* [PATCH 2/3] SPI: spi_sh_msiof: consolidate data in 8-bit mode into 32-bit words
@ 2011-01-21 15:56 Guennadi Liakhovetski
2011-01-21 17:02 ` Grant Likely
0 siblings, 1 reply; 2+ messages in thread
From: Guennadi Liakhovetski @ 2011-01-21 15:56 UTC (permalink / raw)
To: spi-devel-general; +Cc: linux-sh
Instead of sending data 8 bits at a time in 8-bit SPI mode, swap bytes
and send and receive them 32 bits at a time. Tested with an SD-card,
with which this patch reduced the number of interrupts by 50%, when
reading 5MiB of data (there are also small service packets, the number
of interrupts, produced by 512-byte sectors should, of course, drop by
75%), and improved throughput by more than 40%.
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
---
drivers/spi/spi_sh_msiof.c | 59 ++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 59 insertions(+), 0 deletions(-)
diff --git a/drivers/spi/spi_sh_msiof.c b/drivers/spi/spi_sh_msiof.c
index 07b4ead..658bd05 100644
--- a/drivers/spi/spi_sh_msiof.c
+++ b/drivers/spi/spi_sh_msiof.c
@@ -267,6 +267,26 @@ static void sh_msiof_spi_write_fifo_32u(struct sh_msiof_spi_priv *p,
sh_msiof_write(p, TFDR, get_unaligned(&buf_32[k]) << fs);
}
+static void sh_msiof_spi_write_fifo_s32(struct sh_msiof_spi_priv *p,
+ const void *tx_buf, int words, int fs)
+{
+ const u32 *buf_32 = tx_buf;
+ int k;
+
+ for (k = 0; k < words; k++)
+ sh_msiof_write(p, TFDR, swab32(buf_32[k] << fs));
+}
+
+static void sh_msiof_spi_write_fifo_s32u(struct sh_msiof_spi_priv *p,
+ const void *tx_buf, int words, int fs)
+{
+ const u32 *buf_32 = tx_buf;
+ int k;
+
+ for (k = 0; k < words; k++)
+ sh_msiof_write(p, TFDR, swab32(get_unaligned(&buf_32[k]) << fs));
+}
+
static void sh_msiof_spi_read_fifo_8(struct sh_msiof_spi_priv *p,
void *rx_buf, int words, int fs)
{
@@ -317,6 +337,26 @@ static void sh_msiof_spi_read_fifo_32u(struct sh_msiof_spi_priv *p,
put_unaligned(sh_msiof_read(p, RFDR) >> fs, &buf_32[k]);
}
+static void sh_msiof_spi_read_fifo_s32(struct sh_msiof_spi_priv *p,
+ void *rx_buf, int words, int fs)
+{
+ u32 *buf_32 = rx_buf;
+ int k;
+
+ for (k = 0; k < words; k++)
+ buf_32[k] = swab32(sh_msiof_read(p, RFDR) >> fs);
+}
+
+static void sh_msiof_spi_read_fifo_s32u(struct sh_msiof_spi_priv *p,
+ void *rx_buf, int words, int fs)
+{
+ u32 *buf_32 = rx_buf;
+ int k;
+
+ for (k = 0; k < words; k++)
+ put_unaligned(swab32(sh_msiof_read(p, RFDR) >> fs), &buf_32[k]);
+}
+
static int sh_msiof_spi_bits(struct spi_device *spi, struct spi_transfer *t)
{
int bits;
@@ -468,9 +508,17 @@ static int sh_msiof_spi_txrx(struct spi_device *spi, struct spi_transfer *t)
int bytes_done;
int words;
int n;
+ bool swab;
bits = sh_msiof_spi_bits(spi, t);
+ if (bits <= 8 && t->len > 15 && !(t->len & 3)) {
+ bits = 32;
+ swab = true;
+ } else {
+ swab = false;
+ }
+
/* setup bytes per word and fifo read/write functions */
if (bits <= 8) {
bytes_per_word = 1;
@@ -487,6 +535,17 @@ static int sh_msiof_spi_txrx(struct spi_device *spi, struct spi_transfer *t)
rx_fifo = sh_msiof_spi_read_fifo_16u;
else
rx_fifo = sh_msiof_spi_read_fifo_16;
+ } else if (swab) {
+ bytes_per_word = 4;
+ if ((unsigned long)t->tx_buf & 0x03)
+ tx_fifo = sh_msiof_spi_write_fifo_s32u;
+ else
+ tx_fifo = sh_msiof_spi_write_fifo_s32;
+
+ if ((unsigned long)t->rx_buf & 0x03)
+ rx_fifo = sh_msiof_spi_read_fifo_s32u;
+ else
+ rx_fifo = sh_msiof_spi_read_fifo_s32;
} else {
bytes_per_word = 4;
if ((unsigned long)t->tx_buf & 0x03)
--
1.7.2.3
^ permalink raw reply related [flat|nested] 2+ messages in thread* Re: [PATCH 2/3] SPI: spi_sh_msiof: consolidate data in 8-bit mode into 32-bit words
2011-01-21 15:56 [PATCH 2/3] SPI: spi_sh_msiof: consolidate data in 8-bit mode into 32-bit words Guennadi Liakhovetski
@ 2011-01-21 17:02 ` Grant Likely
0 siblings, 0 replies; 2+ messages in thread
From: Grant Likely @ 2011-01-21 17:02 UTC (permalink / raw)
To: Guennadi Liakhovetski; +Cc: spi-devel-general, linux-sh
On Fri, Jan 21, 2011 at 04:56:42PM +0100, Guennadi Liakhovetski wrote:
> Instead of sending data 8 bits at a time in 8-bit SPI mode, swap bytes
> and send and receive them 32 bits at a time. Tested with an SD-card,
> with which this patch reduced the number of interrupts by 50%, when
> reading 5MiB of data (there are also small service packets, the number
> of interrupts, produced by 512-byte sectors should, of course, drop by
> 75%), and improved throughput by more than 40%.
>
> Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Merged, thanks.
g.
> ---
> drivers/spi/spi_sh_msiof.c | 59 ++++++++++++++++++++++++++++++++++++++++++++
> 1 files changed, 59 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/spi/spi_sh_msiof.c b/drivers/spi/spi_sh_msiof.c
> index 07b4ead..658bd05 100644
> --- a/drivers/spi/spi_sh_msiof.c
> +++ b/drivers/spi/spi_sh_msiof.c
> @@ -267,6 +267,26 @@ static void sh_msiof_spi_write_fifo_32u(struct sh_msiof_spi_priv *p,
> sh_msiof_write(p, TFDR, get_unaligned(&buf_32[k]) << fs);
> }
>
> +static void sh_msiof_spi_write_fifo_s32(struct sh_msiof_spi_priv *p,
> + const void *tx_buf, int words, int fs)
> +{
> + const u32 *buf_32 = tx_buf;
> + int k;
> +
> + for (k = 0; k < words; k++)
> + sh_msiof_write(p, TFDR, swab32(buf_32[k] << fs));
> +}
> +
> +static void sh_msiof_spi_write_fifo_s32u(struct sh_msiof_spi_priv *p,
> + const void *tx_buf, int words, int fs)
> +{
> + const u32 *buf_32 = tx_buf;
> + int k;
> +
> + for (k = 0; k < words; k++)
> + sh_msiof_write(p, TFDR, swab32(get_unaligned(&buf_32[k]) << fs));
> +}
> +
> static void sh_msiof_spi_read_fifo_8(struct sh_msiof_spi_priv *p,
> void *rx_buf, int words, int fs)
> {
> @@ -317,6 +337,26 @@ static void sh_msiof_spi_read_fifo_32u(struct sh_msiof_spi_priv *p,
> put_unaligned(sh_msiof_read(p, RFDR) >> fs, &buf_32[k]);
> }
>
> +static void sh_msiof_spi_read_fifo_s32(struct sh_msiof_spi_priv *p,
> + void *rx_buf, int words, int fs)
> +{
> + u32 *buf_32 = rx_buf;
> + int k;
> +
> + for (k = 0; k < words; k++)
> + buf_32[k] = swab32(sh_msiof_read(p, RFDR) >> fs);
> +}
> +
> +static void sh_msiof_spi_read_fifo_s32u(struct sh_msiof_spi_priv *p,
> + void *rx_buf, int words, int fs)
> +{
> + u32 *buf_32 = rx_buf;
> + int k;
> +
> + for (k = 0; k < words; k++)
> + put_unaligned(swab32(sh_msiof_read(p, RFDR) >> fs), &buf_32[k]);
> +}
> +
> static int sh_msiof_spi_bits(struct spi_device *spi, struct spi_transfer *t)
> {
> int bits;
> @@ -468,9 +508,17 @@ static int sh_msiof_spi_txrx(struct spi_device *spi, struct spi_transfer *t)
> int bytes_done;
> int words;
> int n;
> + bool swab;
>
> bits = sh_msiof_spi_bits(spi, t);
>
> + if (bits <= 8 && t->len > 15 && !(t->len & 3)) {
> + bits = 32;
> + swab = true;
> + } else {
> + swab = false;
> + }
> +
> /* setup bytes per word and fifo read/write functions */
> if (bits <= 8) {
> bytes_per_word = 1;
> @@ -487,6 +535,17 @@ static int sh_msiof_spi_txrx(struct spi_device *spi, struct spi_transfer *t)
> rx_fifo = sh_msiof_spi_read_fifo_16u;
> else
> rx_fifo = sh_msiof_spi_read_fifo_16;
> + } else if (swab) {
> + bytes_per_word = 4;
> + if ((unsigned long)t->tx_buf & 0x03)
> + tx_fifo = sh_msiof_spi_write_fifo_s32u;
> + else
> + tx_fifo = sh_msiof_spi_write_fifo_s32;
> +
> + if ((unsigned long)t->rx_buf & 0x03)
> + rx_fifo = sh_msiof_spi_read_fifo_s32u;
> + else
> + rx_fifo = sh_msiof_spi_read_fifo_s32;
> } else {
> bytes_per_word = 4;
> if ((unsigned long)t->tx_buf & 0x03)
> --
> 1.7.2.3
>
>
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2011-01-21 15:56 [PATCH 2/3] SPI: spi_sh_msiof: consolidate data in 8-bit mode into 32-bit words Guennadi Liakhovetski
2011-01-21 17:02 ` Grant Likely
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