1 // SPDX-License-Identifier: GPL-2.0
3 * Designware master SPI core controller driver
5 * Copyright (C) 2014 Stefan Roese <sr@denx.de>
7 * Very loosely based on the Linux driver:
8 * drivers/spi/spi-dw.c, which is:
9 * Copyright (c) 2009, Intel Corporation.
13 #include <asm-generic/gpio.h>
21 #include <dm/device_compat.h>
22 #include <linux/compat.h>
23 #include <linux/iopoll.h>
26 /* Register offsets */
27 #define DW_SPI_CTRL0 0x00
28 #define DW_SPI_CTRL1 0x04
29 #define DW_SPI_SSIENR 0x08
30 #define DW_SPI_MWCR 0x0c
31 #define DW_SPI_SER 0x10
32 #define DW_SPI_BAUDR 0x14
33 #define DW_SPI_TXFLTR 0x18
34 #define DW_SPI_RXFLTR 0x1c
35 #define DW_SPI_TXFLR 0x20
36 #define DW_SPI_RXFLR 0x24
37 #define DW_SPI_SR 0x28
38 #define DW_SPI_IMR 0x2c
39 #define DW_SPI_ISR 0x30
40 #define DW_SPI_RISR 0x34
41 #define DW_SPI_TXOICR 0x38
42 #define DW_SPI_RXOICR 0x3c
43 #define DW_SPI_RXUICR 0x40
44 #define DW_SPI_MSTICR 0x44
45 #define DW_SPI_ICR 0x48
46 #define DW_SPI_DMACR 0x4c
47 #define DW_SPI_DMATDLR 0x50
48 #define DW_SPI_DMARDLR 0x54
49 #define DW_SPI_IDR 0x58
50 #define DW_SPI_VERSION 0x5c
51 #define DW_SPI_DR 0x60
53 /* Bit fields in CTRLR0 */
54 #define SPI_DFS_OFFSET 0
56 #define SPI_FRF_OFFSET 4
57 #define SPI_FRF_SPI 0x0
58 #define SPI_FRF_SSP 0x1
59 #define SPI_FRF_MICROWIRE 0x2
60 #define SPI_FRF_RESV 0x3
62 #define SPI_MODE_OFFSET 6
63 #define SPI_SCPH_OFFSET 6
64 #define SPI_SCOL_OFFSET 7
66 #define SPI_TMOD_OFFSET 8
67 #define SPI_TMOD_MASK (0x3 << SPI_TMOD_OFFSET)
68 #define SPI_TMOD_TR 0x0 /* xmit & recv */
69 #define SPI_TMOD_TO 0x1 /* xmit only */
70 #define SPI_TMOD_RO 0x2 /* recv only */
71 #define SPI_TMOD_EPROMREAD 0x3 /* eeprom read mode */
73 #define SPI_SLVOE_OFFSET 10
74 #define SPI_SRL_OFFSET 11
75 #define SPI_CFS_OFFSET 12
77 /* Bit fields in SR, 7 bits */
78 #define SR_MASK GENMASK(6, 0) /* cover 7 bits */
79 #define SR_BUSY BIT(0)
80 #define SR_TF_NOT_FULL BIT(1)
81 #define SR_TF_EMPT BIT(2)
82 #define SR_RF_NOT_EMPT BIT(3)
83 #define SR_RF_FULL BIT(4)
84 #define SR_TX_ERR BIT(5)
85 #define SR_DCOL BIT(6)
87 #define RX_TIMEOUT 1000 /* timeout in ms */
89 struct dw_spi_platdata {
90 s32 frequency; /* Default clock frequency, -1 for none */
96 unsigned int freq; /* Default frequency */
99 unsigned long bus_clk_rate;
101 struct gpio_desc cs_gpio; /* External chip-select gpio */
104 u8 cs; /* chip select pin */
105 u8 tmode; /* TR/TO/RO/EEPROM */
106 u8 type; /* SPI/SSP/MicroWire */
109 u32 fifo_len; /* depth of the FIFO buffer */
115 struct reset_ctl_bulk resets;
118 static inline u32 dw_read(struct dw_spi_priv *priv, u32 offset)
120 return __raw_readl(priv->regs + offset);
123 static inline void dw_write(struct dw_spi_priv *priv, u32 offset, u32 val)
125 __raw_writel(val, priv->regs + offset);
128 static int request_gpio_cs(struct udevice *bus)
130 #if CONFIG_IS_ENABLED(DM_GPIO) && !defined(CONFIG_SPL_BUILD)
131 struct dw_spi_priv *priv = dev_get_priv(bus);
134 /* External chip select gpio line is optional */
135 ret = gpio_request_by_name(bus, "cs-gpio", 0, &priv->cs_gpio, 0);
140 printf("Error: %d: Can't get %s gpio!\n", ret, bus->name);
144 if (dm_gpio_is_valid(&priv->cs_gpio)) {
145 dm_gpio_set_dir_flags(&priv->cs_gpio,
146 GPIOD_IS_OUT | GPIOD_IS_OUT_ACTIVE);
149 debug("%s: used external gpio for CS management\n", __func__);
154 static int dw_spi_ofdata_to_platdata(struct udevice *bus)
156 struct dw_spi_platdata *plat = bus->platdata;
158 plat->regs = (struct dw_spi *)devfdt_get_addr(bus);
160 /* Use 500KHz as a suitable default */
161 plat->frequency = dev_read_u32_default(bus, "spi-max-frequency",
163 debug("%s: regs=%p max-frequency=%d\n", __func__, plat->regs,
166 return request_gpio_cs(bus);
169 static inline void spi_enable_chip(struct dw_spi_priv *priv, int enable)
171 dw_write(priv, DW_SPI_SSIENR, (enable ? 1 : 0));
174 /* Restart the controller, disable all interrupts, clean rx fifo */
175 static void spi_hw_init(struct dw_spi_priv *priv)
177 spi_enable_chip(priv, 0);
178 dw_write(priv, DW_SPI_IMR, 0xff);
179 spi_enable_chip(priv, 1);
182 * Try to detect the FIFO depth if not set by interface driver,
183 * the depth could be from 2 to 256 from HW spec
185 if (!priv->fifo_len) {
188 for (fifo = 1; fifo < 256; fifo++) {
189 dw_write(priv, DW_SPI_TXFLTR, fifo);
190 if (fifo != dw_read(priv, DW_SPI_TXFLTR))
194 priv->fifo_len = (fifo == 1) ? 0 : fifo;
195 dw_write(priv, DW_SPI_TXFLTR, 0);
197 debug("%s: fifo_len=%d\n", __func__, priv->fifo_len);
201 * We define dw_spi_get_clk function as 'weak' as some targets
202 * (like SOCFPGA_GEN5 and SOCFPGA_ARRIA10) don't use standard clock API
203 * and implement dw_spi_get_clk their own way in their clock manager.
205 __weak int dw_spi_get_clk(struct udevice *bus, ulong *rate)
207 struct dw_spi_priv *priv = dev_get_priv(bus);
210 ret = clk_get_by_index(bus, 0, &priv->clk);
214 ret = clk_enable(&priv->clk);
215 if (ret && ret != -ENOSYS && ret != -ENOTSUPP)
218 *rate = clk_get_rate(&priv->clk);
222 debug("%s: get spi controller clk via device tree: %lu Hz\n",
228 clk_disable(&priv->clk);
229 clk_free(&priv->clk);
234 static int dw_spi_reset(struct udevice *bus)
237 struct dw_spi_priv *priv = dev_get_priv(bus);
239 ret = reset_get_bulk(bus, &priv->resets);
242 * Return 0 if error due to !CONFIG_DM_RESET and reset
243 * DT property is not present.
245 if (ret == -ENOENT || ret == -ENOTSUPP)
248 dev_warn(bus, "Can't get reset: %d\n", ret);
252 ret = reset_deassert_bulk(&priv->resets);
254 reset_release_bulk(&priv->resets);
255 dev_err(bus, "Failed to reset: %d\n", ret);
262 static int dw_spi_probe(struct udevice *bus)
264 struct dw_spi_platdata *plat = dev_get_platdata(bus);
265 struct dw_spi_priv *priv = dev_get_priv(bus);
268 priv->regs = plat->regs;
269 priv->freq = plat->frequency;
271 ret = dw_spi_get_clk(bus, &priv->bus_clk_rate);
275 ret = dw_spi_reset(bus);
279 /* Currently only bits_per_word == 8 supported */
280 priv->bits_per_word = 8;
282 priv->tmode = 0; /* Tx & Rx */
290 /* Return the max entries we can fill into tx fifo */
291 static inline u32 tx_max(struct dw_spi_priv *priv)
293 u32 tx_left, tx_room, rxtx_gap;
295 tx_left = (priv->tx_end - priv->tx) / (priv->bits_per_word >> 3);
296 tx_room = priv->fifo_len - dw_read(priv, DW_SPI_TXFLR);
299 * Another concern is about the tx/rx mismatch, we
300 * thought about using (priv->fifo_len - rxflr - txflr) as
301 * one maximum value for tx, but it doesn't cover the
302 * data which is out of tx/rx fifo and inside the
303 * shift registers. So a control from sw point of
306 rxtx_gap = ((priv->rx_end - priv->rx) - (priv->tx_end - priv->tx)) /
307 (priv->bits_per_word >> 3);
309 return min3(tx_left, tx_room, (u32)(priv->fifo_len - rxtx_gap));
312 /* Return the max entries we should read out of rx fifo */
313 static inline u32 rx_max(struct dw_spi_priv *priv)
315 u32 rx_left = (priv->rx_end - priv->rx) / (priv->bits_per_word >> 3);
317 return min_t(u32, rx_left, dw_read(priv, DW_SPI_RXFLR));
320 static void dw_writer(struct dw_spi_priv *priv)
322 u32 max = tx_max(priv);
326 /* Set the tx word if the transfer's original "tx" is not null */
327 if (priv->tx_end - priv->len) {
328 if (priv->bits_per_word == 8)
329 txw = *(u8 *)(priv->tx);
331 txw = *(u16 *)(priv->tx);
333 dw_write(priv, DW_SPI_DR, txw);
334 debug("%s: tx=0x%02x\n", __func__, txw);
335 priv->tx += priv->bits_per_word >> 3;
339 static void dw_reader(struct dw_spi_priv *priv)
341 u32 max = rx_max(priv);
345 rxw = dw_read(priv, DW_SPI_DR);
346 debug("%s: rx=0x%02x\n", __func__, rxw);
348 /* Care about rx if the transfer's original "rx" is not null */
349 if (priv->rx_end - priv->len) {
350 if (priv->bits_per_word == 8)
351 *(u8 *)(priv->rx) = rxw;
353 *(u16 *)(priv->rx) = rxw;
355 priv->rx += priv->bits_per_word >> 3;
359 static int poll_transfer(struct dw_spi_priv *priv)
364 } while (priv->rx_end > priv->rx);
370 * We define external_cs_manage function as 'weak' as some targets
371 * (like MSCC Ocelot) don't control the external CS pin using a GPIO
372 * controller. These SoCs use specific registers to control by
373 * software the SPI pins (and especially the CS).
375 __weak void external_cs_manage(struct udevice *dev, bool on)
377 #if CONFIG_IS_ENABLED(DM_GPIO) && !defined(CONFIG_SPL_BUILD)
378 struct dw_spi_priv *priv = dev_get_priv(dev->parent);
380 if (!dm_gpio_is_valid(&priv->cs_gpio))
383 dm_gpio_set_value(&priv->cs_gpio, on ? 1 : 0);
387 static int dw_spi_xfer(struct udevice *dev, unsigned int bitlen,
388 const void *dout, void *din, unsigned long flags)
390 struct udevice *bus = dev->parent;
391 struct dw_spi_priv *priv = dev_get_priv(bus);
399 /* spi core configured to do 8 bit transfers */
401 debug("Non byte aligned SPI transfer.\n");
405 /* Start the transaction if necessary. */
406 if (flags & SPI_XFER_BEGIN)
407 external_cs_manage(dev, false);
409 cr0 = (priv->bits_per_word - 1) | (priv->type << SPI_FRF_OFFSET) |
410 (priv->mode << SPI_MODE_OFFSET) |
411 (priv->tmode << SPI_TMOD_OFFSET);
414 priv->tmode = SPI_TMOD_TR;
416 priv->tmode = SPI_TMOD_RO;
419 * In transmit only mode (SPI_TMOD_TO) input FIFO never gets
420 * any data which breaks our logic in poll_transfer() above.
422 priv->tmode = SPI_TMOD_TR;
424 cr0 &= ~SPI_TMOD_MASK;
425 cr0 |= (priv->tmode << SPI_TMOD_OFFSET);
427 priv->len = bitlen >> 3;
428 debug("%s: rx=%p tx=%p len=%d [bytes]\n", __func__, rx, tx, priv->len);
430 priv->tx = (void *)tx;
431 priv->tx_end = priv->tx + priv->len;
433 priv->rx_end = priv->rx + priv->len;
435 /* Disable controller before writing control registers */
436 spi_enable_chip(priv, 0);
438 debug("%s: cr0=%08x\n", __func__, cr0);
439 /* Reprogram cr0 only if changed */
440 if (dw_read(priv, DW_SPI_CTRL0) != cr0)
441 dw_write(priv, DW_SPI_CTRL0, cr0);
444 * Configure the desired SS (slave select 0...3) in the controller
445 * The DW SPI controller will activate and deactivate this CS
446 * automatically. So no cs_activate() etc is needed in this driver.
448 cs = spi_chip_select(dev);
449 dw_write(priv, DW_SPI_SER, 1 << cs);
451 /* Enable controller after writing control registers */
452 spi_enable_chip(priv, 1);
454 /* Start transfer in a polling loop */
455 ret = poll_transfer(priv);
458 * Wait for current transmit operation to complete.
459 * Otherwise if some data still exists in Tx FIFO it can be
460 * silently flushed, i.e. dropped on disabling of the controller,
461 * which happens when writing 0 to DW_SPI_SSIENR which happens
462 * in the beginning of new transfer.
464 if (readl_poll_timeout(priv->regs + DW_SPI_SR, val,
465 (val & SR_TF_EMPT) && !(val & SR_BUSY),
466 RX_TIMEOUT * 1000)) {
470 /* Stop the transaction if necessary */
471 if (flags & SPI_XFER_END)
472 external_cs_manage(dev, true);
477 static int dw_spi_set_speed(struct udevice *bus, uint speed)
479 struct dw_spi_platdata *plat = bus->platdata;
480 struct dw_spi_priv *priv = dev_get_priv(bus);
483 if (speed > plat->frequency)
484 speed = plat->frequency;
486 /* Disable controller before writing control registers */
487 spi_enable_chip(priv, 0);
489 /* clk_div doesn't support odd number */
490 clk_div = priv->bus_clk_rate / speed;
491 clk_div = (clk_div + 1) & 0xfffe;
492 dw_write(priv, DW_SPI_BAUDR, clk_div);
494 /* Enable controller after writing control registers */
495 spi_enable_chip(priv, 1);
498 debug("%s: regs=%p speed=%d clk_div=%d\n", __func__, priv->regs,
499 priv->freq, clk_div);
504 static int dw_spi_set_mode(struct udevice *bus, uint mode)
506 struct dw_spi_priv *priv = dev_get_priv(bus);
509 * Can't set mode yet. Since this depends on if rx, tx, or
510 * rx & tx is requested. So we have to defer this to the
511 * real transfer function.
514 debug("%s: regs=%p, mode=%d\n", __func__, priv->regs, priv->mode);
519 static int dw_spi_remove(struct udevice *bus)
521 struct dw_spi_priv *priv = dev_get_priv(bus);
524 ret = reset_release_bulk(&priv->resets);
528 #if CONFIG_IS_ENABLED(CLK)
529 ret = clk_disable(&priv->clk);
533 ret = clk_free(&priv->clk);
540 static const struct dm_spi_ops dw_spi_ops = {
542 .set_speed = dw_spi_set_speed,
543 .set_mode = dw_spi_set_mode,
545 * cs_info is not needed, since we require all chip selects to be
546 * in the device tree explicitly
550 static const struct udevice_id dw_spi_ids[] = {
551 { .compatible = "snps,dw-apb-ssi" },
555 U_BOOT_DRIVER(dw_spi) = {
558 .of_match = dw_spi_ids,
560 .ofdata_to_platdata = dw_spi_ofdata_to_platdata,
561 .platdata_auto_alloc_size = sizeof(struct dw_spi_platdata),
562 .priv_auto_alloc_size = sizeof(struct dw_spi_priv),
563 .probe = dw_spi_probe,
564 .remove = dw_spi_remove,