From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from 14.mo1.mail-out.ovh.net ([178.32.97.215] helo=mo1.mail-out.ovh.net) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1TJj80-0002hs-AL for barebox@lists.infradead.org; Thu, 04 Oct 2012 10:58:05 +0000 Received: from mail615.ha.ovh.net (b6.ovh.net [213.186.33.56]) by mo1.mail-out.ovh.net (Postfix) with SMTP id 51623FF94D9 for ; Thu, 4 Oct 2012 13:07:08 +0200 (CEST) From: Jean-Christophe PLAGNIOL-VILLARD Date: Thu, 4 Oct 2012 12:55:35 +0200 Message-Id: <1349348135-509-1-git-send-email-plagnioj@jcrosoft.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: barebox-bounces@lists.infradead.org Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: [PATCH 1/1 v2] arm: add generic smp twd timer To: barebox@lists.infradead.org on Cortex A9 and Cortex A5 we have a generic timer which we can use as clocksource Limit the timer frequency to < 25Mhz Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD --- v2: move to clocksource drop header Best Regards, J. drivers/Kconfig | 1 + drivers/Makefile | 1 + drivers/clocksource/arm_smp_twd.c | 101 +++++++++++++++++++++++++++++++++++++ 3 files changed, 103 insertions(+) create mode 100644 drivers/clocksource/arm_smp_twd.c diff --git a/drivers/Kconfig b/drivers/Kconfig index d0b5e3a..6f78644 100644 --- a/drivers/Kconfig +++ b/drivers/Kconfig @@ -11,6 +11,7 @@ source "drivers/usb/Kconfig" source "drivers/video/Kconfig" source "drivers/mci/Kconfig" source "drivers/clk/Kconfig" +source "drivers/clocksource/Kconfig" source "drivers/mfd/Kconfig" source "drivers/misc/Kconfig" source "drivers/led/Kconfig" diff --git a/drivers/Makefile b/drivers/Makefile index 2a1f8b0..742a5bd 100644 --- a/drivers/Makefile +++ b/drivers/Makefile @@ -11,6 +11,7 @@ obj-$(CONFIG_I2C) += i2c/ obj-$(CONFIG_MCI) += mci/ obj-$(CONFIG_VIDEO) += video/ obj-y += clk/ +obj-y += clocksource/ obj-y += mfd/ obj-$(CONFIG_LED) += led/ obj-y += eeprom/ diff --git a/drivers/clocksource/arm_smp_twd.c b/drivers/clocksource/arm_smp_twd.c new file mode 100644 index 0000000..746d566 --- /dev/null +++ b/drivers/clocksource/arm_smp_twd.c @@ -0,0 +1,101 @@ +/* + * Copyright (C) 2012 Jean-Christophe PLAGNIOL-VILLARD + * + * Under GPL v2 + */ +#include +#include +#include +#include +#include +#include +#include +#include + +#define TWD_TIMER_LOAD 0x00 +#define TWD_TIMER_COUNTER 0x04 +#define TWD_TIMER_CONTROL 0x08 +#define TWD_TIMER_INTSTAT 0x0C + +#define TWD_TIMER_CONTROL_ENABLE (1 << 0) +#define TWD_TIMER_CONTROL_ONESHOT (0 << 1) +#define TWD_TIMER_CONTROL_PERIODIC (1 << 1) +#define TWD_TIMER_CONTROL_IT_ENABLE (1 << 2) + +#define TWD_TIMER_CONTROL_PRESC(x) (((x) & 0xff) << 8) + +static __iomem void *twd_base; +static struct clk *twd_clk; + +static uint64_t smp_twd_read(void) +{ + return ~readl(twd_base + TWD_TIMER_COUNTER); +} + +static struct clocksource smp_twd_clksrc = { + .read = smp_twd_read, + .shift = 20, + .mask = CLOCKSOURCE_MASK(32), +}; + +#define SMP_TWD_MAX_FREQ (25 *1000 * 1000) + +static int smp_twd_probe(struct device_d *dev) +{ + u32 tick_rate; + u32 val; + int ret; + u32 presc = 0; + + twd_clk = clk_get(dev, NULL); + if (IS_ERR(twd_clk)) { + ret = PTR_ERR(twd_clk); + dev_err(dev, "clock not found: %d\n", ret); + return ret; + } + + ret = clk_enable(twd_clk); + if (ret < 0) { + dev_err(dev, "clock failed to enable: %d\n", ret); + clk_put(twd_clk); + return ret; + } + + twd_base = dev_request_mem_region(dev, 0); + + tick_rate = clk_get_rate(twd_clk); + if (tick_rate > SMP_TWD_MAX_FREQ) { + presc = tick_rate / SMP_TWD_MAX_FREQ; + if (presc) + presc--; + presc = min((u32)0xff, presc); + tick_rate /= presc + 1; + } + + val = TWD_TIMER_CONTROL_PRESC(presc) | + TWD_TIMER_CONTROL_PERIODIC; + writel(val, twd_base + TWD_TIMER_CONTROL); + + writel(0xffffffff, twd_base + TWD_TIMER_LOAD); + + val = readl(twd_base + TWD_TIMER_CONTROL); + val |= TWD_TIMER_CONTROL_ENABLE; + writel(val, twd_base + TWD_TIMER_CONTROL); + + smp_twd_clksrc.mult = clocksource_hz2mult(tick_rate, smp_twd_clksrc.shift); + + init_clock(&smp_twd_clksrc); + + return 0; +} + +static struct driver_d smp_twd_driver = { + .name = "smp_twd", + .probe = smp_twd_probe, +}; + +static int smp_twd_init(void) +{ + return platform_driver_register(&smp_twd_driver); +} +coredevice_initcall(smp_twd_init); -- 1.7.10.4 _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox