Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
serial: imx: Switch to nbcon console
Implements the necessary callbacks to switch the imx console driver to
perform as an nbcon console.
Add implementations for the nbcon consoles (write_atomic, write_thread,
driver_enter, driver_exit) and add CON_NBCON to the initial flags.
The legacy code is kept in order to easily switch back to legacy mode
by defining CONFIG_SERIAL_IMX_LEGACY_CONSOLE.
Signed-off-by: Esben Haabendal <esben@geanix.com>
Link: https://lore.kernel.org/r/20240913-serial-imx-nbcon-v3-1-4c627302335b@geanix.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
authored by
Esben Haabendal
and committed by
Greg Kroah-Hartman
70acca67
fd29e1e4
+101
-19
+101
-19
drivers/tty/serial/imx.c
+101
-19
drivers/tty/serial/imx.c
···
230
230
unsigned int saved_reg[10];
231
231
bool context_saved;
232
232
233
+
bool last_putchar_was_newline;
234
+
233
235
enum imx_tx_state tx_state;
234
236
struct hrtimer trigger_start_tx;
235
237
struct hrtimer trigger_stop_tx;
···
2066
2064
barrier();
2067
2065
2068
2066
imx_uart_writel(sport, ch, URTX0);
2067
+
2068
+
sport->last_putchar_was_newline = (ch == '\n');
2069
2069
}
2070
2070
2071
-
/*
2072
-
* Interrupts are disabled on entering
2073
-
*/
2074
-
static void
2075
-
imx_uart_console_write(struct console *co, const char *s, unsigned int count)
2071
+
static void imx_uart_console_device_lock(struct console *co, unsigned long *flags)
2072
+
{
2073
+
struct uart_port *up = &imx_uart_ports[co->index]->port;
2074
+
2075
+
return __uart_port_lock_irqsave(up, flags);
2076
+
}
2077
+
2078
+
static void imx_uart_console_device_unlock(struct console *co, unsigned long flags)
2079
+
{
2080
+
struct uart_port *up = &imx_uart_ports[co->index]->port;
2081
+
2082
+
return __uart_port_unlock_irqrestore(up, flags);
2083
+
}
2084
+
2085
+
static void imx_uart_console_write_atomic(struct console *co,
2086
+
struct nbcon_write_context *wctxt)
2076
2087
{
2077
2088
struct imx_port *sport = imx_uart_ports[co->index];
2089
+
struct uart_port *port = &sport->port;
2078
2090
struct imx_port_ucrs old_ucr;
2079
-
unsigned long flags;
2080
2091
unsigned int ucr1, usr2;
2081
-
int locked = 1;
2082
2092
2083
-
if (sport->port.sysrq)
2084
-
locked = 0;
2085
-
else if (oops_in_progress)
2086
-
locked = uart_port_trylock_irqsave(&sport->port, &flags);
2087
-
else
2088
-
uart_port_lock_irqsave(&sport->port, &flags);
2093
+
if (!nbcon_enter_unsafe(wctxt))
2094
+
return;
2089
2095
2090
2096
/*
2091
2097
* First, save UCR1/2/3 and then disable interrupts
···
2107
2097
ucr1 &= ~(UCR1_TRDYEN | UCR1_RRDYEN | UCR1_RTSDEN);
2108
2098
2109
2099
imx_uart_writel(sport, ucr1, UCR1);
2110
-
2111
2100
imx_uart_writel(sport, old_ucr.ucr2 | UCR2_TXEN, UCR2);
2112
2101
2113
-
uart_console_write(&sport->port, s, count, imx_uart_console_putchar);
2102
+
if (!sport->last_putchar_was_newline)
2103
+
uart_console_write(port, "\n", 1, imx_uart_console_putchar);
2104
+
uart_console_write(port, wctxt->outbuf, wctxt->len,
2105
+
imx_uart_console_putchar);
2114
2106
2115
2107
/*
2116
2108
* Finally, wait for transmitter to become empty
···
2122
2110
0, USEC_PER_SEC, false, sport, USR2);
2123
2111
imx_uart_ucrs_restore(sport, &old_ucr);
2124
2112
2125
-
if (locked)
2126
-
uart_port_unlock_irqrestore(&sport->port, flags);
2113
+
nbcon_exit_unsafe(wctxt);
2114
+
}
2115
+
2116
+
static void imx_uart_console_write_thread(struct console *co,
2117
+
struct nbcon_write_context *wctxt)
2118
+
{
2119
+
struct imx_port *sport = imx_uart_ports[co->index];
2120
+
struct uart_port *port = &sport->port;
2121
+
struct imx_port_ucrs old_ucr;
2122
+
unsigned int ucr1, usr2;
2123
+
2124
+
if (!nbcon_enter_unsafe(wctxt))
2125
+
return;
2126
+
2127
+
/*
2128
+
* First, save UCR1/2/3 and then disable interrupts
2129
+
*/
2130
+
imx_uart_ucrs_save(sport, &old_ucr);
2131
+
ucr1 = old_ucr.ucr1;
2132
+
2133
+
if (imx_uart_is_imx1(sport))
2134
+
ucr1 |= IMX1_UCR1_UARTCLKEN;
2135
+
ucr1 |= UCR1_UARTEN;
2136
+
ucr1 &= ~(UCR1_TRDYEN | UCR1_RRDYEN | UCR1_RTSDEN);
2137
+
2138
+
imx_uart_writel(sport, ucr1, UCR1);
2139
+
imx_uart_writel(sport, old_ucr.ucr2 | UCR2_TXEN, UCR2);
2140
+
2141
+
if (nbcon_exit_unsafe(wctxt)) {
2142
+
int len = READ_ONCE(wctxt->len);
2143
+
int i;
2144
+
2145
+
/*
2146
+
* Write out the message. Toggle unsafe for each byte in order
2147
+
* to give another (higher priority) context the opportunity
2148
+
* for a friendly takeover. If such a takeover occurs, this
2149
+
* context must reacquire ownership in order to perform final
2150
+
* actions (such as re-enabling the interrupts).
2151
+
*
2152
+
* IMPORTANT: wctxt->outbuf and wctxt->len are no longer valid
2153
+
* after a reacquire so writing the message must be
2154
+
* aborted.
2155
+
*/
2156
+
for (i = 0; i < len; i++) {
2157
+
if (!nbcon_enter_unsafe(wctxt))
2158
+
break;
2159
+
2160
+
uart_console_write(port, wctxt->outbuf + i, 1,
2161
+
imx_uart_console_putchar);
2162
+
2163
+
if (!nbcon_exit_unsafe(wctxt))
2164
+
break;
2165
+
}
2166
+
}
2167
+
2168
+
while (!nbcon_enter_unsafe(wctxt))
2169
+
nbcon_reacquire_nobuf(wctxt);
2170
+
2171
+
/*
2172
+
* Finally, wait for transmitter to become empty
2173
+
* and restore UCR1/2/3
2174
+
*/
2175
+
read_poll_timeout(imx_uart_readl, usr2, usr2 & USR2_TXDC,
2176
+
0, USEC_PER_SEC, false, sport, USR2);
2177
+
imx_uart_ucrs_restore(sport, &old_ucr);
2178
+
2179
+
nbcon_exit_unsafe(wctxt);
2127
2180
}
2128
2181
2129
2182
/*
···
2280
2203
if (retval)
2281
2204
goto error_console;
2282
2205
2206
+
sport->last_putchar_was_newline = true;
2207
+
2283
2208
if (options)
2284
2209
uart_parse_options(options, &baud, &parity, &bits, &flow);
2285
2210
else
···
2318
2239
static struct uart_driver imx_uart_uart_driver;
2319
2240
static struct console imx_uart_console = {
2320
2241
.name = DEV_NAME,
2321
-
.write = imx_uart_console_write,
2242
+
.write_atomic = imx_uart_console_write_atomic,
2243
+
.write_thread = imx_uart_console_write_thread,
2244
+
.device_lock = imx_uart_console_device_lock,
2245
+
.device_unlock = imx_uart_console_device_unlock,
2246
+
.flags = CON_PRINTBUFFER | CON_NBCON,
2322
2247
.device = uart_console_device,
2323
2248
.setup = imx_uart_console_setup,
2324
2249
.exit = imx_uart_console_exit,
2325
-
.flags = CON_PRINTBUFFER,
2326
2250
.index = -1,
2327
2251
.data = &imx_uart_uart_driver,
2328
2252
};