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Message-Id: <1269340170-6558-1-git-send-email-chripell@fsfe.org>
Date: Tue, 23 Mar 2010 11:29:30 +0100
From: Christian Pellegrin <chripell@...e.org>
To: feng.tang@...el.com, akpm@...ux-foundation.org, greg@...ah.com,
david-b@...bell.net, grant.likely@...retlab.ca,
alan@...rguk.ukuu.org.uk, spi-devel-general@...ts.sourceforge.net,
linux-serial@...r.kernel.org, linux-kernel@...r.kernel.org
Cc: Christian Pellegrin <chripell@...e.org>
Subject: [PATCH v1 3/4] max3100: adds console support for MAX3100
This patch adds console support for the MAX3100 UART
(console=ttyMAX0,11500). The SPI subsystem and an
suitable SPI master driver have to be compiled in the kernel.
Signed-off-by: Christian Pellegrin <chripell@...e.org>
---
drivers/serial/Kconfig | 7 ++
drivers/serial/max3100.c | 217 +++++++++++++++++++++++++++++++++++++---
include/linux/serial_max3100.h | 4 +
3 files changed, 212 insertions(+), 16 deletions(-)
diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
index 9ff47db..acd758c 100644
--- a/drivers/serial/Kconfig
+++ b/drivers/serial/Kconfig
@@ -547,6 +547,13 @@ config SERIAL_MAX3100
help
MAX3100 chip support
+config SERIAL_MAX3100_CONSOLE
+ bool "Support console on MAX3100"
+ depends on SERIAL_MAX3100=y
+ select SERIAL_CORE_CONSOLE
+ help
+ Console on MAX3100
+
config SERIAL_DZ
bool "DECstation DZ serial driver"
depends on MACH_DECSTATION && 32BIT
diff --git a/drivers/serial/max3100.c b/drivers/serial/max3100.c
index 0c972c6..ec3e13a 100644
--- a/drivers/serial/max3100.c
+++ b/drivers/serial/max3100.c
@@ -48,6 +48,7 @@
#include <linux/kthread.h>
#include <linux/interrupt.h>
#include <linux/bitops.h>
+#include <linux/console.h>
#include <linux/serial_max3100.h>
@@ -131,6 +132,22 @@ struct max3100_port {
int poll_time;
/* and its timer */
struct timer_list timer;
+
+ int console_flags;
+ /* is this port a console? */
+#define MAX3100_IS_CONSOLE (1 << 0)
+ /* are we in suspend/resume? */
+#define MAX3100_SUSPENDING (1 << 1)
+#ifdef CONFIG_SERIAL_MAX3100_CONSOLE
+ /* console buffer */
+#define CONSOLE_BUF_SIZE 4096
+ char *console_buf;
+ int console_head, console_tail;
+ /* delayed console work because we may have to sleep */
+ struct work_struct console_work;
+ /* char tx timeout */
+ int console_tout;
+#endif
};
static struct max3100_port *max3100s[MAX_MAX3100]; /* the chips */
@@ -175,7 +192,9 @@ static void max3100_resume_work(struct work_struct *w)
struct max3100_port *s = container_of(w, struct max3100_port,
resume_work);
- raise_threaded_irq(s->irq);
+ if (s->irq)
+ raise_threaded_irq(s->irq);
+ s->console_flags &= ~MAX3100_SUSPENDING;
}
static void max3100_timeout(unsigned long data)
@@ -552,14 +571,16 @@ static void max3100_shutdown(struct uart_port *port)
if (s->irq)
free_irq(s->irq, s);
- /* set shutdown mode to save power */
- if (s->max3100_hw_suspend)
- s->max3100_hw_suspend(1);
- else {
- u16 tx, rx;
+ if (!(s->console_flags & MAX3100_IS_CONSOLE)) {
+ /* set shutdown mode to save power */
+ if (s->max3100_hw_suspend) {
+ s->max3100_hw_suspend(1);
+ } else {
+ u16 tx, rx;
- tx = MAX3100_WC | MAX3100_SHDN;
- max3100_sr(s, tx, &rx);
+ tx = MAX3100_WC | MAX3100_SHDN;
+ max3100_sr(s, tx, &rx);
+ }
}
}
@@ -578,8 +599,6 @@ static int max3100_startup(struct uart_port *port)
s->parity = 0;
s->rts = 0;
- INIT_WORK(&s->resume_work, max3100_resume_work);
-
if (request_threaded_irq(s->irq, NULL, max3100_ist,
IRQF_TRIGGER_FALLING, "max3100", s) < 0) {
dev_err(&s->spi->dev, "cannot allocate irq %d\n", s->irq);
@@ -699,6 +718,147 @@ static struct uart_ops max3100_ops = {
.verify_port = max3100_verify_port,
};
+#ifdef CONFIG_SERIAL_MAX3100_CONSOLE
+
+static void max3100_console_work(struct work_struct *w)
+{
+ struct max3100_port *s = container_of(w, struct max3100_port,
+ console_work);
+ unsigned long start;
+ u16 tx, rx;
+
+ while (s->console_head != s->console_tail &&
+ (s->console_flags & MAX3100_SUSPENDING) == 0) {
+ start = jiffies;
+ do {
+ tx = MAX3100_RC;
+ max3100_sr(s, tx, &rx);
+ } while ((rx & MAX3100_T) == 0 &&
+ !time_after(jiffies, start + s->console_tout));
+ tx = s->console_buf[s->console_tail];
+ max3100_calc_parity(s, &tx);
+ tx |= MAX3100_WD | MAX3100_RTS;
+ max3100_sr(s, tx, &rx);
+ s->console_tail = (s->console_tail + 1) % CONSOLE_BUF_SIZE;
+ }
+}
+
+static void max3100_console_putchar(struct uart_port *port, int ch)
+{
+ struct max3100_port *s = to_max3100_port(port);
+ int next = (s->console_head + 1) % CONSOLE_BUF_SIZE;
+
+ if (next != s->console_tail) {
+ s->console_buf[next] = ch;
+ s->console_head = next;
+ }
+}
+
+static void max3100_console_write(struct console *co,
+ const char *str, unsigned int count)
+{
+ struct max3100_port *s = max3100s[co->index];;
+
+ uart_console_write(&s->port, str, count, max3100_console_putchar);
+ schedule_work(&s->console_work);
+}
+
+static int max3100_console_setup(struct console *co, char *options)
+{
+ struct max3100_port *s;
+ int baud = 115200;
+ int bits = 8;
+ int parity = 'n';
+ int flow = 'n';
+ int ret;
+ u16 tx, rx;
+
+ if (co->index == -1 || co->index >= MAX_MAX3100)
+ co->index = 0;
+ s = max3100s[co->index];
+ if (!s)
+ return -ENOENT;
+
+ s->console_buf = kmalloc(CONSOLE_BUF_SIZE, GFP_KERNEL);
+ if (!s->console_buf)
+ return -ENOMEM;
+ INIT_WORK(&s->console_work, max3100_console_work);
+ s->console_flags |= MAX3100_IS_CONSOLE;
+
+ if (options)
+ uart_parse_options(options, &baud, &parity, &bits, &flow);
+ ret = uart_set_options(&s->port, co, baud, parity, bits, flow);
+
+ tx = 0;
+ switch (baud) {
+ case 300:
+ tx = 15;
+ break;
+ case 600:
+ tx = 14 + s->crystal;
+ break;
+ case 1200:
+ tx = 13 + s->crystal;
+ break;
+ case 2400:
+ tx = 12 + s->crystal;
+ break;
+ case 4800:
+ tx = 11 + s->crystal;
+ break;
+ case 9600:
+ tx = 10 + s->crystal;
+ break;
+ case 19200:
+ tx = 9 + s->crystal;
+ break;
+ case 38400:
+ tx = 8 + s->crystal;
+ break;
+ case 57600:
+ tx = 1 + s->crystal;
+ break;
+ case 115200:
+ tx = 0 + s->crystal;
+ break;
+ case 230400:
+ tx = 0;
+ break;
+ }
+ if (bits == 7) {
+ tx |= MAX3100_L;
+ s->parity |= MAX3100_7BIT;
+ }
+ if (parity == 'o' || parity == 'e') {
+ tx |= MAX3100_PE;
+ s->parity |= MAX3100_PARITY_ON;
+ }
+ if (parity == 'o')
+ s->parity |= MAX3100_PARITY_ODD;
+ s->console_tout = 1 + (20 * HZ) / baud; /* jiffies to send 20 bits */
+
+ tx |= MAX3100_WC;
+ max3100_sr(s, tx, &rx);
+
+ /* wait for oscilator to stabilize. Data sheet says 25ms,
+ * apply "multiply by two" engineer's rule */
+ msleep(50);
+ return ret;
+}
+
+static struct uart_driver max3100_uart_driver;
+static struct console max3100_console = {
+ .name = "ttyMAX",
+ .write = max3100_console_write,
+ .device = uart_console_device,
+ .setup = max3100_console_setup,
+ .flags = CON_PRINTBUFFER,
+ .index = -1,
+ .data = &max3100_uart_driver,
+};
+static int max3100_console_registered;
+#endif
+
static struct uart_driver max3100_uart_driver = {
.owner = THIS_MODULE,
.driver_name = "ttyMAX",
@@ -706,6 +866,9 @@ static struct uart_driver max3100_uart_driver = {
.major = MAX3100_MAJOR,
.minor = MAX3100_MINOR,
.nr = MAX_MAX3100,
+#ifdef CONFIG_SERIAL_MAX3100_CONSOLE
+ .cons = &max3100_console,
+#endif
};
static int uart_driver_registered;
@@ -768,18 +931,27 @@ static int __devinit max3100_probe(struct spi_device *spi)
max3100s[i]->port.line = i;
max3100s[i]->port.type = PORT_MAX3100;
max3100s[i]->port.dev = &spi->dev;
+ INIT_WORK(&max3100s[i]->resume_work, max3100_resume_work);
retval = uart_add_one_port(&max3100_uart_driver, &max3100s[i]->port);
if (retval < 0)
dev_warn(&spi->dev,
"uart_add_one_port failed for line %d with error %d\n",
i, retval);
- /* set shutdown mode to save power. Will be woken-up on open */
- if (max3100s[i]->max3100_hw_suspend)
- max3100s[i]->max3100_hw_suspend(1);
- else {
- tx = MAX3100_WC | MAX3100_SHDN;
- max3100_sr(max3100s[i], tx, &rx);
+#ifdef CONFIG_SERIAL_MAX3100_CONSOLE
+ if (pdata->console && !max3100_console_registered) {
+ register_console(&max3100_console);
+ max3100_console_registered = 1;
+ }
+#endif
+ if (!(max3100s[i]->console_flags & MAX3100_IS_CONSOLE)) {
+ /* set shutdown mode to save power. Will be woken-up on open */
+ if (max3100s[i]->max3100_hw_suspend) {
+ max3100s[i]->max3100_hw_suspend(1);
+ } else {
+ tx = MAX3100_WC | MAX3100_SHDN;
+ max3100_sr(max3100s[i], tx, &rx);
+ }
}
mutex_unlock(&max3100s_lock);
return 0;
@@ -792,12 +964,24 @@ static int __devexit max3100_remove(struct spi_device *spi)
mutex_lock(&max3100s_lock);
+#ifdef CONFIG_SERIAL_MAX3100_CONSOLE
+ if (max3100_console_registered) {
+ unregister_console(&max3100_console);
+ max3100_console_registered = 0;
+ }
+#endif
/* find out the index for the chip we are removing */
for (i = 0; i < MAX_MAX3100; i++)
if (max3100s[i] == s)
break;
dev_dbg(&spi->dev, "%s: removing port %d\n", __func__, i);
+#ifdef CONFIG_SERIAL_MAX3100_CONSOLE
+ if (s->console_buf) {
+ flush_work(&s->console_work);
+ kfree(s->console_buf);
+ }
+#endif
uart_remove_one_port(&max3100_uart_driver, &max3100s[i]->port);
kfree(max3100s[i]);
max3100s[i] = NULL;
@@ -823,6 +1007,7 @@ static int max3100_suspend(struct spi_device *spi, pm_message_t state)
dev_dbg(&s->spi->dev, "%s\n", __func__);
+ s->console_flags |= MAX3100_SUSPENDING;
disable_irq(s->irq);
if (s->max3100_hw_suspend)
diff --git a/include/linux/serial_max3100.h b/include/linux/serial_max3100.h
index 4976bef..71fb862 100644
--- a/include/linux/serial_max3100.h
+++ b/include/linux/serial_max3100.h
@@ -21,6 +21,9 @@
* called on suspend and resume to activate it.
* @poll_time: poll time for CTS signal in ms, 0 disables (so no hw
* flow ctrl is possible but you have less CPU usage)
+ * @console: 1 if this MAX3100 is the last one on the system
+ * (in the order of spi_board_info enumeration) that
+ * can act as a console.
*
* You should use this structure in your machine description to specify
* how the MAX3100 is connected. Example:
@@ -47,6 +50,7 @@ struct plat_max3100 {
int crystal;
void (*max3100_hw_suspend) (int suspend);
int poll_time;
+ int console;
};
#endif
--
1.5.6.5
--
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