Commit 031e3601 authored by Zhichang Yuan's avatar Zhichang Yuan Committed by Bjorn Helgaas
Browse files

lib: Add generic PIO mapping method 



41f8bba7 ("of/pci: Add pci_register_io_range() and
pci_pio_to_address()") added support for PCI I/O space mapped into CPU
physical memory space.  With that support, the I/O ranges configured for
PCI/PCIe hosts on some architectures can be mapped to logical PIO and
converted easily between CPU address and the corresponding logical PIO.
Based on this, PCI I/O port space can be accessed via in/out accessors that
use memory read/write.

But on some platforms, there are bus hosts that access I/O port space with
host-local I/O port addresses rather than memory addresses.

Add a more generic I/O mapping method to support those devices.  With 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.

Tested-by: default avatardann frazier <dann.frazier@canonical.com>
Signed-off-by: default avatarZhichang Yuan <yuanzhichang@hisilicon.com>
Signed-off-by: default avatarGabriele Paoloni <gabriele.paoloni@huawei.com>
Signed-off-by: default avatarJohn Garry <john.garry@huawei.com>
[bhelgaas: remove -EFAULT return from logic_pio_register_range() per
https://lkml.kernel.org/r/20180403143909.GA21171@ulmo, fix NULL pointer
checking per https://lkml.kernel.org/r/20180403211505.GA29612@embeddedor.com

]
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: default avatarAndy Shevchenko <andy.shevchenko@gmail.com>
parent 7928b2cb

include/asm-generic/io.h

+2 −0
Original line number Diff line number Diff line
@@ -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

include/linux/logic_pio.h

0 → 100644
+123 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0+

/*

 * Copyright (C) 2017 HiSilicon Limited, All Rights Reserved.

 * Author: Gabriele Paoloni <gabriele.paoloni@huawei.com>

 * Author: Zhichang Yuan <yuanzhichang@hisilicon.com>

 */



#ifndef __LINUX_LOGIC_PIO_H

#define __LINUX_LOGIC_PIO_H



#include <linux/fwnode.h>



enum {

	LOGIC_PIO_INDIRECT,		/* Indirect IO flag */

	LOGIC_PIO_CPU_MMIO,		/* 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 *hostdata;

	const struct logic_pio_host_ops *ops;

};



struct logic_pio_host_ops {

	u32 (*in)(void *hostdata, unsigned long addr, size_t dwidth);

	void (*out)(void *hostdata, unsigned long addr, u32 val,

		    size_t dwidth);

	u32 (*ins)(void *hostdata, unsigned long addr, void *buffer,

		   size_t dwidth, unsigned int count);

	void (*outs)(void *hostdata, unsigned long addr, const void *buffer,

		     size_t dwidth, 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);



#ifndef inb

#define inb logic_inb

#endif



#ifndef inw

#define inw logic_inw

#endif



#ifndef inl

#define inl logic_inl

#endif



#ifndef outb

#define outb logic_outb

#endif



#ifndef outw

#define outw logic_outw

#endif



#ifndef outl

#define outl logic_outl

#endif



#ifndef insb

#define insb logic_insb

#endif



#ifndef insw

#define insw logic_insw

#endif



#ifndef insl

#define insl logic_insl

#endif



#ifndef outsb

#define outsb logic_outsb

#endif



#ifndef outsw

#define outsw logic_outsw

#endif



#ifndef outsl

#define outsl logic_outsl

#endif



/*

 * We reserve 0x4000 bytes for Indirect IO as so far this library is only

 * used by the HiSilicon LPC Host. If needed, we can 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 /* CONFIG_INDIRECT_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);

resource_size_t logic_pio_to_hwaddr(unsigned long pio);

unsigned long logic_pio_trans_cpuaddr(resource_size_t hw_addr);



#endif /* __LINUX_LOGIC_PIO_H */

lib/Kconfig

+16 −0
Original line number Diff line number Diff line
@@ -55,6 +55,22 @@ config ARCH_USE_CMPXCHG_LOCKREF 
config ARCH_HAS_FAST_MULTIPLIER

	bool



config INDIRECT_PIO

	bool "Access I/O in non-MMIO mode"

	depends on ARM64

	help

	  On some platforms where no separate I/O space exists, there are I/O

	  hosts which can not be accessed in MMIO mode. Using the logical 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 the

	  system can access the I/O devices with the mapped-logic PIO through

	  I/O accessors.



	  This way has relatively little I/O performance cost. Please make

	  sure your devices really need this configure item enabled.



	  When in doubt, say N.



config CRC_CCITT

	tristate "CRC-CCITT functions"

	help

lib/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -81,6 +81,8 @@ 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-y += logic_pio.o



obj-$(CONFIG_GENERIC_HWEIGHT) += hweight.o



obj-$(CONFIG_BTREE) += btree.o

lib/logic_pio.c

0 → 100644
+280 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0+

/*

 * Copyright (C) 2017 HiSilicon Limited, All Rights Reserved.

 * Author: Gabriele Paoloni <gabriele.paoloni@huawei.com>

 * Author: Zhichang Yuan <yuanzhichang@hisilicon.com>

 */



#define pr_fmt(fmt)	"LOGIC PIO: " fmt



#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);



/* Consider a kernel general helper for this */

#define in_range(b, first, len)        ((b) >= (first) && (b) < (first) + (len))



/**

 * logic_pio_register_range - register logical PIO range for a host

 * @new_range: pointer to the IO range to be registered.

 *

 * Returns 0 on success, the error code in case of failure.

 *

 * Register a new IO range node in the IO range list.

 */

int logic_pio_register_range(struct logic_pio_hwaddr *new_range)

{

	struct logic_pio_hwaddr *range;

	resource_size_t start;

	resource_size_t end;

	resource_size_t mmio_sz = 0;

	resource_size_t iio_sz = MMIO_UPPER_LIMIT;

	int ret = 0;



	if (!new_range || !new_range->fwnode || !new_range->size)

		return -EINVAL;



	start = new_range->hw_start;

	end = new_range->hw_start + new_range->size;



	mutex_lock(&io_range_mutex);

	list_for_each_entry_rcu(range, &io_range_list, list) {

		if (range->fwnode == new_range->fwnode) {

			/* range already there */

			goto end_register;

		}

		if (range->flags == LOGIC_PIO_CPU_MMIO &&

		    new_range->flags == LOGIC_PIO_CPU_MMIO) {

			/* for MMIO ranges we need to check for overlap */

			if (start >= range->hw_start + range->size ||

			    end < range->hw_start) {

				mmio_sz += range->size;

			} else {

				ret = -EFAULT;

				goto end_register;

			}

		} else if (range->flags == LOGIC_PIO_INDIRECT &&

			   new_range->flags == LOGIC_PIO_INDIRECT) {

			iio_sz += range->size;

		}

	}



	/* range not registered yet, check for available space */

	if (new_range->flags == LOGIC_PIO_CPU_MMIO) {

		if (mmio_sz + new_range->size - 1 > MMIO_UPPER_LIMIT) {

			/* if it's too big check if 64K space can be reserved */

			if (mmio_sz + 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 = mmio_sz;

	} else if (new_range->flags == LOGIC_PIO_INDIRECT) {

		if (iio_sz + new_range->size - 1 > IO_SPACE_LIMIT) {

			ret = -E2BIG;

			goto end_register;

		}

		new_range->io_start = iio_sz;

	} 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;

}



/**

 * find_io_range_by_fwnode - find logical PIO range for given FW node

 * @fwnode: FW node handle associated with logical PIO range

 *

 * Returns pointer to node on success, NULL otherwise.

 *

 * Traverse the io_range_list to find the registered node for @fwnode.

 */

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 (in_range(pio, range->io_start, range->size))

			return range;

	}

	pr_err("PIO entry token %lx invalid\n", pio);

	return NULL;

}



/**

 * logic_pio_to_hwaddr - translate logical PIO to HW address

 * @pio: logical PIO value

 *

 * Returns HW address if valid, ~0 otherwise.

 *

 * 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;



	range = find_io_range(pio);

	if (range)

		return range->hw_start + pio - range->io_start;



	return (resource_size_t)~0;

}



/**

 * logic_pio_trans_hwaddr - translate HW address to logical PIO

 * @fwnode: FW node reference for the host

 * @addr: Host-relative HW address

 * @size: size to translate

 *

 * Returns Logical PIO value if successful, ~0UL otherwise

 */

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 == LOGIC_PIO_CPU_MMIO) {

		pr_err("IO range not found or invalid\n");

		return ~0UL;

	}

	if (range->size < size) {

		pr_err("resource size %pa cannot fit in IO range size %pa\n",

		       &size, &range->size);

		return ~0UL;

	}

	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 != LOGIC_PIO_CPU_MMIO)

			continue;

		if (in_range(addr, range->hw_start, range->size))

			return addr - range->hw_start + range->io_start;

	}

	pr_err("addr %llx not registered in io_range_list\n",

	       (unsigned long long) addr);

	return ~0UL;

}



#if defined(CONFIG_INDIRECT_PIO) && defined(PCI_IOBASE)

#define BUILD_LOGIC_IO(bw, type)					\

type logic_in##bw(unsigned long addr)					\

{									\

	type ret = (type)~0;						\

									\

	if (addr < MMIO_UPPER_LIMIT) {					\

		ret = read##bw(PCI_IOBASE + addr);			\

	} else if (addr >= MMIO_UPPER_LIMIT && addr < IO_SPACE_LIMIT) { \

		struct logic_pio_hwaddr *entry = find_io_range(addr);	\

									\

		if (entry && entry->ops)				\

			ret = entry->ops->in(entry->hostdata,		\

					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 if (addr >= MMIO_UPPER_LIMIT && addr < IO_SPACE_LIMIT) {	\

		struct logic_pio_hwaddr *entry = find_io_range(addr);	\

									\

		if (entry && entry->ops)				\

			entry->ops->out(entry->hostdata,		\

					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 if (addr >= MMIO_UPPER_LIMIT && addr < IO_SPACE_LIMIT) {	\

		struct logic_pio_hwaddr *entry = find_io_range(addr);	\

									\

		if (entry && entry->ops)				\

			entry->ops->ins(entry->hostdata,		\

				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 if (addr >= MMIO_UPPER_LIMIT && addr < IO_SPACE_LIMIT) {	\

		struct logic_pio_hwaddr *entry = find_io_range(addr);	\

									\

		if (entry && entry->ops)				\

			entry->ops->outs(entry->hostdata,		\

				addr, buffer, sizeof(type), count);	\

		else							\

			WARN_ON_ONCE(1);				\

	}								\

}



BUILD_LOGIC_IO(b, u8)

EXPORT_SYMBOL(logic_inb);

EXPORT_SYMBOL(logic_insb);

EXPORT_SYMBOL(logic_outb);

EXPORT_SYMBOL(logic_outsb);



BUILD_LOGIC_IO(w, u16)

EXPORT_SYMBOL(logic_inw);

EXPORT_SYMBOL(logic_insw);

EXPORT_SYMBOL(logic_outw);

EXPORT_SYMBOL(logic_outsw);



BUILD_LOGIC_IO(l, u32)

EXPORT_SYMBOL(logic_inl);

EXPORT_SYMBOL(logic_insl);

EXPORT_SYMBOL(logic_outl);

EXPORT_SYMBOL(logic_outsl);



#endif /* CONFIG_INDIRECT_PIO && PCI_IOBASE */

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