| Message ID | 20230123063208.19590-1-samuel@sholland.org |
|---|---|
| State | Accepted |
| Headers | show |
| Series | [v2,1/2] lib: utils: Add fdt_add_cpu_idle_states() helper function | expand |
On Mon, Jan 23, 2023 at 12:02 PM Samuel Holland <samuel@sholland.org> wrote: > > Since the availability and latency properties of CPU idle states depend > on the specific SBI HSM implementation, it is appropriate that the idle > states are added to the devicetree at runtime by that implementation. > > This helper function adds a platform-provided array of idle states to > the devicetree, following the SBI idle state binding. > > Reviewed-by: Anup Patel <anup@brainfault.org> > Signed-off-by: Samuel Holland <samuel@sholland.org> Applied this patch to the riscv/opensbi repo. Thanks, Anup > --- > > Changes in v2: > - Do nothing if the idle-states node already exists > > include/sbi_utils/fdt/fdt_fixup.h | 23 +++++++++ > lib/utils/fdt/fdt_fixup.c | 85 +++++++++++++++++++++++++++++++ > 2 files changed, 108 insertions(+) > > diff --git a/include/sbi_utils/fdt/fdt_fixup.h b/include/sbi_utils/fdt/fdt_fixup.h > index fb076ba..cab3f0f 100644 > --- a/include/sbi_utils/fdt/fdt_fixup.h > +++ b/include/sbi_utils/fdt/fdt_fixup.h > @@ -9,6 +9,29 @@ > #ifndef __FDT_FIXUP_H__ > #define __FDT_FIXUP_H__ > > +struct sbi_cpu_idle_state { > + const char *name; > + uint32_t suspend_param; > + bool local_timer_stop; > + uint32_t entry_latency_us; > + uint32_t exit_latency_us; > + uint32_t min_residency_us; > + uint32_t wakeup_latency_us; > +}; > + > +/** > + * Add CPU idle states to cpu nodes in the DT > + * > + * Add information about CPU idle states to the devicetree. This function > + * assumes that CPU idle states are not already present in the devicetree, and > + * that all CPU states are equally applicable to all CPUs. > + * > + * @param fdt: device tree blob > + * @param states: array of idle state descriptions, ending with empty element > + * @return zero on success and -ve on failure > + */ > +int fdt_add_cpu_idle_states(void *dtb, const struct sbi_cpu_idle_state *state); > + > /** > * Fix up the CPU node in the device tree > * > diff --git a/lib/utils/fdt/fdt_fixup.c b/lib/utils/fdt/fdt_fixup.c > index 42692cc..e57a4e1 100644 > --- a/lib/utils/fdt/fdt_fixup.c > +++ b/lib/utils/fdt/fdt_fixup.c > @@ -18,6 +18,91 @@ > #include <sbi_utils/fdt/fdt_pmu.h> > #include <sbi_utils/fdt/fdt_helper.h> > > +int fdt_add_cpu_idle_states(void *fdt, const struct sbi_cpu_idle_state *state) > +{ > + int cpu_node, cpus_node, err, idle_states_node; > + uint32_t count, phandle; > + > + err = fdt_open_into(fdt, fdt, fdt_totalsize(fdt) + 1024); > + if (err < 0) > + return err; > + > + err = fdt_find_max_phandle(fdt, &phandle); > + phandle++; > + if (err < 0) > + return err; > + > + cpus_node = fdt_path_offset(fdt, "/cpus"); > + if (cpus_node < 0) > + return cpus_node; > + > + /* Do nothing if the idle-states node already exists. */ > + idle_states_node = fdt_subnode_offset(fdt, cpus_node, "idle-states"); > + if (idle_states_node >= 0) > + return 0; > + > + /* Create the idle-states node and its child nodes. */ > + idle_states_node = fdt_add_subnode(fdt, cpus_node, "idle-states"); > + if (idle_states_node < 0) > + return idle_states_node; > + > + for (count = 0; state->name; count++, phandle++, state++) { > + int idle_state_node; > + > + idle_state_node = fdt_add_subnode(fdt, idle_states_node, > + state->name); > + if (idle_state_node < 0) > + return idle_state_node; > + > + fdt_setprop_string(fdt, idle_state_node, "compatible", > + "riscv,idle-state"); > + fdt_setprop_u32(fdt, idle_state_node, > + "riscv,sbi-suspend-param", > + state->suspend_param); > + if (state->local_timer_stop) > + fdt_setprop_empty(fdt, idle_state_node, > + "local-timer-stop"); > + fdt_setprop_u32(fdt, idle_state_node, "entry-latency-us", > + state->entry_latency_us); > + fdt_setprop_u32(fdt, idle_state_node, "exit-latency-us", > + state->exit_latency_us); > + fdt_setprop_u32(fdt, idle_state_node, "min-residency-us", > + state->min_residency_us); > + if (state->wakeup_latency_us) > + fdt_setprop_u32(fdt, idle_state_node, > + "wakeup-latency-us", > + state->wakeup_latency_us); > + fdt_setprop_u32(fdt, idle_state_node, "phandle", phandle); > + } > + > + if (count == 0) > + return 0; > + > + /* Link each cpu node to the idle state nodes. */ > + fdt_for_each_subnode(cpu_node, fdt, cpus_node) { > + const char *device_type; > + fdt32_t *value; > + > + /* Only process child nodes with device_type = "cpu". */ > + device_type = fdt_getprop(fdt, cpu_node, "device_type", NULL); > + if (!device_type || strcmp(device_type, "cpu")) > + continue; > + > + /* Allocate space for the list of phandles. */ > + err = fdt_setprop_placeholder(fdt, cpu_node, "cpu-idle-states", > + count * sizeof(phandle), > + (void **)&value); > + if (err < 0) > + return err; > + > + /* Fill in the phandles of the idle state nodes. */ > + for (uint32_t i = 0; i < count; ++i) > + value[i] = cpu_to_fdt32(phandle - count + i); > + } > + > + return 0; > +} > + > void fdt_cpu_fixup(void *fdt) > { > struct sbi_domain *dom = sbi_domain_thishart_ptr(); > -- > 2.37.4 >
diff --git a/include/sbi_utils/fdt/fdt_fixup.h b/include/sbi_utils/fdt/fdt_fixup.h index fb076ba..cab3f0f 100644 --- a/include/sbi_utils/fdt/fdt_fixup.h +++ b/include/sbi_utils/fdt/fdt_fixup.h @@ -9,6 +9,29 @@ #ifndef __FDT_FIXUP_H__ #define __FDT_FIXUP_H__ +struct sbi_cpu_idle_state { + const char *name; + uint32_t suspend_param; + bool local_timer_stop; + uint32_t entry_latency_us; + uint32_t exit_latency_us; + uint32_t min_residency_us; + uint32_t wakeup_latency_us; +}; + +/** + * Add CPU idle states to cpu nodes in the DT + * + * Add information about CPU idle states to the devicetree. This function + * assumes that CPU idle states are not already present in the devicetree, and + * that all CPU states are equally applicable to all CPUs. + * + * @param fdt: device tree blob + * @param states: array of idle state descriptions, ending with empty element + * @return zero on success and -ve on failure + */ +int fdt_add_cpu_idle_states(void *dtb, const struct sbi_cpu_idle_state *state); + /** * Fix up the CPU node in the device tree * diff --git a/lib/utils/fdt/fdt_fixup.c b/lib/utils/fdt/fdt_fixup.c index 42692cc..e57a4e1 100644 --- a/lib/utils/fdt/fdt_fixup.c +++ b/lib/utils/fdt/fdt_fixup.c @@ -18,6 +18,91 @@ #include <sbi_utils/fdt/fdt_pmu.h> #include <sbi_utils/fdt/fdt_helper.h> +int fdt_add_cpu_idle_states(void *fdt, const struct sbi_cpu_idle_state *state) +{ + int cpu_node, cpus_node, err, idle_states_node; + uint32_t count, phandle; + + err = fdt_open_into(fdt, fdt, fdt_totalsize(fdt) + 1024); + if (err < 0) + return err; + + err = fdt_find_max_phandle(fdt, &phandle); + phandle++; + if (err < 0) + return err; + + cpus_node = fdt_path_offset(fdt, "/cpus"); + if (cpus_node < 0) + return cpus_node; + + /* Do nothing if the idle-states node already exists. */ + idle_states_node = fdt_subnode_offset(fdt, cpus_node, "idle-states"); + if (idle_states_node >= 0) + return 0; + + /* Create the idle-states node and its child nodes. */ + idle_states_node = fdt_add_subnode(fdt, cpus_node, "idle-states"); + if (idle_states_node < 0) + return idle_states_node; + + for (count = 0; state->name; count++, phandle++, state++) { + int idle_state_node; + + idle_state_node = fdt_add_subnode(fdt, idle_states_node, + state->name); + if (idle_state_node < 0) + return idle_state_node; + + fdt_setprop_string(fdt, idle_state_node, "compatible", + "riscv,idle-state"); + fdt_setprop_u32(fdt, idle_state_node, + "riscv,sbi-suspend-param", + state->suspend_param); + if (state->local_timer_stop) + fdt_setprop_empty(fdt, idle_state_node, + "local-timer-stop"); + fdt_setprop_u32(fdt, idle_state_node, "entry-latency-us", + state->entry_latency_us); + fdt_setprop_u32(fdt, idle_state_node, "exit-latency-us", + state->exit_latency_us); + fdt_setprop_u32(fdt, idle_state_node, "min-residency-us", + state->min_residency_us); + if (state->wakeup_latency_us) + fdt_setprop_u32(fdt, idle_state_node, + "wakeup-latency-us", + state->wakeup_latency_us); + fdt_setprop_u32(fdt, idle_state_node, "phandle", phandle); + } + + if (count == 0) + return 0; + + /* Link each cpu node to the idle state nodes. */ + fdt_for_each_subnode(cpu_node, fdt, cpus_node) { + const char *device_type; + fdt32_t *value; + + /* Only process child nodes with device_type = "cpu". */ + device_type = fdt_getprop(fdt, cpu_node, "device_type", NULL); + if (!device_type || strcmp(device_type, "cpu")) + continue; + + /* Allocate space for the list of phandles. */ + err = fdt_setprop_placeholder(fdt, cpu_node, "cpu-idle-states", + count * sizeof(phandle), + (void **)&value); + if (err < 0) + return err; + + /* Fill in the phandles of the idle state nodes. */ + for (uint32_t i = 0; i < count; ++i) + value[i] = cpu_to_fdt32(phandle - count + i); + } + + return 0; +} + void fdt_cpu_fixup(void *fdt) { struct sbi_domain *dom = sbi_domain_thishart_ptr();