iPXE
threewire.c
Go to the documentation of this file.
1 /*
2  * Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public License as
6  * published by the Free Software Foundation; either version 2 of the
7  * License, or any later version.
8  *
9  * This program is distributed in the hope that it will be useful, but
10  * WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12  * General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
17  * 02110-1301, USA.
18  *
19  * You can also choose to distribute this program under the terms of
20  * the Unmodified Binary Distribution Licence (as given in the file
21  * COPYING.UBDL), provided that you have satisfied its requirements.
22  */
23 
24 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
25 
26 #include <stddef.h>
27 #include <string.h>
28 #include <assert.h>
29 #include <unistd.h>
30 #include <ipxe/threewire.h>
31 
32 /** @file
33  *
34  * Three-wire serial devices
35  *
36  */
37 
38 /**
39  * Read data from three-wire device
40  *
41  * @v nvs NVS device
42  * @v address Address from which to read
43  * @v data Data buffer
44  * @v len Length of data buffer
45  * @ret rc Return status code
46  */
47 int threewire_read ( struct nvs_device *nvs, unsigned int address,
48  void *data, size_t len ) {
49  struct spi_device *device = nvs_to_spi ( nvs );
50  struct spi_bus *bus = device->bus;
51  int rc;
52 
53  assert ( bus->mode == SPI_MODE_THREEWIRE );
54 
55  DBGC ( device, "3wire %p reading %zd bytes at %04x\n",
56  device, len, address );
57 
58  if ( ( rc = bus->rw ( bus, device, THREEWIRE_READ, address,
59  NULL, data, len ) ) != 0 ) {
60  DBGC ( device, "3wire %p could not read: %s\n",
61  device, strerror ( rc ) );
62  return rc;
63  }
64 
65  return 0;
66 }
67 
68 /**
69  * Write data to three-wire device
70  *
71  * @v nvs NVS device
72  * @v address Address from which to read
73  * @v data Data buffer
74  * @v len Length of data buffer
75  * @ret rc Return status code
76  */
77 int threewire_write ( struct nvs_device *nvs, unsigned int address,
78  const void *data, size_t len ) {
79  struct spi_device *device = nvs_to_spi ( nvs );
80  struct spi_bus *bus = device->bus;
81  int rc;
82 
83  assert ( bus->mode == SPI_MODE_THREEWIRE );
84 
85  DBGC ( device, "3wire %p writing %zd bytes at %04x\n",
86  device, len, address );
87 
88  /* Enable device for writing */
89  if ( ( rc = bus->rw ( bus, device, THREEWIRE_EWEN,
90  THREEWIRE_EWEN_ADDRESS, NULL, NULL, 0 ) ) != 0 ){
91  DBGC ( device, "3wire %p could not enable writing: %s\n",
92  device, strerror ( rc ) );
93  return rc;
94  }
95 
96  /* Write data */
97  if ( ( rc = bus->rw ( bus, device, THREEWIRE_WRITE, address,
98  data, NULL, len ) ) != 0 ) {
99  DBGC ( device, "3wire %p could not write: %s\n",
100  device, strerror ( rc ) );
101  return rc;
102  }
103 
104  /* Our model of an SPI bus doesn't provide a mechanism for
105  * "assert CS, wait for MISO to become high, so just wait for
106  * long enough to ensure that the write has completed.
107  */
109 
110  return 0;
111 }
112 
113 /**
114  * Autodetect device address length
115  *
116  * @v device SPI device
117  * @ret rc Return status code
118  */
120  struct nvs_device *nvs = &device->nvs;
121  int rc;
122 
123  DBGC ( device, "3wire %p autodetecting address length\n", device );
124 
125  device->address_len = SPI_AUTODETECT_ADDRESS_LEN;
126  if ( ( rc = threewire_read ( nvs, 0, NULL,
127  ( 1 << nvs->word_len_log2 ) ) ) != 0 ) {
128  DBGC ( device, "3wire %p could not autodetect address "
129  "length: %s\n", device, strerror ( rc ) );
130  return rc;
131  }
132 
133  DBGC ( device, "3wire %p autodetected address length %d\n",
134  device, device->address_len );
135  return 0;
136 }
struct arbelprm_rc_send_wqe rc
Definition: arbel.h:14
unsigned int word_len_log2
Word length.
Definition: nvs.h:22
int threewire_write(struct nvs_device *nvs, unsigned int address, const void *data, size_t len)
Write data to three-wire device.
Definition: threewire.c:77
A non-volatile storage device.
Definition: nvs.h:15
uint64_t address
Base address.
Definition: ena.h:24
An SPI bus.
Definition: spi.h:126
#define DBGC(...)
Definition: compiler.h:505
#define THREEWIRE_READ
Read data from memory array.
Definition: threewire.h:24
int threewire_read(struct nvs_device *nvs, unsigned int address, void *data, size_t len)
Read data from three-wire device.
Definition: threewire.c:47
A hardware device.
Definition: device.h:73
Three-wire serial interface.
#define THREEWIRE_WRITE_MDELAY
Time to wait for write cycles to complete.
Definition: threewire.h:40
Assertions.
assert((readw(&hdr->flags) &(GTF_reading|GTF_writing))==0)
#define THREEWIRE_EWEN_ADDRESS
Address to be used for write enable command.
Definition: threewire.h:33
char * strerror(int errno)
Retrieve string representation of error number.
Definition: strerror.c:78
FILE_LICENCE(GPL2_OR_LATER_OR_UBDL)
int threewire_detect_address_len(struct spi_device *device)
Autodetect device address length.
Definition: threewire.c:119
struct nvs_device nvs
NVS device.
Definition: spi.h:88
void mdelay(unsigned long msecs)
Delay for a fixed number of milliseconds.
Definition: timer.c:78
uint32_t len
Length.
Definition: ena.h:14
#define THREEWIRE_WRITE
Write data to memory array.
Definition: threewire.h:27
An SPI device.
Definition: spi.h:86
#define SPI_MODE_THREEWIRE
Threewire-compatible mode.
Definition: spi.h:199
struct arbelprm_port_state_change_st data
Message.
Definition: arbel.h:12
#define THREEWIRE_EWEN
Write enable.
Definition: threewire.h:30
#define NULL
NULL pointer (VOID *)
Definition: Base.h:362
String functions.
uint8_t bus
Bus.
Definition: edd.h:14
#define SPI_AUTODETECT_ADDRESS_LEN
SPI magic autodetection address length.
Definition: spi.h:113