1 // SPDX-License-Identifier: GPL-2.0-only
2 /* drivers/net/ethernet/micrel/ks8851.c
3 *
4 * Copyright 2009 Simtec Electronics
5 * http://www.simtec.co.uk/
6 * Ben Dooks <ben@simtec.co.uk>
7 */
8
9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10
11 #include <linux/interrupt.h>
12 #include <linux/module.h>
13 #include <linux/kernel.h>
14 #include <linux/netdevice.h>
15 #include <linux/etherdevice.h>
16 #include <linux/ethtool.h>
17 #include <linux/iopoll.h>
18 #include <linux/mii.h>
19
20 #include <linux/platform_device.h>
21 #include <linux/of_net.h>
22
23 #include "ks8851.h"
24
25 static int msg_enable;
26
27 #define BE3 0x8000 /* Byte Enable 3 */
28 #define BE2 0x4000 /* Byte Enable 2 */
29 #define BE1 0x2000 /* Byte Enable 1 */
30 #define BE0 0x1000 /* Byte Enable 0 */
31
32 /**
33 * struct ks8851_net_par - KS8851 Parallel driver private data
34 * @ks8851: KS8851 driver common private data
35 * @lock: Lock to ensure that the device is not accessed when busy.
36 * @hw_addr : start address of data register.
37 * @hw_addr_cmd : start address of command register.
38 * @cmd_reg_cache : command register cached.
39 *
40 * The @lock ensures that the chip is protected when certain operations are
41 * in progress. When the read or write packet transfer is in progress, most
42 * of the chip registers are not accessible until the transfer is finished
43 * and the DMA has been de-asserted.
44 */
45 struct ks8851_net_par {
46 struct ks8851_net ks8851;
47 spinlock_t lock;
48 void __iomem *hw_addr;
49 void __iomem *hw_addr_cmd;
50 u16 cmd_reg_cache;
51 };
52
53 #define to_ks8851_par(ks) container_of((ks), struct ks8851_net_par, ks8851)
54
55 /**
56 * ks8851_lock_par - register access lock
57 * @ks: The chip state
58 * @flags: Spinlock flags
59 *
60 * Claim chip register access lock
61 */
ks8851_lock_par(struct ks8851_net * ks,unsigned long * flags)62 static void ks8851_lock_par(struct ks8851_net *ks, unsigned long *flags)
63 {
64 struct ks8851_net_par *ksp = to_ks8851_par(ks);
65
66 spin_lock_irqsave(&ksp->lock, *flags);
67 }
68
69 /**
70 * ks8851_unlock_par - register access unlock
71 * @ks: The chip state
72 * @flags: Spinlock flags
73 *
74 * Release chip register access lock
75 */
ks8851_unlock_par(struct ks8851_net * ks,unsigned long * flags)76 static void ks8851_unlock_par(struct ks8851_net *ks, unsigned long *flags)
77 {
78 struct ks8851_net_par *ksp = to_ks8851_par(ks);
79
80 spin_unlock_irqrestore(&ksp->lock, *flags);
81 }
82
83 /**
84 * ks_check_endian - Check whether endianness of the bus is correct
85 * @ks : The chip information
86 *
87 * The KS8851-16MLL EESK pin allows selecting the endianness of the 16bit
88 * bus. To maintain optimum performance, the bus endianness should be set
89 * such that it matches the endianness of the CPU.
90 */
ks_check_endian(struct ks8851_net * ks)91 static int ks_check_endian(struct ks8851_net *ks)
92 {
93 struct ks8851_net_par *ksp = to_ks8851_par(ks);
94 u16 cider;
95
96 /*
97 * Read CIDER register first, however read it the "wrong" way around.
98 * If the endian strap on the KS8851-16MLL in incorrect and the chip
99 * is operating in different endianness than the CPU, then the meaning
100 * of BE[3:0] byte-enable bits is also swapped such that:
101 * BE[3,2,1,0] becomes BE[1,0,3,2]
102 *
103 * Luckily for us, the byte-enable bits are the top four MSbits of
104 * the address register and the CIDER register is at offset 0xc0.
105 * Hence, by reading address 0xc0c0, which is not impacted by endian
106 * swapping, we assert either BE[3:2] or BE[1:0] while reading the
107 * CIDER register.
108 *
109 * If the bus configuration is correct, reading 0xc0c0 asserts
110 * BE[3:2] and this read returns 0x0000, because to read register
111 * with bottom two LSbits of address set to 0, BE[1:0] must be
112 * asserted.
113 *
114 * If the bus configuration is NOT correct, reading 0xc0c0 asserts
115 * BE[1:0] and this read returns non-zero 0x8872 value.
116 */
117 iowrite16(BE3 | BE2 | KS_CIDER, ksp->hw_addr_cmd);
118 cider = ioread16(ksp->hw_addr);
119 if (!cider)
120 return 0;
121
122 netdev_err(ks->netdev, "incorrect EESK endian strap setting\n");
123
124 return -EINVAL;
125 }
126
127 /**
128 * ks8851_wrreg16_par - write 16bit register value to chip
129 * @ks: The chip state
130 * @reg: The register address
131 * @val: The value to write
132 *
133 * Issue a write to put the value @val into the register specified in @reg.
134 */
ks8851_wrreg16_par(struct ks8851_net * ks,unsigned int reg,unsigned int val)135 static void ks8851_wrreg16_par(struct ks8851_net *ks, unsigned int reg,
136 unsigned int val)
137 {
138 struct ks8851_net_par *ksp = to_ks8851_par(ks);
139
140 ksp->cmd_reg_cache = (u16)reg | ((BE1 | BE0) << (reg & 0x02));
141 iowrite16(ksp->cmd_reg_cache, ksp->hw_addr_cmd);
142 iowrite16(val, ksp->hw_addr);
143 }
144
145 /**
146 * ks8851_rdreg16_par - read 16 bit register from chip
147 * @ks: The chip information
148 * @reg: The register address
149 *
150 * Read a 16bit register from the chip, returning the result
151 */
ks8851_rdreg16_par(struct ks8851_net * ks,unsigned int reg)152 static unsigned int ks8851_rdreg16_par(struct ks8851_net *ks, unsigned int reg)
153 {
154 struct ks8851_net_par *ksp = to_ks8851_par(ks);
155
156 ksp->cmd_reg_cache = (u16)reg | ((BE1 | BE0) << (reg & 0x02));
157 iowrite16(ksp->cmd_reg_cache, ksp->hw_addr_cmd);
158 return ioread16(ksp->hw_addr);
159 }
160
161 /**
162 * ks8851_rdfifo_par - read data from the receive fifo
163 * @ks: The device state.
164 * @buff: The buffer address
165 * @len: The length of the data to read
166 *
167 * Issue an RXQ FIFO read command and read the @len amount of data from
168 * the FIFO into the buffer specified by @buff.
169 */
ks8851_rdfifo_par(struct ks8851_net * ks,u8 * buff,unsigned int len)170 static void ks8851_rdfifo_par(struct ks8851_net *ks, u8 *buff, unsigned int len)
171 {
172 struct ks8851_net_par *ksp = to_ks8851_par(ks);
173
174 netif_dbg(ks, rx_status, ks->netdev,
175 "%s: %d@%p\n", __func__, len, buff);
176
177 ioread16_rep(ksp->hw_addr, (u16 *)buff + 1, len / 2);
178 }
179
180 /**
181 * ks8851_wrfifo_par - write packet to TX FIFO
182 * @ks: The device state.
183 * @txp: The sk_buff to transmit.
184 * @irq: IRQ on completion of the packet.
185 *
186 * Send the @txp to the chip. This means creating the relevant packet header
187 * specifying the length of the packet and the other information the chip
188 * needs, such as IRQ on completion. Send the header and the packet data to
189 * the device.
190 */
ks8851_wrfifo_par(struct ks8851_net * ks,struct sk_buff * txp,bool irq)191 static void ks8851_wrfifo_par(struct ks8851_net *ks, struct sk_buff *txp,
192 bool irq)
193 {
194 struct ks8851_net_par *ksp = to_ks8851_par(ks);
195 unsigned int len = ALIGN(txp->len, 4);
196 unsigned int fid = 0;
197
198 netif_dbg(ks, tx_queued, ks->netdev, "%s: skb %p, %d@%p, irq %d\n",
199 __func__, txp, txp->len, txp->data, irq);
200
201 fid = ks->fid++;
202 fid &= TXFR_TXFID_MASK;
203
204 if (irq)
205 fid |= TXFR_TXIC; /* irq on completion */
206
207 iowrite16(fid, ksp->hw_addr);
208 iowrite16(txp->len, ksp->hw_addr);
209
210 iowrite16_rep(ksp->hw_addr, txp->data, len / 2);
211 }
212
ks8851_rdreg16_par_txqcr(struct ks8851_net * ks)213 static unsigned int ks8851_rdreg16_par_txqcr(struct ks8851_net *ks)
214 {
215 return ks8851_rdreg16_par(ks, KS_TXQCR);
216 }
217
218 /**
219 * ks8851_start_xmit_par - transmit packet
220 * @skb: The buffer to transmit
221 * @dev: The device used to transmit the packet.
222 *
223 * Called by the network layer to transmit the @skb. Queue the packet for
224 * the device and schedule the necessary work to transmit the packet when
225 * it is free.
226 *
227 * We do this to firstly avoid sleeping with the network device locked,
228 * and secondly so we can round up more than one packet to transmit which
229 * means we can try and avoid generating too many transmit done interrupts.
230 */
ks8851_start_xmit_par(struct sk_buff * skb,struct net_device * dev)231 static netdev_tx_t ks8851_start_xmit_par(struct sk_buff *skb,
232 struct net_device *dev)
233 {
234 struct ks8851_net *ks = netdev_priv(dev);
235 netdev_tx_t ret = NETDEV_TX_OK;
236 unsigned long flags;
237 unsigned int txqcr;
238 u16 txmir;
239 int err;
240
241 netif_dbg(ks, tx_queued, ks->netdev,
242 "%s: skb %p, %d@%p\n", __func__, skb, skb->len, skb->data);
243
244 ks8851_lock_par(ks, &flags);
245
246 txmir = ks8851_rdreg16_par(ks, KS_TXMIR) & 0x1fff;
247
248 if (likely(txmir >= skb->len + 12)) {
249 ks8851_wrreg16_par(ks, KS_RXQCR, ks->rc_rxqcr | RXQCR_SDA);
250 ks8851_wrfifo_par(ks, skb, false);
251 ks8851_wrreg16_par(ks, KS_RXQCR, ks->rc_rxqcr);
252 ks8851_wrreg16_par(ks, KS_TXQCR, TXQCR_METFE);
253
254 err = readx_poll_timeout_atomic(ks8851_rdreg16_par_txqcr, ks,
255 txqcr, !(txqcr & TXQCR_METFE),
256 5, 1000000);
257 if (err)
258 ret = NETDEV_TX_BUSY;
259
260 ks8851_done_tx(ks, skb);
261 } else {
262 ret = NETDEV_TX_BUSY;
263 }
264
265 ks8851_unlock_par(ks, &flags);
266
267 return ret;
268 }
269
ks8851_probe_par(struct platform_device * pdev)270 static int ks8851_probe_par(struct platform_device *pdev)
271 {
272 struct device *dev = &pdev->dev;
273 struct ks8851_net_par *ksp;
274 struct net_device *netdev;
275 struct ks8851_net *ks;
276 int ret;
277
278 netdev = devm_alloc_etherdev(dev, sizeof(struct ks8851_net_par));
279 if (!netdev)
280 return -ENOMEM;
281
282 ks = netdev_priv(netdev);
283
284 ks->lock = ks8851_lock_par;
285 ks->unlock = ks8851_unlock_par;
286 ks->rdreg16 = ks8851_rdreg16_par;
287 ks->wrreg16 = ks8851_wrreg16_par;
288 ks->rdfifo = ks8851_rdfifo_par;
289 ks->wrfifo = ks8851_wrfifo_par;
290 ks->start_xmit = ks8851_start_xmit_par;
291
292 #define STD_IRQ (IRQ_LCI | /* Link Change */ \
293 IRQ_RXI | /* RX done */ \
294 IRQ_RXPSI) /* RX process stop */
295 ks->rc_ier = STD_IRQ;
296
297 ksp = to_ks8851_par(ks);
298 spin_lock_init(&ksp->lock);
299
300 ksp->hw_addr = devm_platform_ioremap_resource(pdev, 0);
301 if (IS_ERR(ksp->hw_addr))
302 return PTR_ERR(ksp->hw_addr);
303
304 ksp->hw_addr_cmd = devm_platform_ioremap_resource(pdev, 1);
305 if (IS_ERR(ksp->hw_addr_cmd))
306 return PTR_ERR(ksp->hw_addr_cmd);
307
308 ret = ks_check_endian(ks);
309 if (ret)
310 return ret;
311
312 netdev->irq = platform_get_irq(pdev, 0);
313 if (netdev->irq < 0)
314 return netdev->irq;
315
316 return ks8851_probe_common(netdev, dev, msg_enable);
317 }
318
ks8851_remove_par(struct platform_device * pdev)319 static int ks8851_remove_par(struct platform_device *pdev)
320 {
321 ks8851_remove_common(&pdev->dev);
322
323 return 0;
324 }
325
326 static const struct of_device_id ks8851_match_table[] = {
327 { .compatible = "micrel,ks8851-mll" },
328 { }
329 };
330 MODULE_DEVICE_TABLE(of, ks8851_match_table);
331
332 static struct platform_driver ks8851_driver = {
333 .driver = {
334 .name = "ks8851",
335 .of_match_table = ks8851_match_table,
336 .pm = &ks8851_pm_ops,
337 },
338 .probe = ks8851_probe_par,
339 .remove = ks8851_remove_par,
340 };
341 module_platform_driver(ks8851_driver);
342
343 MODULE_DESCRIPTION("KS8851 Network driver");
344 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
345 MODULE_LICENSE("GPL");
346
347 module_param_named(message, msg_enable, int, 0);
348 MODULE_PARM_DESC(message, "Message verbosity level (0=none, 31=all)");
349