Add timer support for T20/T30/T114 and T124 based devices.
Driver is based on DM, has device tree support and can be
used on SPL and early boot stage.

Tested-by: Andreas Westman Dorcsak <hed...@yahoo.com> # ASUS TF600T T30
Tested-by: Jonas Schwöbel <jonasschwoe...@yahoo.de> # Surface RT T30
Tested-by: Robert Eckelmann <longnose...@gmail.com> # ASUS TF101 T20
Tested-by: Svyatoslav Ryhel <clamo...@gmail.com> # LG P895 T30
Co-developed-by: Jonas Schwöbel <jonasschwoe...@yahoo.de>
Signed-off-by: Jonas Schwöbel <jonasschwoe...@yahoo.de>
Signed-off-by: Svyatoslav Ryhel <clamo...@gmail.com>
---
 drivers/timer/Kconfig       |   8 +++
 drivers/timer/Makefile      |   1 +
 drivers/timer/tegra-timer.c | 124 ++++++++++++++++++++++++++++++++++++
 3 files changed, 133 insertions(+)
 create mode 100644 drivers/timer/tegra-timer.c

diff --git a/drivers/timer/Kconfig b/drivers/timer/Kconfig
index 6d6665005c..f32bd16227 100644
--- a/drivers/timer/Kconfig
+++ b/drivers/timer/Kconfig
@@ -252,6 +252,14 @@ config STM32_TIMER
          Select this to enable support for the timer found on
          STM32 devices.
 
+config TEGRA_TIMER
+       bool "Tegra timer support"
+       depends on TIMER
+       select TIMER_EARLY
+       help
+         Select this to enable support for the timer found on
+         Tegra devices.
+
 config X86_TSC_TIMER
        bool "x86 Time-Stamp Counter (TSC) timer support"
        depends on TIMER && X86
diff --git a/drivers/timer/Makefile b/drivers/timer/Makefile
index 6470fd5426..3c92113fc6 100644
--- a/drivers/timer/Makefile
+++ b/drivers/timer/Makefile
@@ -27,6 +27,7 @@ obj-$(CONFIG_SP804_TIMER)     += sp804_timer.o
 obj-$(CONFIG_$(SPL_)SIFIVE_CLINT) += sifive_clint_timer.o
 obj-$(CONFIG_ARM_GLOBAL_TIMER) += arm_global_timer.o
 obj-$(CONFIG_STM32_TIMER)      += stm32_timer.o
+obj-$(CONFIG_TEGRA_TIMER)      += tegra-timer.o
 obj-$(CONFIG_X86_TSC_TIMER)    += tsc_timer.o
 obj-$(CONFIG_MTK_TIMER)                += mtk_timer.o
 obj-$(CONFIG_MCHP_PIT64B_TIMER)        += mchp-pit64b-timer.o
diff --git a/drivers/timer/tegra-timer.c b/drivers/timer/tegra-timer.c
new file mode 100644
index 0000000000..cda460921f
--- /dev/null
+++ b/drivers/timer/tegra-timer.c
@@ -0,0 +1,124 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2022 Svyatoslav Ryhel <clamo...@gmail.com>
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <timer.h>
+
+#include <asm/io.h>
+#include <asm/arch/clock.h>
+#include <asm/arch/tegra.h>
+
+#define TEGRA_OSC_CLK_ENB_L_SET                (NV_PA_CLK_RST_BASE + 0x320)
+#define TEGRA_OSC_SET_CLK_ENB_TMR      BIT(5)
+
+#define TEGRA_TIMER_USEC_CNTR          (NV_PA_TMRUS_BASE + 0)
+#define TEGRA_TIMER_USEC_CFG           (NV_PA_TMRUS_BASE + 4)
+
+#define TEGRA_TIMER_RATE               1000000 /* 1 MHz */
+
+u64 notrace timer_early_get_count(void)
+{
+       /* At this stage raw timer is used */
+       return readl(TEGRA_TIMER_USEC_CNTR);
+}
+
+unsigned long notrace timer_early_get_rate(void)
+{
+       return TEGRA_TIMER_RATE;
+}
+
+#if CONFIG_IS_ENABLED(BOOTSTAGE)
+ulong timer_get_boot_us(void)
+{
+       u64 ticks = 0;
+       int ret;
+
+       ret = dm_timer_init();
+       if (!ret)
+               timer_get_count(gd->timer, &ticks);
+       else
+               ticks = timer_early_get_count();
+
+       return ticks;
+}
+#endif
+
+static notrace u64 tegra_timer_get_count(struct udevice *dev)
+{
+       u32 val = timer_early_get_count();
+       return timer_conv_64(val);
+}
+
+static int tegra_timer_probe(struct udevice *dev)
+{
+       struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
+       u32 usec_config, value;
+
+       /* Timer rate has to be set unconditionally */
+       uc_priv->clock_rate = TEGRA_TIMER_RATE;
+
+       /*
+        * Configure microsecond timers to have 1MHz clock
+        * Config register is 0xqqww, where qq is "dividend", ww is "divisor"
+        * Uses n+1 scheme
+        */
+       switch (clock_get_osc_freq()) {
+       case CLOCK_OSC_FREQ_13_0:
+               usec_config = 0x000c; /* (12+1)/(0+1) */
+               break;
+       case CLOCK_OSC_FREQ_19_2:
+               usec_config = 0x045f; /* (95+1)/(4+1) */
+               break;
+       case CLOCK_OSC_FREQ_12_0:
+               usec_config = 0x000b; /* (11+1)/(0+1) */
+               break;
+       case CLOCK_OSC_FREQ_26_0:
+               usec_config = 0x0019; /* (25+1)/(0+1) */
+               break;
+       case CLOCK_OSC_FREQ_16_8:
+               usec_config = 0x0453; /* (83+1)/(4+1) */
+               break;
+       case CLOCK_OSC_FREQ_38_4:
+               usec_config = 0x04bf; /* (191+1)/(4+1) */
+               break;
+       case CLOCK_OSC_FREQ_48_0:
+               usec_config = 0x002f; /* (47+1)/(0+1) */
+               break;
+       default:
+               return -EINVAL;
+       }
+
+       /* Enable clock to timer hardware */
+       value = readl_relaxed(TEGRA_OSC_CLK_ENB_L_SET);
+       writel_relaxed(value | TEGRA_OSC_SET_CLK_ENB_TMR,
+                      TEGRA_OSC_CLK_ENB_L_SET);
+
+       writel_relaxed(usec_config, TEGRA_TIMER_USEC_CFG);
+
+       return 0;
+}
+
+static const struct timer_ops tegra_timer_ops = {
+       .get_count = tegra_timer_get_count,
+};
+
+static const struct udevice_id tegra_timer_ids[] = {
+       { .compatible = "nvidia,tegra20-timer" },
+       { .compatible = "nvidia,tegra30-timer" },
+       { .compatible = "nvidia,tegra114-timer" },
+       { .compatible = "nvidia,tegra124-timer" },
+       { }
+};
+
+U_BOOT_DRIVER(tegra_timer) = {
+       .name           = "tegra_timer",
+       .id             = UCLASS_TIMER,
+       .of_match       = tegra_timer_ids,
+       .probe          = tegra_timer_probe,
+       .ops            = &tegra_timer_ops,
+       .flags          = DM_FLAG_PRE_RELOC,
+};
-- 
2.37.2

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