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spi: SAM add spin lock around all tx/rx/txrx funcs

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The fast tx/rx/txrx functions will leave the SPI bus in an
inoperable state if interrupted, potentially spinning forever waiting on
some data. Wrapping these operations in what amounts to a critical section
using spin locks to avoid the issue.

Signed-off-by: Tom Burdick <thomas.burdick@intel.com>
This commit is contained in:
Tom Burdick 2022-09-28 12:50:59 -05:00 committed by Stephanos Ioannidis
parent bcee4ed34e
commit 86af9bcce1
1 changed files with 15 additions and 0 deletions
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15
drivers/spi/spi_sam.c
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@ -180,6 +180,9 @@ static void spi_sam_finish(Spi *regs)
/* Fast path that transmits a buf */ /* Fast path that transmits a buf */
static void spi_sam_fast_tx(Spi *regs, const struct spi_buf *tx_buf) static void spi_sam_fast_tx(Spi *regs, const struct spi_buf *tx_buf)
{ {
struct k_spinlock lock;
k_spinlock_key_t key = k_spin_lock(&lock);
const uint8_t *p = tx_buf->buf; const uint8_t *p = tx_buf->buf;
const uint8_t *pend = (uint8_t *)tx_buf->buf + tx_buf->len; const uint8_t *pend = (uint8_t *)tx_buf->buf + tx_buf->len;
uint8_t ch; uint8_t ch;
@ -194,11 +197,16 @@ static void spi_sam_fast_tx(Spi *regs, const struct spi_buf *tx_buf)
} }
spi_sam_finish(regs); spi_sam_finish(regs);
k_spin_unlock(&lock, key);
} }
/* Fast path that reads into a buf */ /* Fast path that reads into a buf */
static void spi_sam_fast_rx(Spi *regs, const struct spi_buf *rx_buf) static void spi_sam_fast_rx(Spi *regs, const struct spi_buf *rx_buf)
{ {
struct k_spinlock lock;
k_spinlock_key_t key = k_spin_lock(&lock);
uint8_t *rx = rx_buf->buf; uint8_t *rx = rx_buf->buf;
int len = rx_buf->len; int len = rx_buf->len;
@ -234,6 +242,8 @@ static void spi_sam_fast_rx(Spi *regs, const struct spi_buf *rx_buf)
*rx = (uint8_t)regs->SPI_RDR; *rx = (uint8_t)regs->SPI_RDR;
spi_sam_finish(regs); spi_sam_finish(regs);
k_spin_unlock(&lock, key);
} }
#ifdef CONFIG_SPI_SAM_DMA #ifdef CONFIG_SPI_SAM_DMA
@ -383,6 +393,9 @@ static void spi_sam_fast_txrx(Spi *regs,
const struct spi_buf *tx_buf, const struct spi_buf *tx_buf,
const struct spi_buf *rx_buf) const struct spi_buf *rx_buf)
{ {
struct k_spinlock lock;
k_spinlock_key_t key = k_spin_lock(&lock);
const uint8_t *tx = tx_buf->buf; const uint8_t *tx = tx_buf->buf;
const uint8_t *txend = (uint8_t *)tx_buf->buf + tx_buf->len; const uint8_t *txend = (uint8_t *)tx_buf->buf + tx_buf->len;
uint8_t *rx = rx_buf->buf; uint8_t *rx = rx_buf->buf;
@ -431,6 +444,8 @@ static void spi_sam_fast_txrx(Spi *regs,
*rx = (uint8_t)regs->SPI_RDR; *rx = (uint8_t)regs->SPI_RDR;
spi_sam_finish(regs); spi_sam_finish(regs);
k_spin_unlock(&lock, key);
} }
static inline void spi_sam_rx(const struct device *dev, static inline void spi_sam_rx(const struct device *dev,