mvebu: backport linkstation-poweroff upstream driver

Backport the Linkstation poweroff driver from the kernel upstream (commit
a7f79f99541ef)

This driver is required by the Buffalo LinkStation LS421DE for a correct
power off operation. It also allows to use the WoL feature.

Signed-off-by: Daniel González Cabanelas <dgcbueu@gmail.com>

2 files changed, 198 insertions, 0 deletions

diff --git a/target/linux/mvebu/modules.mk b/target/linux/mvebu/modules.mk
new file mode 100644
index 0000000000..3a5e316788
--- /dev/null
+++ b/target/linux/mvebu/modules.mk
@@ -0,0 +1,21 @@
+define KernelPackage/linkstation-poweroff
+  SUBMENU:=$(OTHER_MENU)
+  DEPENDS:=@TARGET_mvebu
+  TITLE:=Buffalo LinkStation power off driver
+  KCONFIG:= \
+	CONFIG_POWER_RESET=y \
+	CONFIG_POWER_RESET_LINKSTATION \
+	CONFIG_POWER_RESET_QNAP=n
+
+  FILES:=$(LINUX_DIR)/drivers/power/reset/linkstation-poweroff.ko
+  AUTOLOAD:=$(call AutoLoad,31,linkstation-poweroff,1)
+endef
+
+define KernelPackage/linkstation-poweroff/description
+  This driver supports turning off some Buffalo LinkStations by
+  setting an output pin at the ethernet PHY to the correct state.
+  It also makes the device compatible with the WoL function.
+  Say Y here if you have a Buffalo LinkStation LS421D/E.
+endef
+
+$(eval $(call KernelPackage,linkstation-poweroff))
diff --git a/target/linux/mvebu/patches-5.4/030-linkstation-poweroff.patch b/target/linux/mvebu/patches-5.4/030-linkstation-poweroff.patch
new file mode 100644
index 0000000000..e4dee5c09e
--- /dev/null
+++ b/target/linux/mvebu/patches-5.4/030-linkstation-poweroff.patch
@@ -0,0 +1,177 @@
+--- a/drivers/power/reset/Kconfig
++++ b/drivers/power/reset/Kconfig
+@@ -99,6 +99,17 @@
+ 	help
+ 	  Reboot support for Hisilicon boards.
+ 
++config POWER_RESET_LINKSTATION
++	tristate "Buffalo LinkStation power-off driver"
++	depends on ARCH_MVEBU || COMPILE_TEST
++	depends on OF_MDIO && PHYLIB
++	help
++	  This driver supports turning off some Buffalo LinkStations by
++	  setting an output pin at the ethernet PHY to the correct state.
++	  It also makes the device compatible with the WoL function.
++
++	  Say Y here if you have a Buffalo LinkStation LS421D/E.
++
+ config POWER_RESET_MSM
+ 	bool "Qualcomm MSM power-off driver"
+ 	depends on ARCH_QCOM
+--- a/drivers/power/reset/Makefile
++++ b/drivers/power/reset/Makefile
+@@ -10,6 +10,7 @@
+ obj-$(CONFIG_POWER_RESET_GPIO) += gpio-poweroff.o
+ obj-$(CONFIG_POWER_RESET_GPIO_RESTART) += gpio-restart.o
+ obj-$(CONFIG_POWER_RESET_HISI) += hisi-reboot.o
++obj-${CONFIG_POWER_RESET_LINKSTATION} += linkstation-poweroff.o
+ obj-$(CONFIG_POWER_RESET_MSM) += msm-poweroff.o
+ obj-$(CONFIG_POWER_RESET_QCOM_PON) += qcom-pon.o
+ obj-$(CONFIG_POWER_RESET_OCELOT_RESET) += ocelot-reset.o
+--- a/dev/null
++++ b/drivers/power/reset/linkstation-poweroff.c
+@@ -0,0 +1,144 @@
++// SPDX-License-Identifier: GPL-2.0
++/*
++ * LinkStation power off restart driver
++ * Copyright (C) 2020 Daniel González Cabanelas <dgcbueu@gmail.com>
++ */
++
++#include <linux/module.h>
++#include <linux/notifier.h>
++#include <linux/of.h>
++#include <linux/of_mdio.h>
++#include <linux/of_platform.h>
++#include <linux/reboot.h>
++#include <linux/phy.h>
++
++/* Defines from the eth phy Marvell driver */
++#define MII_MARVELL_COPPER_PAGE		0
++#define MII_MARVELL_LED_PAGE		3
++#define MII_MARVELL_WOL_PAGE		17
++#define MII_MARVELL_PHY_PAGE		22
++
++#define MII_PHY_LED_CTRL		16
++#define MII_88E1318S_PHY_LED_TCR	18
++#define MII_88E1318S_PHY_WOL_CTRL	16
++#define MII_M1011_IEVENT		19
++
++#define MII_88E1318S_PHY_LED_TCR_INTn_ENABLE		BIT(7)
++#define MII_88E1318S_PHY_LED_TCR_FORCE_INT		BIT(15)
++#define MII_88E1318S_PHY_WOL_CTRL_CLEAR_WOL_STATUS	BIT(12)
++#define LED2_FORCE_ON					(0x8 << 8)
++#define LEDMASK						GENMASK(11,8)
++
++static struct phy_device *phydev;
++
++static void mvphy_reg_intn(u16 data)
++{
++	int rc = 0, saved_page;
++
++	saved_page = phy_select_page(phydev, MII_MARVELL_LED_PAGE);
++	if (saved_page < 0)
++		goto err;
++
++	/* Force manual LED2 control to let INTn work */
++	__phy_modify(phydev, MII_PHY_LED_CTRL, LEDMASK, LED2_FORCE_ON);
++
++	/* Set the LED[2]/INTn pin to the required state */
++	__phy_modify(phydev, MII_88E1318S_PHY_LED_TCR,
++		     MII_88E1318S_PHY_LED_TCR_FORCE_INT,
++		     MII_88E1318S_PHY_LED_TCR_INTn_ENABLE | data);
++
++	if (!data) {
++		/* Clear interrupts to ensure INTn won't be holded in high state */
++		__phy_write(phydev, MII_MARVELL_PHY_PAGE, MII_MARVELL_COPPER_PAGE);
++		__phy_read(phydev, MII_M1011_IEVENT);
++
++		/* If WOL was enabled and a magic packet was received before powering
++		 * off, we won't be able to wake up by sending another magic packet. 
++		 * Clear WOL status.
++		 */
++		__phy_write(phydev, MII_MARVELL_PHY_PAGE, MII_MARVELL_WOL_PAGE);
++		__phy_set_bits(phydev, MII_88E1318S_PHY_WOL_CTRL,
++			       MII_88E1318S_PHY_WOL_CTRL_CLEAR_WOL_STATUS);
++	}
++err:
++	rc = phy_restore_page(phydev, saved_page, rc);
++	if (rc < 0)
++		dev_err(&phydev->mdio.dev, "Write register failed, %d\n", rc);
++
++	if (!data) {
++		/* Slow down the PHY to save energy */
++		rc= phy_speed_down(phydev, false);
++		if (rc < 0)
++			dev_err(&phydev->mdio.dev, "PHY speed down failed, %d\n", rc);
++	}
++}
++
++static int linkstation_reboot_notifier(struct notifier_block *nb,
++				       unsigned long action, void *unused)
++{
++	if (action == SYS_RESTART)
++		mvphy_reg_intn(MII_88E1318S_PHY_LED_TCR_FORCE_INT);
++
++	return NOTIFY_DONE;
++}
++
++static struct notifier_block linkstation_reboot_nb = {
++	.notifier_call = linkstation_reboot_notifier,
++};
++
++static void linkstation_poweroff(void)
++{
++	unregister_reboot_notifier(&linkstation_reboot_nb);
++	mvphy_reg_intn(0);
++
++	kernel_restart("Power off");
++}
++
++static const struct of_device_id ls_poweroff_of_match[] = {
++	{ .compatible = "buffalo,ls421d" },
++	{ .compatible = "buffalo,ls421de" },
++	{ },
++};
++
++static int __init linkstation_poweroff_init(void)
++{
++	struct mii_bus *bus;
++	struct device_node *dn;
++
++	dn = of_find_matching_node(NULL, ls_poweroff_of_match);
++	if (!dn)
++		return -ENODEV;
++	of_node_put(dn);
++
++	dn = of_find_node_by_name(NULL, "mdio");
++	if (!dn)
++		return -ENODEV;
++
++	bus = of_mdio_find_bus(dn);
++	of_node_put(dn);
++	if (!bus)
++		return -EPROBE_DEFER;
++
++	phydev = phy_find_first(bus);
++	if (!phydev)
++		return -EPROBE_DEFER;
++
++	register_reboot_notifier(&linkstation_reboot_nb);
++	pm_power_off = linkstation_poweroff;
++
++	pr_info("LinkStation power off driver registered\n");
++	return 0;
++}
++
++static void __exit linkstation_poweroff_exit(void)
++{
++	pm_power_off = NULL;
++	unregister_reboot_notifier(&linkstation_reboot_nb);
++}
++
++module_init(linkstation_poweroff_init);
++module_exit(linkstation_poweroff_exit);
++
++MODULE_AUTHOR("Daniel González Cabanelas <dgcbueu@gmail.com>");
++MODULE_DESCRIPTION("LinkStation power off driver");
++MODULE_LICENSE("GPL v2");