fsl_ocotp.c revision 266200 
1/*-
2 * Copyright (c) 2014 Steven Lawrance <stl@koffein.net>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD: stable/10/sys/arm/freescale/fsl_ocotp.c 266200 2014-05-15 22:35:04Z ian $");
29
30/*
31 * Access to the Freescale i.MX6 On-Chip One-Time-Programmable Memory
32 */
33
34#include <sys/param.h>
35#include <sys/systm.h>
36#include <sys/kernel.h>
37#include <sys/module.h>
38#include <sys/bus.h>
39#include <sys/rman.h>
40
41#include <dev/ofw/ofw_bus.h>
42#include <dev/ofw/ofw_bus_subr.h>
43
44#include <machine/bus.h>
45
46#include <arm/freescale/fsl_ocotpreg.h>
47#include <arm/freescale/fsl_ocotpvar.h>
48
49/*
50 * Find the physical address and size of the ocotp registers and devmap them,
51 * returning a pointer to the virtual address of the base.
52 *
53 * XXX This is temporary until we've worked out all the details of controlling
54 * the load order of devices.  In an ideal world this device would be up and
55 * running before anything that needs it.  When we're at a point to make that
56 * happen, this little block of code, and the few lines in fsl_ocotp_read_4()
57 * that refer to it can be deleted.
58 */
59#include <vm/vm.h>
60#include <vm/pmap.h>
61#include <dev/fdt/fdt_common.h>
62#include <machine/devmap.h>
63
64static uint32_t   *ocotp_regs;
65static vm_size_t   ocotp_size;
66
67static void
68fsl_ocotp_devmap(void)
69{
70	phandle_t child, root;
71	u_long base, size;
72
73	if ((root = OF_finddevice("/")) == 0)
74		goto fatal;
75	if ((child = fdt_depth_search_compatible(root, "fsl,imx6q-ocotp", 0)) == 0)
76		goto fatal;
77	if (fdt_regsize(child, &base, &size) != 0)
78		goto fatal;
79
80	ocotp_size = (vm_size_t)size;
81
82	if ((ocotp_regs = pmap_mapdev((vm_offset_t)base, ocotp_size)) == NULL)
83		goto fatal;
84
85	return;
86fatal:
87	panic("cannot find/map the ocotp registers");
88}
89/* XXX end of temporary code */
90
91struct ocotp_softc {
92	device_t	dev;
93	struct resource	*mem_res;
94};
95
96static struct ocotp_softc *ocotp_sc;
97
98static inline uint32_t
99RD4(struct ocotp_softc *sc, bus_size_t off)
100{
101
102	return (bus_read_4(sc->mem_res, off));
103}
104
105static int
106ocotp_detach(device_t dev)
107{
108
109	/* The ocotp registers are always accessible. */
110	return (EBUSY);
111}
112
113static int
114ocotp_attach(device_t dev)
115{
116	struct ocotp_softc *sc;
117	int err, rid;
118
119	sc = device_get_softc(dev);
120	sc->dev = dev;
121
122	/* Allocate bus_space resources. */
123	rid = 0;
124	sc->mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid,
125	    RF_ACTIVE);
126	if (sc->mem_res == NULL) {
127		device_printf(dev, "Cannot allocate memory resources\n");
128		err = ENXIO;
129		goto out;
130	}
131
132	ocotp_sc = sc;
133
134	/* We're done with the temporary mapping now. */
135	if (ocotp_regs != NULL)
136		pmap_unmapdev((vm_offset_t)ocotp_regs, ocotp_size);
137
138	err = 0;
139
140out:
141	if (err != 0)
142		ocotp_detach(dev);
143
144	return (err);
145}
146
147static int
148ocotp_probe(device_t dev)
149{
150
151	if (!ofw_bus_status_okay(dev))
152		return (ENXIO);
153
154	if (ofw_bus_is_compatible(dev, "fsl,imx6q-ocotp") == 0)
155		return (ENXIO);
156
157	device_set_desc(dev,
158	    "Freescale On-Chip One-Time-Programmable Memory");
159
160	return (BUS_PROBE_DEFAULT);
161}
162
163uint32_t
164fsl_ocotp_read_4(bus_size_t off)
165{
166
167	if (off > FSL_OCOTP_LAST_REG)
168		panic("fsl_ocotp_read_4: offset out of range");
169
170	/* If we have a softcontext use the regular bus_space read. */
171	if (ocotp_sc != NULL)
172		return (RD4(ocotp_sc, off));
173
174	/*
175	 * Otherwise establish a tempory device mapping if necessary, and read
176	 * the device without any help from bus_space.
177	 *
178	 * XXX Eventually the code from there down can be deleted.
179	 */
180	if (ocotp_regs == NULL)
181		fsl_ocotp_devmap();
182
183	return (ocotp_regs[off / 4]);
184}
185
186static device_method_t ocotp_methods[] = {
187	/* Device interface */
188	DEVMETHOD(device_probe,  ocotp_probe),
189	DEVMETHOD(device_attach, ocotp_attach),
190	DEVMETHOD(device_detach, ocotp_detach),
191
192	DEVMETHOD_END
193};
194
195static driver_t ocotp_driver = {
196	"ocotp",
197	ocotp_methods,
198	sizeof(struct ocotp_softc)
199};
200
201static devclass_t ocotp_devclass;
202
203DRIVER_MODULE(ocotp, simplebus, ocotp_driver, ocotp_devclass, 0, 0);
204
205