lib: irqchip/plic: Add priority save/restore helpers

These can be used by platform code to save the PLIC priority state, if
it would otherwise be lost during non-retentive suspend. The platform
is responsible for allocating all necessary storage.

As a space optimization, store the saved priority values as 8-bit
integers, since that is large enough to hold any priority value on the
relevant platforms.

Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Samuel Holland <samuel@sholland.org>
This commit is contained in:
Samuel Holland 2022-06-12 20:03:52 -05:00 committed by Anup Patel
parent 415ecf28f7
commit 2b79b694a8
2 changed files with 24 additions and 0 deletions

View file

@ -17,6 +17,11 @@ struct plic_data {
unsigned long num_src;
};
/* So far, priorities on all consumers of these functions fit in 8 bits. */
void plic_priority_save(const struct plic_data *plic, u8 *priority);
void plic_priority_restore(const struct plic_data *plic, const u8 *priority);
void plic_context_save(const struct plic_data *plic, int context_id,
u32 *enable, u32 *threshold);

View file

@ -22,6 +22,13 @@
#define PLIC_CONTEXT_BASE 0x200000
#define PLIC_CONTEXT_STRIDE 0x1000
static u32 plic_get_priority(const struct plic_data *plic, u32 source)
{
volatile void *plic_priority = (char *)plic->addr +
PLIC_PRIORITY_BASE + 4 * source;
return readl(plic_priority);
}
static void plic_set_priority(const struct plic_data *plic, u32 source, u32 val)
{
volatile void *plic_priority = (char *)plic->addr +
@ -29,6 +36,18 @@ static void plic_set_priority(const struct plic_data *plic, u32 source, u32 val)
writel(val, plic_priority);
}
void plic_priority_save(const struct plic_data *plic, u8 *priority)
{
for (u32 i = 0; i < plic->num_src; i++)
priority[i] = plic_get_priority(plic, i);
}
void plic_priority_restore(const struct plic_data *plic, const u8 *priority)
{
for (u32 i = 0; i < plic->num_src; i++)
plic_set_priority(plic, i, priority[i]);
}
static u32 plic_get_thresh(const struct plic_data *plic, u32 cntxid)
{
volatile void *plic_thresh;