From: Ahmad Fatoum <a.fatoum@pengutronix.de>
To: barebox@lists.infradead.org
Subject: [PATCH v2 07/16] ARM: at91: import early_udelay from at91bootstrap
Date: Tue, 19 Feb 2019 18:21:41 +0100 [thread overview]
Message-ID: <20190219172150.11901-8-a.fatoum@pengutronix.de> (raw)
In-Reply-To: <20190219172150.11901-1-a.fatoum@pengutronix.de>
For use by the incoming at91bootstrap DDRAMC initialization code,
this commit provides an early_udelay function usable in PBL imported from
https://github.com/linux4sam/at91bootstrap/blob/v3.8.12/driver/at91_pit.c
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
arch/arm/mach-at91/Makefile | 1 +
arch/arm/mach-at91/early_udelay.c | 53 +++++++++++++++++++
.../include/mach/at91_lowlevel_clock.h | 9 ++++
.../arm/mach-at91/include/mach/early_udelay.h | 13 +++++
4 files changed, 76 insertions(+)
create mode 100644 arch/arm/mach-at91/early_udelay.c
create mode 100644 arch/arm/mach-at91/include/mach/early_udelay.h
diff --git a/arch/arm/mach-at91/Makefile b/arch/arm/mach-at91/Makefile
index 7c4c58b080a1..b8ff6428d05a 100644
--- a/arch/arm/mach-at91/Makefile
+++ b/arch/arm/mach-at91/Makefile
@@ -1,5 +1,6 @@
obj-y += setup.o
pbl-y += lowlevel_clock.o
+pbl-$(CONFIG_CLOCKSOURCE_ATMEL_PIT) += early_udelay.o
ifeq ($(CONFIG_COMMON_CLK_OF_PROVIDER),)
obj-y += clock.o
diff --git a/arch/arm/mach-at91/early_udelay.c b/arch/arm/mach-at91/early_udelay.c
new file mode 100644
index 000000000000..fb8d8bba5434
--- /dev/null
+++ b/arch/arm/mach-at91/early_udelay.c
@@ -0,0 +1,53 @@
+// SPDX-License-Identifier: BSD-1-Clause
+/*
+ * Copyright (c) 2012, Atmel Corporation
+ */
+
+#include <mach/hardware.h>
+#include <asm/io.h>
+#include <mach/at91_lowlevel_clock.h>
+#include <mach/at91_pit.h>
+#include <mach/early_udelay.h>
+
+static unsigned int master_clock;
+static void __iomem *pmc, *pit;
+
+/* Because the below statement is used in the function:
+ * ((MASTER_CLOCK >> 10) * usec) is used,
+ * to our 32-bit system. the argu "usec" maximum value is:
+ * supposed "MASTER_CLOCK" is 132M.
+ * 132000000 / 1024 = 128906
+ * (0xffffffff) / 128906 = 33318.
+ * So the maximum delay time is 33318 us.
+ */
+/* requires PIT to be initialized, but not the clocksource framework */
+void early_udelay(unsigned int usec)
+{
+ unsigned int delay;
+ unsigned int current;
+ unsigned int base = readl(pit + AT91_PIT_PIIR);
+
+ if (at91_pmc_check_mck_h32mxdiv(pmc))
+ master_clock /= 2;
+
+ delay = ((master_clock >> 10) * usec) >> 14;
+
+ do {
+ current = readl(pit + AT91_PIT_PIIR);
+ current -= base;
+ } while (current < delay);
+}
+
+void early_udelay_init(void __iomem *pmc_base,
+ void __iomem *pit_base,
+ unsigned clock,
+ unsigned int master_clock_rate)
+{
+ master_clock = master_clock_rate;
+ pmc = pmc_base;
+ pit = pit_base;
+
+ writel(AT91_PIT_PIV | AT91_PIT_PITEN, pit + AT91_PIT_MR);
+
+ at91_pmc_enable_periph_clock(pmc_base, clock);
+}
diff --git a/arch/arm/mach-at91/include/mach/at91_lowlevel_clock.h b/arch/arm/mach-at91/include/mach/at91_lowlevel_clock.h
index 8d04e30b644b..e4bdaade740c 100644
--- a/arch/arm/mach-at91/include/mach/at91_lowlevel_clock.h
+++ b/arch/arm/mach-at91/include/mach/at91_lowlevel_clock.h
@@ -9,6 +9,7 @@
#include <errno.h>
#include <asm/io.h>
#include <mach/at91_pmc.h>
+#include <linux/types.h>
void at91_lowlevel_clock_init(void __iomem *pmc_base);
void at91_pmc_cfg_mck(void __iomem *pmc_base, u32 pmc_mckr);
@@ -40,4 +41,12 @@ static inline int at91_pmc_enable_periph_clock(void __iomem *pmc_base,
return 0;
}
+static inline bool at91_pmc_check_mck_h32mxdiv(void __iomem *pmc_base)
+{
+ if (IS_ENABLED(CONFIG_HAVE_AT91_H32MX))
+ return readl(pmc_base + AT91_PMC_MCKR) & AT91_PMC_H32MXDIV;
+
+ return false;
+}
+
#endif
diff --git a/arch/arm/mach-at91/include/mach/early_udelay.h b/arch/arm/mach-at91/include/mach/early_udelay.h
new file mode 100644
index 000000000000..120b586310f0
--- /dev/null
+++ b/arch/arm/mach-at91/include/mach/early_udelay.h
@@ -0,0 +1,13 @@
+#ifndef __EARLY_UDELAY_H__
+#define __EARLY_UDELAY_H__
+
+#include <linux/compiler.h>
+
+/* requires PIT to be initialized, but not the clocksource framework */
+void early_udelay(unsigned int usec);
+void early_udelay_init(void __iomem *pmc_base,
+ void __iomem *pit_base,
+ unsigned clock,
+ unsigned int master_clock_rate);
+
+#endif
--
2.20.1
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next prev parent reply other threads:[~2019-02-19 17:21 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-19 17:21 [PATCH v2 00/16] ARM: at91: microchip-kz9477-evb: support first stage boot Ahmad Fatoum
2019-02-19 17:21 ` [PATCH v2 01/16] LICENSES: add BSD-1-Clause license Ahmad Fatoum
2019-02-19 17:21 ` [PATCH v2 02/16] ARM: at91: import at91bootstrap's at91_ddrsdrc.h Ahmad Fatoum
2019-02-22 13:33 ` Roland Hieber
2019-02-26 9:04 ` Ahmad Fatoum
2019-02-19 17:21 ` [PATCH v2 03/16] ARM: at91: migrate at91sam9_ddrsdr.h to use " Ahmad Fatoum
2019-02-19 17:21 ` [PATCH v2 04/16] ARM: at91: replace at91sam9_ddrsdr.h with " Ahmad Fatoum
2019-02-20 9:07 ` Sascha Hauer
2019-02-19 17:21 ` [PATCH v2 05/16] ARM: at91: watchdog: implement at91_wdt_disable Ahmad Fatoum
2019-02-19 17:21 ` [PATCH v2 06/16] ARM: at91: import lowlevel clock initialization from at91bootstrap Ahmad Fatoum
2019-02-20 9:11 ` Sascha Hauer
2019-02-19 17:21 ` Ahmad Fatoum [this message]
2019-02-20 9:20 ` [PATCH v2 07/16] ARM: at91: import early_udelay " Sascha Hauer
2019-02-20 9:23 ` Sascha Hauer
2019-02-19 17:21 ` [PATCH v2 08/16] ARM: at91: import low level DDRAMC initialization code " Ahmad Fatoum
2019-02-19 17:21 ` [PATCH v2 09/16] ARM: at91: import lowlevel dbgu UART init " Ahmad Fatoum
2019-02-19 17:21 ` [PATCH v2 10/16] images: at91: differentiate between first and second stage images Ahmad Fatoum
2019-02-19 17:21 ` [PATCH v2 11/16] ARM: at91: sama5: specify 0x10000 as first stage max size Ahmad Fatoum
2019-02-19 17:21 ` [PATCH v2 12/16] ARM: at91: microchip-ksz9477-evb: use compressed DTB Ahmad Fatoum
2019-02-19 17:21 ` [PATCH v2 13/16] ARM: dts: microchip-ksz9477-evb: add dummy first stage device tree Ahmad Fatoum
2019-02-19 17:21 ` [PATCH v2 14/16] ARM: at91: microchip-ksz9477-evb: implement first stage Ahmad Fatoum
2019-02-22 13:45 ` Roland Hieber
2019-02-26 9:05 ` Ahmad Fatoum
2019-02-19 17:21 ` [PATCH v2 15/16] ARM: at91: microchip-ksz9477: provide board code fallback Ahmad Fatoum
2019-02-20 9:27 ` Sascha Hauer
2019-02-19 17:21 ` [PATCH v2 16/16] doc: microchip-ksz9477-evb: add documentation Ahmad Fatoum
2019-02-24 12:42 ` [PATCH v2 00/16] ARM: at91: microchip-kz9477-evb: support first stage boot Sam Ravnborg
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