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 
25 struct 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 
ath9k_pci_fixup(struct pci_dev * pdev,const u16 * cal_data,size_t cal_len)36 static 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 
owl_rescan(struct pci_dev * pdev)113 static 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 
owl_fw_cb(const struct firmware * fw,void * context)126 static void owl_fw_cb(const struct firmware *fw, void *context)
127 {
128 	struct owl_ctx *ctx = (struct owl_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 
owl_get_eeprom_name(struct pci_dev * pdev)141 static 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 
owl_nvmem_work(struct work_struct * work)159 static 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 
owl_nvmem_probe(struct owl_ctx * ctx)177 static 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 
owl_probe(struct pci_dev * pdev,const struct pci_device_id * id)196 static 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 
owl_remove(struct pci_dev * pdev)235 static 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 
245 static const struct pci_device_id owl_pci_table[] = {
246 	{ PCI_VDEVICE(ATHEROS, 0xff1c) }, /* PCIe */
247 	{ PCI_VDEVICE(ATHEROS, 0xff1d) }, /* PCI */
248 	{ },
249 };
250 MODULE_DEVICE_TABLE(pci, owl_pci_table);
251 
252 static struct pci_driver owl_driver = {
253 	.name		= KBUILD_MODNAME,
254 	.id_table	= owl_pci_table,
255 	.probe		= owl_probe,
256 	.remove		= owl_remove,
257 };
258 module_pci_driver(owl_driver);
259 MODULE_AUTHOR("Christian Lamparter <chunkeey@gmail.com>");
260 MODULE_DESCRIPTION("External EEPROM data loader for Atheros AR500X to AR92XX");
261 MODULE_LICENSE("Dual BSD/GPL");
262