iPXE
spi.c
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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 <errno.h>
28 #include <unistd.h>
29 #include <ipxe/spi.h>
30 
31 /** @file
32  *
33  * SPI devices
34  *
35  */
36 
37 /**
38  * Munge SPI device address into command
39  *
40  * @v command SPI command
41  * @v address Address
42  * @v munge_address Device requires address munging
43  * @ret command Actual SPI command to use
44  *
45  * Some devices with 9-bit addresses (e.g. AT25040A EEPROM) use bit 3
46  * of the command byte as address bit A8, rather than having a
47  * two-byte address. This function takes care of generating the
48  * appropriate command.
49  */
50 static inline unsigned int spi_command ( unsigned int command,
51  unsigned int address,
52  int munge_address ) {
53  return ( command | ( ( ( address >> 8 ) & munge_address ) << 3 ) );
54 }
55 
56 /**
57  * Wait for SPI device to complete operation
58  *
59  * @v device SPI device
60  * @ret rc Return status code
61  */
62 static int spi_wait ( struct spi_device *device ) {
63  struct spi_bus *bus = device->bus;
65  int i;
66  int rc;
67 
68  for ( i = 0 ; i < 50 ; i++ ) {
69  udelay ( 20 );
70  if ( ( rc = bus->rw ( bus, device, SPI_RDSR, -1, NULL,
71  &status, sizeof ( status ) ) ) != 0 )
72  return rc;
73  if ( ! ( status & SPI_STATUS_NRDY ) )
74  return 0;
75  }
76  DBG ( "SPI %p timed out\n", device );
77  return -ETIMEDOUT;
78 }
79 
80 /**
81  * Read data from SPI device
82  *
83  * @v nvs NVS device
84  * @v address Address from which to read
85  * @v data Data buffer
86  * @v len Length of data buffer
87  * @ret rc Return status code
88  */
89 int spi_read ( struct nvs_device *nvs, unsigned int address,
90  void *data, size_t len ) {
91  struct spi_device *device = nvs_to_spi ( nvs );
92  struct spi_bus *bus = device->bus;
93  unsigned int command = spi_command ( SPI_READ, address,
94  device->munge_address );
95  int rc;
96 
97  DBG ( "SPI %p reading %zd bytes from %#04x\n", device, len, address );
98  if ( ( rc = bus->rw ( bus, device, command, address,
99  NULL, data, len ) ) != 0 ) {
100  DBG ( "SPI %p failed to read data from device\n", device );
101  return rc;
102  }
103 
104  return 0;
105 }
106 
107 /**
108  * Write data to SPI device
109  *
110  * @v nvs NVS device
111  * @v address Address from which to read
112  * @v data Data buffer
113  * @v len Length of data buffer
114  * @ret rc Return status code
115  */
116 int spi_write ( struct nvs_device *nvs, unsigned int address,
117  const void *data, size_t len ) {
118  struct spi_device *device = nvs_to_spi ( nvs );
119  struct spi_bus *bus = device->bus;
120  unsigned int command = spi_command ( SPI_WRITE, address,
121  device->munge_address );
122  int rc;
123 
124  DBG ( "SPI %p writing %zd bytes to %#04x\n", device, len, address );
125 
126  if ( ( rc = bus->rw ( bus, device, SPI_WREN, -1,
127  NULL, NULL, 0 ) ) != 0 ) {
128  DBG ( "SPI %p failed to write-enable device\n", device );
129  return rc;
130  }
131 
132  if ( ( rc = bus->rw ( bus, device, command, address,
133  data, NULL, len ) ) != 0 ) {
134  DBG ( "SPI %p failed to write data to device\n", device );
135  return rc;
136  }
137 
138  if ( ( rc = spi_wait ( device ) ) != 0 ) {
139  DBG ( "SPI %p failed to complete write operation\n", device );
140  return rc;
141  }
142 
143  return 0;
144 }
145 
struct arbelprm_rc_send_wqe rc
Definition: arbel.h:14
#define SPI_WREN
Set write enable latch.
Definition: spi.h:35
#define SPI_RDSR
Read status register.
Definition: spi.h:32
Error codes.
A command-line command.
Definition: command.h:9
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
uint8_t status
Status.
Definition: ena.h:16
A hardware device.
Definition: device.h:73
SPI interface.
int spi_write(struct nvs_device *nvs, unsigned int address, const void *data, size_t len)
Write data to SPI device.
Definition: spi.c:116
int spi_read(struct nvs_device *nvs, unsigned int address, void *data, size_t len)
Read data from SPI device.
Definition: spi.c:89
#define SPI_READ
Read data from memory array.
Definition: spi.h:26
void udelay(unsigned long usecs)
Delay for a fixed number of microseconds.
Definition: timer.c:60
#define SPI_WRITE
Write data to memory array.
Definition: spi.h:23
FILE_LICENCE(GPL2_OR_LATER_OR_UBDL)
static int spi_wait(struct spi_device *device)
Wait for SPI device to complete operation.
Definition: spi.c:62
#define SPI_STATUS_NRDY
Device busy flag.
Definition: spi.h:76
unsigned char uint8_t
Definition: stdint.h:10
static unsigned int spi_command(unsigned int command, unsigned int address, int munge_address)
Munge SPI device address into command.
Definition: spi.c:50
struct nvs_device nvs
NVS device.
Definition: spi.h:88
uint32_t len
Length.
Definition: ena.h:14
An SPI device.
Definition: spi.h:86
struct arbelprm_port_state_change_st data
Message.
Definition: arbel.h:12
#define DBG(...)
Print a debugging message.
Definition: compiler.h:498
#define NULL
NULL pointer (VOID *)
Definition: Base.h:362
#define ETIMEDOUT
Connection timed out.
Definition: errno.h:669
uint8_t bus
Bus.
Definition: edd.h:14