[PATCH 005/111] leon3: make timer initialization configurable

[Gedare Bloom]

exported variables should be in a proper namespace.

On Thu, Feb 26, 2015 at 11:38 AM, Daniel Hellstrom <daniel at gaisler.com> wrote:
> Its now possible to select which timer core will be used for
> system clock timer and to control the timer prescaler that
> affects all timer instances on that timer core.
>
> The timer and interrupt controller AMBA devices are exported
> to make it possible for other code to get detailed information.
> For example the frequency of the timer and interrupt controller
> is required by the cpucounter support.
> ---
>  c/src/lib/libbsp/sparc/leon3/amba/amba.c    |   18 ++++++++++++++++--
>  c/src/lib/libbsp/sparc/leon3/include/leon.h |   24 ++++++++++++++++++++++++
>  2 files changed, 40 insertions(+), 2 deletions(-)
>
> diff --git a/c/src/lib/libbsp/sparc/leon3/amba/amba.c b/c/src/lib/libbsp/sparc/leon3/amba/amba.c
> index 9706b25..8655ee3 100644
> --- a/c/src/lib/libbsp/sparc/leon3/amba/amba.c
> +++ b/c/src/lib/libbsp/sparc/leon3/amba/amba.c
> @@ -16,6 +16,9 @@
>  #include <leon.h>
>  #include <ambapp.h>
>
> +unsigned int leon3_timer_prescaler __attribute__((weak)) = 0;
> +int leon3_timer_core_index __attribute__((weak)) = 0;
> +
>  /* AMBA Plug&Play information description.
>   *
>   * After software has scanned AMBA PnP it builds a tree to make
> @@ -28,6 +31,8 @@ rtems_interrupt_lock LEON3_IrqCtrl_Lock =
>
>  /* Pointers to Interrupt Controller configuration registers */
>  volatile struct irqmp_regs *LEON3_IrqCtrl_Regs;
> +struct ambapp_dev *irqmp_dev;
> +struct ambapp_dev *timer_dev;
>
>  /*
>   *  amba_initialize
> @@ -64,6 +69,7 @@ void amba_initialize(void)
>    }
>
>    LEON3_IrqCtrl_Regs = (volatile struct irqmp_regs *)DEV_TO_APB(adev)->start;
> +  irqmp_dev = adev;
>    if ((LEON3_IrqCtrl_Regs->ampctrl >> 28) > 0) {
>      /* IRQ Controller has support for multiple IRQ Controllers, each
>       * CPU can be routed to different Controllers, we find out which
> @@ -84,16 +90,24 @@ void amba_initialize(void)
>    /* find GP Timer */
>    adev = (void *)ambapp_for_each(&ambapp_plb, (OPTIONS_ALL|OPTIONS_APB_SLVS),
>                                   VENDOR_GAISLER, GAISLER_GPTIMER,
> -                                 ambapp_find_by_idx, NULL);
> +                                 ambapp_find_by_idx, &leon3_timer_core_index);
>    if (adev) {
>      LEON3_Timer_Regs = (volatile struct gptimer_regs *)DEV_TO_APB(adev)->start;
> +    timer_dev = adev;
>
>      /* Register AMBA Bus Frequency */
>      ambapp_freq_init(
>        &ambapp_plb,
> -      adev,
> +      timer_dev,
>        (LEON3_Timer_Regs->scaler_reload + 1)
>          * LEON3_GPTIMER_0_FREQUENCY_SET_BY_BOOT_LOADER
>      );
> +    /* Set user prescaler configuration. Use this to increase accuracy of timer
> +     * and accociated services like cpucounter.
> +     * Note that minimum value is the number of timer instances present in
> +     * GRTIMER/GPTIMER hardware. See HW manual.
> +     */
> +    if (leon3_timer_prescaler)
> +      LEON3_Timer_Regs->scaler_reload = leon3_timer_prescaler;
>    }
>  }
> diff --git a/c/src/lib/libbsp/sparc/leon3/include/leon.h b/c/src/lib/libbsp/sparc/leon3/include/leon.h
> index c7270cf..6057c42 100644
> --- a/c/src/lib/libbsp/sparc/leon3/include/leon.h
> +++ b/c/src/lib/libbsp/sparc/leon3/include/leon.h
> @@ -94,8 +94,11 @@ extern "C" {
>
>  /* LEON3 Interrupt Controller */
>  extern volatile struct irqmp_regs *LEON3_IrqCtrl_Regs;
> +extern struct ambapp_dev *irqmp_dev;
> +
>  /* LEON3 GP Timer */
>  extern volatile struct gptimer_regs *LEON3_Timer_Regs;
> +extern struct ambapp_dev *timer_dev;
>
>  /* LEON3 CPU Index of boot CPU */
>  extern uint32_t LEON3_Cpu_Index;
> @@ -308,6 +311,27 @@ extern int syscon_uart_index;
>   */
>  extern int debug_uart_index;
>
> +/* Let user override which on-chip TIMER core will be used for system clock
> + * timer. This controls which timer core will be accociated with
> + * LEON3_Timer_Regs registers base address. This value will by destroyed during
> + * initialization.
> + *  0 = Default configuration. GPTIMER[0]
> + *  1 = GPTIMER[1]
> + *  2 = GPTIMER[2]
> + *  ...
> + */
> +extern int leon3_timer_core_index;
> +
> +/* Let user override system clock timer prescaler. This affects all timer
> + * instances on the system clock timer core determined by
> + * leon3_timer_core_index.
> + *  0 = Default configuration. Use bootloader configured value.
> + *  N = Prescaler is set to N. N must not be less that number of timers.
> + *  8 = Prescaler is set to 8 (the fastest prescaler possible on all HW)
> + *  ...
> + */
> +extern unsigned int leon3_timer_prescaler;
> +
>  void leon3_cpu_counter_initialize(void);
>
>  /* GRLIB extended IRQ controller register */
> --
> 1.7.0.4
>
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