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From: Ahmad Fatoum <a.fatoum@pengutronix.de>
To: barebox@lists.infradead.org
Subject: [PATCH 06/11] ARM: at91: import early_udelay from at91bootstrap
Date: Wed, 16 Jan 2019 18:45:54 +0100	[thread overview]
Message-ID: <20190116174559.17416-7-a.fatoum@pengutronix.de> (raw)
In-Reply-To: <20190116174559.17416-1-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/Kconfig                    |  4 ++
 arch/arm/mach-at91/Makefile                   |  1 +
 arch/arm/mach-at91/early_udelay.c             | 61 +++++++++++++++++++
 .../arm/mach-at91/include/mach/early_udelay.h | 13 ++++
 4 files changed, 79 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/Kconfig b/arch/arm/mach-at91/Kconfig
index 63e6e7285931..98d18c8b26db 100644
--- a/arch/arm/mach-at91/Kconfig
+++ b/arch/arm/mach-at91/Kconfig
@@ -15,6 +15,9 @@ config HAVE_AT91_UTMI
 config HAVE_AT91_USB_CLK
 	bool
 
+config HAVE_AT91_H32MXDIV
+	bool
+
 config COMMON_CLK_AT91
 	bool
 	select COMMON_CLK
@@ -196,6 +199,7 @@ config ARCH_SAMA5D4
 	select HAVE_AT91_DBGU2
 	select HAS_MACB
 	select HAVE_MACH_ARM_HEAD
+	select HAVE_AT91_H32MXDIV
 
 endchoice
 
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..b25b5d558833
--- /dev/null
+++ b/arch/arm/mach-at91/early_udelay.c
@@ -0,0 +1,61 @@
+// 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;
+
+static bool pmc_check_mck_h32mxdiv(void)
+{
+	if (IS_ENABLED(CONFIG_HAVE_AT91_H32MXDIV))
+		return __raw_readl(pmc + AT91_PMC_MCKR) & AT91_PMC_H32MXDIV;
+
+	return false;
+}
+
+/* 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 = __raw_readl(pit + AT91_PIT_PIIR);
+
+	if (pmc_check_mck_h32mxdiv())
+		master_clock /= 2;
+
+	delay = ((master_clock >> 10) * usec) >> 14;
+
+	do {
+		current = __raw_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;
+
+	__raw_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/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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  parent reply	other threads:[~2019-01-16 17:46 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-16 17:45 [PATCH 00/11] ARM: at91: microchip-kz9477-evb: support first stage boot Ahmad Fatoum
2019-01-16 17:45 ` [PATCH 01/11] ARM: at91: clk: prune never-compiled h32mx code Ahmad Fatoum
2019-01-16 17:45 ` [PATCH 02/11] ARM: at91: sama5d3: remove never referenced empty header file Ahmad Fatoum
2019-01-16 17:45 ` [PATCH 03/11] ARM: at91: replace at91sam9_ddrsdr.h with at91bootstrap's Ahmad Fatoum
2019-01-16 18:24   ` Sam Ravnborg
2019-01-17  9:28     ` Ahmad Fatoum
2019-01-16 17:45 ` [PATCH 04/11] ARM: at91: watchdog: implement at91_wdt_disable Ahmad Fatoum
2019-01-16 17:45 ` [PATCH 05/11] ARM: at91: import lowlevel clock initialization from at91bootstrap Ahmad Fatoum
2019-01-16 17:45 ` Ahmad Fatoum [this message]
2019-01-16 17:45 ` [PATCH 07/11] ARM: at91: import low level DDRAMC initialization code " Ahmad Fatoum
2019-01-17  8:11   ` Sascha Hauer
2019-01-17  9:28     ` Ahmad Fatoum
2019-01-16 17:45 ` [PATCH 08/11] ARM: at91: import lowlevel dbgu UART init " Ahmad Fatoum
2019-01-16 17:45 ` [PATCH 09/11] ARM: at91: microchip-ksz9477-evb: reintroduce board code for first stage Ahmad Fatoum
2019-01-17  8:25   ` Sascha Hauer
2019-01-17  9:37     ` Ahmad Fatoum
2019-01-16 17:45 ` [PATCH 10/11] ARM: at91: microchip-ksz9477-evb: import low level init from at91bootstrap Ahmad Fatoum
2019-01-16 17:45 ` [PATCH 11/11] ARM: at91: microchip-ksz9477-evb: add first stage MMC defconfig Ahmad Fatoum
2019-01-16 18:47 ` [PATCH 00/11] ARM: at91: microchip-kz9477-evb: support first stage boot Sam Ravnborg
2019-01-17  9:43   ` Ahmad Fatoum

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