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

[Pratik Sampat]

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 
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 */
>>
>