[U-Boot] [PATCH v2 3/4] MIPS: mscc: ocelot: add switch reset support

[Gregory CLEMENT <gregory.clement@bootlin.com>]

Hi Daniel,
 
 On mer., janv. 16 2019, Daniel Schwierzeck <daniel.schwierzeck@gmail.com> wrote:

> Am 16.01.19 um 14:07 schrieb Gregory CLEMENT:
>> On some ocelots platform a workaround is needed in order to be able to
>> reset the switch without resetting the DDR.
>> 
>> Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
>> ---
>>  board/mscc/ocelot/ocelot.c | 26 ++++++++++++++++++++++++++
>>  1 file changed, 26 insertions(+)
>> 
>> diff --git a/board/mscc/ocelot/ocelot.c b/board/mscc/ocelot/ocelot.c
>> index 0f7a532158..77ebe8ae26 100644
>> --- a/board/mscc/ocelot/ocelot.c
>> +++ b/board/mscc/ocelot/ocelot.c
>> @@ -10,6 +10,7 @@
>>  #include <environment.h>
>>  #include <spi.h>
>>  #include <led.h>
>> +#include <wait_bit.h>
>>  
>>  DECLARE_GLOBAL_DATA_PTR;
>>  
>> @@ -18,6 +19,31 @@ enum {
>>  	BOARD_TYPE_PCB123,
>>  };
>>  
>> +void mscc_switch_reset(bool enter)
>> +{
>> +	u32 reg, count = 0;
>> +
>> +	/* Nasty workaround to avoid GPIO19 (DDR!) being reset */
>> +	mscc_gpio_set_alternate(19, 2);
>> +
>> +	debug("applying SwC reset\n");
>> +
>> +	writel(ICPU_RESET_CORE_RST_PROTECT, BASE_CFG + ICPU_RESET);
>> +	writel(PERF_SOFT_RST_SOFT_CHIP_RST, BASE_DEVCPU_GCB + PERF_SOFT_RST);
>> +
>> +	if (wait_for_bit_le32(BASE_DEVCPU_GCB + PERF_SOFT_RST,
>> +			      PERF_SOFT_RST_SOFT_CHIP_RST, false, 5000, false))
>> +		pr_err("Tiemout while waiting for switch reset\n");
>> +
>> +	/*
>> +	 * Reset GPIO19 mode back as regular GPIO, output, high (DDR
>> +	 * not reset) (Order is important)
>> +	 */
>> +	setbits_le32(BASE_DEVCPU_GCB + PERF_GPIO_OE, BIT(19));
>> +	writel(BIT(19), BASE_DEVCPU_GCB + PERF_GPIO_OUT_SET);
>> +	mscc_gpio_set_alternate(19, 0);
>
> have you thought about or maybe planned a reset controller driver?

Actually, here it is not a reset driver, it is just the workaround part
of the stop() function in the network driver. It is not about resetting
the whole platform, for this feature a driver already has been submited.

Gregory

>
>> +}
>> +
>>  void board_debug_uart_init(void)
>>  {
>>  	/* too early for the pinctrl driver, so configure the UART pins here */
>> 
>
> -- 
> - Daniel

-- 
Gregory Clement, Bootlin
Embedded Linux and Kernel engineering
http://bootlin.com