kernel: owl-loader for delayed Atheros ath9k fixup

Some devices (like the Cisco Meraki Z1 Cloud Managed Teleworker Gateway)
need to be able to initialize the PCIe wifi device. Normally, this is done
during the early stages of booting linux, because the necessary init code
is read from the memory mapped SPI and passed to pci_enable_ath9k_fixup.
However,this isn't possible for devices which have the init code for the
Atheros chip stored on NAND in an UBI volume. Hence, this module can be
used to initialze the chip when the user-space is ready to extract the
init code.

Martin Blumenstingl made a few fixes and added support for lantiq:
kernel: owl-loader: add support for OWL emulation PCI devices
kernel: owl-loader: don't re-scan the bus when ath9k_pci_fixup failed
kernel: owl-loader: use dev_* instead of pr_* logging functions
kernel: owl-loader: auto-generate the eeprom filename as fallback
kernel: owl-loader: add a debug message when swapping the eeprom data
kernel: owl-loader: add missing newlines in log messages
kernel: owl-loader: add support for the lantiq platform

These patches have been integrated. Thanks!

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>

2 files changed, 277 insertions, 0 deletions

diff --git a/target/linux/generic/files/drivers/misc/owl-loader.c b/target/linux/generic/files/drivers/misc/owl-loader.c
new file mode 100644
index 0000000000..30340da486
--- /dev/null
+++ b/target/linux/generic/files/drivers/misc/owl-loader.c
@@ -0,0 +1,246 @@
+/*
+ * Initialize Owl Emulation Devices
+ *
+ * Copyright (C) 2016 Christian Lamparter <chunkeey@googlemail.com>
+ * Copyright (C) 2016 Martin Blumenstingl <martin.blumenstingl@googlemail.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.
+ *
+ * Some devices (like the Cisco Meraki Z1 Cloud Managed Teleworker Gateway)
+ * need to be able to initialize the PCIe wifi device. Normally, this is done
+ * during the early stages of booting linux, because the necessary init code
+ * is read from the memory mapped SPI and passed to pci_enable_ath9k_fixup.
+ * However,this isn't possible for devices which have the init code for the
+ * Atheros chip stored on NAND. Hence, this module can be used to initialze
+ * the chip when the user-space is ready to extract the init code.
+ */
+#include <linux/module.h>
+#include <linux/version.h>
+#include <linux/completion.h>
+#include <linux/etherdevice.h>
+#include <linux/firmware.h>
+#include <linux/pci.h>
+#include <linux/delay.h>
+#include <linux/platform_device.h>
+#include <linux/ath9k_platform.h>
+
+struct owl_ctx {
+	struct completion eeprom_load;
+};
+
+#define EEPROM_FILENAME_LEN 100
+
+#define AR5416_EEPROM_MAGIC 0xa55a
+
+static int ath9k_pci_fixup(struct pci_dev *pdev, const u16 *cal_data,
+			   size_t cal_len)
+{
+	void __iomem *mem;
+	const void *cal_end = (void *)cal_data + cal_len;
+	const struct {
+		__be16 reg;
+		__be16 low_val;
+		__be16 high_val;
+	} __packed *data;
+	u16 cmd;
+	u32 bar0;
+	bool swap_needed = false;
+
+	if (*cal_data != AR5416_EEPROM_MAGIC) {
+		if (*cal_data != swab16(AR5416_EEPROM_MAGIC)) {
+			dev_err(&pdev->dev, "invalid calibration data\n");
+			return -EINVAL;
+		}
+
+		dev_dbg(&pdev->dev, "calibration data needs swapping\n");
+		swap_needed = true;
+	}
+
+	dev_info(&pdev->dev, "fixup device configuration\n");
+
+	mem = pcim_iomap(pdev, 0, 0);
+	if (!mem) {
+		dev_err(&pdev->dev, "ioremap error\n");
+		return -EINVAL;
+	}
+
+	pci_read_config_dword(pdev, PCI_BASE_ADDRESS_0, &bar0);
+	pci_write_config_dword(pdev, PCI_BASE_ADDRESS_0,
+			       pci_resource_start(pdev, 0));
+	pci_read_config_word(pdev, PCI_COMMAND, &cmd);
+	cmd |= PCI_COMMAND_MASTER | PCI_COMMAND_MEMORY;
+	pci_write_config_word(pdev, PCI_COMMAND, cmd);
+
+	/* set pointer to first reg address */
+	for (data = (const void *) (cal_data + 3);
+	     (const void *) data <= cal_end && data->reg != cpu_to_be16(~0);
+	     data++) {
+		u32 val;
+		u16 reg;
+
+		reg = data->reg;
+		val = data->low_val;
+		val |= data->high_val << 16;
+
+		if (swap_needed) {
+			reg = swab16(reg);
+			val = swahb32(val);
+		}
+
+#if CONFIG_LANTIQ
+		val = swab32(val);
+#endif
+
+		__raw_writel(val, mem + reg);
+		udelay(100);
+	}
+
+	pci_read_config_word(pdev, PCI_COMMAND, &cmd);
+	cmd &= ~(PCI_COMMAND_MASTER | PCI_COMMAND_MEMORY);
+	pci_write_config_word(pdev, PCI_COMMAND, cmd);
+
+	pci_write_config_dword(pdev, PCI_BASE_ADDRESS_0, bar0);
+	pcim_iounmap(pdev, mem);
+
+	pci_disable_device(pdev);
+
+	return 0;
+}
+
+static void owl_fw_cb(const struct firmware *fw, void *context)
+{
+	struct pci_dev *pdev = (struct pci_dev *) context;
+	struct owl_ctx *ctx = (struct owl_ctx *) pci_get_drvdata(pdev);
+	struct ath9k_platform_data *pdata = dev_get_platdata(&pdev->dev);
+	struct pci_bus *bus;
+
+	complete(&ctx->eeprom_load);
+
+	if (!fw) {
+		dev_err(&pdev->dev, "no eeprom data received.\n");
+		goto release;
+	}
+
+	/* also note that we are doing *u16 operations on the file */
+	if (fw->size > sizeof(pdata->eeprom_data) || fw->size < 0x200 ||
+	    (fw->size & 1) == 1) {
+		dev_err(&pdev->dev, "eeprom file has an invalid size.\n");
+		goto release;
+	}
+
+	if (pdata) {
+		memcpy(pdata->eeprom_data, fw->data, fw->size);
+
+		/*
+		 * eeprom has been successfully loaded - pass the data to ath9k
+		 * but remove the eeprom_name, so it doesn't try to load it too.
+		 */
+		pdata->eeprom_name = NULL;
+	}
+
+	if (ath9k_pci_fixup(pdev, (const u16 *) fw->data, fw->size))
+		goto release;
+
+	pci_lock_rescan_remove();
+	bus = pdev->bus;
+	pci_stop_and_remove_bus_device(pdev);
+	/*
+	 * the device should come back with the proper
+	 * ProductId. But we have to initiate a rescan.
+	 */
+	pci_rescan_bus(bus);
+	pci_unlock_rescan_remove();
+
+release:
+	release_firmware(fw);
+}
+
+static const char *owl_get_eeprom_name(struct pci_dev *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct ath9k_platform_data *pdata;
+	char *eeprom_name;
+
+	/* try the existing platform data first */
+	pdata = dev_get_platdata(dev);
+	if (pdata && pdata->eeprom_name)
+		return pdata->eeprom_name;
+
+	dev_dbg(dev, "using auto-generated eeprom filename\n");
+
+	eeprom_name = devm_kzalloc(dev, EEPROM_FILENAME_LEN, GFP_KERNEL);
+	if (!eeprom_name)
+		return NULL;
+
+	/* this should match the pattern used in ath9k/init.c */
+	scnprintf(eeprom_name, EEPROM_FILENAME_LEN, "ath9k-eeprom-pci-%s.bin",
+		  dev_name(dev));
+
+	return eeprom_name;
+}
+
+static int owl_probe(struct pci_dev *pdev,
+		    const struct pci_device_id *id)
+{
+	struct owl_ctx *ctx;
+	const char *eeprom_name;
+	int err = 0;
+
+	if (pcim_enable_device(pdev))
+		return -EIO;
+
+	pcim_pin_device(pdev);
+
+	eeprom_name = owl_get_eeprom_name(pdev);
+	if (!eeprom_name) {
+		dev_err(&pdev->dev, "no eeprom filename found.\n");
+		return -ENODEV;
+	}
+
+	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+	if (!ctx) {
+		dev_err(&pdev->dev, "failed to alloc device context.\n");
+		return -ENOMEM;
+	}
+	init_completion(&ctx->eeprom_load);
+
+	pci_set_drvdata(pdev, ctx);
+	err = request_firmware_nowait(THIS_MODULE, true, eeprom_name,
+				      &pdev->dev, GFP_KERNEL, pdev, owl_fw_cb);
+	if (err) {
+		dev_err(&pdev->dev, "failed to request caldata (%d).\n", err);
+		kfree(ctx);
+	}
+	return err;
+}
+
+static void owl_remove(struct pci_dev *pdev)
+{
+	struct owl_ctx *ctx = pci_get_drvdata(pdev);
+
+	if (ctx) {
+		wait_for_completion(&ctx->eeprom_load);
+		pci_set_drvdata(pdev, NULL);
+		kfree(ctx);
+	}
+}
+
+static const struct pci_device_id owl_pci_table[] = {
+	{ PCI_VDEVICE(ATHEROS, 0xff1c) }, /* PCIe */
+	{ PCI_VDEVICE(ATHEROS, 0xff1d) }, /* PCI */
+	{ },
+};
+MODULE_DEVICE_TABLE(pci, owl_pci_table);
+
+static struct pci_driver owl_driver = {
+	.name		= "owl-loader",
+	.id_table	= owl_pci_table,
+	.probe		= owl_probe,
+	.remove		= owl_remove,
+};
+module_pci_driver(owl_driver);
+MODULE_AUTHOR("Christian Lamparter <chunkeey@googlemail.com>");
+MODULE_DESCRIPTION("Initializes Atheros' Owl Emulation devices");
+MODULE_LICENSE("GPL v2");
diff --git a/target/linux/generic/patches-4.4/835-misc-owl_loader.patch b/target/linux/generic/patches-4.4/835-misc-owl_loader.patch
new file mode 100644
index 0000000000..bbf19c093d
--- /dev/null
+++ b/target/linux/generic/patches-4.4/835-misc-owl_loader.patch
@@ -0,0 +1,31 @@
+--- a/drivers/misc/Kconfig	2016-09-18 15:23:07.100190724 +0200
++++ b/drivers/misc/Kconfig	2016-09-18 15:26:56.130785350 +0200
+@@ -150,6 +150,18 @@ config SGI_IOC4
+ 	  If you have an SGI Altix with an IOC4-based card say Y.
+ 	  Otherwise say N.
+
++config OWL_LOADER
++	tristate "Owl loader for initializing Atheros PCI(e) Wifi chips"
++	depends on PCI
++	---help---
++	This kernel module helps to initialize certain Qualcomm
++	Atheros' PCI(e) Wifi chips, which have the init data
++	(which contains the PCI device ID for example) stored
++	together with the calibration data in the file system.
++
++	This is necessary for devices like the Cisco Meraki Z1, say M.
++	Otherwise say N.
++
+ config TIFM_CORE
+ 	tristate "TI Flash Media interface support"
+ 	depends on PCI
+--- a/drivers/misc/Makefile	2016-09-18 15:21:56.406675181 +0200
++++ b/drivers/misc/Makefile	2016-09-18 15:22:46.866805239 +0200
+@@ -15,6 +15,7 @@ obj-$(CONFIG_BMP085_SPI)	+= bmp085-spi.o
+ obj-$(CONFIG_DUMMY_IRQ)		+= dummy-irq.o
+ obj-$(CONFIG_ICS932S401)	+= ics932s401.o
+ obj-$(CONFIG_LKDTM)		+= lkdtm.o
++obj-$(CONFIG_OWL_LOADER)	+= owl-loader.o
+ obj-$(CONFIG_TIFM_CORE)       	+= tifm_core.o
+ obj-$(CONFIG_TIFM_7XX1)       	+= tifm_7xx1.o
+ obj-$(CONFIG_PHANTOM)		+= phantom.o