x86/platform/intel-mid: Add Power Management Unit driver

Add Power Management Unit driver to handle power states of South Complex
devices on Intel Tangier. In the future it might be expanded to cover North
Complex devices as well.

With this driver the power state of the host controllers such as SPI, I2C,
UART, eMMC, and DMA would be managed.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: David Cohen <david.a.cohen@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-pci@vger.kernel.org
Link: http://lkml.kernel.org/r/1465928985-12113-1-git-send-email-andriy.shevchenko@linux.intel.com
[ Minor readability edits. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/include/asm/intel-mid.h

@@ -12,9 +12,17 @@
 #define _ASM_X86_INTEL_MID_H
 
 #include <linux/sfi.h>
+#include <linux/pci.h>
 #include <linux/platform_device.h>
 
 extern int intel_mid_pci_init(void);
+extern int intel_mid_pci_set_power_state(struct pci_dev *pdev, pci_power_t state);
+
+#define INTEL_MID_PWR_LSS_OFFSET	4
+#define INTEL_MID_PWR_LSS_TYPE		(1 << 7)
+
+extern int intel_mid_pwr_get_lss_id(struct pci_dev *pdev);
+
 extern int get_gpio_by_name(const char *name);
 extern void intel_scu_device_register(struct platform_device *pdev);
 extern int __init sfi_parse_mrtc(struct sfi_table_header *table);

arch/x86/pci/intel_mid_pci.c

@@ -316,14 +316,44 @@ static void pci_d3delay_fixup(struct pci_dev *dev)
 }
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, PCI_ANY_ID, pci_d3delay_fixup);
 
-static void mrst_power_off_unused_dev(struct pci_dev *dev)
+static void mid_power_off_dev(struct pci_dev *dev)
 {
+	u16 pmcsr;
+
+	/*
+	 * Update current state first, otherwise PCI core enforces PCI_D0 in
+	 * pci_set_power_state() for devices which status was PCI_UNKNOWN.
+	 */
+	pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &pmcsr);
+	dev->current_state = (pci_power_t __force)(pmcsr & PCI_PM_CTRL_STATE_MASK);
+
 	pci_set_power_state(dev, PCI_D3hot);
 }
-DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x0801, mrst_power_off_unused_dev);
-DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x0809, mrst_power_off_unused_dev);
-DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x080C, mrst_power_off_unused_dev);
-DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x0815, mrst_power_off_unused_dev);
+
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x0801, mid_power_off_dev);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x0809, mid_power_off_dev);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x080C, mid_power_off_dev);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x0815, mid_power_off_dev);
+
+static void mrfld_power_off_dev(struct pci_dev *dev)
+{
+	int id;
+
+	if (!pci_soc_mode)
+		return;
+
+	id = intel_mid_pwr_get_lss_id(dev);
+	if (id < 0)
+		return;
+
+	/*
+	 * This sets only PMCSR bits. The actual power off will happen in
+	 * arch/x86/platform/intel-mid/pwr.c.
+	 */
+	mid_power_off_dev(dev);
+}
+
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, PCI_ANY_ID, mrfld_power_off_dev);
 
 /*
  * Langwell devices reside at fixed offsets, don't try to move them.

arch/x86/platform/intel-mid/Makefile

@@ -1,4 +1,4 @@
-obj-$(CONFIG_X86_INTEL_MID) += intel-mid.o intel_mid_vrtc.o mfld.o mrfl.o
+obj-$(CONFIG_X86_INTEL_MID) += intel-mid.o intel_mid_vrtc.o mfld.o mrfl.o pwr.o
 
 # SFI specific code
 ifdef CONFIG_X86_INTEL_MID