[PATCH v4 06/18] pmdomain: thead: 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");

Introduce 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.

The interaction with AUDIO power island e.g trying to turn it OFF proved
to crash the firmware running on the E902 core. Introduce the workaround
to disable interacting with the power island.

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 | 193 +++++++++++++++++++++
 6 files changed, 210 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 4106b0e26589..33c804f1a60f 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -20350,6 +20350,7 @@ 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/dt-bindings/power/thead,th1520-power.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..c7a1ac0c61dc
--- /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 || !TH1520_AON_PROTOCOL
+	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..7cf4ea519623
--- /dev/null
+++ b/drivers/pmdomain/thead/th1520-pm-domains.c
@@ -0,0 +1,193 @@
+// 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/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;
+	bool disabled;
+};
+
+/*
+ * The AUDIO power domain is marked as disabled to prevent the driver from
+ * managing its power state. Direct AON firmware calls to control this power
+ * island trigger a firmware bug causing system instability. Until this
+ * firmware issue is resolved, the AUDIO power domain must remain disabled
+ * to avoid crashes.
+ */
+static const struct th1520_power_info th1520_pd_ranges[] = {
+	[TH1520_AUDIO_PD] = {"audio", TH1520_AON_AUDIO_PD, true },
+	[TH1520_VDEC_PD] = { "vdec", TH1520_AON_VDEC_PD, false },
+	[TH1520_NPU_PD] = { "npu", TH1520_AON_NPU_PD, false },
+	[TH1520_VENC_PD] = { "venc", TH1520_AON_VENC_PD, false },
+	[TH1520_GPU_PD] = { "gpu", TH1520_AON_GPU_PD, false },
+	[TH1520_DSP0_PD] = { "dsp0", TH1520_AON_DSP0_PD, false },
+	[TH1520_DSP1_PD] = { "dsp1", TH1520_AON_DSP1_PD, false }
+};
+
+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;
+
+		if (th1520_pd_ranges[i].disabled)
+			continue;
+
+		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;
+
+		if (th1520_pd_ranges[i].disabled)
+			continue;
+
+		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;
+
+		if (th1520_pd_ranges[i].disabled)
+			continue;
+
+		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->parent->of_node, pd_data);
+}
+
+static struct platform_driver th1520_pd_driver = {
+	.driver = {
+		.name = "th1520-pd",
+	},
+	.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