Hi Christian,
Comments below.
g.
On Fri, Mar 19, 2010 at 2:39 AM, Christian Pellegrin <chripell@xxxxxxxx> wrote:
> 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@xxxxxxxx>
> ---
> drivers/serial/Kconfig | 20 +++++
> drivers/serial/max3100.c | 184 +++++++++++++++++++++++++++++++++++++++++----
> 2 files changed, 187 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
> index 9ff47db..bc72e84 100644
> --- a/drivers/serial/Kconfig
> +++ b/drivers/serial/Kconfig
> @@ -547,6 +547,26 @@ 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_MAX3100_CONSOLE_N
> + int "Number of MAX3100 chips to wait before registering console"
> + depends on SERIAL_MAX3100_CONSOLE=y
> + default "1"
> + help
> + Unfortunately due to the async nature of Linux boot we must
> + know in advance when to register the console. If we do it
> + too early not all the MAX3100 chips are known to the system
> + yet. And we just cannot know how many MAX3100 will be in the
> + system so it's impossible to wait for the last one. If you
> + just want to have the console on the first MAX3100 chip
> + probed (ttyMAX0) it's safe to leave this to 1.
This seems wrong and fragile. It certainly isn't multiplatform safe
to have it as a CONFIG setting because every board will have a
different number of devices that it needs to wait for. I don't know
the console code very well though, but it seems to me that there
should be a way to register the console regardless and then be able to
hold off output until the actual backing device shows up.
Anybody know the right thing to do here?
> +
> 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..f6d250d 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 +132,10 @@ 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)
> };
>
> static struct max3100_port *max3100s[MAX_MAX3100]; /* the chips */
> @@ -175,7 +180,8 @@ 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);
> }
>
> static void max3100_timeout(unsigned long data)
> @@ -552,14 +558,16 @@ 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;
inconsistent braces. If you use {} on the else side, then please use
{} on the if side too.
>
> - tx = MAX3100_WC | MAX3100_SHDN;
> - max3100_sr(s, tx, &rx);
> + tx = MAX3100_WC | MAX3100_SHDN;
> + max3100_sr(s, tx, &rx);
> + }
> }
> }
>
> @@ -578,10 +586,8 @@ 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) {
> + IRQF_TRIGGER_FALLING, "max3100", s) < 0) {
try to avoid unrelated whitespace changes, it adds noise when reviewing.
> dev_err(&s->spi->dev, "cannot allocate irq %d\n", s->irq);
> s->irq = 0;
> return -EBUSY;
> @@ -699,6 +705,136 @@ static struct uart_ops max3100_ops = {
> .verify_port = max3100_verify_port,
> };
>
> +#ifdef CONFIG_SERIAL_MAX3100_CONSOLE
> +
> +static void max3100_console_putchar(struct uart_port *port, int ch)
> +{
> + struct max3100_port *s = container_of(port, struct max3100_port, port);
> + unsigned long tout = 10 * HZ / 1000; /* 10ms */
> + unsigned long start;
> + u16 tx, rx;
> +
> + if (tout == 0)
> + tout = 1;
> + start = jiffies;
> + do {
> + tx = MAX3100_RC;
> + max3100_sr(s, tx, &rx);
> + } while ((rx & MAX3100_T) == 0 &&
> + !time_after(jiffies, start + tout));
> + tx = ch;
> + max3100_calc_parity(s, &tx);
> + tx |= MAX3100_WD | MAX3100_RTS;
> + max3100_sr(s, tx, &rx);
> +}
> +
> +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);
> +}
> +
> +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_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 == 8) {
> + tx &= ~MAX3100_L;
> + s->parity &= ~MAX3100_7BIT;
> + } else {
> + tx |= MAX3100_L;
> + s->parity |= MAX3100_7BIT;
> + }
> +
> + if (parity == 'o' || parity == 'e') {
> + tx |= MAX3100_PE;
> + parity |= MAX3100_PARITY_ON;
s->parity?
> + } else {
> + tx &= ~MAX3100_PE;
> + parity &= ~MAX3100_PARITY_ON;
> + }
> +
> + if (parity == 'o')
> + parity |= MAX3100_PARITY_ODD;
> + else
> + parity &= ~MAX3100_PARITY_ODD;
ditto?
Also, these blocks are really verbose; maybe do this:
tx &= ~(MAX3100_L | MAX3100_PE);
s->parity &= ~(MAX3100_7BIT | MAX3100_PARITY_ON | MAX3100_PARITY_ODD);
if (bits != 8) {
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;
> +
> +
> + tx |= MAX3100_WC;
> + max3100_sr(s, tx, &rx);
> +
> + msleep(50);
Why the sleep? Shouldn't the console driver be able to handle the SPI
device not being ready yet?
> + 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,
> +};
> +#endif
> +
> static struct uart_driver max3100_uart_driver = {
> .owner = THIS_MODULE,
> .driver_name = "ttyMAX",
> @@ -706,6 +842,9 @@ 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 +907,26 @@ 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 (i == (CONFIG_SERIAL_MAX3100_CONSOLE_N - 1))
> + register_console(&max3100_console);
> +#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);
> + }
Same comment on braces as for above.
> }
> mutex_unlock(&max3100s_lock);
> return 0;
> @@ -810,6 +957,9 @@ static int __devexit max3100_remove(struct spi_device *spi)
> }
> pr_debug("removing max3100 driver\n");
> uart_unregister_driver(&max3100_uart_driver);
> +#ifdef CONFIG_SERIAL_MAX3100_CONSOLE
> + unregister_console(&max3100_console);
> +#endif
>
> mutex_unlock(&max3100s_lock);
> return 0;
> --
> 1.5.6.5
>
>
--
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.
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