[RFC PATCH 02/10] pmdomain: imx8m-blk-ctrl: don't turn on a power domain already on

Dario Binacchi
2024-10-28T10:31:20Z

The patch, by informing pm_genpd_init() with the "is_off" parameter that
the power domain is already on, prevents the power_on() callback from being
called, thus avoiding the unnecessary repetition of the hardware power-on
procedure. This feature is crucial when supporting the simple framebuffer,
as the power domains have already been initialized by the bootloader.

Co-developed-by: Michael Trimarchi <michael@amarulasolutions.com>
Signed-off-by: Michael Trimarchi <michael@amarulasolutions.com>
Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
---

drivers/pmdomain/imx/imx8m-blk-ctrl.c | 51 ++++++++++++++++++++++++++-
1 file changed, 50 insertions(+), 1 deletion(-)

diff --git a/drivers/pmdomain/imx/imx8m-blk-ctrl.c b/drivers/pmdomain/imx/imx8m-blk-ctrl.c
index ca942d7929c2..8dc1508571dd 100644
--- a/drivers/pmdomain/imx/imx8m-blk-ctrl.c
+++ b/drivers/pmdomain/imx/imx8m-blk-ctrl.c
@@ -166,6 +166,24 @@ static int imx8m_blk_ctrl_power_off(struct generic_pm_domain *genpd)

static struct lock_class_key blk_ctrl_genpd_lock_class;

+static bool imx8m_blk_ctrl_is_off(struct device *dev, struct generic_pm_domain *genpd)
+{
+ struct device_node *node = dev->of_node;
+ struct imx8m_blk_ctrl_domain *domain = to_imx8m_blk_ctrl_domain(genpd);
+ const struct imx8m_blk_ctrl_domain_data *data = domain->data;
+ u32 boot_on;
+ int index;
+
+ index = of_property_match_string(node, "power-domain-names",
+ data->gpc_name);
+ if (index < 0 || of_property_read_u32_index(node,
+ "fsl,power-domains-boot-on",
+ index, &boot_on))
+ return true;
+
+ return !boot_on;
+}
+
static int imx8m_blk_ctrl_probe(struct platform_device *pdev)
{
const struct imx8m_blk_ctrl_data *bc_data;
@@ -173,6 +191,8 @@ static int imx8m_blk_ctrl_probe(struct platform_device *pdev)
struct imx8m_blk_ctrl *bc;
void __iomem *base;
int i, ret;
+ bool init_off;
+ bool *pm_runtime_cleanup;

struct regmap_config regmap_config = {
.reg_bits = 32,
@@ -221,6 +241,11 @@ static int imx8m_blk_ctrl_probe(struct platform_device *pdev)
"failed to attach power domain \"bus\"\n");
}

+ pm_runtime_cleanup = devm_kcalloc(dev, bc_data->num_domains,
+ sizeof(*pm_runtime_cleanup), GFP_KERNEL);
+ if (!pm_runtime_cleanup)
+ return -ENOMEM;
+
for (i = 0; i < bc_data->num_domains; i++) {
const struct imx8m_blk_ctrl_domain_data *data = &bc_data->domains[i];
struct imx8m_blk_ctrl_domain *domain = &bc->domains[i];
@@ -274,7 +299,8 @@ static int imx8m_blk_ctrl_probe(struct platform_device *pdev)
domain->genpd.power_off = imx8m_blk_ctrl_power_off;
domain->bc = bc;

- ret = pm_genpd_init(&domain->genpd, NULL, true);
+ init_off = imx8m_blk_ctrl_is_off(dev, &domain->genpd);
+ ret = pm_genpd_init(&domain->genpd, NULL, init_off);
if (ret) {
dev_err_probe(dev, ret,
"failed to init power domain \"%s\"\n",
@@ -283,6 +309,24 @@ static int imx8m_blk_ctrl_probe(struct platform_device *pdev)
goto cleanup_pds;
}

+ if (!init_off) {
+ ret = pm_runtime_get_sync(bc->bus_power_dev);
+ if (ret < 0) {
+ pm_runtime_put_noidle(bc->bus_power_dev);
+ dev_err_probe(dev, ret, "failed to power up bus domain\n");
+ goto cleanup_pds;
+ }
+
+ ret = pm_runtime_get_sync(domain->power_dev);
+ if (ret < 0) {
+ pm_runtime_put(bc->bus_power_dev);
+ dev_err_probe(dev, ret, "failed to power up peripheral domain\n");
+ goto cleanup_pds;
+ }
+
+ pm_runtime_cleanup[i] = true;
+ }
+
/*
* We use runtime PM to trigger power on/off of the upstream GPC
* domain, as a strict hierarchical parent/child power domain
@@ -324,6 +368,11 @@ static int imx8m_blk_ctrl_probe(struct platform_device *pdev)
of_genpd_del_provider(dev->of_node);
cleanup_pds:
for (i--; i >= 0; i--) {
+ if (pm_runtime_cleanup[i]) {
+ pm_runtime_put(bc->domains[i].power_dev);
+ pm_runtime_put(bc->bus_power_dev);
+ }
+
pm_genpd_remove(&bc->domains[i].genpd);
dev_pm_domain_detach(bc->domains[i].power_dev, true);
}
--
2.43.0