* Subject: [PATCH] serial:ifx6x60:add swap_buf_32 function in case SPI word width is 32 bits
@ 2012-10-23 8:32 chao bi
2012-10-23 9:39 ` Alan Cox
0 siblings, 1 reply; 3+ messages in thread
From: chao bi @ 2012-10-23 8:32 UTC (permalink / raw)
To: alan; +Cc: linux-serial, richardx.r.gorby, jun.d.chen, chuansheng.liu
SPI protocol driver only provide one function (swap_buf()) to swap SPI data
into big endian format, which is only available when SPI controller's word width
is 16 bits. But per our experiment and validation on medfield platform, 16 bit
word width cannot cover all scenarioes, 32 bits word width is a better choice
to avoid SPI FIFO overrun. Therefore, SPI controller is likely to configure its
word width as either 16 bits or 32 bits. This patch is to implement 2 functions
(swap_buf_16() and swap_buf_32()) to adapt the two configurations.
cc: liu chuansheng <chuansheng.liu@intel.com>
cc: Chen Jun <jun.d.chen@intel.com>
Signed-off-by: channing <chao.bi@intel.com>
---
drivers/tty/serial/ifx6x60.c | 51 +++++++++++++++++++++++++++++++++--------
1 files changed, 41 insertions(+), 10 deletions(-)
diff --git a/drivers/tty/serial/ifx6x60.c b/drivers/tty/serial/ifx6x60.c
index 5b9bc19..ad718ec 100644
--- a/drivers/tty/serial/ifx6x60.c
+++ b/drivers/tty/serial/ifx6x60.c
@@ -151,29 +151,60 @@ ifx_spi_power_state_clear(struct ifx_spi_device *ifx_dev, unsigned char val)
spin_unlock_irqrestore(&ifx_dev->power_lock, flags);
}
+#ifdef SPI_CONTROLLER_USE_32_BITS_PER_WORD
+#define SWAP_BUF swap_buf_32
/**
- * swap_buf
+ * swap_buf_32
* @buf: our buffer
* @len : number of bytes (not words) in the buffer
* @end: end of buffer
*
* Swap the contents of a buffer into big endian format
*/
-static inline void swap_buf(u16 *buf, int len, void *end)
+static inline void swap_buf_32(unsigned char *buf, int len, void *end)
{
int n;
+ u32 *buf_32 = (u32 *)buf;
+ len = (0 == (len&0x03)) ? (len >> 2) : ((len >> 2) + 1);
+
+ if ((void *)&buf_32[len] > end) {
+ pr_err("swap_buf_32: swap exceeds boundary (%p > %p)!\n",
+ &buf_32[len], end);
+ return;
+ }
+ for (n = 0; n < len; n++) {
+ *buf_32 = cpu_to_be32(*buf_32);
+ buf_32++;
+ }
+}
+#else
+#define SWAP_BUF swap_buf_16
+/**
+ * swap_buf_16
+ * @buf: our buffer
+ * @len : number of bytes (not words) in the buffer
+ * @end: end of buffer
+ *
+ * Swap the contents of a buffer into big endian format
+ */
+static inline void swap_buf_16(unsigned char *buf, int len, void *end)
+{
+ int n;
+
+ u16 *buf_16 = (u16 *)buf;
len = ((len + 1) >> 1);
- if ((void *)&buf[len] > end) {
- pr_err("swap_buf: swap exceeds boundary (%p > %p)!",
- &buf[len], end);
+ if ((void *)&buf_16[len] > end) {
+ pr_err("swap_buf_16: swap exceeds boundary (%p > %p)!",
+ &buf_16[len], end);
return;
}
for (n = 0; n < len; n++) {
- *buf = cpu_to_be16(*buf);
- buf++;
+ *buf_16 = cpu_to_be16(*buf_16);
+ buf_16++;
}
}
+#endif
/**
* mrdy_assert - assert MRDY line
@@ -449,7 +480,7 @@ static int ifx_spi_prepare_tx_buffer(struct ifx_spi_device *ifx_dev)
tx_count-IFX_SPI_HEADER_OVERHEAD,
ifx_dev->spi_more);
/* swap actual data in the buffer */
- swap_buf((u16 *)(ifx_dev->tx_buffer), tx_count,
+ SWAP_BUF((ifx_dev->tx_buffer), tx_count,
&ifx_dev->tx_buffer[IFX_SPI_TRANSFER_SIZE]);
return tx_count;
}
@@ -617,7 +648,7 @@ static void ifx_spi_complete(void *ctx)
if (!ifx_dev->spi_msg.status) {
/* check header validity, get comm flags */
- swap_buf((u16 *)ifx_dev->rx_buffer, IFX_SPI_HEADER_OVERHEAD,
+ SWAP_BUF(ifx_dev->rx_buffer, IFX_SPI_HEADER_OVERHEAD,
&ifx_dev->rx_buffer[IFX_SPI_HEADER_OVERHEAD]);
decode_result = ifx_spi_decode_spi_header(ifx_dev->rx_buffer,
&length, &more, &cts);
@@ -636,7 +667,7 @@ static void ifx_spi_complete(void *ctx)
actual_length = min((unsigned int)length,
ifx_dev->spi_msg.actual_length);
- swap_buf((u16 *)(ifx_dev->rx_buffer + IFX_SPI_HEADER_OVERHEAD),
+ SWAP_BUF((ifx_dev->rx_buffer + IFX_SPI_HEADER_OVERHEAD),
actual_length,
&ifx_dev->rx_buffer[IFX_SPI_TRANSFER_SIZE]);
ifx_spi_insert_flip_string(
--
1.7.1
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: Subject: [PATCH] serial:ifx6x60:add swap_buf_32 function in case SPI word width is 32 bits
2012-10-23 8:32 Subject: [PATCH] serial:ifx6x60:add swap_buf_32 function in case SPI word width is 32 bits chao bi
@ 2012-10-23 9:39 ` Alan Cox
2012-10-24 6:43 ` Bi, Chao
0 siblings, 1 reply; 3+ messages in thread
From: Alan Cox @ 2012-10-23 9:39 UTC (permalink / raw)
To: chao bi; +Cc: alan, linux-serial, richardx.r.gorby, jun.d.chen, chuansheng.liu
> is 16 bits. But per our experiment and validation on medfield platform, 16 bit
> word width cannot cover all scenarioes, 32 bits word width is a better choice
> to avoid SPI FIFO overrun. Therefore, SPI controller is likely to configure its
> word width as either 16 bits or 32 bits. This patch is to implement 2 functions
> (swap_buf_16() and swap_buf_32()) to adapt the two configurations.
And how will you get both to work with the same kernel, which is the way
Linux wants to work (and avoids the nasty mess some other embedded
platforms have gotten themselves into).
What you probably want to do is is put a 16/32bit flag into the platform
data and then in ifx_spi_spi_probe() just do
if (pl_data->spi_32)
ifx_dev->swap = swap_buf_32;
else
ifx_dev->swap = swap_buf;
then call
ifx_dev->swap_buf()
Alan
^ permalink raw reply [flat|nested] 3+ messages in thread
* RE: Subject: [PATCH] serial:ifx6x60:add swap_buf_32 function in case SPI word width is 32 bits
2012-10-23 9:39 ` Alan Cox
@ 2012-10-24 6:43 ` Bi, Chao
0 siblings, 0 replies; 3+ messages in thread
From: Bi, Chao @ 2012-10-24 6:43 UTC (permalink / raw)
To: Alan Cox
Cc: alan@linux.intel.com, linux-serial@vger.kernel.org, Gorby, Russ,
Chen, Jun D, Liu, Chuansheng
Hi Alan,
Yes, you're right.
SPI word width is configured by Protocol driver in ifx_spi_spi_probe(), it could be 8/16/32 bits, so Protocol driver should choose diff swap method according to the configuration.
I've update the patch as your suggestion, please check another PATCH mail.
Thanks!
Chao
-----Original Message-----
From: Alan Cox [mailto:alan@lxorguk.ukuu.org.uk]
Sent: Tuesday, October 23, 2012 5:39 PM
To: Bi, Chao
Cc: alan@linux.intel.com; linux-serial@vger.kernel.org; Gorby, Russ; Chen, Jun D; Liu, Chuansheng
Subject: Re: Subject: [PATCH] serial:ifx6x60:add swap_buf_32 function in case SPI word width is 32 bits
> is 16 bits. But per our experiment and validation on medfield
> platform, 16 bit word width cannot cover all scenarioes, 32 bits word
> width is a better choice to avoid SPI FIFO overrun. Therefore, SPI
> controller is likely to configure its word width as either 16 bits or
> 32 bits. This patch is to implement 2 functions
> (swap_buf_16() and swap_buf_32()) to adapt the two configurations.
And how will you get both to work with the same kernel, which is the way Linux wants to work (and avoids the nasty mess some other embedded platforms have gotten themselves into).
What you probably want to do is is put a 16/32bit flag into the platform data and then in ifx_spi_spi_probe() just do
if (pl_data->spi_32)
ifx_dev->swap = swap_buf_32;
else
ifx_dev->swap = swap_buf;
then call
ifx_dev->swap_buf()
Alan
^ permalink raw reply [flat|nested] 3+ messages in thread
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2012-10-23 8:32 Subject: [PATCH] serial:ifx6x60:add swap_buf_32 function in case SPI word width is 32 bits chao bi
2012-10-23 9:39 ` Alan Cox
2012-10-24 6:43 ` Bi, Chao
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