From mboxrd@z Thu Jan  1 00:00:00 1970
From: Marek Vasut <marex@denx.de>
Date: Sun, 22 May 2016 04:02:42 +0200
Subject: [U-Boot] [PATCH 9/9] mips: ath79: Add support for TPLink WDR4300
In-Reply-To: <BLU436-SMTP1919EF1B0F033E0D236AFDCFF4D0@phx.gbl>
References: <1462558241-5494-1-git-send-email-marex@denx.de>
 <1462558241-5494-9-git-send-email-marex@denx.de>
 <BLU436-SMTP172AA7C7A45F1ADE092A45FF4C0@phx.gbl> <57409121.20908@denx.de>
 <BLU436-SMTP1919EF1B0F033E0D236AFDCFF4D0@phx.gbl>
Message-ID: <57411342.9030605@denx.de>
List-Id: <u-boot.lists.denx.de>
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
To: u-boot@lists.denx.de

On 05/22/2016 03:49 AM, Wills Wang wrote:
> 
> 
> On 05/22/2016 12:47 AM, Marek Vasut wrote:
>> On 05/21/2016 06:29 PM, Wills Wang wrote:
>>>
>>> On 05/07/2016 02:10 AM, Marek Vasut wrote:
>>> [...]
>>>> diff --git a/board/tplink/wdr4300/wdr4300.c
>>>> b/board/tplink/wdr4300/wdr4300.c
>>>> new file mode 100644
>>>> index 0000000..6e070fd
>>>> --- /dev/null
>>>> +++ b/board/tplink/wdr4300/wdr4300.c
>>>> @@ -0,0 +1,74 @@
>>>> +/*
>>>> + * Copyright (C) 2016 Marek Vasut <marex@denx.de>
>>>> + *
>>>> + * SPDX-License-Identifier: GPL-2.0+
>>>> + */
>>>> +
>>>> +#include <common.h>
>>>> +#include <asm/io.h>
>>>> +#include <asm/addrspace.h>
>>>> +#include <asm/types.h>
>>>> +#include <mach/ath79.h>
>>>> +#include <mach/ar71xx_regs.h>
>>>> +#include <mach/ddr.h>
>>>> +#include <debug_uart.h>
>>>> +
>>>> +DECLARE_GLOBAL_DATA_PTR;
>>>> +
>>>> +#ifdef CONFIG_USB
>>>> +static void wdr4300_usb_start(void)
>>>> +{
>>>> +    void __iomem *gpio_regs = map_physmem(AR71XX_GPIO_BASE,
>>>> +                          AR71XX_GPIO_SIZE, MAP_NOCACHE);
>>>> +    if (!gpio_regs)
>>>> +        return;
>>>> +
>>>> +    /* Power up the USB HUB. */
>>>> +    clrbits_be32(gpio_regs + AR71XX_GPIO_REG_OE, BIT(21) | BIT(22));
>>>> +    writel(BIT(21) | BIT(22), gpio_regs + AR71XX_GPIO_REG_SET);
>>>> +    mdelay(1);
>>>> +
>>>> +    ath79_usb_reset();
>>>> +}
>>>> +#else
>>>> +static inline void wdr4300_usb_start(void) {}
>>>> +#endif
>>>> +
>>>> +#ifdef CONFIG_BOARD_EARLY_INIT_F
>>>> +int board_early_init_f(void)
>>>> +{
>>>> +    void __iomem *regs;
>>>> +
>>>> +    regs = map_physmem(AR71XX_GPIO_BASE, AR71XX_GPIO_SIZE,
>>>> +               MAP_NOCACHE);
>>>> +
>>>> +    /* Assure JTAG is not disconnected. */
>>>> +    writel(0x40, regs + AR934X_GPIO_REG_FUNC);
>>>> +
>>>> +    /* Configure default GPIO input/output regs. */
>>>> +    writel(0x3031b, regs + AR71XX_GPIO_REG_OE);
>>>> +    writel(0x0f804, regs + AR71XX_GPIO_REG_OUT);
>>>> +
>>>> +    /* Configure pin multiplexing. */
>>>> +    writel(0x00000000, regs + AR934X_GPIO_REG_OUT_FUNC0);
>>>> +    writel(0x0b0a0980, regs + AR934X_GPIO_REG_OUT_FUNC1);
>>>> +    writel(0x00180000, regs + AR934X_GPIO_REG_OUT_FUNC2);
>>>> +    writel(0x00000000, regs + AR934X_GPIO_REG_OUT_FUNC3);
>>>> +    writel(0x0000004d, regs + AR934X_GPIO_REG_OUT_FUNC4);
>>>> +    writel(0x00000000, regs + AR934X_GPIO_REG_OUT_FUNC5);
>>>> +
>>>> +#ifdef CONFIG_DEBUG_UART
>>>> +    debug_uart_init();
>>>> +#endif
>>>> +
>>>> +#ifndef CONFIG_SKIP_LOWLEVEL_INIT
>>>> +    ar934x_pll_init(560, 480, 240);
>>>> +    ar934x_ddr_init(560, 480, 240);
>>>> +#endif
>>> Can we get it to work  if CONFIG_SKIP_LOWLEVEL_INIT is defined?
>> Well no, that's what CONFIG_SKIP_LOWLEVEL_INIT is for -- skipping low
>> level initialization of the hardware.
>>
> So,  i think this macro definition haveno practical purpose.
> 

What do you refer to ? The ifndef ?

The conditional is required when starting the board via JTAG. At that
point, the DRAM is running and reiniting the DRAM would crash U-Boot,
since it is running from that DRAM. So there is very valid use-case for it.

-- 
Best regards,
Marek Vasut