diff mbox

[1/2] eSPI: change the read behavior of the SPIRF

Message ID 1292894768-6737-1-git-send-email-Mingkai.hu@freescale.com (mailing list archive)
State Not Applicable
Delegated to: Grant Likely
Headers show

Commit Message

Mingkai Hu Dec. 21, 2010, 1:26 a.m. UTC
The user must read N bytes of SPIRF (1 <= N <= 4) that do not exceed the
amount of data in the receive FIFO, so read the SPIRF byte by byte when
the data in receive FIFO is less than 4 bytes.

On Simics, when read N bytes that exceed the amout of data in receive
FIFO, we can't read the data out, that is we can't clear the rx FIFO,
then the CPU will loop on the espi rx interrupt.

Signed-off-by: Mingkai Hu <Mingkai.hu@freescale.com>
---
The patch 2/2 is againsted on this patch, so I resent this patch again
for convience which sent several weeks ago.

 drivers/spi/spi_fsl_espi.c |   19 ++++++++++++++++---
 1 files changed, 16 insertions(+), 3 deletions(-)

Comments

Grant Likely Dec. 24, 2010, 8:55 a.m. UTC | #1
On Tue, Dec 21, 2010 at 09:26:07AM +0800, Mingkai Hu wrote:
> The user must read N bytes of SPIRF (1 <= N <= 4) that do not exceed the
> amount of data in the receive FIFO, so read the SPIRF byte by byte when
> the data in receive FIFO is less than 4 bytes.
> 
> On Simics, when read N bytes that exceed the amout of data in receive
> FIFO, we can't read the data out, that is we can't clear the rx FIFO,
> then the CPU will loop on the espi rx interrupt.
> 
> Signed-off-by: Mingkai Hu <Mingkai.hu@freescale.com>

Applied to merge branch for 2.6.27, thanks.

g.

> ---
> The patch 2/2 is againsted on this patch, so I resent this patch again
> for convience which sent several weeks ago.
> 
>  drivers/spi/spi_fsl_espi.c |   19 ++++++++++++++++---
>  1 files changed, 16 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/spi/spi_fsl_espi.c b/drivers/spi/spi_fsl_espi.c
> index e3b4f64..ae78926 100644
> --- a/drivers/spi/spi_fsl_espi.c
> +++ b/drivers/spi/spi_fsl_espi.c
> @@ -507,16 +507,29 @@ void fsl_espi_cpu_irq(struct mpc8xxx_spi *mspi, u32 events)
>  
>  	/* We need handle RX first */
>  	if (events & SPIE_NE) {
> -		u32 rx_data;
> +		u32 rx_data, tmp;
> +		u8 rx_data_8;
>  
>  		/* Spin until RX is done */
>  		while (SPIE_RXCNT(events) < min(4, mspi->len)) {
>  			cpu_relax();
>  			events = mpc8xxx_spi_read_reg(&reg_base->event);
>  		}
> -		mspi->len -= 4;
>  
> -		rx_data = mpc8xxx_spi_read_reg(&reg_base->receive);
> +		if (mspi->len >= 4) {
> +			rx_data = mpc8xxx_spi_read_reg(&reg_base->receive);
> +		} else {
> +			tmp = mspi->len;
> +			rx_data = 0;
> +			while (tmp--) {
> +				rx_data_8 = in_8((u8 *)&reg_base->receive);
> +				rx_data |= (rx_data_8 << (tmp * 8));
> +			}
> +
> +			rx_data <<= (4 - mspi->len) * 8;
> +		}
> +
> +		mspi->len -= 4;
>  
>  		if (mspi->rx)
>  			mspi->get_rx(rx_data, mspi);
> -- 
> 1.6.4
> 
>
diff mbox

Patch

diff --git a/drivers/spi/spi_fsl_espi.c b/drivers/spi/spi_fsl_espi.c
index e3b4f64..ae78926 100644
--- a/drivers/spi/spi_fsl_espi.c
+++ b/drivers/spi/spi_fsl_espi.c
@@ -507,16 +507,29 @@  void fsl_espi_cpu_irq(struct mpc8xxx_spi *mspi, u32 events)
 
 	/* We need handle RX first */
 	if (events & SPIE_NE) {
-		u32 rx_data;
+		u32 rx_data, tmp;
+		u8 rx_data_8;
 
 		/* Spin until RX is done */
 		while (SPIE_RXCNT(events) < min(4, mspi->len)) {
 			cpu_relax();
 			events = mpc8xxx_spi_read_reg(&reg_base->event);
 		}
-		mspi->len -= 4;
 
-		rx_data = mpc8xxx_spi_read_reg(&reg_base->receive);
+		if (mspi->len >= 4) {
+			rx_data = mpc8xxx_spi_read_reg(&reg_base->receive);
+		} else {
+			tmp = mspi->len;
+			rx_data = 0;
+			while (tmp--) {
+				rx_data_8 = in_8((u8 *)&reg_base->receive);
+				rx_data |= (rx_data_8 << (tmp * 8));
+			}
+
+			rx_data <<= (4 - mspi->len) * 8;
+		}
+
+		mspi->len -= 4;
 
 		if (mspi->rx)
 			mspi->get_rx(rx_data, mspi);