cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

serialio.c (8064B)


      1// SPDX-License-Identifier: GPL-2.0
      2#include <linux/interrupt.h>
      3#include <linux/ioport.h>
      4
      5#include "spk_types.h"
      6#include "speakup.h"
      7#include "spk_priv.h"
      8#include "serialio.h"
      9
     10#include <linux/serial_core.h>
     11/* WARNING:  Do not change this to <linux/serial.h> without testing that
     12 * SERIAL_PORT_DFNS does get defined to the appropriate value.
     13 */
     14#include <asm/serial.h>
     15
     16#ifndef SERIAL_PORT_DFNS
     17#define SERIAL_PORT_DFNS
     18#endif
     19
     20static void start_serial_interrupt(int irq);
     21
     22static const struct old_serial_port rs_table[] = {
     23	SERIAL_PORT_DFNS
     24};
     25
     26static const struct old_serial_port *serstate;
     27static int timeouts;
     28
     29static int spk_serial_out(struct spk_synth *in_synth, const char ch);
     30static void spk_serial_send_xchar(struct spk_synth *in_synth, char ch);
     31static void spk_serial_tiocmset(struct spk_synth *in_synth, unsigned int set, unsigned int clear);
     32static unsigned char spk_serial_in(struct spk_synth *in_synth);
     33static unsigned char spk_serial_in_nowait(struct spk_synth *in_synth);
     34static void spk_serial_flush_buffer(struct spk_synth *in_synth);
     35static int spk_serial_wait_for_xmitr(struct spk_synth *in_synth);
     36
     37struct spk_io_ops spk_serial_io_ops = {
     38	.synth_out = spk_serial_out,
     39	.send_xchar = spk_serial_send_xchar,
     40	.tiocmset = spk_serial_tiocmset,
     41	.synth_in = spk_serial_in,
     42	.synth_in_nowait = spk_serial_in_nowait,
     43	.flush_buffer = spk_serial_flush_buffer,
     44	.wait_for_xmitr = spk_serial_wait_for_xmitr,
     45};
     46EXPORT_SYMBOL_GPL(spk_serial_io_ops);
     47
     48const struct old_serial_port *spk_serial_init(int index)
     49{
     50	int baud = 9600, quot = 0;
     51	unsigned int cval = 0;
     52	int cflag = CREAD | HUPCL | CLOCAL | B9600 | CS8;
     53	const struct old_serial_port *ser;
     54	int err;
     55
     56	if (index >= ARRAY_SIZE(rs_table)) {
     57		pr_info("no port info for ttyS%d\n", index);
     58		return NULL;
     59	}
     60	ser = rs_table + index;
     61
     62	/*	Divisor, byte size and parity */
     63	quot = ser->baud_base / baud;
     64	cval = cflag & (CSIZE | CSTOPB);
     65#if defined(__powerpc__) || defined(__alpha__)
     66	cval >>= 8;
     67#else /* !__powerpc__ && !__alpha__ */
     68	cval >>= 4;
     69#endif /* !__powerpc__ && !__alpha__ */
     70	if (cflag & PARENB)
     71		cval |= UART_LCR_PARITY;
     72	if (!(cflag & PARODD))
     73		cval |= UART_LCR_EPAR;
     74	if (synth_request_region(ser->port, 8)) {
     75		/* try to take it back. */
     76		pr_info("Ports not available, trying to steal them\n");
     77		__release_region(&ioport_resource, ser->port, 8);
     78		err = synth_request_region(ser->port, 8);
     79		if (err) {
     80			pr_warn("Unable to allocate port at %x, errno %i",
     81				ser->port, err);
     82			return NULL;
     83		}
     84	}
     85
     86	/*	Disable UART interrupts, set DTR and RTS high
     87	 *	and set speed.
     88	 */
     89	outb(cval | UART_LCR_DLAB, ser->port + UART_LCR);	/* set DLAB */
     90	outb(quot & 0xff, ser->port + UART_DLL);	/* LS of divisor */
     91	outb(quot >> 8, ser->port + UART_DLM);		/* MS of divisor */
     92	outb(cval, ser->port + UART_LCR);		/* reset DLAB */
     93
     94	/* Turn off Interrupts */
     95	outb(0, ser->port + UART_IER);
     96	outb(UART_MCR_DTR | UART_MCR_RTS, ser->port + UART_MCR);
     97
     98	/* If we read 0xff from the LSR, there is no UART here. */
     99	if (inb(ser->port + UART_LSR) == 0xff) {
    100		synth_release_region(ser->port, 8);
    101		serstate = NULL;
    102		return NULL;
    103	}
    104
    105	mdelay(1);
    106	speakup_info.port_tts = ser->port;
    107	serstate = ser;
    108
    109	start_serial_interrupt(ser->irq);
    110
    111	return ser;
    112}
    113
    114static irqreturn_t synth_readbuf_handler(int irq, void *dev_id)
    115{
    116	unsigned long flags;
    117	int c;
    118
    119	spin_lock_irqsave(&speakup_info.spinlock, flags);
    120	while (inb_p(speakup_info.port_tts + UART_LSR) & UART_LSR_DR) {
    121		c = inb_p(speakup_info.port_tts + UART_RX);
    122		synth->read_buff_add((u_char)c);
    123	}
    124	spin_unlock_irqrestore(&speakup_info.spinlock, flags);
    125	return IRQ_HANDLED;
    126}
    127
    128static void start_serial_interrupt(int irq)
    129{
    130	int rv;
    131
    132	if (!synth->read_buff_add)
    133		return;
    134
    135	rv = request_irq(irq, synth_readbuf_handler, IRQF_SHARED,
    136			 "serial", (void *)synth_readbuf_handler);
    137
    138	if (rv)
    139		pr_err("Unable to request Speakup serial I R Q\n");
    140	/* Set MCR */
    141	outb(UART_MCR_DTR | UART_MCR_RTS | UART_MCR_OUT2,
    142	     speakup_info.port_tts + UART_MCR);
    143	/* Turn on Interrupts */
    144	outb(UART_IER_MSI | UART_IER_RLSI | UART_IER_RDI,
    145	     speakup_info.port_tts + UART_IER);
    146	inb(speakup_info.port_tts + UART_LSR);
    147	inb(speakup_info.port_tts + UART_RX);
    148	inb(speakup_info.port_tts + UART_IIR);
    149	inb(speakup_info.port_tts + UART_MSR);
    150	outb(1, speakup_info.port_tts + UART_FCR);	/* Turn FIFO On */
    151}
    152
    153static void spk_serial_send_xchar(struct spk_synth *synth, char ch)
    154{
    155	int timeout = SPK_XMITR_TIMEOUT;
    156
    157	while (spk_serial_tx_busy()) {
    158		if (!--timeout)
    159			break;
    160		udelay(1);
    161	}
    162	outb(ch, speakup_info.port_tts);
    163}
    164
    165static void spk_serial_tiocmset(struct spk_synth *in_synth, unsigned int set, unsigned int clear)
    166{
    167	int old = inb(speakup_info.port_tts + UART_MCR);
    168
    169	outb((old & ~clear) | set, speakup_info.port_tts + UART_MCR);
    170}
    171
    172int spk_serial_synth_probe(struct spk_synth *synth)
    173{
    174	const struct old_serial_port *ser;
    175	int failed = 0;
    176
    177	if ((synth->ser >= SPK_LO_TTY) && (synth->ser <= SPK_HI_TTY)) {
    178		ser = spk_serial_init(synth->ser);
    179		if (!ser) {
    180			failed = -1;
    181		} else {
    182			outb_p(0, ser->port);
    183			mdelay(1);
    184			outb_p('\r', ser->port);
    185		}
    186	} else {
    187		failed = -1;
    188		pr_warn("ttyS%i is an invalid port\n", synth->ser);
    189	}
    190	if (failed) {
    191		pr_info("%s: not found\n", synth->long_name);
    192		return -ENODEV;
    193	}
    194	pr_info("%s: ttyS%i, Driver Version %s\n",
    195		synth->long_name, synth->ser, synth->version);
    196	synth->alive = 1;
    197	return 0;
    198}
    199EXPORT_SYMBOL_GPL(spk_serial_synth_probe);
    200
    201void spk_stop_serial_interrupt(void)
    202{
    203	if (speakup_info.port_tts == 0)
    204		return;
    205
    206	if (!synth->read_buff_add)
    207		return;
    208
    209	/* Turn off interrupts */
    210	outb(0, speakup_info.port_tts + UART_IER);
    211	/* Free IRQ */
    212	free_irq(serstate->irq, (void *)synth_readbuf_handler);
    213}
    214EXPORT_SYMBOL_GPL(spk_stop_serial_interrupt);
    215
    216static int spk_serial_wait_for_xmitr(struct spk_synth *in_synth)
    217{
    218	int tmout = SPK_XMITR_TIMEOUT;
    219
    220	if ((in_synth->alive) && (timeouts >= NUM_DISABLE_TIMEOUTS)) {
    221		pr_warn("%s: too many timeouts, deactivating speakup\n",
    222			in_synth->long_name);
    223		in_synth->alive = 0;
    224		/* No synth any more, so nobody will restart TTYs, and we thus
    225		 * need to do it ourselves.  Now that there is no synth we can
    226		 * let application flood anyway
    227		 */
    228		speakup_start_ttys();
    229		timeouts = 0;
    230		return 0;
    231	}
    232	while (spk_serial_tx_busy()) {
    233		if (--tmout == 0) {
    234			pr_warn("%s: timed out (tx busy)\n",
    235				in_synth->long_name);
    236			timeouts++;
    237			return 0;
    238		}
    239		udelay(1);
    240	}
    241	tmout = SPK_CTS_TIMEOUT;
    242	while (!((inb_p(speakup_info.port_tts + UART_MSR)) & UART_MSR_CTS)) {
    243		/* CTS */
    244		if (--tmout == 0) {
    245			timeouts++;
    246			return 0;
    247		}
    248		udelay(1);
    249	}
    250	timeouts = 0;
    251	return 1;
    252}
    253
    254static unsigned char spk_serial_in(struct spk_synth *in_synth)
    255{
    256	int tmout = SPK_SERIAL_TIMEOUT;
    257
    258	while (!(inb_p(speakup_info.port_tts + UART_LSR) & UART_LSR_DR)) {
    259		if (--tmout == 0) {
    260			pr_warn("time out while waiting for input.\n");
    261			return 0xff;
    262		}
    263		udelay(1);
    264	}
    265	return inb_p(speakup_info.port_tts + UART_RX);
    266}
    267
    268static unsigned char spk_serial_in_nowait(struct spk_synth *in_synth)
    269{
    270	unsigned char lsr;
    271
    272	lsr = inb_p(speakup_info.port_tts + UART_LSR);
    273	if (!(lsr & UART_LSR_DR))
    274		return 0;
    275	return inb_p(speakup_info.port_tts + UART_RX);
    276}
    277
    278static void spk_serial_flush_buffer(struct spk_synth *in_synth)
    279{
    280	/* TODO: flush the UART 16550 buffer */
    281}
    282
    283static int spk_serial_out(struct spk_synth *in_synth, const char ch)
    284{
    285	if (in_synth->alive && spk_serial_wait_for_xmitr(in_synth)) {
    286		outb_p(ch, speakup_info.port_tts);
    287		return 1;
    288	}
    289	return 0;
    290}
    291
    292const char *spk_serial_synth_immediate(struct spk_synth *synth,
    293				       const char *buff)
    294{
    295	u_char ch;
    296
    297	while ((ch = *buff)) {
    298		if (ch == '\n')
    299			ch = synth->procspeech;
    300		if (spk_serial_wait_for_xmitr(synth))
    301			outb(ch, speakup_info.port_tts);
    302		else
    303			return buff;
    304		buff++;
    305	}
    306	return NULL;
    307}
    308EXPORT_SYMBOL_GPL(spk_serial_synth_immediate);
    309
    310void spk_serial_release(struct spk_synth *synth)
    311{
    312	spk_stop_serial_interrupt();
    313	if (speakup_info.port_tts == 0)
    314		return;
    315	synth_release_region(speakup_info.port_tts, 8);
    316	speakup_info.port_tts = 0;
    317}
    318EXPORT_SYMBOL_GPL(spk_serial_release);