1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2003-2015 Broadcom Corporation
4 * All Rights Reserved
5 */
6#include <linux/acpi.h>
7#include <linux/clk.h>
8#include <linux/kernel.h>
9#include <linux/module.h>
10#include <linux/platform_device.h>
11#include <linux/spi/spi.h>
12#include <linux/interrupt.h>
13
14/* SPI Configuration Register */
15#define XLP_SPI_CONFIG			0x00
16#define XLP_SPI_CPHA			BIT(0)
17#define XLP_SPI_CPOL			BIT(1)
18#define XLP_SPI_CS_POL			BIT(2)
19#define XLP_SPI_TXMISO_EN		BIT(3)
20#define XLP_SPI_TXMOSI_EN		BIT(4)
21#define XLP_SPI_RXMISO_EN		BIT(5)
22#define XLP_SPI_CS_LSBFE		BIT(10)
23#define XLP_SPI_RXCAP_EN		BIT(11)
24
25/* SPI Frequency Divider Register */
26#define XLP_SPI_FDIV			0x04
27
28/* SPI Command Register */
29#define XLP_SPI_CMD			0x08
30#define XLP_SPI_CMD_IDLE_MASK		0x0
31#define XLP_SPI_CMD_TX_MASK		0x1
32#define XLP_SPI_CMD_RX_MASK		0x2
33#define XLP_SPI_CMD_TXRX_MASK		0x3
34#define XLP_SPI_CMD_CONT		BIT(4)
35#define XLP_SPI_XFR_BITCNT_SHIFT	16
36
37/* SPI Status Register */
38#define XLP_SPI_STATUS			0x0c
39#define XLP_SPI_XFR_PENDING		BIT(0)
40#define XLP_SPI_XFR_DONE		BIT(1)
41#define XLP_SPI_TX_INT			BIT(2)
42#define XLP_SPI_RX_INT			BIT(3)
43#define XLP_SPI_TX_UF			BIT(4)
44#define XLP_SPI_RX_OF			BIT(5)
45#define XLP_SPI_STAT_MASK		0x3f
46
47/* SPI Interrupt Enable Register */
48#define XLP_SPI_INTR_EN			0x10
49#define XLP_SPI_INTR_DONE		BIT(0)
50#define XLP_SPI_INTR_TXTH		BIT(1)
51#define XLP_SPI_INTR_RXTH		BIT(2)
52#define XLP_SPI_INTR_TXUF		BIT(3)
53#define XLP_SPI_INTR_RXOF		BIT(4)
54
55/* SPI FIFO Threshold Register */
56#define XLP_SPI_FIFO_THRESH		0x14
57
58/* SPI FIFO Word Count Register */
59#define XLP_SPI_FIFO_WCNT		0x18
60#define XLP_SPI_RXFIFO_WCNT_MASK	0xf
61#define XLP_SPI_TXFIFO_WCNT_MASK	0xf0
62#define XLP_SPI_TXFIFO_WCNT_SHIFT	4
63
64/* SPI Transmit Data FIFO Register */
65#define XLP_SPI_TXDATA_FIFO		0x1c
66
67/* SPI Receive Data FIFO Register */
68#define XLP_SPI_RXDATA_FIFO		0x20
69
70/* SPI System Control Register */
71#define XLP_SPI_SYSCTRL			0x100
72#define XLP_SPI_SYS_RESET		BIT(0)
73#define XLP_SPI_SYS_CLKDIS		BIT(1)
74#define XLP_SPI_SYS_PMEN		BIT(8)
75
76#define SPI_CS_OFFSET			0x40
77#define XLP_SPI_TXRXTH			0x80
78#define XLP_SPI_FIFO_SIZE		8
79#define XLP_SPI_MAX_CS			4
80#define XLP_SPI_DEFAULT_FREQ		133333333
81#define XLP_SPI_FDIV_MIN		4
82#define XLP_SPI_FDIV_MAX		65535
83/*
84 * SPI can transfer only 28 bytes properly at a time. So split the
85 * transfer into 28 bytes size.
86 */
87#define XLP_SPI_XFER_SIZE		28
88
89struct xlp_spi_priv {
90	struct device		dev;		/* device structure */
91	void __iomem		*base;		/* spi registers base address */
92	const u8		*tx_buf;	/* tx data buffer */
93	u8			*rx_buf;	/* rx data buffer */
94	int			tx_len;		/* tx xfer length */
95	int			rx_len;		/* rx xfer length */
96	int			txerrors;	/* TXFIFO underflow count */
97	int			rxerrors;	/* RXFIFO overflow count */
98	int			cs;		/* target device chip select */
99	u32			spi_clk;	/* spi clock frequency */
100	bool			cmd_cont;	/* cs active */
101	struct completion	done;		/* completion notification */
102};
103
104static inline u32 xlp_spi_reg_read(struct xlp_spi_priv *priv,
105				int cs, int regoff)
106{
107	return readl(priv->base + regoff + cs * SPI_CS_OFFSET);
108}
109
110static inline void xlp_spi_reg_write(struct xlp_spi_priv *priv, int cs,
111				int regoff, u32 val)
112{
113	writel(val, priv->base + regoff + cs * SPI_CS_OFFSET);
114}
115
116static inline void xlp_spi_sysctl_write(struct xlp_spi_priv *priv,
117				int regoff, u32 val)
118{
119	writel(val, priv->base + regoff);
120}
121
122/*
123 * Setup global SPI_SYSCTRL register for all SPI channels.
124 */
125static void xlp_spi_sysctl_setup(struct xlp_spi_priv *xspi)
126{
127	int cs;
128
129	for (cs = 0; cs < XLP_SPI_MAX_CS; cs++)
130		xlp_spi_sysctl_write(xspi, XLP_SPI_SYSCTRL,
131				XLP_SPI_SYS_RESET << cs);
132	xlp_spi_sysctl_write(xspi, XLP_SPI_SYSCTRL, XLP_SPI_SYS_PMEN);
133}
134
135static int xlp_spi_setup(struct spi_device *spi)
136{
137	struct xlp_spi_priv *xspi;
138	u32 fdiv, cfg;
139	int cs;
140
141	xspi = spi_controller_get_devdata(spi->controller);
142	cs = spi_get_chipselect(spi, 0);
143	/*
144	 * The value of fdiv must be between 4 and 65535.
145	 */
146	fdiv = DIV_ROUND_UP(xspi->spi_clk, spi->max_speed_hz);
147	if (fdiv > XLP_SPI_FDIV_MAX)
148		fdiv = XLP_SPI_FDIV_MAX;
149	else if (fdiv < XLP_SPI_FDIV_MIN)
150		fdiv = XLP_SPI_FDIV_MIN;
151
152	xlp_spi_reg_write(xspi, cs, XLP_SPI_FDIV, fdiv);
153	xlp_spi_reg_write(xspi, cs, XLP_SPI_FIFO_THRESH, XLP_SPI_TXRXTH);
154	cfg = xlp_spi_reg_read(xspi, cs, XLP_SPI_CONFIG);
155	if (spi->mode & SPI_CPHA)
156		cfg |= XLP_SPI_CPHA;
157	else
158		cfg &= ~XLP_SPI_CPHA;
159	if (spi->mode & SPI_CPOL)
160		cfg |= XLP_SPI_CPOL;
161	else
162		cfg &= ~XLP_SPI_CPOL;
163	if (!(spi->mode & SPI_CS_HIGH))
164		cfg |= XLP_SPI_CS_POL;
165	else
166		cfg &= ~XLP_SPI_CS_POL;
167	if (spi->mode & SPI_LSB_FIRST)
168		cfg |= XLP_SPI_CS_LSBFE;
169	else
170		cfg &= ~XLP_SPI_CS_LSBFE;
171
172	cfg |= XLP_SPI_TXMOSI_EN | XLP_SPI_RXMISO_EN;
173	if (fdiv == 4)
174		cfg |= XLP_SPI_RXCAP_EN;
175	xlp_spi_reg_write(xspi, cs, XLP_SPI_CONFIG, cfg);
176
177	return 0;
178}
179
180static void xlp_spi_read_rxfifo(struct xlp_spi_priv *xspi)
181{
182	u32 rx_data, rxfifo_cnt;
183	int i, j, nbytes;
184
185	rxfifo_cnt = xlp_spi_reg_read(xspi, xspi->cs, XLP_SPI_FIFO_WCNT);
186	rxfifo_cnt &= XLP_SPI_RXFIFO_WCNT_MASK;
187	while (rxfifo_cnt) {
188		rx_data = xlp_spi_reg_read(xspi, xspi->cs, XLP_SPI_RXDATA_FIFO);
189		j = 0;
190		nbytes = min(xspi->rx_len, 4);
191		for (i = nbytes - 1; i >= 0; i--, j++)
192			xspi->rx_buf[i] = (rx_data >> (j * 8)) & 0xff;
193
194		xspi->rx_len -= nbytes;
195		xspi->rx_buf += nbytes;
196		rxfifo_cnt--;
197	}
198}
199
200static void xlp_spi_fill_txfifo(struct xlp_spi_priv *xspi)
201{
202	u32 tx_data, txfifo_cnt;
203	int i, j, nbytes;
204
205	txfifo_cnt = xlp_spi_reg_read(xspi, xspi->cs, XLP_SPI_FIFO_WCNT);
206	txfifo_cnt &= XLP_SPI_TXFIFO_WCNT_MASK;
207	txfifo_cnt >>= XLP_SPI_TXFIFO_WCNT_SHIFT;
208	while (xspi->tx_len && (txfifo_cnt < XLP_SPI_FIFO_SIZE)) {
209		j = 0;
210		tx_data = 0;
211		nbytes = min(xspi->tx_len, 4);
212		for (i = nbytes - 1; i >= 0; i--, j++)
213			tx_data |= xspi->tx_buf[i] << (j * 8);
214
215		xlp_spi_reg_write(xspi, xspi->cs, XLP_SPI_TXDATA_FIFO, tx_data);
216		xspi->tx_len -= nbytes;
217		xspi->tx_buf += nbytes;
218		txfifo_cnt++;
219	}
220}
221
222static irqreturn_t xlp_spi_interrupt(int irq, void *dev_id)
223{
224	struct xlp_spi_priv *xspi = dev_id;
225	u32 stat;
226
227	stat = xlp_spi_reg_read(xspi, xspi->cs, XLP_SPI_STATUS) &
228		XLP_SPI_STAT_MASK;
229	if (!stat)
230		return IRQ_NONE;
231
232	if (stat & XLP_SPI_TX_INT) {
233		if (xspi->tx_len)
234			xlp_spi_fill_txfifo(xspi);
235		if (stat & XLP_SPI_TX_UF)
236			xspi->txerrors++;
237	}
238
239	if (stat & XLP_SPI_RX_INT) {
240		if (xspi->rx_len)
241			xlp_spi_read_rxfifo(xspi);
242		if (stat & XLP_SPI_RX_OF)
243			xspi->rxerrors++;
244	}
245
246	/* write status back to clear interrupts */
247	xlp_spi_reg_write(xspi, xspi->cs, XLP_SPI_STATUS, stat);
248	if (stat & XLP_SPI_XFR_DONE)
249		complete(&xspi->done);
250
251	return IRQ_HANDLED;
252}
253
254static void xlp_spi_send_cmd(struct xlp_spi_priv *xspi, int xfer_len,
255			int cmd_cont)
256{
257	u32 cmd = 0;
258
259	if (xspi->tx_buf)
260		cmd |= XLP_SPI_CMD_TX_MASK;
261	if (xspi->rx_buf)
262		cmd |= XLP_SPI_CMD_RX_MASK;
263	if (cmd_cont)
264		cmd |= XLP_SPI_CMD_CONT;
265	cmd |= ((xfer_len * 8 - 1) << XLP_SPI_XFR_BITCNT_SHIFT);
266	xlp_spi_reg_write(xspi, xspi->cs, XLP_SPI_CMD, cmd);
267}
268
269static int xlp_spi_xfer_block(struct  xlp_spi_priv *xs,
270		const unsigned char *tx_buf,
271		unsigned char *rx_buf, int xfer_len, int cmd_cont)
272{
273	int timeout;
274	u32 intr_mask = 0;
275
276	xs->tx_buf = tx_buf;
277	xs->rx_buf = rx_buf;
278	xs->tx_len = (xs->tx_buf == NULL) ? 0 : xfer_len;
279	xs->rx_len = (xs->rx_buf == NULL) ? 0 : xfer_len;
280	xs->txerrors = xs->rxerrors = 0;
281
282	/* fill TXDATA_FIFO, then send the CMD */
283	if (xs->tx_len)
284		xlp_spi_fill_txfifo(xs);
285
286	xlp_spi_send_cmd(xs, xfer_len, cmd_cont);
287
288	/*
289	 * We are getting some spurious tx interrupts, so avoid enabling
290	 * tx interrupts when only rx is in process.
291	 * Enable all the interrupts in tx case.
292	 */
293	if (xs->tx_len)
294		intr_mask |= XLP_SPI_INTR_TXTH | XLP_SPI_INTR_TXUF |
295				XLP_SPI_INTR_RXTH | XLP_SPI_INTR_RXOF;
296	else
297		intr_mask |= XLP_SPI_INTR_RXTH | XLP_SPI_INTR_RXOF;
298
299	intr_mask |= XLP_SPI_INTR_DONE;
300	xlp_spi_reg_write(xs, xs->cs, XLP_SPI_INTR_EN, intr_mask);
301
302	timeout = wait_for_completion_timeout(&xs->done,
303				msecs_to_jiffies(1000));
304	/* Disable interrupts */
305	xlp_spi_reg_write(xs, xs->cs, XLP_SPI_INTR_EN, 0x0);
306	if (!timeout) {
307		dev_err(&xs->dev, "xfer timedout!\n");
308		goto out;
309	}
310	if (xs->txerrors || xs->rxerrors)
311		dev_err(&xs->dev, "Over/Underflow rx %d tx %d xfer %d!\n",
312				xs->rxerrors, xs->txerrors, xfer_len);
313
314	return xfer_len;
315out:
316	return -ETIMEDOUT;
317}
318
319static int xlp_spi_txrx_bufs(struct xlp_spi_priv *xs, struct spi_transfer *t)
320{
321	int bytesleft, sz;
322	unsigned char *rx_buf;
323	const unsigned char *tx_buf;
324
325	tx_buf = t->tx_buf;
326	rx_buf = t->rx_buf;
327	bytesleft = t->len;
328	while (bytesleft) {
329		if (bytesleft > XLP_SPI_XFER_SIZE)
330			sz = xlp_spi_xfer_block(xs, tx_buf, rx_buf,
331					XLP_SPI_XFER_SIZE, 1);
332		else
333			sz = xlp_spi_xfer_block(xs, tx_buf, rx_buf,
334					bytesleft, xs->cmd_cont);
335		if (sz < 0)
336			return sz;
337		bytesleft -= sz;
338		if (tx_buf)
339			tx_buf += sz;
340		if (rx_buf)
341			rx_buf += sz;
342	}
343	return bytesleft;
344}
345
346static int xlp_spi_transfer_one(struct spi_controller *host,
347					struct spi_device *spi,
348					struct spi_transfer *t)
349{
350	struct xlp_spi_priv *xspi = spi_controller_get_devdata(host);
351	int ret = 0;
352
353	xspi->cs = spi_get_chipselect(spi, 0);
354	xspi->dev = spi->dev;
355
356	if (spi_transfer_is_last(host, t))
357		xspi->cmd_cont = 0;
358	else
359		xspi->cmd_cont = 1;
360
361	if (xlp_spi_txrx_bufs(xspi, t))
362		ret = -EIO;
363
364	spi_finalize_current_transfer(host);
365	return ret;
366}
367
368static int xlp_spi_probe(struct platform_device *pdev)
369{
370	struct spi_controller *host;
371	struct xlp_spi_priv *xspi;
372	struct clk *clk;
373	int irq, err;
374
375	xspi = devm_kzalloc(&pdev->dev, sizeof(*xspi), GFP_KERNEL);
376	if (!xspi)
377		return -ENOMEM;
378
379	xspi->base = devm_platform_ioremap_resource(pdev, 0);
380	if (IS_ERR(xspi->base))
381		return PTR_ERR(xspi->base);
382
383	irq = platform_get_irq(pdev, 0);
384	if (irq < 0)
385		return irq;
386	err = devm_request_irq(&pdev->dev, irq, xlp_spi_interrupt, 0,
387			pdev->name, xspi);
388	if (err) {
389		dev_err(&pdev->dev, "unable to request irq %d\n", irq);
390		return err;
391	}
392
393	clk = devm_clk_get(&pdev->dev, NULL);
394	if (IS_ERR(clk)) {
395		dev_err(&pdev->dev, "could not get spi clock\n");
396		return PTR_ERR(clk);
397	}
398
399	xspi->spi_clk = clk_get_rate(clk);
400
401	host = spi_alloc_host(&pdev->dev, 0);
402	if (!host) {
403		dev_err(&pdev->dev, "could not alloc host\n");
404		return -ENOMEM;
405	}
406
407	host->bus_num = 0;
408	host->num_chipselect = XLP_SPI_MAX_CS;
409	host->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
410	host->setup = xlp_spi_setup;
411	host->transfer_one = xlp_spi_transfer_one;
412	host->dev.of_node = pdev->dev.of_node;
413
414	init_completion(&xspi->done);
415	spi_controller_set_devdata(host, xspi);
416	xlp_spi_sysctl_setup(xspi);
417
418	/* register spi controller */
419	err = devm_spi_register_controller(&pdev->dev, host);
420	if (err) {
421		dev_err(&pdev->dev, "spi register host failed!\n");
422		spi_controller_put(host);
423		return err;
424	}
425
426	return 0;
427}
428
429#ifdef CONFIG_ACPI
430static const struct acpi_device_id xlp_spi_acpi_match[] = {
431	{ "BRCM900D", 0 },
432	{ "CAV900D",  0 },
433	{ },
434};
435MODULE_DEVICE_TABLE(acpi, xlp_spi_acpi_match);
436#endif
437
438static struct platform_driver xlp_spi_driver = {
439	.probe	= xlp_spi_probe,
440	.driver = {
441		.name	= "xlp-spi",
442		.acpi_match_table = ACPI_PTR(xlp_spi_acpi_match),
443	},
444};
445module_platform_driver(xlp_spi_driver);
446
447MODULE_AUTHOR("Kamlakant Patel <kamlakant.patel@broadcom.com>");
448MODULE_DESCRIPTION("Netlogic XLP SPI controller driver");
449MODULE_LICENSE("GPL v2");
450