[Skiboot] [PATCH Skiboot v1.2 3/3] Advertise the self-save and self-restore attributes in the device tree

[Vasant Hegde]

On 10/14/19 3:07 PM, Pratik Sampat wrote:
> 
> 
> On 11/10/19 4:21 PM, Vasant Hegde wrote:
>> On 10/10/19 5:40 PM, Pratik Rajesh Sampat wrote:
>>> Support for self save and self restore interface is advertised in the
>>> device tree, along with the list of SPRs it supports for each.
>>>
>>> The Special Purpose Register identification is encoded in a 2048 bitmask
>>> structure, where each bit signifies the identification key of that SPR
>>> which is consistent with that of the Linux kernel for that register.
>>
>> I assume this feature needs supported HCODE level. How do you determine 
>> whether HCODE supports
>> new feature or not?
>>
>> -Vasant 
> As far as I know, Skiboot tries to make a stop API call with the highest version 
> in mind,
> if it fails it falls back to older version. The way we determine today if 

In that case shouldn't we check this before advertising capability via DT to kernel?


-Vasant

> self-restore
> works is by checking if the HOMER is populated in the system.
> Ideally we want to do a version check but we leave it to the stop API as it 
> would do it
> anyways and give us an error if something went wrong.
>>>
>>> Signed-off-by: Pratik Rajesh Sampat <psampat at linux.ibm.com>
>>> ---
>>>   hw/slw.c          | 72 +++++++++++++++++++++++++++++++++++++++++++++++
>>>   include/skiboot.h |  1 +
>>>   2 files changed, 73 insertions(+)
>>>
>>> diff --git a/hw/slw.c b/hw/slw.c
>>> index b79aaab3..d9c2d091 100644
>>> --- a/hw/slw.c
>>> +++ b/hw/slw.c
>>> @@ -22,6 +22,7 @@
>>>   #include <opal-api.h>
>>>   #include <nvram.h>
>>>   #include <sbe-p8.h>
>>> +#include <bitmap.h>
>>>
>>>   #include <p9_stop_api.H>
>>>   #include <p8_pore_table_gen_api.H>
>>> @@ -753,6 +754,70 @@ static void slw_late_init_p9(struct proc_chip *chip)
>>>       }
>>>   }
>>>
>>> +/* Add device tree properties to determine self-save | restore */
>>> +void add_cpu_self_save_properties(struct dt_node *power_mgt)
>>> +{
>>> +    int i;
>>> +    struct dt_node *self_restore, *self_save;
>>> +    bitmap_t *self_restore_map, *self_save_map;
>>> +    /* 32 times 64 bits needed to store a 2048 bits bitmask*/
>>> +    const int bits_nr = 32;
>>> +
>>> +    const uint64_t self_restore_regs[] = {
>>> +        0x130, // HSPRG0
>>> +        0x13E, // LPCR
>>> +        0x151, // HMEER
>>> +        0x3F0, // HID0
>>> +        0x3F1, // HID1
>>> +        0x3F4, // HID4
>>> +        0x3F6, // HID5
>>> +        0x7D0, // MSR
>>> +        0x357 // PSCCR
>>> +    };
>>> +
>>> +    const uint64_t self_save_regs[] = {
>>> +        0x130, // HSPRG0
>>> +        0x13E, // LPCR
>>> +        0x151, // HMEER
>>> +        0x7D0, // MSR
>>> +        0x357 // PSCCR
>>> +    };
>>> +    const int self_save_regs_nr    = ARRAY_SIZE(self_save_regs);
>>> +    const int self_restore_regs_nr    = ARRAY_SIZE(self_restore_regs);
>>> +
>>> +    self_save_map = zalloc(BITMAP_BYTES(0x800));
>>> +    self_restore_map = zalloc(BITMAP_BYTES(0x800));
>>> +
>>> +    for (i = 0; i < self_save_regs_nr; i++)
>>> +        bitmap_set_bit(*self_save_map, self_save_regs[i]);
>>> +
>>> +    for (i = 0; i < self_restore_regs_nr; i++)
>>> +        bitmap_set_bit(*self_restore_map, self_restore_regs[i]);
>>> +
>>> +    self_restore = dt_new(power_mgt, "self-restore");
>>> +    if (!self_restore) {
>>> +        prerror("OCC: Failed to create self restore node");
>>> +        return;
>>> +    }
>>> +    dt_add_property_cells(self_restore, "active", 0x1);
>>> +
>>> +    dt_add_property(self_restore, "sprn-bitmask", *self_restore_map,
>>> +            bits_nr * sizeof(uint64_t));
>>> +
>>> +    self_save = dt_new(power_mgt, "self-save");
>>> +    if (!self_save) {
>>> +        prerror("OCC: Failed to create self save node");
>>> +        return;
>>> +    }
>>> +    if (proc_gen == proc_gen_p9) {
>>> +        dt_add_property_cells(self_save, "active", 0x1);
>>> +
>>> +        dt_add_property(self_save, "sprn-bitmask", *self_save_map,
>>> +                bits_nr * sizeof(uint64_t));
>>> +    } else
>>> +        dt_add_property_cells(self_save, "active", 0x0);
>>> +}
>>> +
>>>   /* Add device tree properties to describe idle states */
>>>   void add_cpu_idle_state_properties(void)
>>>   {
>>> @@ -1543,6 +1608,7 @@ opal_call(OPAL_SLW_SELF_SAVE_REG, 
>>> opal_slw_self_save_reg, 2);
>>>   void slw_init(void)
>>>   {
>>>       struct proc_chip *chip;
>>> +    struct dt_node *power_mgt;
>>>
>>>       if (proc_chip_quirks & QUIRK_MAMBO_CALLOUTS) {
>>>           wakeup_engine_state = WAKEUP_ENGINE_NOT_PRESENT;
>>> @@ -1568,4 +1634,10 @@ void slw_init(void)
>>>           }
>>>       }
>>>       add_cpu_idle_state_properties();
>>> +    power_mgt = dt_find_by_path(dt_root, "/ibm,opal/power-mgt");
>>> +    if (!power_mgt) {
>>> +        prerror("OCC: dt node /ibm,opal/power-mgt not found\n");
>>> +        return;
>>> +    }
>>> +    add_cpu_self_save_properties(power_mgt);
>>>   }
>>> diff --git a/include/skiboot.h b/include/skiboot.h
>>> index 1aa8bf7c..e8f0f755 100644
>>> --- a/include/skiboot.h
>>> +++ b/include/skiboot.h
>>> @@ -202,6 +202,7 @@ extern void early_uart_init(void);
>>>   extern void homer_init(void);
>>>   extern void slw_init(void);
>>>   extern void add_cpu_idle_state_properties(void);
>>> +extern void add_cpu_self_save_properties(struct dt_node *power_mgt);
>>>   extern void lpc_rtc_init(void);
>>>
>>>   /* flash support */
>>>
>>
>