From 923ab15e1a5ce6248601304440e9f30fbf3bb6ab Mon Sep 17 00:00:00 2001 From: Heiner Kallweit Date: Sun, 2 Oct 2016 14:22:57 +0200 Subject: [PATCH] spi: fsl-espi: fix handling of word sizes other than 8 bit The code in fsl_espi_tx_buf_lsb and parts of fsl_espi_setup_transfer look very weird and don't reflect the ESPI spec. ESPI stores values with <= 8 bit word size right justified as 8 bit value and values with > 8 bit word size right justified as 16 bit value. Therefore no such shifting is needed. Only case MSB-first with 8 bit word size is correctly handled, and most likely nobody ever used this driver with a different config. On ESPI only the case LSB-first with word size > 8 bit needs a special handling. In this case a little endian 16 bit value has to be written to the TX FIFO what requires a byte swap as the host system is big endian. The same applies to reading from the RX FIFO. Signed-off-by: Heiner Kallweit Signed-off-by: Mark Brown --- drivers/spi/spi-fsl-espi.c | 84 ++++++++++++++++---------------------- 1 file changed, 36 insertions(+), 48 deletions(-) diff --git a/drivers/spi/spi-fsl-espi.c b/drivers/spi/spi-fsl-espi.c index 65bb70d3bfc4..eea5123abb38 100644 --- a/drivers/spi/spi-fsl-espi.c +++ b/drivers/spi/spi-fsl-espi.c @@ -112,6 +112,32 @@ static inline void fsl_espi_write_reg8(struct mpc8xxx_spi *mspi, int offset, iowrite8(val, mspi->reg_base + offset); } +static void fsl_espi_memcpy_swab(void *to, const void *from, + struct spi_message *m, + struct spi_transfer *t) +{ + unsigned int len = t->len; + + if (!(m->spi->mode & SPI_LSB_FIRST) || t->bits_per_word <= 8) { + memcpy(to, from, len); + return; + } + + /* In case of LSB-first and bits_per_word > 8 byte-swap all words */ + while (len) + if (len >= 4) { + *(u32 *)to = swahb32p(from); + to += 4; + from += 4; + len -= 4; + } else { + *(u16 *)to = swab16p(from); + to += 2; + from += 2; + len -= 2; + } +} + static void fsl_espi_copy_to_buf(struct spi_message *m, struct mpc8xxx_spi *mspi) { @@ -120,7 +146,7 @@ static void fsl_espi_copy_to_buf(struct spi_message *m, list_for_each_entry(t, &m->transfers, transfer_list) { if (t->tx_buf) - memcpy(buf, t->tx_buf, t->len); + fsl_espi_memcpy_swab(buf, t->tx_buf, m, t); else memset(buf, 0, t->len); buf += t->len; @@ -135,7 +161,7 @@ static void fsl_espi_copy_from_buf(struct spi_message *m, list_for_each_entry(t, &m->transfers, transfer_list) { if (t->rx_buf) - memcpy(t->rx_buf, buf, t->len); + fsl_espi_memcpy_swab(t->rx_buf, buf, m, t); buf += t->len; } } @@ -194,27 +220,6 @@ static void fsl_espi_change_mode(struct spi_device *spi) local_irq_restore(flags); } -static u32 fsl_espi_tx_buf_lsb(struct mpc8xxx_spi *mpc8xxx_spi) -{ - u32 data; - u16 data_h; - u16 data_l; - const u32 *tx = mpc8xxx_spi->tx; - - if (!tx) - return 0; - - data = *tx++ << mpc8xxx_spi->tx_shift; - data_l = data & 0xffff; - data_h = (data >> 16) & 0xffff; - swab16s(&data_l); - swab16s(&data_h); - data = data_h | data_l; - - mpc8xxx_spi->tx = tx; - return data; -} - static void fsl_espi_setup_transfer(struct spi_device *spi, struct spi_transfer *t) { @@ -224,23 +229,6 @@ static void fsl_espi_setup_transfer(struct spi_device *spi, u8 pm; struct spi_mpc8xxx_cs *cs = spi->controller_state; - cs->rx_shift = 0; - cs->tx_shift = 0; - cs->get_rx = mpc8xxx_spi_rx_buf_u32; - cs->get_tx = mpc8xxx_spi_tx_buf_u32; - if (bits_per_word <= 8) { - cs->rx_shift = 8 - bits_per_word; - } else { - cs->rx_shift = 16 - bits_per_word; - if (spi->mode & SPI_LSB_FIRST) - cs->get_tx = fsl_espi_tx_buf_lsb; - } - - mpc8xxx_spi->rx_shift = cs->rx_shift; - mpc8xxx_spi->tx_shift = cs->tx_shift; - mpc8xxx_spi->get_rx = cs->get_rx; - mpc8xxx_spi->get_tx = cs->get_tx; - /* mask out bits we are going to set */ cs->hw_mode &= ~(CSMODE_LEN(0xF) | CSMODE_DIV16 | CSMODE_PM(0xF)); @@ -271,7 +259,6 @@ static void fsl_espi_setup_transfer(struct spi_device *spi, static int fsl_espi_bufs(struct spi_device *spi, struct spi_transfer *t) { struct mpc8xxx_spi *mpc8xxx_spi = spi_master_get_devdata(spi->master); - u32 word; int ret; mpc8xxx_spi->len = t->len; @@ -290,8 +277,8 @@ static int fsl_espi_bufs(struct spi_device *spi, struct spi_transfer *t) fsl_espi_write_reg(mpc8xxx_spi, ESPI_SPIM, SPIM_RNE); /* transmit word */ - word = mpc8xxx_spi->get_tx(mpc8xxx_spi); - fsl_espi_write_reg(mpc8xxx_spi, ESPI_SPITF, word); + fsl_espi_write_reg(mpc8xxx_spi, ESPI_SPITF, *(u32 *)mpc8xxx_spi->tx); + mpc8xxx_spi->tx += 4; /* Won't hang up forever, SPI bus sometimes got lost interrupts... */ ret = wait_for_completion_timeout(&mpc8xxx_spi->done, 2 * HZ); @@ -468,8 +455,10 @@ static void fsl_espi_cpu_irq(struct mpc8xxx_spi *mspi, u32 events) mspi->len -= rx_nr_bytes; - if (mspi->rx) - mspi->get_rx(rx_data, mspi); + if (mspi->rx) { + *(u32 *)mspi->rx = rx_data; + mspi->rx += 4; + } } if (!(events & SPIE_TNF)) { @@ -487,9 +476,8 @@ static void fsl_espi_cpu_irq(struct mpc8xxx_spi *mspi, u32 events) mspi->count -= 1; if (mspi->count) { - u32 word = mspi->get_tx(mspi); - - fsl_espi_write_reg(mspi, ESPI_SPITF, word); + fsl_espi_write_reg(mspi, ESPI_SPITF, *(u32 *)mspi->tx); + mspi->tx += 4; } else { complete(&mspi->done); } -- 2.39.5