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ARM: OMAP2+: UART: Cleanup part of clock gating mechanism for uart
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Currently we use a shared irq handler to identify uart activity and then
trigger a timer. By default the timeout value is zero and can be set or
modified from sysfs. If there was no uart activity for the period set
through sysfs, the timer will expire and call timer handler this will
set a flag can_sleep using which decision to gate uart clocks can be taken.

Since the clock gating mechanism is outside the uart driver, we currently
use this mechanism. In preparation to runtime implementation for omap-serial
driver we can cleanup this mechanism and use runtime API's to gate uart clocks.

Removes the following:
* timer related info from local uart_state struct
* the code used to set timeout value from sysfs.
* irqflags used to set shared irq handler.
* un-used function omap_uart_check_wakeup.

Signed-off-by: Govindraj.R <govindraj.raja@ti.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de> (for drivers/tty changes)
Signed-off-by: Kevin Hilman <khilman@ti.com>
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Govindraj.R authored and Kevin Hilman committed Dec 14, 2011
1 parent 8a60585 commit 273558b
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Showing 4 changed files with 2 additions and 119 deletions.
118 changes: 2 additions & 116 deletions arch/arm/mach-omap2/serial.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -58,22 +58,16 @@
struct omap_uart_state {
int num;
int can_sleep;
struct timer_list timer;
u32 timeout;

void __iomem *wk_st;
void __iomem *wk_en;
u32 wk_mask;
u32 padconf;
u32 dma_enabled;

struct clk *ick;
struct clk *fck;
int clocked;

int irq;
int regshift;
int irqflags;
void __iomem *membase;
resource_size_t mapbase;

Expand Down Expand Up @@ -331,32 +325,6 @@ static void omap_uart_block_sleep(struct omap_uart_state *uart)

omap_uart_smart_idle_enable(uart, 0);
uart->can_sleep = 0;
if (uart->timeout)
mod_timer(&uart->timer, jiffies + uart->timeout);
else
del_timer(&uart->timer);
}

static void omap_uart_allow_sleep(struct omap_uart_state *uart)
{
if (device_may_wakeup(&uart->pdev->dev))
omap_uart_enable_wakeup(uart);
else
omap_uart_disable_wakeup(uart);

if (!uart->clocked)
return;

omap_uart_smart_idle_enable(uart, 1);
uart->can_sleep = 1;
del_timer(&uart->timer);
}

static void omap_uart_idle_timer(unsigned long data)
{
struct omap_uart_state *uart = (struct omap_uart_state *)data;

omap_uart_allow_sleep(uart);
}

int omap_uart_can_sleep(void)
Expand All @@ -380,35 +348,11 @@ int omap_uart_can_sleep(void)
return can_sleep;
}

/**
* omap_uart_interrupt()
*
* This handler is used only to detect that *any* UART interrupt has
* occurred. It does _nothing_ to handle the interrupt. Rather,
* any UART interrupt will trigger the inactivity timer so the
* UART will not idle or sleep for its timeout period.
*
**/
/* static int first_interrupt; */
static irqreturn_t omap_uart_interrupt(int irq, void *dev_id)
{
struct omap_uart_state *uart = dev_id;

omap_uart_block_sleep(uart);

return IRQ_NONE;
}

static void omap_uart_idle_init(struct omap_uart_state *uart)
{
int ret;

uart->can_sleep = 0;
uart->timeout = DEFAULT_TIMEOUT;
setup_timer(&uart->timer, omap_uart_idle_timer,
(unsigned long) uart);
if (uart->timeout)
mod_timer(&uart->timer, jiffies + uart->timeout);
omap_uart_smart_idle_enable(uart, 0);

if (cpu_is_omap34xx() && !(cpu_is_ti81xx() || cpu_is_am33xx())) {
Expand Down Expand Up @@ -470,59 +414,15 @@ static void omap_uart_idle_init(struct omap_uart_state *uart)
uart->wk_mask = 0;
uart->padconf = 0;
}

uart->irqflags |= IRQF_SHARED;
ret = request_threaded_irq(uart->irq, NULL, omap_uart_interrupt,
IRQF_SHARED, "serial idle", (void *)uart);
WARN_ON(ret);
}

static ssize_t sleep_timeout_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct platform_device *pdev = to_platform_device(dev);
struct omap_device *odev = to_omap_device(pdev);
struct omap_uart_state *uart = odev->hwmods[0]->dev_attr;

return sprintf(buf, "%u\n", uart->timeout / HZ);
}

static ssize_t sleep_timeout_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t n)
{
struct platform_device *pdev = to_platform_device(dev);
struct omap_device *odev = to_omap_device(pdev);
struct omap_uart_state *uart = odev->hwmods[0]->dev_attr;
unsigned int value;

if (sscanf(buf, "%u", &value) != 1) {
dev_err(dev, "sleep_timeout_store: Invalid value\n");
return -EINVAL;
}

uart->timeout = value * HZ;
if (uart->timeout)
mod_timer(&uart->timer, jiffies + uart->timeout);
else
/* A zero value means disable timeout feature */
omap_uart_block_sleep(uart);

return n;
}

static DEVICE_ATTR(sleep_timeout, 0644, sleep_timeout_show,
sleep_timeout_store);
#define DEV_CREATE_FILE(dev, attr) WARN_ON(device_create_file(dev, attr))
#else
static inline void omap_uart_idle_init(struct omap_uart_state *uart) {}
static void omap_uart_block_sleep(struct omap_uart_state *uart)
{
/* Needed to enable UART clocks when built without CONFIG_PM */
omap_uart_enable_clocks(uart);
}
#define DEV_CREATE_FILE(dev, attr)
#endif /* CONFIG_PM */

static int __init omap_serial_early_init(void)
Expand Down Expand Up @@ -606,8 +506,7 @@ void __init omap_serial_init_port(struct omap_board_data *bdata)
omap_up.uartclk = OMAP24XX_BASE_BAUD * 16;
omap_up.mapbase = oh->slaves[0]->addr->pa_start;
omap_up.membase = omap_hwmod_get_mpu_rt_va(oh);
omap_up.irqflags = IRQF_SHARED;
omap_up.flags = UPF_BOOT_AUTOCONF | UPF_SHARE_IRQ;
omap_up.flags = UPF_BOOT_AUTOCONF;

pdata = &omap_up;
pdata_size = sizeof(struct omap_uart_port_info);
Expand All @@ -623,7 +522,6 @@ void __init omap_serial_init_port(struct omap_board_data *bdata)
omap_device_disable_idle_on_suspend(pdev);
oh->mux = omap_hwmod_mux_init(bdata->pads, bdata->pads_cnt);

uart->irq = oh->mpu_irqs[0].irq;
uart->regshift = 2;
uart->mapbase = oh->slaves[0]->addr->pa_start;
uart->membase = omap_hwmod_get_mpu_rt_va(oh);
Expand All @@ -646,24 +544,12 @@ void __init omap_serial_init_port(struct omap_board_data *bdata)
omap_hwmod_enable_wakeup(uart->oh);
omap_device_idle(uart->pdev);

/*
* Need to block sleep long enough for interrupt driven
* driver to start. Console driver is in polling mode
* so device needs to be kept enabled while polling driver
* is in use.
*/
if (uart->timeout)
uart->timeout = (30 * HZ);
omap_uart_block_sleep(uart);
uart->timeout = DEFAULT_TIMEOUT;

console_unlock();

if ((cpu_is_omap34xx() && uart->padconf) ||
(uart->wk_en && uart->wk_mask)) {
(uart->wk_en && uart->wk_mask))
device_init_wakeup(&pdev->dev, true);
DEV_CREATE_FILE(&pdev->dev, &dev_attr_sleep_timeout);
}

/* Enable the MDR1 errata for OMAP3 */
if (cpu_is_omap34xx() && !(cpu_is_ti81xx() || cpu_is_am33xx()))
Expand Down
1 change: 0 additions & 1 deletion arch/arm/plat-omap/include/plat/omap-serial.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -61,7 +61,6 @@ struct omap_uart_port_info {
unsigned int uartclk; /* UART clock rate */
void __iomem *membase; /* ioremap cookie or NULL */
resource_size_t mapbase; /* resource base */
unsigned long irqflags; /* request_irq flags */
upf_t flags; /* UPF_* flags */
};

Expand Down
1 change: 0 additions & 1 deletion arch/arm/plat-omap/include/plat/serial.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -110,7 +110,6 @@ struct omap_board_data;
extern void omap_serial_init(void);
extern void omap_serial_init_port(struct omap_board_data *bdata);
extern int omap_uart_can_sleep(void);
extern void omap_uart_check_wakeup(void);
#endif

#endif
1 change: 0 additions & 1 deletion drivers/tty/serial/omap-serial.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1278,7 +1278,6 @@ static int serial_omap_probe(struct platform_device *pdev)
up->port.membase = omap_up_info->membase;
up->port.mapbase = omap_up_info->mapbase;
up->port.flags = omap_up_info->flags;
up->port.irqflags = omap_up_info->irqflags;
up->port.uartclk = omap_up_info->uartclk;
up->uart_dma.uart_base = mem->start;

Expand Down

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