[RFC PATCH v2 06/19] soc: thead: power-domain: Add power-domain driver for TH1520

[Michal Wilczynski <m.wilczynski@samsung.com>]

The T-Head TH1520 SoC contains multiple power islands that can be
programmatically turned on and off using the AON (Always-On) protocol
and a hardware mailbox [1]. The relevant mailbox driver has already been
merged into the mainline kernel in commit 5d4d263e1c6b ("mailbox:
Introduce support for T-head TH1520 Mailbox driver");

This commit introduces a power-domain driver for the TH1520 SoC, which
is using AON firmware protocol to communicate with E902 core through the
hardware mailbox. This way it can send power on/off commands to the E902
core.

Link: https://openbeagle.org/beaglev-ahead/beaglev-ahead/-/blob/main/docs/TH1520%20System%20User%20Manual.pdf [1]

Signed-off-by: Michal Wilczynski <m.wilczynski@samsung.com>
---
 MAINTAINERS                                |   1 +
 drivers/pmdomain/Kconfig                   |   1 +
 drivers/pmdomain/Makefile                  |   1 +
 drivers/pmdomain/thead/Kconfig             |  12 ++
 drivers/pmdomain/thead/Makefile            |   2 +
 drivers/pmdomain/thead/th1520-pm-domains.c | 181 +++++++++++++++++++++
 6 files changed, 198 insertions(+)
 create mode 100644 drivers/pmdomain/thead/Kconfig
 create mode 100644 drivers/pmdomain/thead/Makefile
 create mode 100644 drivers/pmdomain/thead/th1520-pm-domains.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 42aef66bd257..173eeaf3bbe8 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -20200,6 +20200,7 @@ F:	drivers/firmware/thead,th1520-aon.c
 F:	drivers/mailbox/mailbox-th1520.c
 F:	drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
 F:	drivers/pinctrl/pinctrl-th1520.c
+F:	drivers/pmdomain/thead/
 F:	include/dt-bindings/clock/thead,th1520-clk-ap.h
 F:	include/linux/firmware/thead/thead,th1520-aon.h
 
diff --git a/drivers/pmdomain/Kconfig b/drivers/pmdomain/Kconfig
index 23c64851a5b0..91f04ace35d4 100644
--- a/drivers/pmdomain/Kconfig
+++ b/drivers/pmdomain/Kconfig
@@ -16,6 +16,7 @@ source "drivers/pmdomain/st/Kconfig"
 source "drivers/pmdomain/starfive/Kconfig"
 source "drivers/pmdomain/sunxi/Kconfig"
 source "drivers/pmdomain/tegra/Kconfig"
+source "drivers/pmdomain/thead/Kconfig"
 source "drivers/pmdomain/ti/Kconfig"
 source "drivers/pmdomain/xilinx/Kconfig"
 
diff --git a/drivers/pmdomain/Makefile b/drivers/pmdomain/Makefile
index a68ece2f4c68..7030f44a49df 100644
--- a/drivers/pmdomain/Makefile
+++ b/drivers/pmdomain/Makefile
@@ -14,6 +14,7 @@ obj-y					+= st/
 obj-y					+= starfive/
 obj-y					+= sunxi/
 obj-y					+= tegra/
+obj-y					+= thead/
 obj-y					+= ti/
 obj-y					+= xilinx/
 obj-y					+= core.o governor.o
diff --git a/drivers/pmdomain/thead/Kconfig b/drivers/pmdomain/thead/Kconfig
new file mode 100644
index 000000000000..3b61e92dde43
--- /dev/null
+++ b/drivers/pmdomain/thead/Kconfig
@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+config TH1520_PM_DOMAINS
+	tristate "Support TH1520 Power Domains"
+	depends on TH1520_AON_PROTOCOL || COMPILE_TEST
+	select REGMAP_MMIO
+	help
+	  This driver enables power domain management for the T-HEAD
+	  TH-1520 SoC. On this SoC there are number of power domains,
+	  which can be managed independently. For example GPU, NPU,
+	  and DPU reside in their own power domains which can be
+	  turned on/off.
diff --git a/drivers/pmdomain/thead/Makefile b/drivers/pmdomain/thead/Makefile
new file mode 100644
index 000000000000..adfdf5479c68
--- /dev/null
+++ b/drivers/pmdomain/thead/Makefile
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-$(CONFIG_TH1520_PM_DOMAINS)		+= th1520-pm-domains.o
diff --git a/drivers/pmdomain/thead/th1520-pm-domains.c b/drivers/pmdomain/thead/th1520-pm-domains.c
new file mode 100644
index 000000000000..a56ba164a58d
--- /dev/null
+++ b/drivers/pmdomain/thead/th1520-pm-domains.c
@@ -0,0 +1,181 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2021 Alibaba Group Holding Limited.
+ * Copyright (c) 2024 Samsung Electronics Co., Ltd.
+ * Author: Michal Wilczynski <m.wilczynski@samsung.com>
+ */
+
+#include <linux/firmware/thead/thead,th1520-aon.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm_domain.h>
+
+#include <dt-bindings/power/thead,th1520-power.h>
+
+struct th1520_power_domain {
+	struct th1520_aon_chan *aon_chan;
+	struct generic_pm_domain genpd;
+	u32 rsrc;
+};
+
+struct th1520_power_info {
+	const char *name;
+	u32 rsrc;
+};
+
+static const struct th1520_power_info th1520_pd_ranges[] = {
+	{ "vdec", TH1520_AON_VDEC_PD },
+	{ "npu", TH1520_AON_NPU_PD },
+	{ "venc", TH1520_AON_VENC_PD },
+	{ "gpu", TH1520_AON_GPU_PD },
+	{ "dsp0", TH1520_AON_DSP0_PD },
+	{ "dsp1", TH1520_AON_DSP1_PD }
+};
+
+static inline struct th1520_power_domain *
+to_th1520_power_domain(struct generic_pm_domain *genpd)
+{
+	return container_of(genpd, struct th1520_power_domain, genpd);
+}
+
+static int th1520_pd_power_on(struct generic_pm_domain *domain)
+{
+	struct th1520_power_domain *pd = to_th1520_power_domain(domain);
+
+	return th1520_aon_power_update(pd->aon_chan, pd->rsrc, true);
+}
+
+static int th1520_pd_power_off(struct generic_pm_domain *domain)
+{
+	struct th1520_power_domain *pd = to_th1520_power_domain(domain);
+
+	return th1520_aon_power_update(pd->aon_chan, pd->rsrc, false);
+}
+
+static struct generic_pm_domain *th1520_pd_xlate(const struct of_phandle_args *spec,
+						 void *data)
+{
+	struct generic_pm_domain *domain = ERR_PTR(-ENOENT);
+	struct genpd_onecell_data *pd_data = data;
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(th1520_pd_ranges); i++) {
+		struct th1520_power_domain *pd;
+
+		pd = to_th1520_power_domain(pd_data->domains[i]);
+		if (pd->rsrc == spec->args[0]) {
+			domain = &pd->genpd;
+			break;
+		}
+	}
+
+	return domain;
+}
+
+static struct th1520_power_domain *
+th1520_add_pm_domain(struct device *dev, const struct th1520_power_info *pi)
+{
+	struct th1520_power_domain *pd;
+	int ret;
+
+	pd = devm_kzalloc(dev, sizeof(*pd), GFP_KERNEL);
+	if (!pd)
+		return ERR_PTR(-ENOMEM);
+
+	pd->rsrc = pi->rsrc;
+	pd->genpd.power_on = th1520_pd_power_on;
+	pd->genpd.power_off = th1520_pd_power_off;
+	pd->genpd.name = pi->name;
+
+	ret = pm_genpd_init(&pd->genpd, NULL, true);
+	if (ret)
+		return ERR_PTR(ret);
+
+	return pd;
+}
+
+static void th1520_pd_init_all_off(struct generic_pm_domain **domains,
+				   struct device *dev)
+{
+	int ret;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(th1520_pd_ranges); i++) {
+		struct th1520_power_domain *pd =
+			to_th1520_power_domain(domains[i]);
+
+		ret = th1520_aon_power_update(pd->aon_chan, pd->rsrc, false);
+		if (ret)
+			dev_err(dev,
+				"Failed to initially power down power domain %s\n",
+				pd->genpd.name);
+	}
+}
+
+static int th1520_pd_probe(struct platform_device *pdev)
+{
+	struct generic_pm_domain **domains;
+	struct genpd_onecell_data *pd_data;
+	struct th1520_aon_chan *aon_chan;
+	struct device *dev = &pdev->dev;
+	int i;
+
+	aon_chan = dev_get_drvdata(dev->parent);
+	if (!aon_chan) {
+		dev_err(dev, "Failed to get AON channel from parent\n");
+		return -EINVAL;
+	}
+
+	domains = devm_kcalloc(dev, ARRAY_SIZE(th1520_pd_ranges),
+			       sizeof(*domains), GFP_KERNEL);
+	if (!domains)
+		return -ENOMEM;
+
+	pd_data = devm_kzalloc(dev, sizeof(*pd_data), GFP_KERNEL);
+	if (!pd_data)
+		return -ENOMEM;
+
+	for (i = 0; i < ARRAY_SIZE(th1520_pd_ranges); i++) {
+		struct th1520_power_domain *pd;
+
+		pd = th1520_add_pm_domain(dev, &th1520_pd_ranges[i]);
+		if (IS_ERR(pd))
+			return PTR_ERR(pd);
+
+		pd->aon_chan = aon_chan;
+		domains[i] = &pd->genpd;
+		dev_dbg(dev, "added power domain %s\n", pd->genpd.name);
+	}
+
+	pd_data->domains = domains;
+	pd_data->num_domains = ARRAY_SIZE(th1520_pd_ranges);
+	pd_data->xlate = th1520_pd_xlate;
+
+	/*
+	 * Initialize all power domains to off to ensure they start in a
+	 * low-power state. This allows device drivers to manage power
+	 * domains by turning them on or off as needed.
+	 */
+	th1520_pd_init_all_off(domains, dev);
+
+	return of_genpd_add_provider_onecell(dev->of_node, pd_data);
+}
+
+static const struct of_device_id th1520_pd_match[] = {
+	{ .compatible = "thead,th1520-pd" },
+	{ /* sentinel */ }
+};
+
+static struct platform_driver th1520_pd_driver = {
+	.driver = {
+		.name = "th1520-pd",
+		.of_match_table = th1520_pd_match,
+	},
+	.probe = th1520_pd_probe,
+};
+module_platform_driver(th1520_pd_driver);
+
+MODULE_AUTHOR("Michal Wilczynski <m.wilczynski@samsung.com>");
+MODULE_DESCRIPTION("T-HEAD TH1520 SoC power domain controller");
+MODULE_LICENSE("GPL");
-- 
2.34.1