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serial: sh-sci: HSCIF support
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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@gmail.com>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
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Ulrich Hecht authored and Simon Horman committed Jun 17, 2013
1 parent 018222f commit f303b36
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Showing 3 changed files with 106 additions and 11 deletions.
102 changes: 94 additions & 8 deletions drivers/tty/serial/sh-sci.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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,
},

/*
Expand All @@ -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,
},

/*
Expand All @@ -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,
},

/*
Expand All @@ -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,
},

/*
Expand All @@ -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,
},

/*
Expand All @@ -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,
},

/*
Expand All @@ -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 },
},

/*
Expand All @@ -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,
},

/*
Expand All @@ -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,
},

/*
Expand All @@ -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,
},
};

Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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;
Expand All @@ -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.
Expand All @@ -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);

Expand All @@ -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);
Expand Down Expand Up @@ -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;
Expand All @@ -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)
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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,
Expand Down Expand Up @@ -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");
12 changes: 9 additions & 3 deletions include/linux/serial_sci.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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)
Expand All @@ -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)
Expand All @@ -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
Expand All @@ -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,
Expand Down Expand Up @@ -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,
};
Expand All @@ -115,6 +120,7 @@ enum {
SCSMR, SCBRR, SCSCR, SCxSR,
SCFCR, SCFDR, SCxTDR, SCxRDR,
SCLSR, SCTFDR, SCRFDR, SCSPTR,
HSSRR,

SCIx_NR_REGS,
};
Expand All @@ -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 */

Expand Down
3 changes: 3 additions & 0 deletions include/uapi/linux/serial_core.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -226,4 +226,7 @@
/* Rocketport EXPRESS/INFINITY */
#define PORT_RP2 102

/* SH-SCI */
#define PORT_HSCIF 103

#endif /* _UAPILINUX_SERIAL_CORE_H */

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