[U-Boot] [PATCH 02/19] dm: timer: uclass: add timer init to add timer device

[Mugunthan V N]

On Saturday 28 November 2015 01:56 PM, Bin Meng wrote:
> Hi Mugunthan,
> 
> On Fri, Nov 27, 2015 at 4:31 PM, Mugunthan V N <mugunthanvnm at ti.com> wrote:
>> Adding timer_init function to create and initialize the timer
>> device on platforms where u-boot,dm-pre-reloc is not used. Since
>> there will be multiple timer devices in the system, adding a
>> tick-timer node in chosen node to know which timer device to be
>> used as tick timer in u-boot.
>>
>> Signed-off-by: Mugunthan V N <mugunthanvnm at ti.com>
>> ---
>>  doc/device-tree-bindings/chosen.txt | 43 +++++++++++++++++++++++++++++++++++++
>>  drivers/timer/timer-uclass.c        | 34 +++++++++++++++++++++++++++++
>>  lib/time.c                          |  5 +++++
>>  3 files changed, 82 insertions(+)
>>  create mode 100644 doc/device-tree-bindings/chosen.txt
>>
>> diff --git a/doc/device-tree-bindings/chosen.txt b/doc/device-tree-bindings/chosen.txt
>> new file mode 100644
>> index 0000000..58f29f9
>> --- /dev/null
>> +++ b/doc/device-tree-bindings/chosen.txt
>> @@ -0,0 +1,43 @@
>> +The chosen node
>> +---------------
>> +The chosen node does not represent a real device, but serves as a place
>> +for passing data like which serial device to used to print the logs etc
>> +
>> +
>> +stdout-path property
>> +--------------------
>> +Device trees may specify the device to be used for boot console output
>> +with a stdout-path property under /chosen.
>> +
>> +Example
>> +-------
>> +/ {
>> +       chosen {
>> +               stdout-path = "/serial at f00:115200";
>> +       };
>> +
>> +       serial at f00 {
>> +               compatible = "vendor,some-uart";
>> +               reg = <0xf00 0x10>;
>> +       };
>> +};
>> +
>> +tick-timer property
>> +-------------------
>> +In a system there are multiple timers, specify which timer to be used
>> +as the tick-timer. Earlier it was hardcoded in the timer driver now
>> +since device tree has all the timer nodes. Specify which timer to be
>> +used as tick timer.
>> +
>> +Example
>> +-------
>> +/ {
>> +       chosen {
>> +               tick-timer = &timer2;
> 
> I believe this is a wrong device tree syntax as timer2 is not a label.

Will fix it in next version.

> 
>> +       };
>> +
>> +       timer2 at f00 {
>> +               compatible = "vendor,some-uart";
> 
> some-timer
> 
>> +               reg = <0xf00 0x10>;
>> +       };
>> +};
>> diff --git a/drivers/timer/timer-uclass.c b/drivers/timer/timer-uclass.c
>> index 12aee5b..78ec989 100644
>> --- a/drivers/timer/timer-uclass.c
>> +++ b/drivers/timer/timer-uclass.c
>> @@ -6,9 +6,13 @@
>>
>>  #include <common.h>
>>  #include <dm.h>
>> +#include <dm/lists.h>
>> +#include <dm/device-internal.h>
>>  #include <errno.h>
>>  #include <timer.h>
>>
>> +DECLARE_GLOBAL_DATA_PTR;
>> +
>>  /*
>>   * Implement a Timer uclass to work with lib/time.c. The timer is usually
>>   * a 32 bits free-running up counter. The get_rate() method is used to get
>> @@ -35,6 +39,36 @@ unsigned long timer_get_rate(struct udevice *dev)
>>         return uc_priv->clock_rate;
>>  }
>>
>> +int timer_init(void)
> 
> This introduces a timer_init() which won't build for x86 as x86 has a
> timer_init() already.

You mean init_timer() in arch/x86/lib/tsc_timer.c, once x86 timer is
converted to driver model the init_timer() should be removed. Similar
init_timer() is also present in omap as well, but with patch 01 of this
series timer driver is removed from build when CONFIG_TIMER is defined
in defconfig.

> 
>> +{
>> +       const void *blob = gd->fdt_blob;
>> +       struct udevice *dev;
>> +       int node;
>> +
>> +       if (CONFIG_IS_ENABLED(OF_CONTROL) && blob) {
> 
> Why do we need this if check? I think it can be removed.
> 
>> +               /* Check for a chosen timer to be used for tick */
>> +               node = fdtdec_get_chosen_node(blob, "tick-timer");
>> +               if (node < 0)
>> +                       return -ENODEV;
>> +
>> +               if (uclass_get_device_by_of_offset(UCLASS_TIMER, node, &dev)) {
>> +                       /*
>> +                        * If the timer is not marked to be bound before
>> +                        * relocation, bind it anyway.
>> +                        */
>> +                       if (node > 0 &&
>> +                           !lists_bind_fdt(gd->dm_root, blob, node, &dev)) {
>> +                               int ret = device_probe(dev);
>> +                               if (ret)
>> +                                       return ret;
>> +                       }
>> +               }
>> +       }
>> +
>> +       gd->timer = dev;
>> +       return 0;
>> +}
>> +
>>  UCLASS_DRIVER(timer) = {
>>         .id             = UCLASS_TIMER,
>>         .name           = "timer",
>> diff --git a/lib/time.c b/lib/time.c
>> index b001745..22f7d23 100644
>> --- a/lib/time.c
>> +++ b/lib/time.c
>> @@ -47,6 +47,11 @@ static int notrace dm_timer_init(void)
>>         int ret;
>>
>>         if (!gd->timer) {
>> +               /* Check if we have a chosen timer */
>> +               timer_init();
> 
> timer_init() is already called in board_r.c. Can we avoid duplicate
> calls? Maybe we should remove the call in board_r.c for DM.

from board_r.c, timer_init is added only for MICROBLAZE, AVR32 and M68K
architectures. May be those who work on these architectures can initiate
of this removal during timer dm conversion.

Regards
Mugunthan V N