mtd: spi-nor: intel-spi: Add support for Intel Denverton SPI serial flash controller

Intel Denverton exposes the SPI serial flash controller as a PCI device
instead of being part of the LPC chip as previous generations did.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@free-electrons.com>

drivers/mtd/spi-nor/Kconfig

@@ -89,6 +89,22 @@ config SPI_NXP_SPIFI
 config SPI_INTEL_SPI
 	tristate
 
+config SPI_INTEL_SPI_PCI
+	tristate "Intel PCH/PCU SPI flash PCI driver" if EXPERT
+	depends on X86 && PCI
+	select SPI_INTEL_SPI
+	help
+	  This enables PCI support for the Intel PCH/PCU SPI controller in
+	  master mode. This controller is present in modern Intel hardware
+	  and is used to hold BIOS and other persistent settings. Using
+	  this driver it is possible to upgrade BIOS directly from Linux.
+
+	  Say N here unless you know what you are doing. Overwriting the
+	  SPI flash may render the system unbootable.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called intel-spi-pci.
+
 config SPI_INTEL_SPI_PLATFORM
 	tristate "Intel PCH/PCU SPI flash platform driver" if EXPERT
 	depends on X86

drivers/mtd/spi-nor/Makefile

@@ -7,5 +7,6 @@ obj-$(CONFIG_SPI_HISI_SFC)	+= hisi-sfc.o
 obj-$(CONFIG_MTD_MT81xx_NOR)    += mtk-quadspi.o
 obj-$(CONFIG_SPI_NXP_SPIFI)	+= nxp-spifi.o
 obj-$(CONFIG_SPI_INTEL_SPI)	+= intel-spi.o
+obj-$(CONFIG_SPI_INTEL_SPI_PCI)	+= intel-spi-pci.o
 obj-$(CONFIG_SPI_INTEL_SPI_PLATFORM)	+= intel-spi-platform.o
 obj-$(CONFIG_SPI_STM32_QUADSPI)	+= stm32-quadspi.o

drivers/mtd/spi-nor/intel-spi-pci.c

@@ -0,0 +1,82 @@
+/*
+ * Intel PCH/PCU SPI flash PCI driver.
+ *
+ * Copyright (C) 2016, Intel Corporation
+ * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/ioport.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+
+#include "intel-spi.h"
+
+#define BCR		0xdc
+#define BCR_WPD		BIT(0)
+
+static const struct intel_spi_boardinfo bxt_info = {
+	.type = INTEL_SPI_BXT,
+};
+
+static int intel_spi_pci_probe(struct pci_dev *pdev,
+			       const struct pci_device_id *id)
+{
+	struct intel_spi_boardinfo *info;
+	struct intel_spi *ispi;
+	u32 bcr;
+	int ret;
+
+	ret = pcim_enable_device(pdev);
+	if (ret)
+		return ret;
+
+	info = devm_kmemdup(&pdev->dev, (void *)id->driver_data, sizeof(*info),
+			    GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	/* Try to make the chip read/write */
+	pci_read_config_dword(pdev, BCR, &bcr);
+	if (!(bcr & BCR_WPD)) {
+		bcr |= BCR_WPD;
+		pci_write_config_dword(pdev, BCR, bcr);
+		pci_read_config_dword(pdev, BCR, &bcr);
+	}
+	info->writeable = !!(bcr & BCR_WPD);
+
+	ispi = intel_spi_probe(&pdev->dev, &pdev->resource[0], info);
+	if (IS_ERR(ispi))
+		return PTR_ERR(ispi);
+
+	pci_set_drvdata(pdev, ispi);
+	return 0;
+}
+
+static void intel_spi_pci_remove(struct pci_dev *pdev)
+{
+	intel_spi_remove(pci_get_drvdata(pdev));
+}
+
+static const struct pci_device_id intel_spi_pci_ids[] = {
+	{ PCI_VDEVICE(INTEL, 0x19e0), (unsigned long)&bxt_info },
+	{ },
+};
+MODULE_DEVICE_TABLE(pci, intel_spi_pci_ids);
+
+static struct pci_driver intel_spi_pci_driver = {
+	.name = "intel-spi",
+	.id_table = intel_spi_pci_ids,
+	.probe = intel_spi_pci_probe,
+	.remove = intel_spi_pci_remove,
+};
+
+module_pci_driver(intel_spi_pci_driver);
+
+MODULE_DESCRIPTION("Intel PCH/PCU SPI flash PCI driver");
+MODULE_AUTHOR("Mika Westerberg <mika.westerberg@linux.intel.com>");
+MODULE_LICENSE("GPL v2");