controller driver initialized");
+	pr_info("LiteX SoC Controller driver initialized: subreg:%d, align:%d",
+		LITEX_SUBREG_SIZE, LITEX_SUBREG_ALIGN);
 
 	return 0;
 }
 
 struct litex_soc_ctrl_device {
 	void __iomem *base;
+	struct notifier_block reset_nb;
 };
 
+static int litex_reset_handler(struct notifier_block *this, unsigned long mode,
+			       void *cmd)
+{
+	struct litex_soc_ctrl_device *soc_ctrl_dev =
+		container_of(this, struct litex_soc_ctrl_device, reset_nb);
+
+	litex_write32(soc_ctrl_dev->base + RESET_REG_OFF, RESET_REG_VALUE);
+	return NOTIFY_DONE;
+}
+
 #ifdef CONFIG_OF
 static const struct of_device_id litex_soc_ctrl_of_match[] = {
 	{.compatible = "litex,soc-controller"},
@@ -151,6 +95,7 @@ MODULE_DEVICE_TABLE(of, litex_soc_ctrl_of_match);
 static int litex_soc_ctrl_probe(struct platform_device *pdev)
 {
 	struct litex_soc_ctrl_device *soc_ctrl_dev;
+	int error;
 
 	soc_ctrl_dev = devm_kzalloc(&pdev->dev, sizeof(*soc_ctrl_dev), GFP_KERNEL);
 	if (!soc_ctrl_dev)
@@ -160,7 +105,29 @@ static int litex_soc_ctrl_probe(struct platform_device *pdev)
 	if (IS_ERR(soc_ctrl_dev->base))
 		return PTR_ERR(soc_ctrl_dev->base);
 
-	return litex_check_csr_access(soc_ctrl_dev->base);
+	error = litex_check_csr_access(soc_ctrl_dev->base);
+	if (error)
+		return error;
+
+	platform_set_drvdata(pdev, soc_ctrl_dev);
+
+	soc_ctrl_dev->reset_nb.notifier_call = litex_reset_handler;
+	soc_ctrl_dev->reset_nb.priority = 128;
+	error = register_restart_handler(&soc_ctrl_dev->reset_nb);
+	if (error) {
+		dev_warn(&pdev->dev, "cannot register restart handler: %d\n",
+			 error);
+	}
+
+	return 0;
+}
+
+static int litex_soc_ctrl_remove(struct platform_device *pdev)
+{
+	struct litex_soc_ctrl_device *soc_ctrl_dev = platform_get_drvdata(pdev);
+
+	unregister_restart_handler(&soc_ctrl_dev->reset_nb);
+	return 0;
 }
 
 static struct platform_driver litex_soc_ctrl_driver = {
@@ -169,6 +136,7 @@ static struct platform_driver litex_soc_ctrl_driver = {
 		.of_match_table = of_match_ptr(litex_soc_ctrl_of_match)
 	},
 	.probe = litex_soc_ctrl_probe,
+	.remove = litex_soc_ctrl_remove,
 };
 
 module_platform_driver(litex_soc_ctrl_driver);

include/linux/litex.h

@@ -3,9 +3,6 @@
  * Common LiteX header providing
  * helper functions for accessing CSRs.
  *
- * Implementation of the functions is provided by
- * the LiteX SoC Controller driver.
- *
  * Copyright (C) 2019-2020 Antmicro <www.antmicro.com>
  */
 
@@ -13,90 +10,147 @@
 #define _LINUX_LITEX_H
 
 #include <linux/io.h>
-#include <linux/types.h>
-#include <linux/compiler_types.h>
 
-/*
+/* LiteX SoCs support 8- or 32-bit CSR Bus data width (i.e., subreg. size) */
- * The parameters below are true for LiteX SoCs configured for 8-bit CSR Bus,
+#if defined(CONFIG_LITEX_SUBREG_SIZE) && \
- * 32-bit aligned.
+	(CONFIG_LITEX_SUBREG_SIZE == 1 || CONFIG_LITEX_SUBREG_SIZE == 4)
- *
+#define LITEX_SUBREG_SIZE      CONFIG_LITEX_SUBREG_SIZE
- * Supporting other configurations will require extending the logic in this
+#else
- * header and in the LiteX SoC controller driver.
+#error LiteX subregister size (LITEX_SUBREG_SIZE) must be 4 or 1!
- */
+#endif
-#define LITEX_REG_SIZE	  0x4
-#define LITEX_SUBREG_SIZE	0x1
 #define LITEX_SUBREG_SIZE_BIT	 (LITEX_SUBREG_SIZE * 8)
 
-#define WRITE_LITEX_SUBREGISTER(val, base_offset, subreg_id) \
+/* LiteX subregisters of any width are always aligned on a 4-byte boundary */
-	writel((u32 __force)cpu_to_le32(val), base_offset + (LITEX_REG_SIZE * subreg_id))
+#define LITEX_SUBREG_ALIGN	  0x4
 
-#define READ_LITEX_SUBREGISTER(base_offset, subreg_id) \
+static inline void _write_litex_subregister(u32 val, void __iomem *addr)
-	le32_to_cpu((__le32 __force)readl(base_offset + (LITEX_REG_SIZE * subreg_id)))
+{
+	writel((u32 __force)cpu_to_le32(val), addr);
+}
 
-void litex_set_reg(void __iomem *reg, unsigned long reg_sz, unsigned long val);
+static inline u32 _read_litex_subregister(void __iomem *addr)
+{
+	return le32_to_cpu((__le32 __force)readl(addr));
+}
 
-unsigned long litex_get_reg(void __iomem *reg, unsigned long reg_sz);
+/*
+ * LiteX SoC Generator, depending on the configuration, can split a single
+ * logical CSR (Control&Status Register) into a series of consecutive physical
+ * registers.
+ *
+ * For example, in the configuration with 8-bit CSR Bus, a 32-bit aligned,
+ * 32-bit wide logical CSR will be laid out as four 32-bit physical
+ * subregisters, each one containing one byte of meaningful data.
+ *
+ * For details see: https://github.com/enjoy-digital/litex/wiki/CSR-Bus
+ */
+
+/* number of LiteX subregisters needed to store a register of given reg_size */
+#define _litex_num_subregs(reg_size) \
+	(((reg_size) - 1) / LITEX_SUBREG_SIZE + 1)
+
+/*
+ * since the number of 4-byte aligned subregisters required to store a single
+ * LiteX CSR (MMIO) register varies with LITEX_SUBREG_SIZE, the offset of the
+ * next adjacent LiteX CSR register w.r.t. the offset of the current one also
+ * depends on how many subregisters the latter is spread across
+ */
+#define _next_reg_off(off, size) \
+	((off) + _litex_num_subregs(size) * LITEX_SUBREG_ALIGN)
+
+/*
+ * The purpose of `_litex_[set|get]_reg()` is to implement the logic of
+ * writing to/reading from the LiteX CSR in a single place that can be then
+ * reused by all LiteX drivers via the `litex_[write|read][8|16|32|64]()`
+ * accessors for the appropriate data width.
+ * NOTE: direct use of `_litex_[set|get]_reg()` by LiteX drivers is strongly
+ * discouraged, as they perform no error checking on the requested data width!
+ */
+
+/**
+ * _litex_set_reg() - Writes a value to the LiteX CSR (Control&Status Register)
+ * @reg: Address of the CSR
+ * @reg_size: The width of the CSR expressed in the number of bytes
+ * @val: Value to be written to the CSR
+ *
+ * This function splits a single (possibly multi-byte) LiteX CSR write into
+ * a series of subregister writes with a proper offset.
+ * NOTE: caller is responsible for ensuring (0 < reg_size <= sizeof(u64)).
+ */
+static inline void _litex_set_reg(void __iomem *reg, size_t reg_size, u64 val)
+{
+	u8 shift = _litex_num_subregs(reg_size) * LITEX_SUBREG_SIZE_BIT;
+
+	while (shift > 0) {
+		shift -= LITEX_SUBREG_SIZE_BIT;
+		_write_litex_subregister(val >> shift, reg);
+		reg += LITEX_SUBREG_ALIGN;
+	}
+}
+
+/**
+ * _litex_get_reg() - Reads a value of the LiteX CSR (Control&Status Register)
+ * @reg: Address of the CSR
+ * @reg_size: The width of the CSR expressed in the number of bytes
+ *
+ * Return: Value read from the CSR
+ *
+ * This function generates a series of subregister reads with a proper offset
+ * and joins their results into a single (possibly multi-byte) LiteX CSR value.
+ * NOTE: caller is responsible for ensuring (0 < reg_size <= sizeof(u64)).
+ */
+static inline u64 _litex_get_reg(void __iomem *reg, size_t reg_size)
+{
+	u64 r;
+	u8 i;
+
+	r = _read_litex_subregister(reg);
+	for (i = 1; i < _litex_num_subregs(reg_size); i++) {
+		r <<= LITEX_SUBREG_SIZE_BIT;
+		reg += LITEX_SUBREG_ALIGN;
+		r |= _read_litex_subregister(reg);
+	}
+	return r;
+}
 
 static inline void litex_write8(void __iomem *reg, u8 val)
 {
-	WRITE_LITEX_SUBREGISTER(val, reg, 0);
+	_litex_set_reg(reg, sizeof(u8), val);
 }
 
 static inline void litex_write16(void __iomem *reg, u16 val)
 {
-	WRITE_LITEX_SUBREGISTER(val >> 8, reg, 0);
+	_litex_set_reg(reg, sizeof(u16), val);
-	WRITE_LITEX_SUBREGISTER(val, reg, 1);
 }
 
 static inline void litex_write32(void __iomem *reg, u32 val)
 {
-	WRITE_LITEX_SUBREGISTER(val >> 24, reg, 0);
+	_litex_set_reg(reg, sizeof(u32), val);
-	WRITE_LITEX_SUBREGISTER(val >> 16, reg, 1);
-	WRITE_LITEX_SUBREGISTER(val >> 8, reg, 2);
-	WRITE_LITEX_SUBREGISTER(val, reg, 3);
 }
 
 static inline void litex_write64(void __iomem *reg, u64 val)
 {
-	WRITE_LITEX_SUBREGISTER(val >> 56, reg, 0);
+	_litex_set_reg(reg, sizeof(u64), val);
-	WRITE_LITEX_SUBREGISTER(val >> 48, reg, 1);
-	WRITE_LITEX_SUBREGISTER(val >> 40, reg, 2);
-	WRITE_LITEX_SUBREGISTER(val >> 32, reg, 3);
-	WRITE_LITEX_SUBREGISTER(val >> 24, reg, 4);
-	WRITE_LITEX_SUBREGISTER(val >> 16, reg, 5);
-	WRITE_LITEX_SUBREGISTER(val >> 8, reg, 6);
-	WRITE_LITEX_SUBREGISTER(val, reg, 7);
 }
 
 static inline u8 litex_read8(void __iomem *reg)
 {
-	return READ_LITEX_SUBREGISTER(reg, 0);
+	return _litex_get_reg(reg, sizeof(u8));
 }
 
 static inline u16 litex_read16(void __iomem *reg)
 {
-	return (READ_LITEX_SUBREGISTER(reg, 0) << 8)
+	return _litex_get_reg(reg, sizeof(u16));
-		| (READ_LITEX_SUBREGISTER(reg, 1));
 }
 
 static inline u32 litex_read32(void __iomem *reg)
 {
-	return (READ_LITEX_SUBREGISTER(reg, 0) << 24)
+	return _litex_get_reg(reg, sizeof(u32));
-		| (READ_LITEX_SUBREGISTER(reg, 1) << 16)
-		| (READ_LITEX_SUBREGISTER(reg, 2) << 8)
-		| (READ_LITEX_SUBREGISTER(reg, 3));
 }
 
 static inline u64 litex_read64(void __iomem *reg)
 {
-	return ((u64)READ_LITEX_SUBREGISTER(reg, 0) << 56)
+	return _litex_get_reg(reg, sizeof(u64));
-		| ((u64)READ_LITEX_SUBREGISTER(reg, 1) << 48)
-		| ((u64)READ_LITEX_SUBREGISTER(reg, 2) << 40)
-		| ((u64)READ_LITEX_SUBREGISTER(reg, 3) << 32)
-		| ((u64)READ_LITEX_SUBREGISTER(reg, 4) << 24)
-		| ((u64)READ_LITEX_SUBREGISTER(reg, 5) << 16)
-		| ((u64)READ_LITEX_SUBREGISTER(reg, 6) << 8)
-		| ((u64)READ_LITEX_SUBREGISTER(reg, 7));
 }
 
 #endif /* _LINUX_LITEX_H */