mail archive of the barebox mailing list
 help / color / mirror / Atom feed
From: Lucas Stach <dev@lynxeye.de>
To: barebox@lists.infradead.org
Subject: [PATCH v2 4/8] tegra: add lowlevel delay function
Date: Mon, 17 Feb 2014 21:27:37 +0100	[thread overview]
Message-ID: <1392668861-10915-5-git-send-email-dev@lynxeye.de> (raw)
In-Reply-To: <1392668861-10915-1-git-send-email-dev@lynxeye.de>

For proper startup we need to give clocks and IO signals some time to
stabilize. Tegra2 got away without them, but Tegra3 seems to be a bit
pickier.

Signed-off-by: Lucas Stach <dev@lynxeye.de>
---
 arch/arm/mach-tegra/include/mach/lowlevel.h | 44 +++++++++++++++++++++++++++++
 arch/arm/mach-tegra/tegra_avp_init.c        |  5 ++++
 2 files changed, 49 insertions(+)

diff --git a/arch/arm/mach-tegra/include/mach/lowlevel.h b/arch/arm/mach-tegra/include/mach/lowlevel.h
index 20de1b2..85ab7ef 100644
--- a/arch/arm/mach-tegra/include/mach/lowlevel.h
+++ b/arch/arm/mach-tegra/include/mach/lowlevel.h
@@ -183,6 +183,49 @@ int tegra_get_osc_clock(void)
 	}
 }
 
+#define TIMER_CNTR_1US	0x00
+#define TIMER_USEC_CFG	0x04
+
+static __always_inline
+void tegra_ll_delay_setup(void)
+{
+	u32 reg;
+
+	/*
+	 * calibrate timer to run at 1MHz
+	 * TIMERUS_USEC_CFG selects the scale down factor with bits [0:7]
+	 * representing the divisor and bits [8:15] representing the dividend
+	 * each in n+1 form.
+	 */
+	switch (tegra_get_osc_clock()) {
+	case 12000000:
+		reg = 0x000b;
+		break;
+	case 13000000:
+		reg = 0x000c;
+		break;
+	case 19200000:
+		reg = 0x045f;
+		break;
+	case 26000000:
+		reg = 0x0019;
+		break;
+	default:
+		reg = 0;
+		break;
+	}
+
+	writel(reg, TEGRA_TMRUS_BASE + TIMER_USEC_CFG);
+}
+
+static __always_inline
+void tegra_ll_delay_usec(int delay)
+{
+	int timeout = (int)readl(TEGRA_TMRUS_BASE + TIMER_CNTR_1US) + delay;
+
+	while ((int)readl(TEGRA_TMRUS_BASE + TIMER_CNTR_1US) - timeout < 0);
+}
+
 static __always_inline
 void tegra_cpu_lowlevel_setup(void)
 {
@@ -193,6 +236,7 @@ void tegra_cpu_lowlevel_setup(void)
 	r &= ~0x1f;
 	r |= 0xd3;
 	__asm__ __volatile__("msr cpsr, %0" : : "r"(r));
+	tegra_ll_delay_setup();
 }
 
 /* reset vector for the AVP, to be called from board reset vector */
diff --git a/arch/arm/mach-tegra/tegra_avp_init.c b/arch/arm/mach-tegra/tegra_avp_init.c
index 2c2d6fc..9f8ccf3 100644
--- a/arch/arm/mach-tegra/tegra_avp_init.c
+++ b/arch/arm/mach-tegra/tegra_avp_init.c
@@ -158,6 +158,9 @@ static void start_cpu0_clocks(void)
 	reg = readl(TEGRA_CLK_RESET_BASE + CRC_CLK_OUT_ENB_L);
 	reg |= CRC_CLK_OUT_ENB_L_CPU;
 	writel(reg, TEGRA_CLK_RESET_BASE + CRC_CLK_OUT_ENB_L);
+
+	/* give clocks some time to settle */
+	tegra_ll_delay_usec(300);
 }
 
 static void maincomplex_powerup(void)
@@ -175,6 +178,8 @@ static void maincomplex_powerup(void)
 		reg = readl(TEGRA_PMC_BASE + PMC_REMOVE_CLAMPING_CMD);
 		reg |= PMC_REMOVE_CLAMPING_CMD_CPU;
 		writel(reg, TEGRA_PMC_BASE + PMC_REMOVE_CLAMPING_CMD);
+
+		tegra_ll_delay_usec(1000);
 	}
 }
 void tegra_avp_reset_vector(uint32_t boarddata)
-- 
1.8.5.3


_______________________________________________
barebox mailing list
barebox@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/barebox

  parent reply	other threads:[~2014-02-17 20:26 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-02-17 20:27 [PATCH v2 0/8] Lowlevel Tegra3 support Lucas Stach
2014-02-17 20:27 ` [PATCH v2 1/8] tegra: add -fno-jump-tables to lowlevel code Lucas Stach
2014-02-17 20:27 ` [PATCH v2 2/8] tegra: lowlevel: switch to __always_inline macro Lucas Stach
2014-02-17 20:27 ` [PATCH v2 3/8] tegra: add break to switch statements Lucas Stach
2014-02-17 20:27 ` Lucas Stach [this message]
2014-02-17 20:27 ` [PATCH v2 5/8] tegra: add Tegra3 to relevant lowlevel functions Lucas Stach
2014-02-17 20:27 ` [PATCH v2 6/8] tegra: add lowlevel DVC Lucas Stach
2014-02-17 20:27 ` [PATCH v2 7/8] tegra: set AHB clock rate early Lucas Stach
2014-02-17 20:27 ` [PATCH v2 8/8] tegra: add Tegra3 startup Lucas Stach

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1392668861-10915-5-git-send-email-dev@lynxeye.de \
    --to=dev@lynxeye.de \
    --cc=barebox@lists.infradead.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox