summaryrefslogtreecommitdiffstats
path: root/drivers/net/ethernet/micrel/ks8851_par.c
blob: 381b9cd285ebd0bd3f5cf1e568e9b23cf0ba9c85 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
// SPDX-License-Identifier: GPL-2.0-only
/* drivers/net/ethernet/micrel/ks8851.c
 *
 * Copyright 2009 Simtec Electronics
 *	http://www.simtec.co.uk/
 *	Ben Dooks <ben@simtec.co.uk>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/ethtool.h>
#include <linux/iopoll.h>
#include <linux/mii.h>

#include <linux/platform_device.h>
#include <linux/of_net.h>

#include "ks8851.h"

static int msg_enable;

#define BE3             0x8000      /* Byte Enable 3 */
#define BE2             0x4000      /* Byte Enable 2 */
#define BE1             0x2000      /* Byte Enable 1 */
#define BE0             0x1000      /* Byte Enable 0 */

/**
 * struct ks8851_net_par - KS8851 Parallel driver private data
 * @ks8851: KS8851 driver common private data
 * @lock: Lock to ensure that the device is not accessed when busy.
 * @hw_addr	: start address of data register.
 * @hw_addr_cmd	: start address of command register.
 * @cmd_reg_cache	: command register cached.
 *
 * The @lock ensures that the chip is protected when certain operations are
 * in progress. When the read or write packet transfer is in progress, most
 * of the chip registers are not accessible until the transfer is finished
 * and the DMA has been de-asserted.
 */
struct ks8851_net_par {
	struct ks8851_net	ks8851;
	spinlock_t		lock;
	void __iomem		*hw_addr;
	void __iomem		*hw_addr_cmd;
	u16			cmd_reg_cache;
};

#define to_ks8851_par(ks) container_of((ks), struct ks8851_net_par, ks8851)

/**
 * ks8851_lock_par - register access lock
 * @ks: The chip state
 * @flags: Spinlock flags
 *
 * Claim chip register access lock
 */
static void ks8851_lock_par(struct ks8851_net *ks, unsigned long *flags)
{
	struct ks8851_net_par *ksp = to_ks8851_par(ks);

	spin_lock_irqsave(&ksp->lock, *flags);
}

/**
 * ks8851_unlock_par - register access unlock
 * @ks: The chip state
 * @flags: Spinlock flags
 *
 * Release chip register access lock
 */
static void ks8851_unlock_par(struct ks8851_net *ks, unsigned long *flags)
{
	struct ks8851_net_par *ksp = to_ks8851_par(ks);

	spin_unlock_irqrestore(&ksp->lock, *flags);
}

/**
 * ks_check_endian - Check whether endianness of the bus is correct
 * @ks	  : The chip information
 *
 * The KS8851-16MLL EESK pin allows selecting the endianness of the 16bit
 * bus. To maintain optimum performance, the bus endianness should be set
 * such that it matches the endianness of the CPU.
 */
static int ks_check_endian(struct ks8851_net *ks)
{
	struct ks8851_net_par *ksp = to_ks8851_par(ks);
	u16 cider;

	/*
	 * Read CIDER register first, however read it the "wrong" way around.
	 * If the endian strap on the KS8851-16MLL in incorrect and the chip
	 * is operating in different endianness than the CPU, then the meaning
	 * of BE[3:0] byte-enable bits is also swapped such that:
	 *    BE[3,2,1,0] becomes BE[1,0,3,2]
	 *
	 * Luckily for us, the byte-enable bits are the top four MSbits of
	 * the address register and the CIDER register is at offset 0xc0.
	 * Hence, by reading address 0xc0c0, which is not impacted by endian
	 * swapping, we assert either BE[3:2] or BE[1:0] while reading the
	 * CIDER register.
	 *
	 * If the bus configuration is correct, reading 0xc0c0 asserts
	 * BE[3:2] and this read returns 0x0000, because to read register
	 * with bottom two LSbits of address set to 0, BE[1:0] must be
	 * asserted.
	 *
	 * If the bus configuration is NOT correct, reading 0xc0c0 asserts
	 * BE[1:0] and this read returns non-zero 0x8872 value.
	 */
	iowrite16(BE3 | BE2 | KS_CIDER, ksp->hw_addr_cmd);
	cider = ioread16(ksp->hw_addr);
	if (!cider)
		return 0;

	netdev_err(ks->netdev, "incorrect EESK endian strap setting\n");

	return -EINVAL;
}

/**
 * ks8851_wrreg16_par - write 16bit register value to chip
 * @ks: The chip state
 * @reg: The register address
 * @val: The value to write
 *
 * Issue a write to put the value @val into the register specified in @reg.
 */
static void ks8851_wrreg16_par(struct ks8851_net *ks, unsigned int reg,
			       unsigned int val)
{
	struct ks8851_net_par *ksp = to_ks8851_par(ks);

	ksp->cmd_reg_cache = (u16)reg | ((BE1 | BE0) << (reg & 0x02));
	iowrite16(ksp->cmd_reg_cache, ksp->hw_addr_cmd);
	iowrite16(val, ksp->hw_addr);
}

/**
 * ks8851_rdreg16_par - read 16 bit register from chip
 * @ks: The chip information
 * @reg: The register address
 *
 * Read a 16bit register from the chip, returning the result
 */
static unsigned int ks8851_rdreg16_par(struct ks8851_net *ks, unsigned int reg)
{
	struct ks8851_net_par *ksp = to_ks8851_par(ks);

	ksp->cmd_reg_cache = (u16)reg | ((BE1 | BE0) << (reg & 0x02));
	iowrite16(ksp->cmd_reg_cache, ksp->hw_addr_cmd);
	return ioread16(ksp->hw_addr);
}

/**
 * ks8851_rdfifo_par - read data from the receive fifo
 * @ks: The device state.
 * @buff: The buffer address
 * @len: The length of the data to read
 *
 * Issue an RXQ FIFO read command and read the @len amount of data from
 * the FIFO into the buffer specified by @buff.
 */
static void ks8851_rdfifo_par(struct ks8851_net *ks, u8 *buff, unsigned int len)
{
	struct ks8851_net_par *ksp = to_ks8851_par(ks);

	netif_dbg(ks, rx_status, ks->netdev,
		  "%s: %d@%p\n", __func__, len, buff);

	ioread16_rep(ksp->hw_addr, (u16 *)buff + 1, len / 2);
}

/**
 * ks8851_wrfifo_par - write packet to TX FIFO
 * @ks: The device state.
 * @txp: The sk_buff to transmit.
 * @irq: IRQ on completion of the packet.
 *
 * Send the @txp to the chip. This means creating the relevant packet header
 * specifying the length of the packet and the other information the chip
 * needs, such as IRQ on completion. Send the header and the packet data to
 * the device.
 */
static void ks8851_wrfifo_par(struct ks8851_net *ks, struct sk_buff *txp,
			      bool irq)
{
	struct ks8851_net_par *ksp = to_ks8851_par(ks);
	unsigned int len = ALIGN(txp->len, 4);
	unsigned int fid = 0;

	netif_dbg(ks, tx_queued, ks->netdev, "%s: skb %p, %d@%p, irq %d\n",
		  __func__, txp, txp->len, txp->data, irq);

	fid = ks->fid++;
	fid &= TXFR_TXFID_MASK;

	if (irq)
		fid |= TXFR_TXIC;	/* irq on completion */

	iowrite16(fid, ksp->hw_addr);
	iowrite16(txp->len, ksp->hw_addr);

	iowrite16_rep(ksp->hw_addr, txp->data, len / 2);
}

static unsigned int ks8851_rdreg16_par_txqcr(struct ks8851_net *ks)
{
	return ks8851_rdreg16_par(ks, KS_TXQCR);
}

/**
 * ks8851_start_xmit_par - transmit packet
 * @skb: The buffer to transmit
 * @dev: The device used to transmit the packet.
 *
 * Called by the network layer to transmit the @skb. Queue the packet for
 * the device and schedule the necessary work to transmit the packet when
 * it is free.
 *
 * We do this to firstly avoid sleeping with the network device locked,
 * and secondly so we can round up more than one packet to transmit which
 * means we can try and avoid generating too many transmit done interrupts.
 */
static netdev_tx_t ks8851_start_xmit_par(struct sk_buff *skb,
					 struct net_device *dev)
{
	struct ks8851_net *ks = netdev_priv(dev);
	netdev_tx_t ret = NETDEV_TX_OK;
	unsigned long flags;
	unsigned int txqcr;
	u16 txmir;
	int err;

	netif_dbg(ks, tx_queued, ks->netdev,
		  "%s: skb %p, %d@%p\n", __func__, skb, skb->len, skb->data);

	ks8851_lock_par(ks, &flags);

	txmir = ks8851_rdreg16_par(ks, KS_TXMIR) & 0x1fff;

	if (likely(txmir >= skb->len + 12)) {
		ks8851_wrreg16_par(ks, KS_RXQCR, ks->rc_rxqcr | RXQCR_SDA);
		ks8851_wrfifo_par(ks, skb, false);
		ks8851_wrreg16_par(ks, KS_RXQCR, ks->rc_rxqcr);
		ks8851_wrreg16_par(ks, KS_TXQCR, TXQCR_METFE);

		err = readx_poll_timeout_atomic(ks8851_rdreg16_par_txqcr, ks,
						txqcr, !(txqcr & TXQCR_METFE),
						5, 1000000);
		if (err)
			ret = NETDEV_TX_BUSY;

		ks8851_done_tx(ks, skb);
	} else {
		ret = NETDEV_TX_BUSY;
	}

	ks8851_unlock_par(ks, &flags);

	return ret;
}

static int ks8851_probe_par(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct ks8851_net_par *ksp;
	struct net_device *netdev;
	struct ks8851_net *ks;
	int ret;

	netdev = devm_alloc_etherdev(dev, sizeof(struct ks8851_net_par));
	if (!netdev)
		return -ENOMEM;

	ks = netdev_priv(netdev);

	ks->lock = ks8851_lock_par;
	ks->unlock = ks8851_unlock_par;
	ks->rdreg16 = ks8851_rdreg16_par;
	ks->wrreg16 = ks8851_wrreg16_par;
	ks->rdfifo = ks8851_rdfifo_par;
	ks->wrfifo = ks8851_wrfifo_par;
	ks->start_xmit = ks8851_start_xmit_par;

#define STD_IRQ (IRQ_LCI |	/* Link Change */	\
		 IRQ_RXI |	/* RX done */		\
		 IRQ_RXPSI)	/* RX process stop */
	ks->rc_ier = STD_IRQ;

	ksp = to_ks8851_par(ks);
	spin_lock_init(&ksp->lock);

	ksp->hw_addr = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(ksp->hw_addr))
		return PTR_ERR(ksp->hw_addr);

	ksp->hw_addr_cmd = devm_platform_ioremap_resource(pdev, 1);
	if (IS_ERR(ksp->hw_addr_cmd))
		return PTR_ERR(ksp->hw_addr_cmd);

	ret = ks_check_endian(ks);
	if (ret)
		return ret;

	netdev->irq = platform_get_irq(pdev, 0);
	if (netdev->irq < 0)
		return netdev->irq;

	return ks8851_probe_common(netdev, dev, msg_enable);
}

static void ks8851_remove_par(struct platform_device *pdev)
{
	ks8851_remove_common(&pdev->dev);
}

static const struct of_device_id ks8851_match_table[] = {
	{ .compatible = "micrel,ks8851-mll" },
	{ }
};
MODULE_DEVICE_TABLE(of, ks8851_match_table);

static struct platform_driver ks8851_driver = {
	.driver = {
		.name = "ks8851",
		.of_match_table = ks8851_match_table,
		.pm = &ks8851_pm_ops,
	},
	.probe = ks8851_probe_par,
	.remove_new = ks8851_remove_par,
};
module_platform_driver(ks8851_driver);

MODULE_DESCRIPTION("KS8851 Network driver");
MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
MODULE_LICENSE("GPL");

module_param_named(message, msg_enable, int, 0);
MODULE_PARM_DESC(message, "Message verbosity level (0=none, 31=all)");