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nvmem: Add nvmem interface and helpers

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The nvmem interface helps provider of nvmem data to expose themselves to consumer.
NVMEM is generally present on some embedded board in a form of eeprom or fuses.
The nvmem api are helpers for consumer to read/write the cell data from a provider.

Differential Revision:	https://reviews.freebsd.org/D16419
This commit is contained in:
Emmanuel Vadot 2018-07-31 19:08:24 +00:00
parent 8608db1eb6
commit cfe196fbed
7 changed files with 464 additions and 0 deletions
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157
share/man/man9/nvmem.9 Normal file
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.\" Copyright (c) 2018 Emmanuel Vadot <manu@freebsd.org>
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR
.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT,
.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
.\"
.\" $FreeBSD$
.\"
.Dd July 24, 2018
.Dt nvmem 9
.Os
.Sh NAME
.Nm nvmem
.Nm nvmem_get_cell_len ,
.Nm nvmem_read_cell_by_name ,
.Nm nvmem_read_cell_by_idx ,
.Nm nvmem_write_cell_by_name ,
.Nm nvmem_write_cell_by_idx ,
.Sh SYNOPSIS
.Cd "options EXT_RESOURCES"
.Cd "options FDT"
.Cd "device nvmem"
.In sys/extres/nvmem/nvmem.h
.Ft int
.Fn nvmem_get_cell_len "phandle_t node" "const char *name"
.Ft int
.Fn nvmem_read_cell_by_name "phandle_t node" "const char *name" "void *cell" "size_t buflen"
.Ft int
.Fn nvmem_read_cell_by_idx "phandle_t node" "int idx" "void *cell" "size_t buflen"
.Ft int
.Fn nvmem_write_cell_by_name "phandle_t node" "const char *name" "void *cell" "size_t buflen"
.Ft int
.Fn nvmem_write_cell_by_idx "phandle_t node" "int idx" "void *cell" "size_t buflen"
.Sh DESCRIPTION
On some embedded boards, the manufacturer stored some data on a NVMEM
(Non-Volatile Memory), this is generally stored in some eeprom or fuses.
.Pp
The
.Nm
API consist of helpers functions for consumer and device methods for
providers.
.Sh FUNCTIONS
.Bl -tag -width indent
.It Fn nvmem_get_cell_len "phandle_t node" "const char *name"
Get the size of the cell base on the reg property on the node.
Return the size or ENOENT if the cell name wasn't found
.It Fn nvmem_read_cell_by_name "phandle_t node" "const char *name" "void *cell" "size_t buflen"
Get the cell content based on the name.
Return 0 on sucess or ENOENT if the cell doesn't exists, ENXIO if no provider device was found,
EINVAL if the size isn't correct.
.It Fn nvmem_read_cell_by_idx "phandle_t node" "int idx" "void *cell" "size_t buflen"
Get the cell content based on the id.
Return 0 on sucess or ENOENT if the cell doesn't exists, ENXIO if no provider device was found,
EINVAL if the size isn't correct.
.It Fn nvmem_write_cell_by_name "phandle_t node" "const char *name" "void *cell" "size_t buflen"
Write the cell content based on the name.
Return 0 on sucess or ENOENT if the cell doesn't exists, ENXIO if no provider device was found,
EINVAL if the size isn't correct.
.It Fn nvmem_write_cell_by_idx "phandle_t node" "int idx" "void *cell" "size_t buflen"
Write the cell content based on the id.
Return 0 on sucess or ENOENT if the cell doesn't exists, ENXIO if no provider device was found,
EINVAL if the size isn't correct.
.El
.Sh DEVICE METHODS
.Bl -tag -width indent
.It Fn nvmem_read "device_t dev" "uint32_t offset" "uint32_t size" "uint8_t *buffer"
Provider device method to read a cell content.
.It Fn nvmem_write "device_t dev" "uint32_t offset" "uint32_t size" "uint8_t *buffer"
Provider device method to write a cell content.
.El
.Sh EXAMPLES
Consider this DTS
.Bd -literal
/* Provider */
eeprom: eeprom@20000 {
board_id: id@0 {
reg = <0x0 0x4>;
};
};
/* Consumer */
device@30000 {
...
nvmem-cells = <&board_id>
nvmem-cell-names = "boardid";
};
.Ed
.Pp
The device driver for eeprom@20000 needs to expose itself as a provider
.Bd -literal
#include "nvmem_if.h"
int
foo_nvmem_read(device_t dev, uint32_t offset, uint32_t size, uint8_t *buffer)
{
/* Read the data */
}
int
foo_attach(device_t dev)
{
phandle_t node;
node = ofw_bus_get_node(dev);
...
/* Registering the device so the consumers can find us */
OF_device_register_xref(OF_xref_from_node(node), dev);
...
}
static device_method_t foo_methods[] = {
...
/* nvmem interface */
DEVMETHOD(nvmem_read, foo_nvmem_read),
/* Terminate method list */
DEVMETHOD_END
};
.Ed
.Pp
The consumer device driver for device@30000 can now read the nvmem data
.Bd -literal
int
bar_attach(device_t dev)
{
phandle_t node;
uint32_t boardid;
...
node = ofw_bus_get_node(dev);
nvmem_read_cell_by_name(node, "boardid", (void *)&boardid, sizeof(boardid));
...
}
.Ed
.Sh HISTORY
The nvmem related function first appear in
.Fx 12.0 .
The nvmem interface and manual page was written by
.An Emmanuel Vadot Aq Mt manu@FreeBSD.org .

1
sys/arm/conf/GENERIC
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@ -72,6 +72,7 @@ options EXT_RESOURCES
device clk
device phy
device hwreset
device nvmem
device regulator
device syscon

1
sys/arm64/conf/GENERIC
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@ -251,6 +251,7 @@ options EXT_RESOURCES
device clk
device phy
device hwreset
device nvmem
device regulator
device syscon

2
sys/conf/files
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@ -1750,6 +1750,8 @@ dev/extres/phy/phydev_if.m optional ext_resources phy fdt
dev/extres/phy/phynode_if.m optional ext_resources phy fdt
dev/extres/hwreset/hwreset.c optional ext_resources hwreset fdt
dev/extres/hwreset/hwreset_if.m optional ext_resources hwreset fdt
dev/extres/nvmem/nvmem.c optional ext_resources nvmem fdt
dev/extres/nvmem/nvmem_if.m optional ext_resources nvmem fdt
dev/extres/regulator/regdev_if.m optional ext_resources regulator fdt
dev/extres/regulator/regnode_if.m optional ext_resources regulator fdt
dev/extres/regulator/regulator.c optional ext_resources regulator fdt

199
sys/dev/extres/nvmem/nvmem.c Normal file
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/*-
* Copyright 2018 Emmanuel Vadot <manu@FreeBSD.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <dev/fdt/fdt_common.h>
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
#include "nvmem.h"
#include "nvmem_if.h"
static int
nvmem_get_cell_node(phandle_t node, int idx, phandle_t *cell)
{
phandle_t *p_cell;
phandle_t cell_node;
int ncell;
if (!OF_hasprop(node, "nvmem-cells") ||
!OF_hasprop(node, "nvmem-cell-names"))
return (ENOENT);
ncell = OF_getencprop_alloc_multi(node, "nvmem-cells", sizeof(*p_cell), (void **)&p_cell);
if (ncell <= 0)
return (ENOENT);
cell_node = OF_node_from_xref(p_cell[idx]);
if (cell_node == p_cell[idx]) {
if (bootverbose)
printf("nvmem_get_node: Cannot resolve phandle %x\n",
p_cell[idx]);
OF_prop_free(p_cell);
return (ENOENT);
}
OF_prop_free(p_cell);
*cell = cell_node;
return (0);
}
int
nvmem_get_cell_len(phandle_t node, const char *name)
{
phandle_t cell_node;
uint32_t reg[2];
int rv, idx;
rv = ofw_bus_find_string_index(node, "nvmem-cell-names", name, &idx);
if (rv != 0)
return (rv);
rv = nvmem_get_cell_node(node, idx, &cell_node);
if (rv != 0)
return (rv);
if (OF_getencprop(cell_node, "reg", reg, sizeof(reg)) != sizeof(reg)) {
if (bootverbose)
printf("nvmem_get_cell_len: Cannot parse reg property of cell %s\n",
name);
return (ENOENT);
}
return (reg[1]);
}
int
nvmem_read_cell_by_idx(phandle_t node, int idx, void *cell, size_t buflen)
{
phandle_t cell_node;
device_t provider;
uint32_t reg[2];
int rv;
rv = nvmem_get_cell_node(node, idx, &cell_node);
if (rv != 0)
return (rv);
/* Validate the reg property */
if (OF_getencprop(cell_node, "reg", reg, sizeof(reg)) != sizeof(reg)) {
if (bootverbose)
printf("nvmem_get_cell_by_name: Cannot parse reg property of cell %d\n",
idx);
return (ENOENT);
}
if (buflen != reg[1])
return (EINVAL);
provider = OF_device_from_xref(OF_xref_from_node(OF_parent(cell_node)));
if (provider == NULL) {
if (bootverbose)
printf("nvmem_get_cell_by_idx: Cannot find the nvmem device\n");
return (ENXIO);
}
rv = NVMEM_READ(provider, reg[0], reg[1], cell);
if (rv != 0) {
return (rv);
}
return (0);
}
int
nvmem_read_cell_by_name(phandle_t node, const char *name, void *cell, size_t buflen)
{
int rv, idx;
rv = ofw_bus_find_string_index(node, "nvmem-cell-names", name, &idx);
if (rv != 0)
return (rv);
return (nvmem_read_cell_by_idx(node, idx, cell, buflen));
}
int
nvmem_write_cell_by_idx(phandle_t node, int idx, void *cell, size_t buflen)
{
phandle_t cell_node, prov_node;
device_t provider;
uint32_t reg[2];
int rv;
rv = nvmem_get_cell_node(node, idx, &cell_node);
if (rv != 0)
return (rv);
prov_node = OF_parent(cell_node);
if (OF_hasprop(prov_node, "read-only"))
return (ENXIO);
/* Validate the reg property */
if (OF_getencprop(cell_node, "reg", reg, sizeof(reg)) != sizeof(reg)) {
if (bootverbose)
printf("nvmem_get_cell_by_idx: Cannot parse reg property of cell %d\n",
idx);
return (ENXIO);
}
if (buflen != reg[1])
return (EINVAL);
provider = OF_device_from_xref(OF_xref_from_node(prov_node));
if (provider == NULL) {
if (bootverbose)
printf("nvmem_get_cell_by_idx: Cannot find the nvmem device\n");
return (ENXIO);
}
rv = NVMEM_WRITE(provider, reg[0], reg[1], cell);
if (rv != 0) {
return (rv);
}
return (0);
}
int
nvmem_write_cell_by_name(phandle_t node, const char *name, void *cell, size_t buflen)
{
int rv, idx;
rv = ofw_bus_find_string_index(node, "nvmem-cell-names", name, &idx);
if (rv != 0)
return (rv);
return (nvmem_write_cell_by_idx(node, idx, cell, buflen));
}

37
sys/dev/extres/nvmem/nvmem.h Normal file
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@ -0,0 +1,37 @@
/*-
* Copyright 2018 Emmanuel Vadot <manu@FreeBSD.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef _DEV_EXTRES_NVMEM_H_
#define _DEV_EXTRES_NVMEM_H_
int nvmem_get_cell_len(phandle_t node, const char *name);
int nvmem_read_cell_by_name(phandle_t node, const char *name, void *cell, size_t buflen);
int nvmem_read_cell_by_idx(phandle_t node, int idx, void *cell, size_t buflen);
int nvmem_write_cell_by_name(phandle_t node, const char *name, void *cell, size_t buflen);
int nvmem_write_cell_by_idx(phandle_t node, int idx, void *cell, size_t buflen);
#endif /* _DEV_EXTRES_NVMEM_H_ */

67
sys/dev/extres/nvmem/nvmem_if.m Normal file
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@ -0,0 +1,67 @@
#-
# Copyright (c) 2018 Emmanuel Vadot <manu@FreeBSD.org>
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.
#
# $FreeBSD$
#
INTERFACE nvmem;
#
# Default implementations of some methods.
#
CODE {
static int
null_nvmem_read(device_t dev __unused, uint32_t offset __unused, uint32_t size __unused, uint8_t *buffer __unused)
{
return (ENXIO);
}
static int
null_nvmem_write(device_t dev __unused, uint32_t offset __unused, uint32_t size __unused, uint8_t *buffer __unused)
{
return (ENXIO);
}
};
#
# Read
#
METHOD int read {
device_t dev;
uint32_t offset;
uint32_t size;
uint8_t *buffer;
} DEFAULT null_nvmem_read;
#
# Write
#
METHOD int write {
device_t dev;
uint32_t offset;
uint32_t size;
uint8_t *buffer;
} DEFAULT null_nvmem_write;