[PATCH v6 08/19] dm: Add support for simple-pm-bus

Sean Anderson
2020-03-05T18:12:56Z

This type of bus is used in Linux to designate buses which have power
domains and/or clocks which need to be enabled before their child devices
can be used. Because power domains are automatically enabled before probing
in U-Boot, we just need to enable any clocks present.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
---

Changes in v5:
- Reorder includes (simple pm)

Changes in v4:
- Split the bus off into its own driver
- Add test
- Fix line spacing in Kconfig
- Lint

Changes in v3:
- New

arch/sandbox/dts/test.dts | 6 ++
arch/sandbox/include/asm/clk.h | 1 +
configs/sandbox_defconfig | 1 +
.../bus/simple-pm-bus.txt | 44 +++++++++++++++
drivers/core/Kconfig | 7 +++
drivers/core/Makefile | 1 +
drivers/core/simple-pm-bus.c | 56 +++++++++++++++++++
test/dm/Makefile | 1 +
test/dm/simple-pm-bus.c | 45 +++++++++++++++
9 files changed, 162 insertions(+)
create mode 100644 doc/device-tree-bindings/bus/simple-pm-bus.txt
create mode 100644 drivers/core/simple-pm-bus.c
create mode 100644 test/dm/simple-pm-bus.c

diff --git a/arch/sandbox/dts/test.dts b/arch/sandbox/dts/test.dts
index 4a277934a7..96e0b55eed 100644
--- a/arch/sandbox/dts/test.dts
+++ b/arch/sandbox/dts/test.dts
@@ -934,6 +934,12 @@
mdio: mdio-test {
compatible = "sandbox,mdio";
};
+
+ pm-bus-test {
+ compatible = "simple-pm-bus";
+ clocks = <&clk_sandbox 4>;
+ power-domains = <&pwrdom 1>;
+ };
};

#include "sandbox_pmic.dtsi"
diff --git a/arch/sandbox/include/asm/clk.h b/arch/sandbox/include/asm/clk.h
index 1573e4a134..c184c4bffc 100644
--- a/arch/sandbox/include/asm/clk.h
+++ b/arch/sandbox/include/asm/clk.h
@@ -21,6 +21,7 @@ enum sandbox_clk_id {
SANDBOX_CLK_ID_I2C,
SANDBOX_CLK_ID_UART1,
SANDBOX_CLK_ID_UART2,
+ SANDBOX_CLK_ID_BUS,

SANDBOX_CLK_ID_COUNT,
};
diff --git a/configs/sandbox_defconfig b/configs/sandbox_defconfig
index 45b5475b79..db0d2bbdc7 100644
--- a/configs/sandbox_defconfig
+++ b/configs/sandbox_defconfig
@@ -90,6 +90,7 @@ CONFIG_REGMAP=y
CONFIG_SYSCON=y
CONFIG_DEVRES=y
CONFIG_DEBUG_DEVRES=y
+CONFIG_SIMPLE_PM_BUS=y
CONFIG_ADC=y
CONFIG_ADC_SANDBOX=y
CONFIG_AXI=y
diff --git a/doc/device-tree-bindings/bus/simple-pm-bus.txt b/doc/device-tree-bindings/bus/simple-pm-bus.txt
new file mode 100644
index 0000000000..6f15037131
--- /dev/null
+++ b/doc/device-tree-bindings/bus/simple-pm-bus.txt
@@ -0,0 +1,44 @@
+Simple Power-Managed Bus
+========================
+
+A Simple Power-Managed Bus is a transparent bus that doesn't need a real
+driver, as it's typically initialized by the boot loader.
+
+However, its bus controller is part of a PM domain, or under the control of a
+functional clock. Hence, the bus controller's PM domain and/or clock must be
+enabled for child devices connected to the bus (either on-SoC or externally)
+to function.
+
+While "simple-pm-bus" follows the "simple-bus" set of properties, as specified
+in the Devicetree Specification, it is not an extension of "simple-bus".
+
+
+Required properties:
+ - compatible: Must contain at least "simple-pm-bus".
+ Must not contain "simple-bus".
+ It's recommended to let this be preceded by one or more
+ vendor-specific compatible values.
+ - #address-cells, #size-cells, ranges: Must describe the mapping between
+ parent address and child address spaces.
+
+Optional platform-specific properties for clock or PM domain control (at least
+one of them is required):
+ - clocks: Must contain a reference to the functional clock(s),
+ - power-domains: Must contain a reference to the PM domain.
+Please refer to the binding documentation for the clock and/or PM domain
+providers for more details.
+
+
+Example:
+
+ bsc: bus at fec10000 {
+ compatible = "renesas,bsc-sh73a0", "renesas,bsc",
+ "simple-pm-bus";
+ #address-cells = <1>;
+ #size-cells = <1>;
+ ranges = <0 0 0x20000000>;
+ reg = <0xfec10000 0x400>;
+ interrupts = <0 39 IRQ_TYPE_LEVEL_HIGH>;
+ clocks = <&zb_clk>;
+ power-domains = <&pd_a4s>;
+ };
diff --git a/drivers/core/Kconfig b/drivers/core/Kconfig
index 3b95b5387b..0cd687526e 100644
--- a/drivers/core/Kconfig
+++ b/drivers/core/Kconfig
@@ -195,6 +195,13 @@ config SPL_SIMPLE_BUS
Supports the 'simple-bus' driver, which is used on some systems
in SPL.

+config SIMPLE_PM_BUS
+ bool "Support simple-pm-bus driver"
+ depends on DM && OF_CONTROL && CLK && POWER_DOMAIN
+ help
+ Supports the 'simple-pm-bus' driver, which is used for busses that
+ have power domains and/or clocks which need to be enabled before use.
+
config OF_TRANSLATE
bool "Translate addresses using fdt_translate_address"
depends on DM && OF_CONTROL
diff --git a/drivers/core/Makefile b/drivers/core/Makefile
index bce7467da1..284af7caaa 100644
--- a/drivers/core/Makefile
+++ b/drivers/core/Makefile
@@ -6,6 +6,7 @@ obj-y += device.o fdtaddr.o lists.o root.o uclass.o util.o
obj-$(CONFIG_DEVRES) += devres.o
obj-$(CONFIG_$(SPL_)DM_DEVICE_REMOVE) += device-remove.o
obj-$(CONFIG_$(SPL_)SIMPLE_BUS) += simple-bus.o
+obj-$(CONFIG_SIMPLE_PM_BUS) += simple-pm-bus.o
obj-$(CONFIG_DM) += dump.o
obj-$(CONFIG_$(SPL_TPL_)REGMAP) += regmap.o
obj-$(CONFIG_$(SPL_TPL_)SYSCON) += syscon-uclass.o
diff --git a/drivers/core/simple-pm-bus.c b/drivers/core/simple-pm-bus.c
new file mode 100644
index 0000000000..2313bd9a27
--- /dev/null
+++ b/drivers/core/simple-pm-bus.c
@@ -0,0 +1,56 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2020 Sean Anderson <seanga2@gmail.com>
+ */
+
+#include <common.h>
+#include <clk.h>
+#include <dm.h>
+
+/*
+ * Power domains are taken care of by driver_probe, so we just have to enable
+ * clocks
+ */
+static const int simple_pm_bus_probe(struct udevice *dev)
+{
+ int ret;
+ struct clk_bulk *bulk = dev_get_priv(dev);
+
+ ret = clk_get_bulk(dev, bulk);
+ if (ret)
+ return ret;
+
+ ret = clk_enable_bulk(bulk);
+ if (ret && ret != -ENOSYS && ret != -ENOTSUPP) {
+ clk_release_bulk(bulk);
+ return ret;
+ }
+ return 0;
+}
+
+static const int simple_pm_bus_remove(struct udevice *dev)
+{
+ int ret;
+ struct clk_bulk *bulk = dev_get_priv(dev);
+
+ ret = clk_release_bulk(bulk);
+ if (ret && ret != -ENOSYS && ret != -ENOTSUPP)
+ return ret;
+ else
+ return 0;
+}
+
+static const struct udevice_id simple_pm_bus_ids[] = {
+ { .compatible = "simple-pm-bus" },
+ { }
+};
+
+U_BOOT_DRIVER(simple_pm_bus_drv) = {
+ .name = "simple_pm_bus",
+ .id = UCLASS_SIMPLE_BUS,
+ .of_match = simple_pm_bus_ids,
+ .probe = simple_pm_bus_probe,
+ .remove = simple_pm_bus_remove,
+ .priv_auto_alloc_size = sizeof(struct clk_bulk),
+ .flags = DM_FLAG_PRE_RELOC,
+};
diff --git a/test/dm/Makefile b/test/dm/Makefile
index ef6065b60f..e0be0d684f 100644
--- a/test/dm/Makefile
+++ b/test/dm/Makefile
@@ -71,4 +71,5 @@ obj-$(CONFIG_DM_MDIO) += mdio.o
obj-$(CONFIG_DM_MDIO_MUX) += mdio_mux.o
obj-$(CONFIG_DM_RNG) += rng.o
obj-$(CONFIG_CLK_K210_SET_RATE) += k210_pll.o
+obj-$(CONFIG_SIMPLE_PM_BUS) += simple-pm-bus.o
endif
diff --git a/test/dm/simple-pm-bus.c b/test/dm/simple-pm-bus.c
new file mode 100644
index 0000000000..978c7f191e
--- /dev/null
+++ b/test/dm/simple-pm-bus.c
@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020 Sean Anderson <seanga2@gmail.com>
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <dm/test.h>
+#include <dm/device-internal.h>
+#include <test/ut.h>
+#include <asm/clk.h>
+#include <asm/power-domain.h>
+
+/* These must match the ids in the device tree */
+#define TEST_CLOCK_ID 4
+#define TEST_POWER_ID 1
+
+static int dm_test_simple_pm_bus(struct unit_test_state *uts)
+{
+ struct udevice *power;
+ struct udevice *clock;
+ struct udevice *bus;
+
+ ut_assertok(uclass_get_device_by_name(UCLASS_POWER_DOMAIN,
+ "power-domain", &power));
+ ut_assertok(uclass_get_device_by_name(UCLASS_CLK, "clk-sbox",
+ &clock));
+ ut_asserteq(0, sandbox_power_domain_query(power, TEST_POWER_ID));
+ ut_asserteq(0, sandbox_clk_query_enable(clock, TEST_CLOCK_ID));
+
+ ut_assertok(uclass_get_device_by_name(UCLASS_SIMPLE_BUS, "pm-bus-test",
+ &bus));
+ ut_asserteq(1, sandbox_power_domain_query(power, TEST_POWER_ID));
+ ut_asserteq(1, sandbox_clk_query_enable(clock, TEST_CLOCK_ID));
+
+ ut_assertok(device_remove(bus, DM_REMOVE_NORMAL));
+ /* must re-probe since device_remove also removes the power domain */
+ ut_assertok(uclass_get_device_by_name(UCLASS_POWER_DOMAIN,
+ "power-domain", &power));
+ ut_asserteq(0, sandbox_power_domain_query(power, TEST_POWER_ID));
+ ut_asserteq(0, sandbox_clk_query_enable(clock, TEST_CLOCK_ID));
+
+ return 0;
+}
+DM_TEST(dm_test_simple_pm_bus, DM_TESTF_SCAN_FDT);
--
2.25.0