[U-Boot] [PATCH 04/31] powerpc: 82xx serial: add configurable SMC Rx buffer len

[Heiko Schocher <hs@denx.de>]

This patch adds the configuration option CONFIG_SYS_SMC_RXBUFLEN.
With this option it is possible to allow the receive
buffer for the SMC on 82xx to be greater then 1. In case
CONFIG_SYS_SMC_RXBUFLEN == 1 or it is not defined this driver
works as the old version.

Signed-off-by: Heiko Schocher <hs@denx.de>
---
 cpu/mpc8260/serial_smc.c |   94 +++++++++++++++++++++++++++++++---------------
 include/configs/mgcoge.h |    1 +
 2 files changed, 64 insertions(+), 31 deletions(-)

diff --git a/cpu/mpc8260/serial_smc.c b/cpu/mpc8260/serial_smc.c
index a6efa66..6825e2e 100644
--- a/cpu/mpc8260/serial_smc.c
+++ b/cpu/mpc8260/serial_smc.c
@@ -64,6 +64,18 @@ DECLARE_GLOBAL_DATA_PTR;

 #endif

+typedef volatile struct serialbuffer {
+	cbd_t	rxbd;		/* Rx BD */
+	cbd_t	txbd;		/* Tx BD */
+#ifdef CONFIG_SYS_SMC_RXBUFLEN
+	uint	rxindex;	/* index for next character to read */
+	volatile uchar	rxbuf[CONFIG_SYS_SMC_RXBUFLEN];/* rx buffers */
+#else
+	volatile uchar	rxbuf[1];	/* rx buffers */
+#endif
+	volatile uchar	txbuf;	/* tx buffers */
+} serialbuffer_t;
+
 /* map rs_table index to baud rate generator index */
 static unsigned char brg_map[] = {
 	6,	/* BRG7 for SMC1 */
@@ -79,9 +91,9 @@ int serial_init (void)
 	volatile immap_t *im = (immap_t *)CONFIG_SYS_IMMR;
 	volatile smc_t *sp;
 	volatile smc_uart_t *up;
-	volatile cbd_t *tbdf, *rbdf;
 	volatile cpm8260_t *cp = &(im->im_cpm);
 	uint	dpaddr;
+	volatile serialbuffer_t *rtx;

 	/* initialize pointers to SMC */

@@ -99,17 +111,21 @@ int serial_init (void)
 	 * damm: allocating space after the two buffers for rx/tx data
 	 */

-	dpaddr = m8260_cpm_dpalloc((2 * sizeof (cbd_t)) + 2, 16);
+	/* allocate
+	 * size of struct serialbuffer with bd rx/tx, buffer rx/tx and rx index
+	 */
+	dpaddr = m8260_cpm_dpalloc((sizeof(serialbuffer_t)), 16);
+
+	rtx = (serialbuffer_t *)&im->im_dprambase[dpaddr];

 	/* Set the physical address of the host memory buffers in
 	 * the buffer descriptors.
 	 */
-	rbdf = (cbd_t *)&im->im_dprambase[dpaddr];
-	rbdf->cbd_bufaddr = (uint) (rbdf+2);
-	rbdf->cbd_sc = 0;
-	tbdf = rbdf + 1;
-	tbdf->cbd_bufaddr = ((uint) (rbdf+2)) + 1;
-	tbdf->cbd_sc = 0;
+	rtx->rxbd.cbd_bufaddr = (uint) &rtx->rxbuf;
+	rtx->rxbd.cbd_sc      = 0;
+
+	rtx->txbd.cbd_bufaddr = (uint) &rtx->txbuf;
+	rtx->txbd.cbd_sc      = 0;

 	/* Set up the uart parameters in the parameter ram.
 	*/
@@ -142,13 +158,21 @@ int serial_init (void)

 	/* Make the first buffer the only buffer.
 	*/
-	tbdf->cbd_sc |= BD_SC_WRAP;
-	rbdf->cbd_sc |= BD_SC_EMPTY | BD_SC_WRAP;
+	rtx->txbd.cbd_sc |= BD_SC_WRAP;
+	rtx->rxbd.cbd_sc |= BD_SC_EMPTY | BD_SC_WRAP;

+#ifdef CONFIG_SYS_SMC_RXBUFLEN
+	/* multi-character receive.
+	*/
+	up->smc_mrblr = CONFIG_SYS_SMC_RXBUFLEN;
+	up->smc_maxidl = 10;
+	rtx->rxindex = 0;
+#else
 	/* Single character receive.
 	*/
 	up->smc_mrblr = 1;
 	up->smc_maxidl = 0;
+#endif

 	/* Initialize Tx/Rx parameters.
 	*/
@@ -183,27 +207,24 @@ serial_setbrg (void)
 void
 serial_putc(const char c)
 {
-	volatile cbd_t		*tbdf;
-	volatile char		*buf;
 	volatile smc_uart_t	*up;
 	volatile immap_t	*im = (immap_t *)CONFIG_SYS_IMMR;
+	volatile serialbuffer_t	*rtx;

 	if (c == '\n')
 		serial_putc ('\r');

 	up = (smc_uart_t *)&(im->im_dprambase[PROFF_SMC]);

-	tbdf = (cbd_t *)&im->im_dprambase[up->smc_tbase];
+	rtx = (serialbuffer_t *)&im->im_dprambase[up->smc_rbase];

 	/* Wait for last character to go.
 	*/
-	buf = (char *)tbdf->cbd_bufaddr;
-	while (tbdf->cbd_sc & BD_SC_READY)
+	while (rtx->txbd.cbd_sc & BD_SC_READY & BD_SC_READY)
 		;
-
-	*buf = c;
-	tbdf->cbd_datlen = 1;
-	tbdf->cbd_sc |= BD_SC_READY;
+	rtx->txbuf = c;
+	rtx->txbd.cbd_datlen = 1;
+	rtx->txbd.cbd_sc |= BD_SC_READY;
 }

 void
@@ -217,39 +238,50 @@ serial_puts (const char *s)
 int
 serial_getc(void)
 {
-	volatile cbd_t		*rbdf;
-	volatile unsigned char	*buf;
 	volatile smc_uart_t	*up;
 	volatile immap_t	*im = (immap_t *)CONFIG_SYS_IMMR;
-	unsigned char		c;
+	volatile serialbuffer_t	*rtx;
+	unsigned char  c;

 	up = (smc_uart_t *)&(im->im_dprambase[PROFF_SMC]);

-	rbdf = (cbd_t *)&im->im_dprambase[up->smc_rbase];
+	rtx = (serialbuffer_t *)&im->im_dprambase[up->smc_rbase];

 	/* Wait for character to show up.
 	*/
-	buf = (unsigned char *)rbdf->cbd_bufaddr;
-	while (rbdf->cbd_sc & BD_SC_EMPTY)
+	while (rtx->rxbd.cbd_sc & BD_SC_EMPTY)
 		;
-	c = *buf;
-	rbdf->cbd_sc |= BD_SC_EMPTY;

+#ifdef CONFIG_SYS_SMC_RXBUFLEN
+	/* the characters are read one by one,
+	 * use the rxindex to know the next char to deliver
+	 */
+	c = *(unsigned char *) (rtx->rxbd.cbd_bufaddr+rtx->rxindex);
+	rtx->rxindex++;
+
+	/* check if all char are readout, then make prepare for next receive */
+	if (rtx->rxindex >= rtx->rxbd.cbd_datlen) {
+		rtx->rxindex = 0;
+	rtx->rxbd.cbd_sc |= BD_SC_EMPTY;
+	}
+#else
+	c = *(unsigned char *) (rtx->rxbd.cbd_bufaddr);
+	rtx->rxbd.cbd_sc |= BD_SC_EMPTY;
+#endif
 	return(c);
 }

 int
 serial_tstc()
 {
-	volatile cbd_t		*rbdf;
 	volatile smc_uart_t	*up;
 	volatile immap_t	*im = (immap_t *)CONFIG_SYS_IMMR;
+	volatile serialbuffer_t	*rtx;

 	up = (smc_uart_t *)&(im->im_dprambase[PROFF_SMC]);
+	rtx = (serialbuffer_t *)&im->im_dprambase[up->smc_rbase];

-	rbdf = (cbd_t *)&im->im_dprambase[up->smc_rbase];
-
-	return(!(rbdf->cbd_sc & BD_SC_EMPTY));
+	return !(rtx->rxbd.cbd_sc & BD_SC_EMPTY);
 }

 #endif	/* CONFIG_CONS_ON_SMC */
diff --git a/include/configs/mgcoge.h b/include/configs/mgcoge.h
index 9416a03..ddb06aa 100644
--- a/include/configs/mgcoge.h
+++ b/include/configs/mgcoge.h
@@ -49,6 +49,7 @@
 #undef  CONFIG_CONS_ON_SCC		/* It's not on SCC           */
 #undef	CONFIG_CONS_NONE		/* It's not on external UART */
 #define CONFIG_CONS_INDEX	2	/* SMC2 is used for console  */
+#define CONFIG_SYS_SMC_RXBUFLEN	16

 /*
  * Select ethernet configuration
-- 
1.6.0.6

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany