1// SPDX-License-Identifier: ISC
2/* Initialize Owl Emulation Devices
3 *
4 * Copyright (C) 2016 Christian Lamparter <chunkeey@gmail.com>
5 * Copyright (C) 2016 Martin Blumenstingl <martin.blumenstingl@googlemail.com>
6 *
7 * Some devices (like the Cisco Meraki Z1 Cloud Managed Teleworker Gateway)
8 * need to be able to initialize the PCIe wifi device. Normally, this is done
9 * during the early stages as a pci quirk.
10 * However, this isn't possible for devices which have the init code for the
11 * Atheros chip stored on UBI Volume on NAND. Hence, this module can be used to
12 * initialize the chip when the user-space is ready to extract the init code.
13 */
14#include <linux/module.h>
15#include <linux/completion.h>
16#include <linux/etherdevice.h>
17#include <linux/firmware.h>
18#include <linux/pci.h>
19#include <linux/delay.h>
20#include <linux/platform_device.h>
21#include <linux/ath9k_platform.h>
22#include <linux/nvmem-consumer.h>
23#include <linux/workqueue.h>
24
25struct owl_ctx {
26	struct pci_dev *pdev;
27	struct completion eeprom_load;
28	struct work_struct work;
29	struct nvmem_cell *cell;
30};
31
32#define EEPROM_FILENAME_LEN 100
33
34#define AR5416_EEPROM_MAGIC 0xa55a
35
36static int ath9k_pci_fixup(struct pci_dev *pdev, const u16 *cal_data,
37			   size_t cal_len)
38{
39	void __iomem *mem;
40	const void *cal_end = (void *)cal_data + cal_len;
41	const struct {
42		u16 reg;
43		u16 low_val;
44		u16 high_val;
45	} __packed * data;
46	u16 cmd;
47	u32 bar0;
48	bool swap_needed = false;
49
50	/* also note that we are doing *u16 operations on the file */
51	if (cal_len > 4096 || cal_len < 0x200 || (cal_len & 1) == 1) {
52		dev_err(&pdev->dev, "eeprom has an invalid size.\n");
53		return -EINVAL;
54	}
55
56	if (*cal_data != AR5416_EEPROM_MAGIC) {
57		if (*cal_data != swab16(AR5416_EEPROM_MAGIC)) {
58			dev_err(&pdev->dev, "invalid calibration data\n");
59			return -EINVAL;
60		}
61
62		dev_dbg(&pdev->dev, "calibration data needs swapping\n");
63		swap_needed = true;
64	}
65
66	dev_info(&pdev->dev, "fixup device configuration\n");
67
68	mem = pcim_iomap(pdev, 0, 0);
69	if (!mem) {
70		dev_err(&pdev->dev, "ioremap error\n");
71		return -EINVAL;
72	}
73
74	pci_read_config_dword(pdev, PCI_BASE_ADDRESS_0, &bar0);
75	pci_write_config_dword(pdev, PCI_BASE_ADDRESS_0,
76			       pci_resource_start(pdev, 0));
77	pci_read_config_word(pdev, PCI_COMMAND, &cmd);
78	cmd |= PCI_COMMAND_MASTER | PCI_COMMAND_MEMORY;
79	pci_write_config_word(pdev, PCI_COMMAND, cmd);
80
81	/* set pointer to first reg address */
82	for (data = (const void *)(cal_data + 3);
83	     (const void *)data <= cal_end && data->reg != (u16)~0;
84	     data++) {
85		u32 val;
86		u16 reg;
87
88		reg = data->reg;
89		val = data->low_val;
90		val |= ((u32)data->high_val) << 16;
91
92		if (swap_needed) {
93			reg = swab16(reg);
94			val = swahb32(val);
95		}
96
97		iowrite32(val, mem + reg);
98		usleep_range(100, 120);
99	}
100
101	pci_read_config_word(pdev, PCI_COMMAND, &cmd);
102	cmd &= ~(PCI_COMMAND_MASTER | PCI_COMMAND_MEMORY);
103	pci_write_config_word(pdev, PCI_COMMAND, cmd);
104
105	pci_write_config_dword(pdev, PCI_BASE_ADDRESS_0, bar0);
106	pcim_iounmap(pdev, mem);
107
108	pci_disable_device(pdev);
109
110	return 0;
111}
112
113static void owl_rescan(struct pci_dev *pdev)
114{
115	struct pci_bus *bus = pdev->bus;
116
117	pci_lock_rescan_remove();
118	pci_stop_and_remove_bus_device(pdev);
119	/* the device should come back with the proper
120	 * ProductId. But we have to initiate a rescan.
121	 */
122	pci_rescan_bus(bus);
123	pci_unlock_rescan_remove();
124}
125
126static void owl_fw_cb(const struct firmware *fw, void *context)
127{
128	struct owl_ctx *ctx = context;
129
130	complete(&ctx->eeprom_load);
131
132	if (fw) {
133		ath9k_pci_fixup(ctx->pdev, (const u16 *)fw->data, fw->size);
134		owl_rescan(ctx->pdev);
135	} else {
136		dev_err(&ctx->pdev->dev, "no eeprom data received.\n");
137	}
138	release_firmware(fw);
139}
140
141static const char *owl_get_eeprom_name(struct pci_dev *pdev)
142{
143	struct device *dev = &pdev->dev;
144	char *eeprom_name;
145
146	dev_dbg(dev, "using auto-generated eeprom filename\n");
147
148	eeprom_name = devm_kzalloc(dev, EEPROM_FILENAME_LEN, GFP_KERNEL);
149	if (!eeprom_name)
150		return NULL;
151
152	/* this should match the pattern used in ath9k/init.c */
153	scnprintf(eeprom_name, EEPROM_FILENAME_LEN, "ath9k-eeprom-pci-%s.bin",
154		  dev_name(dev));
155
156	return eeprom_name;
157}
158
159static void owl_nvmem_work(struct work_struct *work)
160{
161	struct owl_ctx *ctx = container_of(work, struct owl_ctx, work);
162	void *buf;
163	size_t len;
164
165	complete(&ctx->eeprom_load);
166
167	buf = nvmem_cell_read(ctx->cell, &len);
168	if (!IS_ERR(buf)) {
169		ath9k_pci_fixup(ctx->pdev, buf, len);
170		kfree(buf);
171		owl_rescan(ctx->pdev);
172	} else {
173		dev_err(&ctx->pdev->dev, "no nvmem data received.\n");
174	}
175}
176
177static int owl_nvmem_probe(struct owl_ctx *ctx)
178{
179	int err;
180
181	ctx->cell = devm_nvmem_cell_get(&ctx->pdev->dev, "calibration");
182	if (IS_ERR(ctx->cell)) {
183		err = PTR_ERR(ctx->cell);
184		if (err == -ENOENT || err == -EOPNOTSUPP)
185			return 1; /* not present, try firmware_request */
186
187		return err;
188	}
189
190	INIT_WORK(&ctx->work, owl_nvmem_work);
191	schedule_work(&ctx->work);
192
193	return 0;
194}
195
196static int owl_probe(struct pci_dev *pdev,
197		     const struct pci_device_id *id)
198{
199	struct owl_ctx *ctx;
200	const char *eeprom_name;
201	int err = 0;
202
203	if (pcim_enable_device(pdev))
204		return -EIO;
205
206	pcim_pin_device(pdev);
207
208	ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
209	if (!ctx)
210		return -ENOMEM;
211
212	init_completion(&ctx->eeprom_load);
213	ctx->pdev = pdev;
214
215	pci_set_drvdata(pdev, ctx);
216
217	err = owl_nvmem_probe(ctx);
218	if (err <= 0)
219		return err;
220
221	eeprom_name = owl_get_eeprom_name(pdev);
222	if (!eeprom_name) {
223		dev_err(&pdev->dev, "no eeprom filename found.\n");
224		return -ENODEV;
225	}
226
227	err = request_firmware_nowait(THIS_MODULE, true, eeprom_name,
228				      &pdev->dev, GFP_KERNEL, ctx, owl_fw_cb);
229	if (err)
230		dev_err(&pdev->dev, "failed to request caldata (%d).\n", err);
231
232	return err;
233}
234
235static void owl_remove(struct pci_dev *pdev)
236{
237	struct owl_ctx *ctx = pci_get_drvdata(pdev);
238
239	if (ctx) {
240		wait_for_completion(&ctx->eeprom_load);
241		pci_set_drvdata(pdev, NULL);
242	}
243}
244
245static const struct pci_device_id owl_pci_table[] = {
246	{ PCI_VDEVICE(ATHEROS, 0xff1c) }, /* PCIe */
247	{ PCI_VDEVICE(ATHEROS, 0xff1d) }, /* PCI */
248	{ },
249};
250MODULE_DEVICE_TABLE(pci, owl_pci_table);
251
252static struct pci_driver owl_driver = {
253	.name		= KBUILD_MODNAME,
254	.id_table	= owl_pci_table,
255	.probe		= owl_probe,
256	.remove		= owl_remove,
257};
258module_pci_driver(owl_driver);
259MODULE_AUTHOR("Christian Lamparter <chunkeey@gmail.com>");
260MODULE_DESCRIPTION("External EEPROM data loader for Atheros AR500X to AR92XX");
261MODULE_LICENSE("Dual BSD/GPL");
262