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Diffstat (limited to 'src/drivers/bitbash/spi_bit.c')
-rw-r--r--src/drivers/bitbash/spi_bit.c125
1 files changed, 74 insertions, 51 deletions
diff --git a/src/drivers/bitbash/spi_bit.c b/src/drivers/bitbash/spi_bit.c
index 20ad412cc..462fd72e8 100644
--- a/src/drivers/bitbash/spi_bit.c
+++ b/src/drivers/bitbash/spi_bit.c
@@ -19,11 +19,12 @@
#include <stddef.h>
#include <stdint.h>
#include <string.h>
+#include <byteswap.h>
#include <errno.h>
#include <assert.h>
#include <timer.h>
#include <gpxe/bitbash.h>
-#include <gpxe/spi.h>
+#include <gpxe/spi_bit.h>
/** @file
*
@@ -32,65 +33,43 @@
*/
/** Delay between SCLK changes and around SS changes */
-static void spi_delay ( void ) {
- udelay ( SPI_UDELAY );
+static void spi_bit_delay ( void ) {
+ udelay ( SPI_BIT_UDELAY );
}
+/** Chip select line will be asserted */
+#define SELECT_SLAVE 0
+
+/** Chip select line will be deasserted */
+#define DESELECT_SLAVE SPI_MODE_SSPOL
+
/**
* Select/deselect slave
*
- * @v spi SPI bit-bashing interface
+ * @v spibit SPI bit-bashing interface
* @v slave Slave number
* @v state Slave select state
*
- * @c state must be set to zero to select the specified slave, or to
- * @c SPI_MODE_SSPOL to deselect the slave.
+ * @c state must be @c SELECT_SLAVE or @c DESELECT_SLAVE.
*/
static void spi_bit_set_slave_select ( struct spi_bit_basher *spibit,
unsigned int slave,
unsigned int state ) {
struct bit_basher *basher = &spibit->basher;
- state ^= ( spibit->spi.mode & SPI_MODE_SSPOL );
+ state ^= ( spibit->bus.mode & SPI_MODE_SSPOL );
DBG ( "Setting slave %d select %s\n", slave,
( state ? "high" : "low" ) );
- spi_delay();
+ spi_bit_delay();
write_bit ( basher, SPI_BIT_SS ( slave ), state );
- spi_delay();
-}
-
-/**
- * Select slave
- *
- * @v spi SPI interface
- * @v slave Slave number
- */
-static void spi_bit_select_slave ( struct spi_interface *spi,
- unsigned int slave ) {
- struct spi_bit_basher *spibit
- = container_of ( spi, struct spi_bit_basher, spi );
-
- spibit->slave = slave;
- spi_bit_set_slave_select ( spibit, slave, 0 );
+ spi_bit_delay();
}
/**
- * Deselect slave
+ * Transfer bits over SPI bit-bashing bus
*
- * @v spi SPI interface
- */
-static void spi_bit_deselect_slave ( struct spi_interface *spi ) {
- struct spi_bit_basher *spibit
- = container_of ( spi, struct spi_bit_basher, spi );
-
- spi_bit_set_slave_select ( spibit, spibit->slave, SPI_MODE_SSPOL );
-}
-
-/**
- * Transfer bits over SPI bit-bashing interface
- *
- * @v spi SPI interface
+ * @v bus SPI bus
* @v data_out TX data buffer (or NULL)
* @v data_in RX data buffer (or NULL)
* @v len Length of transfer (in @b bits)
@@ -101,19 +80,19 @@ static void spi_bit_deselect_slave ( struct spi_interface *spi ) {
* NULL, then the data sent will be all zeroes. If @c data_in is
* NULL, then the incoming data will be discarded.
*/
-static void spi_bit_transfer ( struct spi_interface *spi, const void *data_out,
- void *data_in, unsigned int len ) {
- struct spi_bit_basher *spibit
- = container_of ( spi, struct spi_bit_basher, spi );
+static void spi_bit_transfer ( struct spi_bit_basher *spibit,
+ const void *data_out, void *data_in,
+ unsigned int len ) {
+ struct spi_bus *bus = &spibit->bus;
struct bit_basher *basher = &spibit->basher;
- unsigned int sclk = ( ( spi->mode & SPI_MODE_CPOL ) ? 1 : 0 );
- unsigned int cpha = ( ( spi->mode & SPI_MODE_CPHA ) ? 1 : 0 );
+ unsigned int sclk = ( ( bus->mode & SPI_MODE_CPOL ) ? 1 : 0 );
+ unsigned int cpha = ( ( bus->mode & SPI_MODE_CPHA ) ? 1 : 0 );
unsigned int offset;
unsigned int mask;
unsigned int bit;
int step;
- DBG ( "Transferring %d bits in mode %x\n", len, spi->mode );
+ DBG ( "Transferring %d bits in mode %x\n", len, bus->mode );
for ( step = ( ( len * 2 ) - 1 ) ; step >= 0 ; step-- ) {
/* Calculate byte offset within data and bit mask */
@@ -145,21 +124,65 @@ static void spi_bit_transfer ( struct spi_interface *spi, const void *data_out,
}
/* Toggle clock line */
- spi_delay();
+ spi_bit_delay();
sclk = ~sclk;
write_bit ( basher, SPI_BIT_SCLK, sclk );
}
}
/**
+ * Read/write data via SPI bit-bashing bus
+ *
+ * @v bus SPI bus
+ * @v device SPI device
+ * @v command Command
+ * @v address Address to read/write (<0 for no address)
+ * @v data_out TX data buffer (or NULL)
+ * @v data_in RX data buffer (or NULL)
+ * @v len Length of transfer (in @b words)
+ * @ret rc Return status code
+ */
+static int spi_bit_rw ( struct spi_bus *bus, struct spi_device *device,
+ unsigned int command, int address,
+ const void *data_out, void *data_in,
+ unsigned int len ) {
+ struct spi_bit_basher *spibit
+ = container_of ( bus, struct spi_bit_basher, bus );
+ struct spi_device_type *devtype = device->type;
+ uint32_t tmp;
+
+ /* Assert chip select on specified slave */
+ spi_bit_set_slave_select ( spibit, device->slave, SELECT_SLAVE );
+
+ /* Transmit command */
+ assert ( devtype->command_len <= ( 8 * sizeof ( tmp ) ) );
+ tmp = cpu_to_le32 ( command );
+ spi_bit_transfer ( spibit, &tmp, NULL, devtype->command_len );
+
+ /* Transmit address, if present */
+ if ( address >= 0 ) {
+ assert ( devtype->address_len <= ( 8 * sizeof ( tmp ) ) );
+ tmp = cpu_to_le32 ( address );
+ spi_bit_transfer ( spibit, &tmp, NULL, devtype->address_len );
+ }
+
+ /* Transmit/receive data */
+ spi_bit_transfer ( spibit, data_out, data_in,
+ ( len * devtype->word_len ) );
+
+ /* Deassert chip select on specified slave */
+ spi_bit_set_slave_select ( spibit, device->slave, DESELECT_SLAVE );
+
+ return 0;
+}
+
+/**
* Initialise SPI bit-bashing interface
*
* @v spibit SPI bit-bashing interface
*/
void init_spi_bit_basher ( struct spi_bit_basher *spibit ) {
- assert ( &spibit->basher.read != NULL );
- assert ( &spibit->basher.write != NULL );
- spibit->spi.select_slave = spi_bit_select_slave;
- spibit->spi.deselect_slave = spi_bit_deselect_slave;
- spibit->spi.transfer = spi_bit_transfer;
+ assert ( &spibit->basher.op->read != NULL );
+ assert ( &spibit->basher.op->write != NULL );
+ spibit->bus.rw = spi_bit_rw;
}