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      1 /* $NetBSD: stasc.c,v 1.3 2024/02/08 10:30:25 andvar Exp $ */
      2 /*
      3  * Copyright (c) 2020 Valery Ushakov
      4  * All rights reserved.
      5  *
      6  * Redistribution and use in source and binary forms, with or without
      7  * modification, are permitted provided that the following conditions
      8  * are met:
      9  * 1. Redistributions of source code must retain the above copyright
     10  *    notice, this list of conditions and the following disclaimer.
     11  * 2. Redistributions in binary form must reproduce the above copyright
     12  *    notice, this list of conditions and the following disclaimer in the
     13  *    documentation and/or other materials provided with the distribution.
     14  *
     15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     25  */
     26 
     27 /*
     28  * STMicroelectronics ST40 Asynchronous Serial Controller
     29  */
     30 #include <sys/cdefs.h>
     31 __KERNEL_RCSID(0, "$NetBSD: stasc.c,v 1.3 2024/02/08 10:30:25 andvar Exp $");
     32 
     33 #include <sys/param.h>
     34 #include <sys/systm.h>
     35 #include <sys/conf.h>
     36 #include <sys/device.h>
     37 #include <sys/kernel.h>
     38 
     39 #include <dev/cons.h>
     40 
     41 
     42 #define STM_ASC_BASE	0xfd032000
     43 
     44 #define ASC_BAUDRATE_OFFSET	0x00
     45 #define ASC_TX_BUFF_OFFSET	0x04
     46 #define ASC_RX_BUFF_OFFSET	0x08
     47 #define ASC_CTRL_OFFSET		0x0C
     48 #define ASC_INT_EN_OFFSET	0x10
     49 #define ASC_INT_STA_OFFSET	0x14
     50 #define ASC_GUARDTIME_OFFSET	0x18
     51 #define ASC_TIMEOUT_OFFSET	0x1C
     52 #define ASC_TX_RST_OFFSET	0x20
     53 #define ASC_RX_RST_OFFSET	0x24
     54 #define ASC_RETRIES_OFFSET	0x28
     55 
     56 #define ASC_TX_BUFF	(*(volatile uint32_t *)(STM_ASC_BASE + ASC_TX_BUFF_OFFSET))
     57 #define ASC_RX_BUFF	(*(volatile uint32_t *)(STM_ASC_BASE + ASC_RX_BUFF_OFFSET))
     58 #define ASC_INT_EN	(*(volatile uint32_t *)(STM_ASC_BASE + ASC_INT_EN_OFFSET))
     59 #define ASC_INT_STA	(*(volatile uint32_t *)(STM_ASC_BASE + ASC_INT_STA_OFFSET))
     60 
     61 
     62 #define ASC_CTRL_NACK_DISABLE	0x2000
     63 #define ASC_CTRL_BAUDMODE	0x1000
     64 #define ASC_CTRL_CTS_EN		0x0800
     65 #define ASC_CTRL_FIFO_EN	0x0400
     66 #define ASC_CTRL_SC_EN		0x0200
     67 #define ASC_CTRL_RX_EN		0x0100
     68 #define ASC_CTRL_RUN		0x0080
     69 #define ASC_CTRL_LOOPBACK	0x0040
     70 #define ASC_CTRL_PARITYODD	0x0020
     71 #define ASC_CTRL_STOPBITS_MASK	0x0018
     72 #define     ASC_CTRL_STOPBITS_0_5	0x0000
     73 #define     ASC_CTRL_STOPBITS_1_0	0x0008
     74 #define     ASC_CTRL_STOPBITS_1_5	0x0010
     75 #define     ASC_CTRL_STOPBITS_2_0	0x0018
     76 #define ASC_CTRL_MODE_MASK	0x0007
     77 #define     ASC_CTRL_MODE_8N		0x0001 /* 8 bit */
     78 #define     ASC_CTRL_MODE_7P		0x0003 /* 7 bit + parity  */
     79 #define     ASC_CTRL_MODE_9N		0x0004 /* 9 bit */
     80 #define     ASC_CTRL_MODE_8W		0x0005 /* 8 bit + wakeup */
     81 #define     ASC_CTRL_MODE_8P		0x0007 /* 8 bit + parity */
     82 
     83 
     84 #define ASC_INT_EN_RHF		0x0100 /* ASC_INT_STA_RHF */
     85 #define ASC_INT_EN_TOE		0x0080 /* ASC_INT_STA_TOE */
     86 #define ASC_INT_EN_TNE		0x0040 /* ASC_INT_STA_TNE */
     87 #define ASC_INT_EN_OE		0x0020 /* ASC_INT_STA_OE */
     88 #define ASC_INT_EN_FE		0x0010 /* ASC_INT_STA_FE */
     89 #define ASC_INT_EN_PE		0x0008 /* ASC_INT_STA_PE */
     90 #define	ASC_INT_EN_THE		0x0004 /* ASC_INT_STA_THE */
     91 #define ASC_INT_EN_TE		0x0002 /* ASC_INT_STA_TE */
     92 #define ASC_INT_EN_RBF		0x0001 /* ASC_INT_STA_RBF */
     93 
     94 #define ASC_INT_STA_NKD		0x0400 /* Tx: NACK Data */
     95 #define ASC_INT_STA_TF		0x0200 /* Tx: Transmitter Full */
     96 #define ASC_INT_STA_RHF		0x0100 /* Rx: Receiver FIFO Half Full */
     97 #define ASC_INT_STA_TOE		0x0080 /* Rx: Timeout Or Empty */
     98 #define ASC_INT_STA_TNE		0x0040 /* Rx: Timeout Or Not Empty */
     99 #define ASC_INT_STA_OE		0x0020 /* Rx: Overrun Error */
    100 #define ASC_INT_STA_FE		0x0010 /* Rx: Frame Error */
    101 #define ASC_INT_STA_PE		0x0008 /* Rx: Parity Error */
    102 #define	ASC_INT_STA_THE		0x0004 /* Tx: Transmitter FIFO Half Empty */
    103 #define ASC_INT_STA_TE		0x0002 /* Tx: Transmitter Empty */
    104 #define ASC_INT_STA_RBF		0x0001 /* Rx: Receiver Buffer Full */
    105 
    106 
    107 
    108 struct stasc_softc {
    109 	device_t sc_dev;
    110 };
    111 
    112 
    113 static int stasc_match(device_t, cfdata_t, void *);
    114 static void stasc_attach(device_t, device_t, void *);
    115 
    116 CFATTACH_DECL_NEW(stasc, sizeof(struct stasc_softc),
    117     stasc_match, stasc_attach, NULL, NULL);
    118 
    119 
    120 /* console */
    121 cons_decl(stasc_)
    122 
    123 /* assign to cn_tab after cleaning bss to get printf early for the cpu setup */
    124 struct consdev stasc_earlycons = cons_init(stasc_);
    125 
    126 extern struct cfdriver stasc_cd;
    127 
    128 const struct cdevsw stasc_cdevsw = {
    129 	.d_open = noopen,
    130 	.d_close = noclose,
    131 	.d_read = noread,
    132 	.d_write = nowrite,
    133 	.d_ioctl = noioctl,
    134 	.d_stop = nostop,
    135 	.d_tty = notty,
    136 	.d_poll = nopoll,
    137 	.d_mmap = nommap,
    138 	.d_kqfilter = nokqfilter,
    139 	.d_discard = nodiscard,
    140 	.d_flag = D_TTY
    141 };
    142 
    143 
    144 
    145 static int
    146 stasc_match(device_t parent, cfdata_t cfp, void *aux)
    147 {
    148 
    149 	if (strcmp(cfp->cf_name, "stasc") != 0)
    150 		return 0;
    151 
    152 	return 0;		/* just stub it out for now */
    153 }
    154 
    155 
    156 static void
    157 stasc_attach(device_t parent, device_t self, void *aux)
    158 {
    159 	struct stasc_softc *sc;
    160 
    161 	sc = device_private(self);
    162 	sc->sc_dev = self;
    163 
    164 	aprint_normal("\n");
    165 }
    166 
    167 
    168 void
    169 stasc_cnprobe(struct consdev *cp)
    170 {
    171 
    172 	cp->cn_pri = CN_NORMAL;
    173 }
    174 
    175 
    176 void
    177 stasc_cninit(struct consdev *cp)
    178 {
    179 
    180 	return;
    181 }
    182 
    183 
    184 int
    185 stasc_cngetc(dev_t dev)
    186 {
    187 	int s = splserial();
    188 	uint32_t status;
    189 	int c;
    190 
    191 	/* don't block if Rx buffer is empty */
    192 	status = ASC_INT_STA;
    193 	if (!ISSET(status, ASC_INT_STA_RBF)) {
    194 		splx(s);
    195 		return -1;
    196 	}
    197 
    198 	/* can read the character now */
    199 	c = ASC_RX_BUFF;
    200 	splx(s);
    201 	return (unsigned char)c;
    202 }
    203 
    204 
    205 void
    206 stasc_cnputc(dev_t dev, int c)
    207 {
    208 	int s = splserial();
    209 	uint32_t timo, status;
    210 
    211 	/* wait for Tx Full to become clear */
    212 	timo = 150000;
    213 	do {
    214 		status = ASC_INT_STA;
    215 	} while (ISSET(status, ASC_INT_STA_TF) && --timo);
    216 
    217 	/* can write the character now */
    218 	ASC_TX_BUFF = c;
    219 	splx(s);
    220 }
    221 
    222 
    223 void
    224 stasc_cnpollc(dev_t dev, int on)
    225 {
    226 
    227 	return;
    228 }
    229