linux-kernel - Re: [PATCH v2] MIPS: Loongson64: Add Loongson-2K1000 reset support

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Date:   Mon, 28 Jun 2021 09:44:58 +0800
From:   zhangqing <zhangqing@...ngson.cn>
To:     Jiaxun Yang <jiaxun.yang@...goat.com>,
        Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        Rob Herring <robh+dt@...nel.org>,
        Huacai Chen <chenhuacai@...nel.org>
Cc:     devicetree@...r.kernel.org, linux-mips@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] MIPS: Loongson64: Add Loongson-2K1000 reset support

On 06/28/2021 09:12 AM, Jiaxun Yang wrote:
>
> 在 2021/6/27 下午3:38, Qing Zhang 写道:
>> Add power management register operations to support reboot and poweroff.
>>
>> Signed-off-by: Qing Zhang <zhangqing@...ngson.cn>
>> ---
>>
>> v1-v2:
>> - Add pm block node
>>
>> Signed-off-by: Qing Zhang <zhangqing@...ngson.cn>
>>
>> diff --git a/arch/mips/boot/dts/loongson/loongson64-2k1000.dtsi 
>> b/arch/mips/boot/dts/loongson/loongson64-2k1000.dtsi
>> index 569e814def83..929e8ddf86eb 100644
>> --- a/arch/mips/boot/dts/loongson/loongson64-2k1000.dtsi
>> +++ b/arch/mips/boot/dts/loongson/loongson64-2k1000.dtsi
>> @@ -101,6 +101,14 @@ uart0: serial@...00000 {
>>               no-loopback-test;
>>           };
>>   +        pm: power-controller {
>> +            device_type = "power management";
>
> Hi Qing,
>
> Not compatible?
>
>
>> +            reg = <0 0x1fe0700c 0 0x8>,
>> +                <0 0x1fe07014 0 0x8>,
>> +                <0 0x1fe07030 0 0x8>;
>> +            reg-names = "pm1_sts", "pm1_cnt", "rst_cnt";
>> +        };
>> +
>>           pci@...00000 {
>>               compatible = "loongson,ls2k-pci";
>>               device_type = "pci";
>> diff --git a/arch/mips/loongson64/reset.c b/arch/mips/loongson64/reset.c
>> index c97bfdc8c922..ea125e925d44 100644
>> --- a/arch/mips/loongson64/reset.c
>> +++ b/arch/mips/loongson64/reset.c
>> @@ -10,6 +10,7 @@
>>   #include <linux/delay.h>
>>   #include <linux/init.h>
>>   #include <linux/kexec.h>
>> +#include <linux/of_address.h>
>>   #include <linux/pm.h>
>>   #include <linux/slab.h>
>>   @@ -20,12 +21,50 @@
>>   #include <loongson.h>
>>   #include <boot_param.h>
>>   +static char *pm_reg_name[] = {"pm1_sts", "pm1_cnt", "rst_cnt"};
>> +
>> +static void __iomem *get_reg_byname(struct device_node *node, const 
>> char *name)
>> +{
>> +    int index = of_property_match_string(node, "reg-names", name);
>> +
>> +    if (index < 0)
>> +        return NULL;
>> +
>> +    return of_iomap(node, index);
>> +}
>
> We do have that helper in of_address.h.
>
> Btw, I'd prefer make it as a driver in driver/platform/mips.
>
> Also the approach using PRID to tell protocol type doesn't really make 
> sense to me.
>
> You can override _machine_restart callback in diver once FDT node is 
> found.

Hi jiaxun,

Thanks for your suggestion,
I will send v3 in the soon.

Thanks.,

Qing
>
> Thanks.
>
> - Jiaxun
>
>> +
>> +static int  __init loongson_fdt_reset_init(void)
>> +{
>> +    struct device_node *np;
>> +    int i;
>> +
>> +    np = of_find_node_by_type(NULL, "power management");
>> +    if (!np) {
>> +        pr_info("Failed to get PM node\n");
>> +        return -ENODEV;
>> +    }
>> +
>> +    for (i = 0; i < sizeof(pm_reg_name)/sizeof(char *); i++) {
>> +        pm_reg_name[i] = get_reg_byname(np, pm_reg_name[i]);
>> +        if (!pm_reg_name[i])
>> +            iounmap(pm_reg_name[i]);
>> +    }
>> +
>> +    of_node_put(np);
>> +    return 0;
>> +}
>> +arch_initcall(loongson_fdt_reset_init);
>> +
>>   static void loongson_restart(char *command)
>>   {
>> +    if ((read_c0_prid() & PRID_IMP_MASK) == PRID_IMP_LOONGSON_64R) {
>> +        writel(0x1, (void *)pm_reg_name[2]);
>> +    } else {
>> +        void (*fw_restart)(void) = (void 
>> *)loongson_sysconf.restart_addr;
>>   -    void (*fw_restart)(void) = (void *)loongson_sysconf.restart_addr;
>> +        fw_restart();
>> +    }
>>   -    fw_restart();
>>       while (1) {
>>           if (cpu_wait)
>>               cpu_wait();
>> @@ -34,9 +73,18 @@ static void loongson_restart(char *command)
>>     static void loongson_poweroff(void)
>>   {
>> -    void (*fw_poweroff)(void) = (void *)loongson_sysconf.poweroff_addr;
>> +    if ((read_c0_prid() & PRID_IMP_MASK) == PRID_IMP_LOONGSON_64R) {
>> +        /* Clear */
>> +        writel((readl((void *)pm_reg_name[0]) & 0xffffffff), (void 
>> *)pm_reg_name[0]);
>> +        /* Sleep Enable | Soft Off*/
>> +        writel(GENMASK(12, 10)|BIT(13), (void *)pm_reg_name[1]);
>> +    } else {
>> +
>> +        void (*fw_poweroff)(void) = (void 
>> *)loongson_sysconf.poweroff_addr;
>> +
>> +        fw_poweroff();
>> +    }
>>   -    fw_poweroff();
>>       while (1) {
>>           if (cpu_wait)
>>               cpu_wait();