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    Subject[PATCH v10 1/9] LIB: Introduce a generic PIO mapping method
    Date
    From: "zhichang.yuan" <yuanzhichang@hisilicon.com>

    In commit 41f8bba7f555 ("of/pci: Add pci_register_io_range() and
    pci_pio_to_address()"), a new I/O space management was supported. With
    that driver, the I/O ranges configured for PCI/PCIE hosts on some
    architectures can be mapped to logical PIO, converted easily between
    CPU address and the corresponding logicial PIO. Based on this, PCI
    I/O devices can be accessed in a memory read/write way through the
    unified in/out accessors.

    But on some archs/platforms, there are bus hosts which access I/O
    peripherals with host-local I/O port addresses rather than memory
    addresses after memory-mapped.
    To support those devices, a more generic I/O mapping method is introduced
    here. Through this patch, both the CPU addresses and the host-local port
    can be mapped into the logical PIO space with different logical/fake PIOs.
    After this, all the I/O accesses to either PCI MMIO devices or host-local
    I/O peripherals can be unified into the existing I/O accessors defined in
    asm-generic/io.h and be redirected to the right device-specific hooks
    based on the input logical PIO.

    Signed-off-by: zhichang.yuan <yuanzhichang@hisilicon.com>
    Signed-off-by: Gabriele Paoloni <gabriele.paoloni@huawei.com>
    ---
    include/asm-generic/io.h | 26 +++++
    include/linux/logic_pio.h | 118 +++++++++++++++++++
    lib/Kconfig | 26 +++++
    lib/Makefile | 2 +
    lib/logic_pio.c | 286 ++++++++++++++++++++++++++++++++++++++++++++++
    5 files changed, 458 insertions(+)
    create mode 100644 include/linux/logic_pio.h
    create mode 100644 lib/logic_pio.c

    diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
    index 7ef015e..334e5db 100644
    --- a/include/asm-generic/io.h
    +++ b/include/asm-generic/io.h
    @@ -351,6 +351,8 @@ static inline void writesq(volatile void __iomem *addr, const void *buffer,
    #define IO_SPACE_LIMIT 0xffff
    #endif

    +#include <linux/logic_pio.h>
    +
    /*
    * {in,out}{b,w,l}() access little endian I/O. {in,out}{b,w,l}_p() can be
    * implemented on hardware that needs an additional delay for I/O accesses to
    @@ -358,51 +360,75 @@ static inline void writesq(volatile void __iomem *addr, const void *buffer,
    */

    #ifndef inb
    +#ifdef CONFIG_INDIRECT_PIO
    +#define inb logic_inb
    +#else
    #define inb inb
    static inline u8 inb(unsigned long addr)
    {
    return readb(PCI_IOBASE + addr);
    }
    +#endif /* CONFIG_INDIRECT_PIO */
    #endif

    #ifndef inw
    +#ifdef CONFIG_INDIRECT_PIO
    +#define inw logic_inw
    +#else
    #define inw inw
    static inline u16 inw(unsigned long addr)
    {
    return readw(PCI_IOBASE + addr);
    }
    +#endif /* CONFIG_INDIRECT_PIO */
    #endif

    #ifndef inl
    +#ifdef CONFIG_INDIRECT_PIO
    +#define inl logic_inl
    +#else
    #define inl inl
    static inline u32 inl(unsigned long addr)
    {
    return readl(PCI_IOBASE + addr);
    }
    +#endif /* CONFIG_INDIRECT_PIO */
    #endif

    #ifndef outb
    +#ifdef CONFIG_INDIRECT_PIO
    +#define outb logic_outb
    +#else
    #define outb outb
    static inline void outb(u8 value, unsigned long addr)
    {
    writeb(value, PCI_IOBASE + addr);
    }
    +#endif /* CONFIG_INDIRECT_PIO */
    #endif

    #ifndef outw
    +#ifdef CONFIG_INDIRECT_PIO
    +#define outw logic_outw
    +#else
    #define outw outw
    static inline void outw(u16 value, unsigned long addr)
    {
    writew(value, PCI_IOBASE + addr);
    }
    +#endif /* CONFIG_INDIRECT_PIO */
    #endif

    #ifndef outl
    +#ifdef CONFIG_INDIRECT_PIO
    +#define outl logic_outl
    +#else
    #define outl outl
    static inline void outl(u32 value, unsigned long addr)
    {
    writel(value, PCI_IOBASE + addr);
    }
    +#endif /* CONFIG_INDIRECT_PIO */
    #endif

    #ifndef inb_p
    diff --git a/include/linux/logic_pio.h b/include/linux/logic_pio.h
    new file mode 100644
    index 0000000..f0a6f15
    --- /dev/null
    +++ b/include/linux/logic_pio.h
    @@ -0,0 +1,118 @@
    +/*
    + * Copyright (C) 2017 Hisilicon Limited, All Rights Reserved.
    + * Author: Gabriele Paoloni <gabriele.paoloni@huawei.com>
    + * Author: Zhichang Yuan <yuanzhichang@hisilicon.com>
    + *
    + * 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 __LINUX_LOGIC_PIO_H
    +#define __LINUX_LOGIC_PIO_H
    +
    +#ifdef __KERNEL__
    +
    +#include <linux/fwnode.h>
    +
    +#define PIO_INDIRECT 0x01UL /* indirect IO flag */
    +#define PIO_CPU_MMIO 0x00UL /* memory mapped io flag */
    +
    +struct logic_pio_hwaddr {
    + struct list_head list;
    + struct fwnode_handle *fwnode;
    + resource_size_t hw_start;
    + resource_size_t io_start;
    + resource_size_t size; /* range size populated */
    + unsigned long flags;
    +
    + void *devpara; /* private parameter of the host device */
    + struct hostio_ops *ops; /* ops operating on this node */
    +};
    +
    +struct hostio_ops {
    + u32 (*pfin)(void *devobj, unsigned long ptaddr, size_t dlen);
    + void (*pfout)(void *devobj, unsigned long ptaddr, u32 outval,
    + size_t dlen);
    + u32 (*pfins)(void *devobj, unsigned long ptaddr, void *inbuf,
    + size_t dlen, unsigned int count);
    + void (*pfouts)(void *devobj, unsigned long ptaddr,
    + const void *outbuf, size_t dlen, unsigned int count);
    +};
    +
    +#ifdef CONFIG_INDIRECT_PIO
    +u8 logic_inb(unsigned long addr);
    +void logic_outb(u8 value, unsigned long addr);
    +void logic_outw(u16 value, unsigned long addr);
    +void logic_outl(u32 value, unsigned long addr);
    +u16 logic_inw(unsigned long addr);
    +u32 logic_inl(unsigned long addr);
    +void logic_outb(u8 value, unsigned long addr);
    +void logic_outw(u16 value, unsigned long addr);
    +void logic_outl(u32 value, unsigned long addr);
    +void logic_insb(unsigned long addr, void *buffer, unsigned int count);
    +void logic_insl(unsigned long addr, void *buffer, unsigned int count);
    +void logic_insw(unsigned long addr, void *buffer, unsigned int count);
    +void logic_outsb(unsigned long addr, const void *buffer, unsigned int count);
    +void logic_outsw(unsigned long addr, const void *buffer, unsigned int count);
    +void logic_outsl(unsigned long addr, const void *buffer, unsigned int count);
    +
    +#define insb logic_insb
    +#define insw logic_insw
    +#define insl logic_insl
    +#define outsb logic_outsb
    +#define outsw logic_outsw
    +#define outsl logic_outsl
    +
    +/*
    + * Below we reserve 0x4000 bytes for Indirect IO as so far this library is only
    + * used by Hisilicon LPC Host. If needed in future we may reserve a wider IO
    + * area by redefining the macro below.
    + */
    +#define PIO_INDIRECT_SIZE 0x4000
    +#define MMIO_UPPER_LIMIT (IO_SPACE_LIMIT - PIO_INDIRECT_SIZE)
    +#else
    +#define MMIO_UPPER_LIMIT IO_SPACE_LIMIT
    +#endif
    +
    +#ifdef CONFIG_LOGIC_PIO
    +struct logic_pio_hwaddr *find_io_range_by_fwnode(struct fwnode_handle *fwnode);
    +
    +unsigned long logic_pio_trans_hwaddr(struct fwnode_handle *fwnode,
    + resource_size_t hw_addr, resource_size_t size);
    +
    +int logic_pio_register_range(struct logic_pio_hwaddr *newrange);
    +#else
    +static inline struct logic_pio_hwaddr
    +*find_io_range_by_fwnode(struct fwnode_handle *fwnode)
    +{
    + return NULL;
    +}
    +
    +static inline unsigned long logic_pio_trans_hwaddr(struct fwnode_handle *fwnode,
    + resource_size_t hw_addr, resource_size_t size);
    +{
    + return -1;
    +}
    +
    +static inline struct logic_pio_hwaddr
    +*logic_pio_register_range(struct logic_pio_hwaddr *newrange);
    +{
    + return NULL;
    +}
    +#endif
    +
    +extern resource_size_t logic_pio_to_hwaddr(unsigned long pio);
    +
    +extern unsigned long logic_pio_trans_cpuaddr(resource_size_t hw_addr);
    +
    +#endif /* __KERNEL__ */
    +#endif /* __LINUX_LOGIC_PIO_H */
    diff --git a/lib/Kconfig b/lib/Kconfig
    index 6762529..d7443a6 100644
    --- a/lib/Kconfig
    +++ b/lib/Kconfig
    @@ -59,6 +59,32 @@ config ARCH_USE_CMPXCHG_LOCKREF
    config ARCH_HAS_FAST_MULTIPLIER
    bool

    +config LOGIC_PIO
    + bool "Generic logical I/O management"
    + def_bool y if PCI && !X86 && !IA64 && !POWERPC
    + help
    + For some architectures, there are no IO space. To support the
    + accesses to legacy I/O devices on those architectures, kernel
    + implemented the memory mapped I/O mechanism based on bridge bus
    + supports. But for some buses which do not support MMIO, the
    + peripherals there should be accessed with device-specific way.
    + To abstract those different I/O accesses into unified I/O accessors,
    + this option provide a generic I/O space management way after mapping
    + the device I/O to system logical/fake I/O and help to hide all the
    + hardware detail.
    +
    +config INDIRECT_PIO
    + bool "Access I/O in non-MMIO mode" if LOGIC_PIO
    + help
    + On some platforms where no separate I/O space exist, there are I/O
    + hosts which can not be accessed in MMIO mode. Based on LOGIC_PIO
    + mechanism, the host-local I/O resource can be mapped into system
    + logic PIO space shared with MMIO hosts, such as PCI/PCIE, then system
    + can access the I/O devices with the mapped logic PIO through I/O
    + accessors.
    + This way has a little I/O performance cost. Please make sure your
    + devices really need this configure item enabled.
    +
    config CRC_CCITT
    tristate "CRC-CCITT functions"
    help
    diff --git a/lib/Makefile b/lib/Makefile
    index 40c1837..e0246ad 100644
    --- a/lib/Makefile
    +++ b/lib/Makefile
    @@ -77,6 +77,8 @@ obj-$(CONFIG_HAS_IOMEM) += iomap_copy.o devres.o
    obj-$(CONFIG_CHECK_SIGNATURE) += check_signature.o
    obj-$(CONFIG_DEBUG_LOCKING_API_SELFTESTS) += locking-selftest.o

    +obj-$(CONFIG_LOGIC_PIO) += logic_pio.o
    +
    obj-$(CONFIG_GENERIC_HWEIGHT) += hweight.o

    obj-$(CONFIG_BTREE) += btree.o
    diff --git a/lib/logic_pio.c b/lib/logic_pio.c
    new file mode 100644
    index 0000000..f8427cb
    --- /dev/null
    +++ b/lib/logic_pio.c
    @@ -0,0 +1,286 @@
    +/*
    + * Copyright (C) 2017 Hisilicon Limited, All Rights Reserved.
    + * Author: Gabriele Paoloni <gabriele.paoloni@huawei.com>
    + * Author: Zhichang Yuan <yuanzhichang@hisilicon.com>
    + *
    + * 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/>.
    + */
    +
    +#include <linux/of.h>
    +#include <linux/io.h>
    +#include <linux/logic_pio.h>
    +#include <linux/mm.h>
    +#include <linux/rculist.h>
    +#include <linux/sizes.h>
    +#include <linux/slab.h>
    +
    +/* The unique hardware address list. */
    +static LIST_HEAD(io_range_list);
    +static DEFINE_MUTEX(io_range_mutex);
    +
    +/*
    + * register a new io range node in the io range list.
    + *
    + * @newrange: pointer to the io range to be registered.
    + *
    + * returns 0 on success, the error code in case of failure
    + */
    +int logic_pio_register_range(struct logic_pio_hwaddr *new_range)
    +{
    + struct logic_pio_hwaddr *range;
    + int ret = 0;
    + resource_size_t start = new_range->hw_start;
    + resource_size_t end = new_range->hw_start + new_range->size;
    + resource_size_t allocated_mmio_size = 0;
    + resource_size_t allocated_iio_size = MMIO_UPPER_LIMIT;
    +
    + if (!new_range || !new_range->fwnode || !new_range->size)
    + return -EINVAL;
    +
    + mutex_lock(&io_range_mutex);
    + list_for_each_entry_rcu(range, &io_range_list, list) {
    +
    + if (range->fwnode == new_range->fwnode) {
    + /* range already there */
    + ret = -EFAULT;
    + goto end_register;
    + }
    + if (range->flags == PIO_CPU_MMIO &&
    + new_range->flags == PIO_CPU_MMIO) {
    + /* for MMIO ranges we need to check for overlap */
    + if (start >= range->hw_start + range->size ||
    + end < range->hw_start)
    + allocated_mmio_size += range->size;
    + else {
    + ret = -EFAULT;
    + goto end_register;
    + }
    + } else if (range->flags == PIO_INDIRECT &&
    + new_range->flags == PIO_INDIRECT) {
    + allocated_iio_size += range->size;
    + }
    + }
    +
    + /* range not registered yet, check for available space */
    + if (new_range->flags == PIO_CPU_MMIO) {
    +
    + if (allocated_mmio_size + new_range->size - 1 >
    + MMIO_UPPER_LIMIT) {
    + /* if it's too big check if 64K space can be reserved */
    + if (allocated_mmio_size + SZ_64K - 1 >
    + MMIO_UPPER_LIMIT) {
    + ret = -E2BIG;
    + goto end_register;
    + }
    + new_range->size = SZ_64K;
    + pr_warn("Requested IO range too big, new size set to 64K\n");
    + }
    +
    + new_range->io_start = allocated_mmio_size;
    +
    + } else if (new_range->flags == PIO_INDIRECT) {
    +
    + if (allocated_iio_size + new_range->size - 1 >
    + IO_SPACE_LIMIT) {
    + ret = -E2BIG;
    + goto end_register;
    + }
    + new_range->io_start = allocated_iio_size;
    +
    + } else {
    + /* invalid flag */
    + ret = -EINVAL;
    + goto end_register;
    + }
    +
    + list_add_tail_rcu(&new_range->list, &io_range_list);
    +
    +end_register:
    + mutex_unlock(&io_range_mutex);
    + return ret;
    +}
    +
    +/*
    + * traverse the io_range_list to find the registered node whose device node
    + * and/or physical IO address match to.
    + */
    +struct logic_pio_hwaddr *find_io_range_by_fwnode(struct fwnode_handle *fwnode)
    +{
    + struct logic_pio_hwaddr *range;
    +
    + list_for_each_entry_rcu(range, &io_range_list, list) {
    + if (range->fwnode == fwnode)
    + return range;
    + }
    + return NULL;
    +}
    +
    +/* return a registered range given an input PIO token */
    +static struct logic_pio_hwaddr *find_io_range(unsigned long pio)
    +{
    + struct logic_pio_hwaddr *range;
    +
    + list_for_each_entry_rcu(range, &io_range_list, list) {
    + if (pio >= range->io_start &&
    + pio < range->io_start + range->size)
    + return range;
    + }
    + pr_err("PIO entry token invalid\n");
    + return NULL;
    +}
    +
    +/*
    + * Translate the input logical pio to the corresponding hardware address.
    + * The input pio should be unique in the whole logical PIO space.
    + */
    +resource_size_t logic_pio_to_hwaddr(unsigned long pio)
    +{
    + struct logic_pio_hwaddr *range;
    + resource_size_t hwaddr = -1;
    +
    + range = find_io_range(pio);
    + if (range)
    + hwaddr = range->hw_start + pio - range->io_start;
    +
    + return hwaddr;
    +}
    +
    +/*
    + * This function is generic for translating a hardware address to logical PIO.
    + * @hw_addr: the hardware address of host, can be CPU address or host-local
    + * address;
    + */
    +unsigned long
    +logic_pio_trans_hwaddr(struct fwnode_handle *fwnode, resource_size_t addr,
    + resource_size_t size)
    +{
    + struct logic_pio_hwaddr *range;
    +
    + range = find_io_range_by_fwnode(fwnode);
    + if (!range || range->flags == PIO_CPU_MMIO) {
    + pr_err("range not found or invalid\n");
    + return -1;
    + }
    + if (range->size < size) {
    + pr_err("resource size 0x%llx cannot fit in IO range size 0x%llx\n",
    + size, range->size);
    + return -1;
    + }
    + return addr - range->hw_start + range->io_start;
    +}
    +
    +unsigned long
    +logic_pio_trans_cpuaddr(resource_size_t addr)
    +{
    + struct logic_pio_hwaddr *range;
    +
    + list_for_each_entry_rcu(range, &io_range_list, list) {
    + if (range->flags != PIO_CPU_MMIO)
    + continue;
    + if (addr >= range->hw_start &&
    + addr < range->hw_start + range->size)
    + return addr - range->hw_start +
    + range->io_start;
    + }
    + pr_err("addr not registered in io_range_list\n");
    + return -1;
    +}
    +
    +#if defined(CONFIG_INDIRECT_PIO) && defined(PCI_IOBASE)
    +#define BUILD_LOGIC_IO(bw, type) \
    +type logic_in##bw(unsigned long addr) \
    +{ \
    + type ret = -1; \
    + \
    + if (addr < MMIO_UPPER_LIMIT) { \
    + ret = read##bw(PCI_IOBASE + addr); \
    + } else { \
    + struct logic_pio_hwaddr *entry = find_io_range(addr); \
    + \
    + if (entry && entry->ops) \
    + ret = entry->ops->pfin(entry->devpara, \
    + addr, sizeof(type)); \
    + else \
    + WARN_ON_ONCE(1); \
    + } \
    + return ret; \
    +} \
    + \
    +void logic_out##bw(type value, unsigned long addr) \
    +{ \
    + if (addr < MMIO_UPPER_LIMIT) { \
    + write##bw(value, PCI_IOBASE + addr); \
    + } else { \
    + struct logic_pio_hwaddr *entry = find_io_range(addr); \
    + \
    + if (entry && entry->ops) \
    + entry->ops->pfout(entry->devpara, \
    + addr, value, sizeof(type)); \
    + else \
    + WARN_ON_ONCE(1); \
    + } \
    +} \
    + \
    +void logic_ins##bw(unsigned long addr, void *buffer, unsigned int count)\
    +{ \
    + if (addr < MMIO_UPPER_LIMIT) { \
    + reads##bw(PCI_IOBASE + addr, buffer, count); \
    + } else { \
    + struct logic_pio_hwaddr *entry = find_io_range(addr); \
    + \
    + if (entry && entry->ops) \
    + entry->ops->pfins(entry->devpara, \
    + addr, buffer, sizeof(type), count); \
    + else \
    + WARN_ON_ONCE(1); \
    + } \
    + \
    +} \
    + \
    +void logic_outs##bw(unsigned long addr, const void *buffer, \
    + unsigned int count) \
    +{ \
    + if (addr < MMIO_UPPER_LIMIT) \
    + writes##bw(PCI_IOBASE + addr, buffer, count); \
    + else { \
    + struct logic_pio_hwaddr *entry = find_io_range(addr); \
    + \
    + if (entry && entry->ops) \
    + entry->ops->pfouts(entry->devpara, \
    + addr, buffer, sizeof(type), count); \
    + else \
    + WARN_ON_ONCE(1); \
    + } \
    +}
    +
    +BUILD_LOGIC_IO(b, u8)
    +
    +EXPORT_SYMBOL(logic_inb);
    +EXPORT_SYMBOL(logic_outb);
    +EXPORT_SYMBOL(logic_insb);
    +EXPORT_SYMBOL(logic_outsb);
    +
    +BUILD_LOGIC_IO(w, u16)
    +
    +EXPORT_SYMBOL(logic_inw);
    +EXPORT_SYMBOL(logic_outw);
    +EXPORT_SYMBOL(logic_insw);
    +EXPORT_SYMBOL(logic_outsw);
    +
    +BUILD_LOGIC_IO(l, u32)
    +
    +EXPORT_SYMBOL(logic_inl);
    +EXPORT_SYMBOL(logic_outl);
    +EXPORT_SYMBOL(logic_insl);
    +EXPORT_SYMBOL(logic_outsl);
    +#endif /* CONFIG_INDIRECT_PIO && PCI_IOBASE */
    --
    2.7.4

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