[PATCH 1/2] serial: sh-sci: HSCIF support
Simon Horman
horms+renesas at verge.net.au
Thu Jun 13 03:00:53 EDT 2013
From: Ulrich Hecht <ulrich.hecht at gmail.com>
Adds support for "High Speed Serial Communications Interface with FIFO",
essentially a SCIF with 128-byte FIFOs and more accurate baud rate
generator.
Signed-off-by: Ulrich Hecht <ulrich.hecht at gmail.com>
Acked-by: Paul Mundt <lethal at linux-sh.org>
Signed-off-by: Simon Horman <horms+renesas at verge.net.au>
---
drivers/tty/serial/sh-sci.c | 102 ++++++++++++++++++++++++++++++++++++---
include/linux/serial_sci.h | 12 +++--
include/uapi/linux/serial_core.h | 3 ++
3 files changed, 106 insertions(+), 11 deletions(-)
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index 1564186..931d6c3 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -146,6 +146,7 @@ static struct plat_sci_reg sci_regmap[SCIx_NR_REGTYPES][SCIx_NR_REGS] = {
[SCRFDR] = sci_reg_invalid,
[SCSPTR] = sci_reg_invalid,
[SCLSR] = sci_reg_invalid,
+ [HSSRR] = sci_reg_invalid,
},
/*
@@ -165,6 +166,7 @@ static struct plat_sci_reg sci_regmap[SCIx_NR_REGTYPES][SCIx_NR_REGS] = {
[SCRFDR] = sci_reg_invalid,
[SCSPTR] = sci_reg_invalid,
[SCLSR] = sci_reg_invalid,
+ [HSSRR] = sci_reg_invalid,
},
/*
@@ -183,6 +185,7 @@ static struct plat_sci_reg sci_regmap[SCIx_NR_REGTYPES][SCIx_NR_REGS] = {
[SCRFDR] = sci_reg_invalid,
[SCSPTR] = sci_reg_invalid,
[SCLSR] = sci_reg_invalid,
+ [HSSRR] = sci_reg_invalid,
},
/*
@@ -201,6 +204,7 @@ static struct plat_sci_reg sci_regmap[SCIx_NR_REGTYPES][SCIx_NR_REGS] = {
[SCRFDR] = { 0x3c, 16 },
[SCSPTR] = sci_reg_invalid,
[SCLSR] = sci_reg_invalid,
+ [HSSRR] = sci_reg_invalid,
},
/*
@@ -220,6 +224,7 @@ static struct plat_sci_reg sci_regmap[SCIx_NR_REGTYPES][SCIx_NR_REGS] = {
[SCRFDR] = sci_reg_invalid,
[SCSPTR] = { 0x20, 16 },
[SCLSR] = { 0x24, 16 },
+ [HSSRR] = sci_reg_invalid,
},
/*
@@ -238,6 +243,7 @@ static struct plat_sci_reg sci_regmap[SCIx_NR_REGTYPES][SCIx_NR_REGS] = {
[SCRFDR] = sci_reg_invalid,
[SCSPTR] = sci_reg_invalid,
[SCLSR] = sci_reg_invalid,
+ [HSSRR] = sci_reg_invalid,
},
/*
@@ -256,6 +262,26 @@ static struct plat_sci_reg sci_regmap[SCIx_NR_REGTYPES][SCIx_NR_REGS] = {
[SCRFDR] = sci_reg_invalid,
[SCSPTR] = { 0x20, 16 },
[SCLSR] = { 0x24, 16 },
+ [HSSRR] = sci_reg_invalid,
+ },
+
+ /*
+ * Common HSCIF definitions.
+ */
+ [SCIx_HSCIF_REGTYPE] = {
+ [SCSMR] = { 0x00, 16 },
+ [SCBRR] = { 0x04, 8 },
+ [SCSCR] = { 0x08, 16 },
+ [SCxTDR] = { 0x0c, 8 },
+ [SCxSR] = { 0x10, 16 },
+ [SCxRDR] = { 0x14, 8 },
+ [SCFCR] = { 0x18, 16 },
+ [SCFDR] = { 0x1c, 16 },
+ [SCTFDR] = sci_reg_invalid,
+ [SCRFDR] = sci_reg_invalid,
+ [SCSPTR] = { 0x20, 16 },
+ [SCLSR] = { 0x24, 16 },
+ [HSSRR] = { 0x40, 16 },
},
/*
@@ -275,6 +301,7 @@ static struct plat_sci_reg sci_regmap[SCIx_NR_REGTYPES][SCIx_NR_REGS] = {
[SCRFDR] = sci_reg_invalid,
[SCSPTR] = sci_reg_invalid,
[SCLSR] = { 0x24, 16 },
+ [HSSRR] = sci_reg_invalid,
},
/*
@@ -294,6 +321,7 @@ static struct plat_sci_reg sci_regmap[SCIx_NR_REGTYPES][SCIx_NR_REGS] = {
[SCRFDR] = { 0x20, 16 },
[SCSPTR] = { 0x24, 16 },
[SCLSR] = { 0x28, 16 },
+ [HSSRR] = sci_reg_invalid,
},
/*
@@ -313,6 +341,7 @@ static struct plat_sci_reg sci_regmap[SCIx_NR_REGTYPES][SCIx_NR_REGS] = {
[SCRFDR] = sci_reg_invalid,
[SCSPTR] = sci_reg_invalid,
[SCLSR] = sci_reg_invalid,
+ [HSSRR] = sci_reg_invalid,
},
};
@@ -374,6 +403,9 @@ static int sci_probe_regmap(struct plat_sci_port *cfg)
*/
cfg->regtype = SCIx_SH4_SCIF_REGTYPE;
break;
+ case PORT_HSCIF:
+ cfg->regtype = SCIx_HSCIF_REGTYPE;
+ break;
default:
printk(KERN_ERR "Can't probe register map for given port\n");
return -EINVAL;
@@ -1798,6 +1830,42 @@ static unsigned int sci_scbrr_calc(unsigned int algo_id, unsigned int bps,
return ((freq + 16 * bps) / (32 * bps) - 1);
}
+/* calculate sample rate, BRR, and clock select for HSCIF */
+static void sci_baud_calc_hscif(unsigned int bps, unsigned long freq,
+ int *brr, unsigned int *srr,
+ unsigned int *cks)
+{
+ int sr, c, br, err;
+ int min_err = 1000; /* 100% */
+
+ /* Find the combination of sample rate and clock select with the
+ smallest deviation from the desired baud rate. */
+ for (sr = 8; sr <= 32; sr++) {
+ for (c = 0; c <= 3; c++) {
+ /* integerized formulas from HSCIF documentation */
+ br = freq / (sr * (1 << (2 * c + 1)) * bps) - 1;
+ if (br < 0 || br > 255)
+ continue;
+ err = freq / ((br + 1) * bps * sr *
+ (1 << (2 * c + 1)) / 1000) - 1000;
+ if (min_err > err) {
+ min_err = err;
+ *brr = br;
+ *srr = sr - 1;
+ *cks = c;
+ }
+ }
+ }
+
+ if (min_err == 1000) {
+ WARN_ON(1);
+ /* use defaults */
+ *brr = 255;
+ *srr = 15;
+ *cks = 0;
+ }
+}
+
static void sci_reset(struct uart_port *port)
{
struct plat_sci_reg *reg;
@@ -1821,6 +1889,7 @@ static void sci_set_termios(struct uart_port *port, struct ktermios *termios,
struct plat_sci_reg *reg;
unsigned int baud, smr_val, max_baud, cks;
int t = -1;
+ unsigned int srr;
/*
* earlyprintk comes here early on with port->uartclk set to zero.
@@ -1833,8 +1902,17 @@ static void sci_set_termios(struct uart_port *port, struct ktermios *termios,
max_baud = port->uartclk ? port->uartclk / 16 : 115200;
baud = uart_get_baud_rate(port, termios, old, 0, max_baud);
- if (likely(baud && port->uartclk))
- t = sci_scbrr_calc(s->cfg->scbrr_algo_id, baud, port->uartclk);
+ if (likely(baud && port->uartclk)) {
+ if (s->cfg->scbrr_algo_id == SCBRR_ALGO_6) {
+ sci_baud_calc_hscif(baud, port->uartclk, &t, &srr,
+ &cks);
+ } else {
+ t = sci_scbrr_calc(s->cfg->scbrr_algo_id, baud,
+ port->uartclk);
+ for (cks = 0; t >= 256 && cks <= 3; cks++)
+ t >>= 2;
+ }
+ }
sci_port_enable(s);
@@ -1853,15 +1931,15 @@ static void sci_set_termios(struct uart_port *port, struct ktermios *termios,
uart_update_timeout(port, termios->c_cflag, baud);
- for (cks = 0; t >= 256 && cks <= 3; cks++)
- t >>= 2;
-
dev_dbg(port->dev, "%s: SMR %x, cks %x, t %x, SCSCR %x\n",
__func__, smr_val, cks, t, s->cfg->scscr);
if (t >= 0) {
serial_port_out(port, SCSMR, (smr_val & ~3) | cks);
serial_port_out(port, SCBRR, t);
+ reg = sci_getreg(port, HSSRR);
+ if (reg->size)
+ serial_port_out(port, HSSRR, srr | HSCIF_SRE);
udelay((1000000+(baud-1)) / baud); /* Wait one bit interval */
} else
serial_port_out(port, SCSMR, smr_val);
@@ -1947,6 +2025,8 @@ static const char *sci_type(struct uart_port *port)
return "scifa";
case PORT_SCIFB:
return "scifb";
+ case PORT_HSCIF:
+ return "hscif";
}
return NULL;
@@ -1960,7 +2040,10 @@ static inline unsigned long sci_port_size(struct uart_port *port)
* from platform resource data at such a time that ports begin to
* behave more erratically.
*/
- return 64;
+ if (port->type == PORT_HSCIF)
+ return 96;
+ else
+ return 64;
}
static int sci_remap_port(struct uart_port *port)
@@ -2085,6 +2168,9 @@ static int sci_init_single(struct platform_device *dev,
case PORT_SCIFB:
port->fifosize = 256;
break;
+ case PORT_HSCIF:
+ port->fifosize = 128;
+ break;
case PORT_SCIFA:
port->fifosize = 64;
break;
@@ -2325,7 +2411,7 @@ static inline int sci_probe_earlyprintk(struct platform_device *pdev)
#endif /* CONFIG_SERIAL_SH_SCI_CONSOLE */
static char banner[] __initdata =
- KERN_INFO "SuperH SCI(F) driver initialized\n";
+ KERN_INFO "SuperH (H)SCI(F) driver initialized\n";
static struct uart_driver sci_uart_driver = {
.owner = THIS_MODULE,
@@ -2484,4 +2570,4 @@ module_exit(sci_exit);
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:sh-sci");
MODULE_AUTHOR("Paul Mundt");
-MODULE_DESCRIPTION("SuperH SCI(F) serial driver");
+MODULE_DESCRIPTION("SuperH (H)SCI(F) serial driver");
diff --git a/include/linux/serial_sci.h b/include/linux/serial_sci.h
index eb763ad..d340497 100644
--- a/include/linux/serial_sci.h
+++ b/include/linux/serial_sci.h
@@ -5,7 +5,7 @@
#include <linux/sh_dma.h>
/*
- * Generic header for SuperH SCI(F) (used by sh/sh64/h8300 and related parts)
+ * Generic header for SuperH (H)SCI(F) (used by sh/sh64/h8300 and related parts)
*/
#define SCIx_NOT_SUPPORTED (-1)
@@ -16,6 +16,7 @@ enum {
SCBRR_ALGO_3, /* (((clk * 2) + 16 * bps) / (16 * bps) - 1) */
SCBRR_ALGO_4, /* (((clk * 2) + 16 * bps) / (32 * bps) - 1) */
SCBRR_ALGO_5, /* (((clk * 1000 / 32) / bps) - 1) */
+ SCBRR_ALGO_6, /* HSCIF variable sample rate algorithm */
};
#define SCSCR_TIE (1 << 7)
@@ -37,7 +38,7 @@ enum {
#define SCI_DEFAULT_ERROR_MASK (SCI_PER | SCI_FER)
-/* SCxSR SCIF */
+/* SCxSR SCIF, HSCIF */
#define SCIF_ER 0x0080
#define SCIF_TEND 0x0040
#define SCIF_TDFE 0x0020
@@ -55,6 +56,9 @@ enum {
#define SCSPTR_SPB2IO (1 << 1)
#define SCSPTR_SPB2DT (1 << 0)
+/* HSSRR HSCIF */
+#define HSCIF_SRE 0x8000
+
/* Offsets into the sci_port->irqs array */
enum {
SCIx_ERI_IRQ,
@@ -90,6 +94,7 @@ enum {
SCIx_SH4_SCIF_NO_SCSPTR_REGTYPE,
SCIx_SH4_SCIF_FIFODATA_REGTYPE,
SCIx_SH7705_SCIF_REGTYPE,
+ SCIx_HSCIF_REGTYPE,
SCIx_NR_REGTYPES,
};
@@ -115,6 +120,7 @@ enum {
SCSMR, SCBRR, SCSCR, SCxSR,
SCFCR, SCFDR, SCxTDR, SCxRDR,
SCLSR, SCTFDR, SCRFDR, SCSPTR,
+ HSSRR,
SCIx_NR_REGS,
};
@@ -137,7 +143,7 @@ struct plat_sci_port {
unsigned long mapbase; /* resource base */
unsigned int irqs[SCIx_NR_IRQS]; /* ERI, RXI, TXI, BRI */
unsigned int gpios[SCIx_NR_FNS]; /* SCK, RXD, TXD, CTS, RTS */
- unsigned int type; /* SCI / SCIF / IRDA */
+ unsigned int type; /* SCI / SCIF / IRDA / HSCIF */
upf_t flags; /* UPF_* flags */
unsigned long capabilities; /* Port features/capabilities */
diff --git a/include/uapi/linux/serial_core.h b/include/uapi/linux/serial_core.h
index 74c2bf7..26eee07 100644
--- a/include/uapi/linux/serial_core.h
+++ b/include/uapi/linux/serial_core.h
@@ -226,4 +226,7 @@
/* Rocketport EXPRESS/INFINITY */
#define PORT_RP2 102
+/* SH-SCI */
+#define PORT_HSCIF 103
+
#endif /* _UAPILINUX_SERIAL_CORE_H */
--
1.8.2.1
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