Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751989AbbEZSqL (ORCPT ); Tue, 26 May 2015 14:46:11 -0400 Received: from mailapp01.imgtec.com ([195.59.15.196]:44846 "EHLO mailapp01.imgtec.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751126AbbEZSqJ (ORCPT ); Tue, 26 May 2015 14:46:09 -0400 From: Ezequiel Garcia To: , , "Daniel Lezcano" , CC: Thomas Gleixner , Andrew Bresticker , James Hartley , , , James Hogan , Ezequiel Garcia Subject: [PATCH v2 6/7] clocksource: Add Pistachio clocksource-only driver Date: Tue, 26 May 2015 15:41:39 -0300 Message-ID: <1432665699-16154-1-git-send-email-ezequiel.garcia@imgtec.com> X-Mailer: git-send-email 2.3.3 In-Reply-To: <1432665548-16024-1-git-send-email-ezequiel.garcia@imgtec.com> References: <1432665548-16024-1-git-send-email-ezequiel.garcia@imgtec.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.100.200.175] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7189 Lines: 254 The Pistachio SoC provides four general purpose timers, and allow to implement a clocksource driver. This driver can be used as a replacement for the MIPS GIC and MIPS R4K clocksources and sched clocks, which are clocked from the CPU clock. Given the general purpose timers are clocked from an independent clock, this new clocksource driver will be useful to introduce CPUFreq support for Pistachio machines. Signed-off-by: Govindraj Raja Signed-off-by: Ezequiel Garcia --- drivers/clocksource/Kconfig | 4 + drivers/clocksource/Makefile | 1 + drivers/clocksource/time-pistachio.c | 194 +++++++++++++++++++++++++++++++++++ 3 files changed, 199 insertions(+) create mode 100644 drivers/clocksource/time-pistachio.c diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig index 51d7865f..faa16ae 100644 --- a/drivers/clocksource/Kconfig +++ b/drivers/clocksource/Kconfig @@ -106,6 +106,10 @@ config CLKSRC_EFM32 Support to use the timers of EFM32 SoCs as clock source and clock event device. +config CLKSRC_PISTACHIO + bool + select CLKSRC_OF + config ARM_ARCH_TIMER bool select CLKSRC_OF if OF diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile index 5b85f6a..9415def 100644 --- a/drivers/clocksource/Makefile +++ b/drivers/clocksource/Makefile @@ -42,6 +42,7 @@ obj-$(CONFIG_FSL_FTM_TIMER) += fsl_ftm_timer.o obj-$(CONFIG_VF_PIT_TIMER) += vf_pit_timer.o obj-$(CONFIG_CLKSRC_QCOM) += qcom-timer.o obj-$(CONFIG_MTK_TIMER) += mtk_timer.o +obj-$(CONFIG_CLKSRC_PISTACHIO) += time-pistachio.o obj-$(CONFIG_ARM_ARCH_TIMER) += arm_arch_timer.o obj-$(CONFIG_ARM_GLOBAL_TIMER) += arm_global_timer.o diff --git a/drivers/clocksource/time-pistachio.c b/drivers/clocksource/time-pistachio.c new file mode 100644 index 0000000..d461bd1 --- /dev/null +++ b/drivers/clocksource/time-pistachio.c @@ -0,0 +1,194 @@ +/* + * Pistachio clocksource based on general-purpose timers + * + * Copyright (C) 2015 Imagination Technologies + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + */ + +#define pr_fmt(fmt) "%s: " fmt, __func__ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* Top level reg */ +#define CR_TIMER_CTRL_CFG 0x00 +#define TIMER_ME_GLOBAL BIT(0) +#define CR_TIMER_REV 0x10 + +/* Timer specific registers */ +#define TIMER_CFG 0x20 +#define TIMER_ME_LOCAL BIT(0) +#define TIMER_RELOAD_VALUE 0x24 +#define TIMER_CURRENT_VALUE 0x28 +#define TIMER_CURRENT_OVERFLOW_VALUE 0x2C +#define TIMER_IRQ_STATUS 0x30 +#define TIMER_IRQ_CLEAR 0x34 +#define TIMER_IRQ_MASK 0x38 + +#define PERIP_TIMER_CONTROL 0x90 + +/* Timer specific configuration Values */ +#define RELOAD_VALUE 0xffffffff + +static void __iomem *timer_base; +static DEFINE_RAW_SPINLOCK(lock); + +static inline u32 gpt_readl(u32 offset, u32 gpt_id) +{ + return readl(timer_base + 0x20 * gpt_id + offset); +} + +static inline void gpt_writel(u32 value, u32 offset, u32 gpt_id) +{ + writel(value, timer_base + 0x20 * gpt_id + offset); +} + +static cycle_t pistachio_clocksource_read_cycles(struct clocksource *cs) +{ + u32 counter, overflw; + unsigned long flags; + + raw_spin_lock_irqsave(&lock, flags); + overflw = gpt_readl(TIMER_CURRENT_OVERFLOW_VALUE, 0); + counter = gpt_readl(TIMER_CURRENT_VALUE, 0); + raw_spin_unlock_irqrestore(&lock, flags); + + return ~(cycle_t)counter; +} + +static u64 notrace pistachio_read_sched_clock(void) +{ + return pistachio_clocksource_read_cycles(NULL); +} + +static void pistachio_clksrc_enable(int timeridx) +{ + u32 val; + + /* Disable GPT local before loading reload value */ + val = gpt_readl(TIMER_CFG, timeridx); + val &= ~TIMER_ME_LOCAL; + gpt_writel(val, TIMER_CFG, timeridx); + + gpt_writel(RELOAD_VALUE, TIMER_RELOAD_VALUE, timeridx); + + val = gpt_readl(TIMER_CFG, timeridx); + val |= TIMER_ME_LOCAL; + gpt_writel(val, TIMER_CFG, timeridx); +} + +static void pistachio_clksrc_disable(int timeridx) +{ + u32 val; + + /* Disable GPT local */ + val = gpt_readl(TIMER_CFG, timeridx); + val &= ~TIMER_ME_LOCAL; + gpt_writel(val, TIMER_CFG, timeridx); +} + +static int pistachio_clocksource_enable(struct clocksource *cs) +{ + pistachio_clksrc_enable(0); + return 0; +} + +static void pistachio_clocksource_disable(struct clocksource *cs) +{ + pistachio_clksrc_disable(0); +} + +/* Desirable clock source for pistachio platform */ +static struct clocksource pistachio_clocksource_gpt = { + .name = "gptimer", + .rating = 300, + .enable = pistachio_clocksource_enable, + .disable = pistachio_clocksource_disable, + .read = pistachio_clocksource_read_cycles, + .mask = CLOCKSOURCE_MASK(32), + .flags = CLOCK_SOURCE_IS_CONTINUOUS | + CLOCK_SOURCE_SUSPEND_NONSTOP, +}; + +static void __init pistachio_clksrc_of_init(struct device_node *node) +{ + struct clk *sys_clk, *fast_clk; + struct regmap *periph_regs; + unsigned long rate; + int ret; + + timer_base = of_iomap(node, 0); + if (!timer_base) { + pr_err("cannot iomap\n"); + return; + } + + periph_regs = syscon_regmap_lookup_by_phandle(node, "img,cr-periph"); + if (IS_ERR(periph_regs)) { + pr_err("cannot get peripheral regmap (%lu)\n", + PTR_ERR(periph_regs)); + return; + } + + /* Switch to using the fast counter clock */ + ret = regmap_update_bits(periph_regs, PERIP_TIMER_CONTROL, + 0xf, 0x0); + if (ret) + return; + + sys_clk = of_clk_get_by_name(node, "sys"); + if (IS_ERR(sys_clk)) { + pr_err("clock get failed (%lu)\n", PTR_ERR(sys_clk)); + return; + } + + fast_clk = of_clk_get_by_name(node, "fast"); + if (IS_ERR(fast_clk)) { + pr_err("clock get failed (%lu)\n", PTR_ERR(fast_clk)); + return; + } + + ret = clk_prepare_enable(sys_clk); + if (ret < 0) { + pr_err("failed to enable clock (%d)\n", ret); + return; + } + + ret = clk_prepare_enable(fast_clk); + if (ret < 0) { + pr_err("failed to enable clock (%d)\n", ret); + clk_disable_unprepare(sys_clk); + return; + } + + rate = clk_get_rate(fast_clk); + + /* Disable irq's for clocksource usage */ + gpt_writel(0, TIMER_IRQ_MASK, 0); + gpt_writel(0, TIMER_IRQ_MASK, 1); + gpt_writel(0, TIMER_IRQ_MASK, 2); + gpt_writel(0, TIMER_IRQ_MASK, 3); + + /* Enable timer block */ + writel(TIMER_ME_GLOBAL, timer_base); + + sched_clock_register(pistachio_read_sched_clock, 32, rate); + clocksource_register_hz(&pistachio_clocksource_gpt, rate); +} +CLOCKSOURCE_OF_DECLARE(pistachio_gptimer, "img,pistachio-gptimer", + pistachio_clksrc_of_init); -- 2.3.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/