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RISC-V: Device, timer, IRQs, and the SBI 

This patch contains code that interfaces with devices that are mandated
by the RISC-V supervisor specification and that don't have explicit
drivers anywhere else in the tree.  This includes the staticly defined
interrupts, the CSR-mapped timer, and virtualized SBI devices.

Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>
This commit is contained in:
Palmer Dabbelt 2017-07-10 18:05:09 -07:00
parent 7db91e57a0
commit 6d60b6ee0c
9 changed files with 566 additions and 0 deletions
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28
arch/riscv/include/asm/delay.h Normal file
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/*
* Copyright (C) 2009 Chen Liqin <liqin.chen@sunplusct.com>
* Copyright (C) 2016 Regents of the University of California
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#ifndef _ASM_RISCV_DELAY_H
#define _ASM_RISCV_DELAY_H
extern unsigned long riscv_timebase;
#define udelay udelay
extern void udelay(unsigned long usecs);
#define ndelay ndelay
extern void ndelay(unsigned long nsecs);
extern void __delay(unsigned long cycles);
#endif /* _ASM_RISCV_DELAY_H */

38
arch/riscv/include/asm/dma-mapping.h Normal file
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/*
* Copyright (C) 2003-2004 Hewlett-Packard Co
* David Mosberger-Tang <davidm@hpl.hp.com>
* Copyright (C) 2012 ARM Ltd.
* Copyright (C) 2016 SiFive, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef __ASM_RISCV_DMA_MAPPING_H
#define __ASM_RISCV_DMA_MAPPING_H
/* Use ops->dma_mapping_error (if it exists) or assume success */
// #undef DMA_ERROR_CODE
static inline const struct dma_map_ops *get_arch_dma_ops(struct bus_type *bus)
{
return &dma_noop_ops;
}
static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size)
{
if (!dev->dma_mask)
return false;
return addr + size - 1 <= *dev->dma_mask;
}
#endif /* __ASM_RISCV_DMA_MAPPING_H */

28
arch/riscv/include/asm/irq.h Normal file
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/*
* Copyright (C) 2012 Regents of the University of California
* Copyright (C) 2017 SiFive
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#ifndef _ASM_RISCV_IRQ_H
#define _ASM_RISCV_IRQ_H
#define NR_IRQS 0
#define INTERRUPT_CAUSE_SOFTWARE 1
#define INTERRUPT_CAUSE_TIMER 5
#define INTERRUPT_CAUSE_EXTERNAL 9
void riscv_timer_interrupt(void);
#include <asm-generic/irq.h>
#endif /* _ASM_RISCV_IRQ_H */

63
arch/riscv/include/asm/irqflags.h Normal file
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/*
* Copyright (C) 2012 Regents of the University of California
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#ifndef _ASM_RISCV_IRQFLAGS_H
#define _ASM_RISCV_IRQFLAGS_H
#include <asm/processor.h>
#include <asm/csr.h>
/* read interrupt enabled status */
static inline unsigned long arch_local_save_flags(void)
{
return csr_read(sstatus);
}
/* unconditionally enable interrupts */
static inline void arch_local_irq_enable(void)
{
csr_set(sstatus, SR_IE);
}
/* unconditionally disable interrupts */
static inline void arch_local_irq_disable(void)
{
csr_clear(sstatus, SR_IE);
}
/* get status and disable interrupts */
static inline unsigned long arch_local_irq_save(void)
{
return csr_read_clear(sstatus, SR_IE);
}
/* test flags */
static inline int arch_irqs_disabled_flags(unsigned long flags)
{
return !(flags & SR_IE);
}
/* test hardware interrupt enable bit */
static inline int arch_irqs_disabled(void)
{
return arch_irqs_disabled_flags(arch_local_save_flags());
}
/* set interrupt enabled status */
static inline void arch_local_irq_restore(unsigned long flags)
{
csr_set(sstatus, flags & SR_IE);
}
#endif /* _ASM_RISCV_IRQFLAGS_H */

48
arch/riscv/include/asm/pci.h Normal file
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/*
* Copyright (C) 2016 SiFive
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#ifndef __ASM_RISCV_PCI_H
#define __ASM_RISCV_PCI_H
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/dma-mapping.h>
#include <asm/io.h>
#define PCIBIOS_MIN_IO 0
#define PCIBIOS_MIN_MEM 0
/* RISC-V shim does not initialize PCI bus */
#define pcibios_assign_all_busses() 1
/* We do not have an IOMMU */
#define PCI_DMA_BUS_IS_PHYS 1
extern int isa_dma_bridge_buggy;
#ifdef CONFIG_PCI
static inline int pci_get_legacy_ide_irq(struct pci_dev *dev, int channel)
{
/* no legacy IRQ on risc-v */
return -ENODEV;
}
static inline int pci_proc_domain(struct pci_bus *bus)
{
/* always show the domain in /proc */
return 1;
}
#endif /* CONFIG_PCI */
#endif /* __ASM_PCI_H */

100
arch/riscv/include/asm/sbi.h Normal file
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/*
* Copyright (C) 2015 Regents of the University of California
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#ifndef _ASM_RISCV_SBI_H
#define _ASM_RISCV_SBI_H
#include <linux/types.h>
#define SBI_SET_TIMER 0
#define SBI_CONSOLE_PUTCHAR 1
#define SBI_CONSOLE_GETCHAR 2
#define SBI_CLEAR_IPI 3
#define SBI_SEND_IPI 4
#define SBI_REMOTE_FENCE_I 5
#define SBI_REMOTE_SFENCE_VMA 6
#define SBI_REMOTE_SFENCE_VMA_ASID 7
#define SBI_SHUTDOWN 8
#define SBI_CALL(which, arg0, arg1, arg2) ({ \
register uintptr_t a0 asm ("a0") = (uintptr_t)(arg0); \
register uintptr_t a1 asm ("a1") = (uintptr_t)(arg1); \
register uintptr_t a2 asm ("a2") = (uintptr_t)(arg2); \
register uintptr_t a7 asm ("a7") = (uintptr_t)(which); \
asm volatile ("ecall" \
: "+r" (a0) \
: "r" (a1), "r" (a2), "r" (a7) \
: "memory"); \
a0; \
})
/* Lazy implementations until SBI is finalized */
#define SBI_CALL_0(which) SBI_CALL(which, 0, 0, 0)
#define SBI_CALL_1(which, arg0) SBI_CALL(which, arg0, 0, 0)
#define SBI_CALL_2(which, arg0, arg1) SBI_CALL(which, arg0, arg1, 0)
static inline void sbi_console_putchar(int ch)
{
SBI_CALL_1(SBI_CONSOLE_PUTCHAR, ch);
}
static inline int sbi_console_getchar(void)
{
return SBI_CALL_0(SBI_CONSOLE_GETCHAR);
}
static inline void sbi_set_timer(uint64_t stime_value)
{
#if __riscv_xlen == 32
SBI_CALL_2(SBI_SET_TIMER, stime_value, stime_value >> 32);
#else
SBI_CALL_1(SBI_SET_TIMER, stime_value);
#endif
}
static inline void sbi_shutdown(void)
{
SBI_CALL_0(SBI_SHUTDOWN);
}
static inline void sbi_clear_ipi(void)
{
SBI_CALL_0(SBI_CLEAR_IPI);
}
static inline void sbi_send_ipi(const unsigned long *hart_mask)
{
SBI_CALL_1(SBI_SEND_IPI, hart_mask);
}
static inline void sbi_remote_fence_i(const unsigned long *hart_mask)
{
SBI_CALL_1(SBI_REMOTE_FENCE_I, hart_mask);
}
static inline void sbi_remote_sfence_vma(const unsigned long *hart_mask,
unsigned long start,
unsigned long size)
{
SBI_CALL_1(SBI_REMOTE_SFENCE_VMA, hart_mask);
}
static inline void sbi_remote_sfence_vma_asid(const unsigned long *hart_mask,
unsigned long start,
unsigned long size,
unsigned long asid)
{
SBI_CALL_1(SBI_REMOTE_SFENCE_VMA_ASID, hart_mask);
}
#endif

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arch/riscv/include/asm/timex.h Normal file
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/*
* Copyright (C) 2012 Regents of the University of California
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#ifndef _ASM_RISCV_TIMEX_H
#define _ASM_RISCV_TIMEX_H
#include <asm/param.h>
typedef unsigned long cycles_t;
static inline cycles_t get_cycles(void)
{
cycles_t n;
__asm__ __volatile__ (
"rdtime %0"
: "=r" (n));
return n;
}
#ifdef CONFIG_64BIT
static inline uint64_t get_cycles64(void)
{
return get_cycles();
}
#else
static inline uint64_t get_cycles64(void)
{
u32 lo, hi, tmp;
__asm__ __volatile__ (
"1:\n"
"rdtimeh %0\n"
"rdtime %1\n"
"rdtimeh %2\n"
"bne %0, %2, 1b"
: "=&r" (hi), "=&r" (lo), "=&r" (tmp));
return ((u64)hi << 32) | lo;
}
#endif
#define ARCH_HAS_READ_CURRENT_TIMER
static inline int read_current_timer(unsigned long *timer_val)
{
*timer_val = get_cycles();
return 0;
}
#endif /* _ASM_RISCV_TIMEX_H */

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arch/riscv/lib/delay.c Normal file
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/*
* Copyright (C) 2012 Regents of the University of California
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/delay.h>
#include <linux/param.h>
#include <linux/timex.h>
#include <linux/export.h>
/*
* This is copies from arch/arm/include/asm/delay.h
*
* Loop (or tick) based delay:
*
* loops = loops_per_jiffy * jiffies_per_sec * delay_us / us_per_sec
*
* where:
*
* jiffies_per_sec = HZ
* us_per_sec = 1000000
*
* Therefore the constant part is HZ / 1000000 which is a small
* fractional number. To make this usable with integer math, we
* scale up this constant by 2^31, perform the actual multiplication,
* and scale the result back down by 2^31 with a simple shift:
*
* loops = (loops_per_jiffy * delay_us * UDELAY_MULT) >> 31
*
* where:
*
* UDELAY_MULT = 2^31 * HZ / 1000000
* = (2^31 / 1000000) * HZ
* = 2147.483648 * HZ
* = 2147 * HZ + 483648 * HZ / 1000000
*
* 31 is the biggest scale shift value that won't overflow 32 bits for
* delay_us * UDELAY_MULT assuming HZ <= 1000 and delay_us <= 2000.
*/
#define MAX_UDELAY_US 2000
#define MAX_UDELAY_HZ 1000
#define UDELAY_MULT (2147UL * HZ + 483648UL * HZ / 1000000UL)
#define UDELAY_SHIFT 31
#if HZ > MAX_UDELAY_HZ
#error "HZ > MAX_UDELAY_HZ"
#endif
/*
* RISC-V supports both UDELAY and NDELAY. This is largely the same as above,
* but with different constants. I added 10 bits to the shift to get this, but
* the result is that I need a 64-bit multiply, which is slow on 32-bit
* platforms.
*
* NDELAY_MULT = 2^41 * HZ / 1000000000
* = (2^41 / 1000000000) * HZ
* = 2199.02325555 * HZ
* = 2199 * HZ + 23255550 * HZ / 1000000000
*
* The maximum here is to avoid 64-bit overflow, but it isn't checked as it
* won't happen.
*/
#define MAX_NDELAY_NS (1ULL << 42)
#define MAX_NDELAY_HZ MAX_UDELAY_HZ
#define NDELAY_MULT ((unsigned long long)(2199ULL * HZ + 23255550ULL * HZ / 1000000000ULL))
#define NDELAY_SHIFT 41
#if HZ > MAX_NDELAY_HZ
#error "HZ > MAX_NDELAY_HZ"
#endif
void __delay(unsigned long cycles)
{
u64 t0 = get_cycles();
while ((unsigned long)(get_cycles() - t0) < cycles)
cpu_relax();
}
void udelay(unsigned long usecs)
{
unsigned long ucycles = usecs * lpj_fine * UDELAY_MULT;
if (unlikely(usecs > MAX_UDELAY_US)) {
__delay((u64)usecs * riscv_timebase / 1000000ULL);
return;
}
__delay(ucycles >> UDELAY_SHIFT);
}
EXPORT_SYMBOL(udelay);
void ndelay(unsigned long nsecs)
{
/*
* This doesn't bother checking for overflow, as it won't happen (it's
* an hour) of delay.
*/
unsigned long long ncycles = nsecs * lpj_fine * NDELAY_MULT;
__delay(ncycles >> NDELAY_SHIFT);
}
EXPORT_SYMBOL(ndelay);

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arch/riscv/mm/ioremap.c Normal file
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/*
* (C) Copyright 1995 1996 Linus Torvalds
* (C) Copyright 2012 Regents of the University of California
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/export.h>
#include <linux/mm.h>
#include <linux/vmalloc.h>
#include <linux/io.h>
#include <asm/pgtable.h>
/*
* Remap an arbitrary physical address space into the kernel virtual
* address space. Needed when the kernel wants to access high addresses
* directly.
*
* NOTE! We need to allow non-page-aligned mappings too: we will obviously
* have to convert them into an offset in a page-aligned mapping, but the
* caller shouldn't need to know that small detail.
*/
static void __iomem *__ioremap_caller(phys_addr_t addr, size_t size,
pgprot_t prot, void *caller)
{
phys_addr_t last_addr;
unsigned long offset, vaddr;
struct vm_struct *area;
/* Disallow wrap-around or zero size */
last_addr = addr + size - 1;
if (!size || last_addr < addr)
return NULL;
/* Page-align mappings */
offset = addr & (~PAGE_MASK);
addr &= PAGE_MASK;
size = PAGE_ALIGN(size + offset);
area = get_vm_area_caller(size, VM_IOREMAP, caller);
if (!area)
return NULL;
vaddr = (unsigned long)area->addr;
if (ioremap_page_range(vaddr, vaddr + size, addr, prot)) {
free_vm_area(area);
return NULL;
}
return (void __iomem *)(vaddr + offset);
}
/*
* ioremap - map bus memory into CPU space
* @offset: bus address of the memory
* @size: size of the resource to map
*
* ioremap performs a platform specific sequence of operations to
* make bus memory CPU accessible via the readb/readw/readl/writeb/
* writew/writel functions and the other mmio helpers. The returned
* address is not guaranteed to be usable directly as a virtual
* address.
*
* Must be freed with iounmap.
*/
void __iomem *ioremap(phys_addr_t offset, unsigned long size)
{
return __ioremap_caller(offset, size, PAGE_KERNEL,
__builtin_return_address(0));
}
EXPORT_SYMBOL(ioremap);
/**
* iounmap - Free a IO remapping
* @addr: virtual address from ioremap_*
*
* Caller must ensure there is only one unmapping for the same pointer.
*/
void iounmap(void __iomem *addr)
{
vunmap((void *)((unsigned long)addr & PAGE_MASK));
}
EXPORT_SYMBOL(iounmap);