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spi: dw-spi: Convert 16bit accesses to 32bit accesses
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Altera's Arria10 SoC interconnect requires a 32-bit write for APB
peripherals. The current spi-dw driver uses 16-bit accesses in
some locations. This patch converts all the 16-bit reads and
writes to 32-bit reads and writes.

Additional Documentation to Support this Change:
The DW_apb_ssi databook states:
"All registers in the DW_apb_ssi are addressed at 32-bit boundaries
to remain consistent with the AHB bus. Where the physical size of
any register is less than 32-bits wide, the upper unused bits of
the 32-bit boundary are reserved. Writing to these bits has no
effect; reading from these bits returns 0." [1]

[1] Section 6.1 of dw_apb_ssi.pdf (version 3.22a)

Request for test with platforms using the DesignWare SPI IP.

Tested On:
Altera CycloneV development kit
Altera Arria10 development kit
Compile tested for build errors on x86_64 (allyesconfigs)

Signed-off-by: Thor Thayer <tthayer@opensource.altera.com>
Reviewed-and-tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
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Thor Thayer authored and Mark Brown committed Mar 17, 2015
1 parent 2306509 commit dd11444
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Showing 3 changed files with 17 additions and 27 deletions.
10 changes: 5 additions & 5 deletions drivers/spi/spi-dw-mid.c
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Original file line number Diff line number Diff line change
Expand Up @@ -98,12 +98,12 @@ static void mid_spi_dma_exit(struct dw_spi *dws)

static irqreturn_t dma_transfer(struct dw_spi *dws)
{
u16 irq_status = dw_readw(dws, DW_SPI_ISR);
u16 irq_status = dw_readl(dws, DW_SPI_ISR);

if (!irq_status)
return IRQ_NONE;

dw_readw(dws, DW_SPI_ICR);
dw_readl(dws, DW_SPI_ICR);
spi_reset_chip(dws);

dev_err(&dws->master->dev, "%s: FIFO overrun/underrun\n", __func__);
Expand Down Expand Up @@ -228,14 +228,14 @@ static int mid_spi_dma_setup(struct dw_spi *dws, struct spi_transfer *xfer)
{
u16 dma_ctrl = 0;

dw_writew(dws, DW_SPI_DMARDLR, 0xf);
dw_writew(dws, DW_SPI_DMATDLR, 0x10);
dw_writel(dws, DW_SPI_DMARDLR, 0xf);
dw_writel(dws, DW_SPI_DMATDLR, 0x10);

if (xfer->tx_buf)
dma_ctrl |= SPI_DMA_TDMAE;
if (xfer->rx_buf)
dma_ctrl |= SPI_DMA_RDMAE;
dw_writew(dws, DW_SPI_DMACR, dma_ctrl);
dw_writel(dws, DW_SPI_DMACR, dma_ctrl);

/* Set the interrupt mask */
spi_umask_intr(dws, SPI_INT_TXOI | SPI_INT_RXUI | SPI_INT_RXOI);
Expand Down
24 changes: 12 additions & 12 deletions drivers/spi/spi-dw.c
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Original file line number Diff line number Diff line change
Expand Up @@ -157,7 +157,7 @@ static inline u32 tx_max(struct dw_spi *dws)
u32 tx_left, tx_room, rxtx_gap;

tx_left = (dws->tx_end - dws->tx) / dws->n_bytes;
tx_room = dws->fifo_len - dw_readw(dws, DW_SPI_TXFLR);
tx_room = dws->fifo_len - dw_readl(dws, DW_SPI_TXFLR);

/*
* Another concern is about the tx/rx mismatch, we
Expand All @@ -178,7 +178,7 @@ static inline u32 rx_max(struct dw_spi *dws)
{
u32 rx_left = (dws->rx_end - dws->rx) / dws->n_bytes;

return min_t(u32, rx_left, dw_readw(dws, DW_SPI_RXFLR));
return min_t(u32, rx_left, dw_readl(dws, DW_SPI_RXFLR));
}

static void dw_writer(struct dw_spi *dws)
Expand All @@ -194,7 +194,7 @@ static void dw_writer(struct dw_spi *dws)
else
txw = *(u16 *)(dws->tx);
}
dw_writew(dws, DW_SPI_DR, txw);
dw_writel(dws, DW_SPI_DR, txw);
dws->tx += dws->n_bytes;
}
}
Expand All @@ -205,7 +205,7 @@ static void dw_reader(struct dw_spi *dws)
u16 rxw;

while (max--) {
rxw = dw_readw(dws, DW_SPI_DR);
rxw = dw_readl(dws, DW_SPI_DR);
/* Care rx only if the transfer's original "rx" is not null */
if (dws->rx_end - dws->len) {
if (dws->n_bytes == 1)
Expand All @@ -228,11 +228,11 @@ static void int_error_stop(struct dw_spi *dws, const char *msg)

static irqreturn_t interrupt_transfer(struct dw_spi *dws)
{
u16 irq_status = dw_readw(dws, DW_SPI_ISR);
u16 irq_status = dw_readl(dws, DW_SPI_ISR);

/* Error handling */
if (irq_status & (SPI_INT_TXOI | SPI_INT_RXOI | SPI_INT_RXUI)) {
dw_readw(dws, DW_SPI_ICR);
dw_readl(dws, DW_SPI_ICR);
int_error_stop(dws, "interrupt_transfer: fifo overrun/underrun");
return IRQ_HANDLED;
}
Expand All @@ -257,7 +257,7 @@ static irqreturn_t dw_spi_irq(int irq, void *dev_id)
{
struct spi_master *master = dev_id;
struct dw_spi *dws = spi_master_get_devdata(master);
u16 irq_status = dw_readw(dws, DW_SPI_ISR) & 0x3f;
u16 irq_status = dw_readl(dws, DW_SPI_ISR) & 0x3f;

if (!irq_status)
return IRQ_NONE;
Expand Down Expand Up @@ -354,7 +354,7 @@ static int dw_spi_transfer_one(struct spi_master *master,
cr0 |= (chip->tmode << SPI_TMOD_OFFSET);
}

dw_writew(dws, DW_SPI_CTRL0, cr0);
dw_writel(dws, DW_SPI_CTRL0, cr0);

/* Check if current transfer is a DMA transaction */
if (master->can_dma && master->can_dma(master, spi, transfer))
Expand All @@ -375,7 +375,7 @@ static int dw_spi_transfer_one(struct spi_master *master,
}
} else if (!chip->poll_mode) {
txlevel = min_t(u16, dws->fifo_len / 2, dws->len / dws->n_bytes);
dw_writew(dws, DW_SPI_TXFLTR, txlevel);
dw_writel(dws, DW_SPI_TXFLTR, txlevel);

/* Set the interrupt mask */
imask |= SPI_INT_TXEI | SPI_INT_TXOI |
Expand Down Expand Up @@ -499,11 +499,11 @@ static void spi_hw_init(struct device *dev, struct dw_spi *dws)
u32 fifo;

for (fifo = 1; fifo < 256; fifo++) {
dw_writew(dws, DW_SPI_TXFLTR, fifo);
if (fifo != dw_readw(dws, DW_SPI_TXFLTR))
dw_writel(dws, DW_SPI_TXFLTR, fifo);
if (fifo != dw_readl(dws, DW_SPI_TXFLTR))
break;
}
dw_writew(dws, DW_SPI_TXFLTR, 0);
dw_writel(dws, DW_SPI_TXFLTR, 0);

dws->fifo_len = (fifo == 1) ? 0 : fifo;
dev_dbg(dev, "Detected FIFO size: %u bytes\n", dws->fifo_len);
Expand Down
10 changes: 0 additions & 10 deletions drivers/spi/spi-dw.h
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Original file line number Diff line number Diff line change
Expand Up @@ -150,16 +150,6 @@ static inline void dw_writel(struct dw_spi *dws, u32 offset, u32 val)
__raw_writel(val, dws->regs + offset);
}

static inline u16 dw_readw(struct dw_spi *dws, u32 offset)
{
return __raw_readw(dws->regs + offset);
}

static inline void dw_writew(struct dw_spi *dws, u32 offset, u16 val)
{
__raw_writew(val, dws->regs + offset);
}

static inline void spi_enable_chip(struct dw_spi *dws, int enable)
{
dw_writel(dws, DW_SPI_SSIENR, (enable ? 1 : 0));
Expand Down

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