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spi/dw_spi: unify the low level read/write routines 

The original version has many duplicated codes for null/u8/u16 case,
so unify them to make it cleaner

Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
This commit is contained in:
Feng Tang 2011-03-30 23:09:52 +08:00 committed by Grant Likely
parent 0ce790e7d7
commit de6efe0a96
2 changed files with 27 additions and 80 deletions
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105
drivers/spi/dw_spi.c
View File

@ -58,8 +58,6 @@ struct chip_data {
u8 bits_per_word;
u16 clk_div; /* baud rate divider */
u32 speed_hz; /* baud rate */
int (*write)(struct dw_spi *dws);
int (*read)(struct dw_spi *dws);
void (*cs_control)(u32 command);
};
@ -185,80 +183,45 @@ static void flush(struct dw_spi *dws)
wait_till_not_busy(dws);
}
static int null_writer(struct dw_spi *dws)
static int dw_writer(struct dw_spi *dws)
{
u8 n_bytes = dws->n_bytes;
u16 txw = 0;
if (!(dw_readw(dws, sr) & SR_TF_NOT_FULL)
|| (dws->tx == dws->tx_end))
return 0;
dw_writew(dws, dr, 0);
dws->tx += n_bytes;
wait_till_not_busy(dws);
return 1;
}
static int null_reader(struct dw_spi *dws)
{
u8 n_bytes = dws->n_bytes;
while ((dw_readw(dws, sr) & SR_RF_NOT_EMPT)
&& (dws->rx < dws->rx_end)) {
dw_readw(dws, dr);
dws->rx += n_bytes;
}
wait_till_not_busy(dws);
return dws->rx == dws->rx_end;
}
static int u8_writer(struct dw_spi *dws)
{
if (!(dw_readw(dws, sr) & SR_TF_NOT_FULL)
|| (dws->tx == dws->tx_end))
return 0;
dw_writew(dws, dr, *(u8 *)(dws->tx));
++dws->tx;
wait_till_not_busy(dws);
return 1;
}
static int u8_reader(struct dw_spi *dws)
{
while ((dw_readw(dws, sr) & SR_RF_NOT_EMPT)
&& (dws->rx < dws->rx_end)) {
*(u8 *)(dws->rx) = dw_readw(dws, dr);
++dws->rx;
/* Set the tx word if the transfer's original "tx" is not null */
if (dws->tx_end - dws->len) {
if (dws->n_bytes == 1)
txw = *(u8 *)(dws->tx);
else
txw = *(u16 *)(dws->tx);
}
wait_till_not_busy(dws);
return dws->rx == dws->rx_end;
}
static int u16_writer(struct dw_spi *dws)
{
if (!(dw_readw(dws, sr) & SR_TF_NOT_FULL)
|| (dws->tx == dws->tx_end))
return 0;
dw_writew(dws, dr, *(u16 *)(dws->tx));
dws->tx += 2;
dw_writew(dws, dr, txw);
dws->tx += dws->n_bytes;
wait_till_not_busy(dws);
return 1;
}
static int u16_reader(struct dw_spi *dws)
static int dw_reader(struct dw_spi *dws)
{
u16 temp;
u16 rxw;
while ((dw_readw(dws, sr) & SR_RF_NOT_EMPT)
&& (dws->rx < dws->rx_end)) {
temp = dw_readw(dws, dr);
*(u16 *)(dws->rx) = temp;
dws->rx += 2;
rxw = dw_readw(dws, dr);
/* Care rx only if the transfer's original "rx" is not null */
if (dws->rx_end - dws->len) {
if (dws->n_bytes == 1)
*(u8 *)(dws->rx) = rxw;
else
*(u16 *)(dws->rx) = rxw;
}
dws->rx += dws->n_bytes;
}
wait_till_not_busy(dws);
@ -383,8 +346,8 @@ static irqreturn_t interrupt_transfer(struct dw_spi *dws)
left = (left > int_level) ? int_level : left;
while (left--)
dws->write(dws);
dws->read(dws);
dw_writer(dws);
dw_reader(dws);
/* Re-enable the IRQ if there is still data left to tx */
if (dws->tx_end > dws->tx)
@ -417,13 +380,13 @@ static irqreturn_t dw_spi_irq(int irq, void *dev_id)
/* Must be called inside pump_transfers() */
static void poll_transfer(struct dw_spi *dws)
{
while (dws->write(dws))
dws->read(dws);
while (dw_writer(dws))
dw_reader(dws);
/*
* There is a possibility that the last word of a transaction
* will be lost if data is not ready. Re-read to solve this issue.
*/
dws->read(dws);
dw_reader(dws);
dw_spi_xfer_done(dws);
}
@ -483,8 +446,6 @@ static void pump_transfers(unsigned long data)
dws->tx_end = dws->tx + transfer->len;
dws->rx = transfer->rx_buf;
dws->rx_end = dws->rx + transfer->len;
dws->write = dws->tx ? chip->write : null_writer;
dws->read = dws->rx ? chip->read : null_reader;
dws->cs_change = transfer->cs_change;
dws->len = dws->cur_transfer->len;
if (chip != dws->prev_chip)
@ -520,18 +481,10 @@ static void pump_transfers(unsigned long data)
case 8:
dws->n_bytes = 1;
dws->dma_width = 1;
dws->read = (dws->read != null_reader) ?
u8_reader : null_reader;
dws->write = (dws->write != null_writer) ?
u8_writer : null_writer;
break;
case 16:
dws->n_bytes = 2;
dws->dma_width = 2;
dws->read = (dws->read != null_reader) ?
u16_reader : null_reader;
dws->write = (dws->write != null_writer) ?
u16_writer : null_writer;
break;
default:
printk(KERN_ERR "MRST SPI0: unsupported bits:"
@ -733,13 +686,9 @@ static int dw_spi_setup(struct spi_device *spi)
if (spi->bits_per_word <= 8) {
chip->n_bytes = 1;
chip->dma_width = 1;
chip->read = u8_reader;
chip->write = u8_writer;
} else if (spi->bits_per_word <= 16) {
chip->n_bytes = 2;
chip->dma_width = 2;
chip->read = u16_reader;
chip->write = u16_writer;
} else {
/* Never take >16b case for MRST SPIC */
dev_err(&spi->dev, "invalid wordsize\n");

2
drivers/spi/dw_spi.h
View File

@ -137,8 +137,6 @@ struct dw_spi {
u8 max_bits_per_word; /* maxim is 16b */
u32 dma_width;
int cs_change;
int (*write)(struct dw_spi *dws);
int (*read)(struct dw_spi *dws);
irqreturn_t (*transfer_handler)(struct dw_spi *dws);
void (*cs_control)(u32 command);