Merge tag 'arc-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc

Pull ARC updates from Vineet Gupta:

- Support for DSP enabled userspace (save/restore regs)

- Misc other platform fixes

* tag 'arc-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
ARC: allow userspace DSP applications to use AGU extensions
ARC: add support for DSP-enabled userspace applications
ARC: handle DSP presence in HW
ARC: add helpers to sanitize config options
ARC: [plat-axs10x]: PGU: remove unused encoder-slave property

arch/arc/Kconfig

···
 	default y
 
 config ARC_HAS_ACCL_REGS
-	bool "Reg Pair ACCL:ACCH (FPU and/or MPY > 6)"
+	bool "Reg Pair ACCL:ACCH (FPU and/or MPY > 6 and/or DSP)"
 	default y
 	help
 	  Depending on the configuration, CPU can contain accumulator reg-pair
 	  (also referred to as r58:r59). These can also be used by gcc as GPR so
 	  kernel needs to save/restore per process
+
+config ARC_DSP_HANDLED
+	def_bool n
+
+config ARC_DSP_SAVE_RESTORE_REGS
+	def_bool n
+
+choice
+	prompt "DSP support"
+	default ARC_DSP_NONE
+	help
+	  Depending on the configuration, CPU can contain DSP registers
+	  (ACC0_GLO, ACC0_GHI, DSP_BFLY0, DSP_CTRL, DSP_FFT_CTRL).
+	  Bellow is options describing how to handle these registers in
+	  interrupt entry / exit and in context switch.
+
+config ARC_DSP_NONE
+	bool "No DSP extension presence in HW"
+	help
+	  No DSP extension presence in HW
+
+config ARC_DSP_KERNEL
+	bool "DSP extension in HW, no support for userspace"
+	select ARC_HAS_ACCL_REGS
+	select ARC_DSP_HANDLED
+	help
+	  DSP extension presence in HW, no support for DSP-enabled userspace
+	  applications. We don't save / restore DSP registers and only do
+	  some minimal preparations so userspace won't be able to break kernel
+
+config ARC_DSP_USERSPACE
+	bool "Support DSP for userspace apps"
+	select ARC_HAS_ACCL_REGS
+	select ARC_DSP_HANDLED
+	select ARC_DSP_SAVE_RESTORE_REGS
+	help
+	  DSP extension presence in HW, support save / restore DSP registers to
+	  run DSP-enabled userspace applications
+
+config ARC_DSP_AGU_USERSPACE
+	bool "Support DSP with AGU for userspace apps"
+	select ARC_HAS_ACCL_REGS
+	select ARC_DSP_HANDLED
+	select ARC_DSP_SAVE_RESTORE_REGS
+	help
+	  DSP and AGU extensions presence in HW, support save / restore DSP
+	  and AGU registers to run DSP-enabled userspace applications
+endchoice
 
 config ARC_IRQ_NO_AUTOSAVE
 	bool "Disable hardware autosave regfile on interrupts"

arch/arc/boot/dts/axs10x_mb.dtsi

···
 		pgu@17000 {
 			compatible = "snps,arcpgu";
 			reg = <0x17000 0x400>;
-			encoder-slave = <&adv7511>;
 			clocks = <&pguclk>;
 			clock-names = "pxlclk";
 			memory-region = <&frame_buffer>;

arch/arc/include/asm/arcregs.h

···
 #define ARC_AUX_DPFP_2H         0x304
 #define ARC_AUX_DPFP_STAT       0x305
 
+/*
+ * DSP-related registers
+ * Registers names must correspond to dsp_callee_regs structure fields names
+ * for automatic offset calculation in DSP_AUX_SAVE_RESTORE macros.
+ */
+#define ARC_AUX_DSP_BUILD	0x7A
+#define ARC_AUX_ACC0_LO		0x580
+#define ARC_AUX_ACC0_GLO	0x581
+#define ARC_AUX_ACC0_HI		0x582
+#define ARC_AUX_ACC0_GHI	0x583
+#define ARC_AUX_DSP_BFLY0	0x598
+#define ARC_AUX_DSP_CTRL	0x59F
+#define ARC_AUX_DSP_FFT_CTRL	0x59E
+
+#define ARC_AUX_AGU_BUILD	0xCC
+#define ARC_AUX_AGU_AP0		0x5C0
+#define ARC_AUX_AGU_AP1		0x5C1
+#define ARC_AUX_AGU_AP2		0x5C2
+#define ARC_AUX_AGU_AP3		0x5C3
+#define ARC_AUX_AGU_OS0		0x5D0
+#define ARC_AUX_AGU_OS1		0x5D1
+#define ARC_AUX_AGU_MOD0	0x5E0
+#define ARC_AUX_AGU_MOD1	0x5E1
+#define ARC_AUX_AGU_MOD2	0x5E2
+#define ARC_AUX_AGU_MOD3	0x5E3
+
 #ifndef __ASSEMBLY__
 
 #include <soc/arc/aux.h>

arch/arc/include/asm/asserts.h

···
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2020 Synopsys, Inc. (www.synopsys.com)
+ *
+ * Author: Eugeniy Paltsev <[e-mail]>
+ */
+#ifndef __ASM_ARC_ASSERTS_H
+#define __ASM_ARC_ASSERTS_H
+
+/* Helpers to sanitize config options. */
+
+void chk_opt_strict(char *opt_name, bool hw_exists, bool opt_ena);
+void chk_opt_weak(char *opt_name, bool hw_exists, bool opt_ena);
+
+/*
+ * Check required config option:
+ *  - panic in case of OPT enabled but corresponding HW absent.
+ *  - warn in case of OPT disabled but corresponding HW exists.
+*/
+#define CHK_OPT_STRICT(opt_name, hw_exists)				\
+({									\
+	chk_opt_strict(#opt_name, hw_exists, IS_ENABLED(opt_name));	\
+})
+
+/*
+ * Check optional config option:
+ *  - panic in case of OPT enabled but corresponding HW absent.
+*/
+#define CHK_OPT_WEAK(opt_name, hw_exists)				\
+({									\
+	chk_opt_weak(#opt_name, hw_exists, IS_ENABLED(opt_name));	\
+})
+
+#endif /* __ASM_ARC_ASSERTS_H */

arch/arc/include/asm/dsp-impl.h

···
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2020 Synopsys, Inc. (www.synopsys.com)
+ *
+ * Author: Eugeniy Paltsev <[e-mail]>
+ */
+#ifndef __ASM_ARC_DSP_IMPL_H
+#define __ASM_ARC_DSP_IMPL_H
+
+#include <asm/dsp.h>
+
+#define DSP_CTRL_DISABLED_ALL		0
+
+#ifdef __ASSEMBLY__
+
+/* clobbers r5 register */
+.macro DSP_EARLY_INIT
+	lr	r5, [ARC_AUX_DSP_BUILD]
+	bmsk	r5, r5, 7
+	breq    r5, 0, 1f
+	mov	r5, DSP_CTRL_DISABLED_ALL
+	sr	r5, [ARC_AUX_DSP_CTRL]
+1:
+.endm
+
+/* clobbers r10, r11 registers pair */
+.macro DSP_SAVE_REGFILE_IRQ
+#if defined(CONFIG_ARC_DSP_KERNEL)
+	/*
+	 * Drop any changes to DSP_CTRL made by userspace so userspace won't be
+	 * able to break kernel - reset it to DSP_CTRL_DISABLED_ALL value
+	 */
+	mov	r10, DSP_CTRL_DISABLED_ALL
+	sr	r10, [ARC_AUX_DSP_CTRL]
+
+#elif defined(CONFIG_ARC_DSP_SAVE_RESTORE_REGS)
+	/*
+	 * Save DSP_CTRL register and reset it to value suitable for kernel
+	 * (DSP_CTRL_DISABLED_ALL)
+	 */
+	mov	r10, DSP_CTRL_DISABLED_ALL
+	aex	r10, [ARC_AUX_DSP_CTRL]
+	st	r10, [sp, PT_DSP_CTRL]
+
+#endif
+.endm
+
+/* clobbers r10, r11 registers pair */
+.macro DSP_RESTORE_REGFILE_IRQ
+#if defined(CONFIG_ARC_DSP_SAVE_RESTORE_REGS)
+	ld	r10, [sp, PT_DSP_CTRL]
+	sr	r10, [ARC_AUX_DSP_CTRL]
+
+#endif
+.endm
+
+#else /* __ASEMBLY__ */
+
+#include <linux/sched.h>
+#include <asm/asserts.h>
+#include <asm/switch_to.h>
+
+#ifdef CONFIG_ARC_DSP_SAVE_RESTORE_REGS
+
+/*
+ * As we save new and restore old AUX register value in the same place we
+ * can optimize a bit and use AEX instruction (swap contents of an auxiliary
+ * register with a core register) instead of LR + SR pair.
+ */
+#define AUX_SAVE_RESTORE(_saveto, _readfrom, _offt, _aux)		\
+do {									\
+	long unsigned int _scratch;					\
+									\
+	__asm__ __volatile__(						\
+		"ld	%0, [%2, %4]			\n"		\
+		"aex	%0, [%3]			\n"		\
+		"st	%0, [%1, %4]			\n"		\
+		:							\
+		  "=&r" (_scratch)	/* must be early clobber */	\
+		:							\
+		   "r" (_saveto),					\
+		   "r" (_readfrom),					\
+		   "Ir" (_aux),						\
+		   "Ir" (_offt)						\
+		:							\
+		  "memory"						\
+	);								\
+} while (0)
+
+#define DSP_AUX_SAVE_RESTORE(_saveto, _readfrom, _aux)			\
+	AUX_SAVE_RESTORE(_saveto, _readfrom,				\
+		offsetof(struct dsp_callee_regs, _aux),			\
+		ARC_AUX_##_aux)
+
+static inline void dsp_save_restore(struct task_struct *prev,
+					struct task_struct *next)
+{
+	long unsigned int *saveto = &prev->thread.dsp.ACC0_GLO;
+	long unsigned int *readfrom = &next->thread.dsp.ACC0_GLO;
+
+	DSP_AUX_SAVE_RESTORE(saveto, readfrom, ACC0_GLO);
+	DSP_AUX_SAVE_RESTORE(saveto, readfrom, ACC0_GHI);
+
+	DSP_AUX_SAVE_RESTORE(saveto, readfrom, DSP_BFLY0);
+	DSP_AUX_SAVE_RESTORE(saveto, readfrom, DSP_FFT_CTRL);
+
+#ifdef CONFIG_ARC_DSP_AGU_USERSPACE
+	DSP_AUX_SAVE_RESTORE(saveto, readfrom, AGU_AP0);
+	DSP_AUX_SAVE_RESTORE(saveto, readfrom, AGU_AP1);
+	DSP_AUX_SAVE_RESTORE(saveto, readfrom, AGU_AP2);
+	DSP_AUX_SAVE_RESTORE(saveto, readfrom, AGU_AP3);
+
+	DSP_AUX_SAVE_RESTORE(saveto, readfrom, AGU_OS0);
+	DSP_AUX_SAVE_RESTORE(saveto, readfrom, AGU_OS1);
+
+	DSP_AUX_SAVE_RESTORE(saveto, readfrom, AGU_MOD0);
+	DSP_AUX_SAVE_RESTORE(saveto, readfrom, AGU_MOD1);
+	DSP_AUX_SAVE_RESTORE(saveto, readfrom, AGU_MOD2);
+	DSP_AUX_SAVE_RESTORE(saveto, readfrom, AGU_MOD3);
+#endif /* CONFIG_ARC_DSP_AGU_USERSPACE */
+}
+
+#else /* !CONFIG_ARC_DSP_SAVE_RESTORE_REGS */
+#define dsp_save_restore(p, n)
+#endif /* CONFIG_ARC_DSP_SAVE_RESTORE_REGS */
+
+static inline bool dsp_exist(void)
+{
+	struct bcr_generic bcr;
+
+	READ_BCR(ARC_AUX_DSP_BUILD, bcr);
+	return !!bcr.ver;
+}
+
+static inline bool agu_exist(void)
+{
+	struct bcr_generic bcr;
+
+	READ_BCR(ARC_AUX_AGU_BUILD, bcr);
+	return !!bcr.ver;
+}
+
+static inline void dsp_config_check(void)
+{
+	CHK_OPT_STRICT(CONFIG_ARC_DSP_HANDLED, dsp_exist());
+	CHK_OPT_WEAK(CONFIG_ARC_DSP_AGU_USERSPACE, agu_exist());
+}
+
+#endif /* __ASEMBLY__ */
+#endif /* __ASM_ARC_DSP_IMPL_H */

arch/arc/include/asm/dsp.h

···
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2020 Synopsys, Inc. (www.synopsys.com)
+ *
+ * Author: Eugeniy Paltsev <[e-mail]>
+ */
+#ifndef __ASM_ARC_DSP_H
+#define __ASM_ARC_DSP_H
+
+#ifndef __ASSEMBLY__
+
+/*
+ * DSP-related saved registers - need to be saved only when you are
+ * scheduled out.
+ * structure fields name must correspond to aux register defenitions for
+ * automatic offset calculation in DSP_AUX_SAVE_RESTORE macros
+ */
+struct dsp_callee_regs {
+	unsigned long ACC0_GLO, ACC0_GHI, DSP_BFLY0, DSP_FFT_CTRL;
+#ifdef CONFIG_ARC_DSP_AGU_USERSPACE
+	unsigned long AGU_AP0, AGU_AP1, AGU_AP2, AGU_AP3;
+	unsigned long AGU_OS0, AGU_OS1;
+	unsigned long AGU_MOD0, AGU_MOD1, AGU_MOD2, AGU_MOD3;
+#endif
+};
+
+#endif /* !__ASSEMBLY__ */
+
+#endif /* __ASM_ARC_DSP_H */

arch/arc/include/asm/entry-arcv2.h

···
 #define __ASM_ARC_ENTRY_ARCV2_H
 
 #include <asm/asm-offsets.h>
+#include <asm/dsp-impl.h>
 #include <asm/irqflags-arcv2.h>
 #include <asm/thread_info.h>	/* For THREAD_SIZE */
 
···
 	ST2	r58, r59, PT_r58
 #endif
 
+	/* clobbers r10, r11 registers pair */
+	DSP_SAVE_REGFILE_IRQ
 .endm
 
 /*------------------------------------------------------------------------*/
···
 #ifdef CONFIG_ARC_CURR_IN_REG
 	ld	r25, [sp, PT_user_r25]
 #endif
+
+	/* clobbers r10, r11 registers pair */
+	DSP_RESTORE_REGFILE_IRQ
 
 #ifdef CONFIG_ARC_HAS_ACCL_REGS
 	LD2	r58, r59, PT_r58

arch/arc/include/asm/processor.h

···
 #ifndef __ASSEMBLY__
 
 #include <asm/ptrace.h>
+#include <asm/dsp.h>
 #include <asm/fpu.h>
 
 #ifdef CONFIG_ARC_PLAT_EZNPS
···
 	unsigned long ksp;	/* kernel mode stack pointer */
 	unsigned long callee_reg;	/* pointer to callee regs */
 	unsigned long fault_address;	/* dbls as brkpt holder as well */
+#ifdef CONFIG_ARC_DSP_SAVE_RESTORE_REGS
+	struct dsp_callee_regs dsp;
+#endif
 #ifdef CONFIG_ARC_FPU_SAVE_RESTORE
 	struct arc_fpu fpu;
 #endif

arch/arc/include/asm/ptrace.h

···
 #ifdef CONFIG_ARC_HAS_ACCL_REGS
 	unsigned long r58, r59;	/* ACCL/ACCH used by FPU / DSP MPY */
 #endif
+#ifdef CONFIG_ARC_DSP_SAVE_RESTORE_REGS
+	unsigned long DSP_CTRL;
+#endif
 
 	/*------- Below list auto saved by h/w -----------*/
 	unsigned long r0, r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11;

arch/arc/include/asm/switch_to.h

···
 #ifndef __ASSEMBLY__
 
 #include <linux/sched.h>
+#include <asm/dsp-impl.h>
 #include <asm/fpu.h>
 
 #ifdef CONFIG_ARC_PLAT_EZNPS
···
 #define switch_to(prev, next, last)	\
 do {					\
 	ARC_EZNPS_DP_PREV(prev, next);	\
+	dsp_save_restore(prev, next);	\
 	fpu_save_restore(prev, next);	\
 	last = __switch_to(prev, next);\
 	mb();				\

arch/arc/kernel/asm-offsets.c

···
 #include <asm/hardirq.h>
 #include <asm/page.h>
 
+
 int main(void)
 {
 	DEFINE(TASK_THREAD, offsetof(struct task_struct, thread));
···
 #ifdef CONFIG_ARC_HAS_ACCL_REGS
 	OFFSET(PT_r58, pt_regs, r58);
 	OFFSET(PT_r59, pt_regs, r59);
+#endif
+#ifdef CONFIG_ARC_DSP_SAVE_RESTORE_REGS
+	OFFSET(PT_DSP_CTRL, pt_regs, DSP_CTRL);
 #endif
 
 	return 0;

arch/arc/kernel/head.S

···
 #include <asm/entry.h>
 #include <asm/arcregs.h>
 #include <asm/cache.h>
+#include <asm/dsp-impl.h>
 #include <asm/irqflags.h>
 
 .macro CPU_EARLY_SETUP
···
 #endif
 	kflag	r5
 #endif
+	; Config DSP_CTRL properly, so kernel may use integer multiply,
+	; multiply-accumulate, and divide operations
+	DSP_EARLY_INIT
 .endm
 
 	.section .init.text, "ax",@progbits

arch/arc/kernel/setup.c

···
 #include <uapi/linux/mount.h>
 #include <asm/sections.h>
 #include <asm/arcregs.h>
+#include <asm/asserts.h>
 #include <asm/tlb.h>
 #include <asm/setup.h>
 #include <asm/page.h>
···
 #include <asm/unwind.h>
 #include <asm/mach_desc.h>
 #include <asm/smp.h>
+#include <asm/dsp-impl.h>
 
 #define FIX_PTR(x)  __asm__ __volatile__(";" : "+r"(x))
 
···
 	return buf;
 }
 
+void chk_opt_strict(char *opt_name, bool hw_exists, bool opt_ena)
+{
+	if (hw_exists && !opt_ena)
+		pr_warn(" ! Enable %s for working apps\n", opt_name);
+	else if (!hw_exists && opt_ena)
+		panic("Disable %s, hardware NOT present\n", opt_name);
+}
+
+void chk_opt_weak(char *opt_name, bool hw_exists, bool opt_ena)
+{
+	if (!hw_exists && opt_ena)
+		panic("Disable %s, hardware NOT present\n", opt_name);
+}
+
 static void arc_chk_core_config(void)
 {
 	struct cpuinfo_arc *cpu = &cpuinfo_arc700[smp_processor_id()];
-	int saved = 0, present = 0;
-	char *opt_nm = NULL;
+	int present = 0;
 
 	if (!cpu->extn.timer0)
 		panic("Timer0 is not present!\n");
···
 	 */
 
 	if (is_isa_arcompact()) {
-		opt_nm = "CONFIG_ARC_FPU_SAVE_RESTORE";
-		saved = IS_ENABLED(CONFIG_ARC_FPU_SAVE_RESTORE);
-
 		/* only DPDP checked since SP has no arch visible regs */
 		present = cpu->extn.fpu_dp;
+		CHK_OPT_STRICT(CONFIG_ARC_FPU_SAVE_RESTORE, present);
 	} else {
-		opt_nm = "CONFIG_ARC_HAS_ACCL_REGS";
-		saved = IS_ENABLED(CONFIG_ARC_HAS_ACCL_REGS);
-
 		/* Accumulator Low:High pair (r58:59) present if DSP MPY or FPU */
 		present = cpu->extn_mpy.dsp | cpu->extn.fpu_sp | cpu->extn.fpu_dp;
-	}
+		CHK_OPT_STRICT(CONFIG_ARC_HAS_ACCL_REGS, present);
 
-	if (present && !saved)
-		pr_warn("Enable %s for working apps\n", opt_nm);
-	else if (!present && saved)
-		panic("Disable %s, hardware NOT present\n", opt_nm);
+		dsp_config_check();
+	}
 }
 
 /*