spi: bcm53xx: driver for SPI controller on Broadcom bcma SoC
Broadcom 53xx ARM SoCs use bcma bus that contains various cores (AKA
devices). If board has a serial flash, it's connected over SPI and the
bcma bus includes a SPI controller. Example log from such a board:
bus0: Found chip with id 53010, rev 0x00 and package 0x02
(...)
bus0: Core 18 found: SPI flash controller (manuf 0x4BF, id 0x50A, rev 0x01, class 0x0)
This patch adds a bcma driver for SPI core, it registers SPI master
controller and "bcm53xxspiflash" SPI device.
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
diff --git a/drivers/spi/spi-bcm53xx.c b/drivers/spi/spi-bcm53xx.c
new file mode 100644
index 0000000..48f13df
--- /dev/null
+++ b/drivers/spi/spi-bcm53xx.c
@@ -0,0 +1,295 @@
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+#include <linux/bcma/bcma.h>
+#include <linux/spi/spi.h>
+
+#include "spi-bcm53xx.h"
+
+#define BCM53XXSPI_MAX_SPI_BAUD 13500000 /* 216 MHz? */
+
+/* The longest observed required wait was 19 ms */
+#define BCM53XXSPI_SPE_TIMEOUT_MS 80
+
+struct bcm53xxspi {
+ struct bcma_device *core;
+ struct spi_master *master;
+
+ size_t read_offset;
+};
+
+static inline u32 bcm53xxspi_read(struct bcm53xxspi *b53spi, u16 offset)
+{
+ return bcma_read32(b53spi->core, offset);
+}
+
+static inline void bcm53xxspi_write(struct bcm53xxspi *b53spi, u16 offset,
+ u32 value)
+{
+ bcma_write32(b53spi->core, offset, value);
+}
+
+static inline unsigned int bcm53xxspi_calc_timeout(size_t len)
+{
+ /* Do some magic calculation based on length and buad. Add 10% and 1. */
+ return (len * 9000 / BCM53XXSPI_MAX_SPI_BAUD * 110 / 100) + 1;
+}
+
+static int bcm53xxspi_wait(struct bcm53xxspi *b53spi, unsigned int timeout_ms)
+{
+ unsigned long deadline;
+ u32 tmp;
+
+ /* SPE bit has to be 0 before we read MSPI STATUS */
+ deadline = jiffies + BCM53XXSPI_SPE_TIMEOUT_MS * HZ / 1000;
+ do {
+ tmp = bcm53xxspi_read(b53spi, B53SPI_MSPI_SPCR2);
+ if (!(tmp & B53SPI_MSPI_SPCR2_SPE))
+ break;
+ udelay(5);
+ } while (!time_after_eq(jiffies, deadline));
+
+ if (tmp & B53SPI_MSPI_SPCR2_SPE)
+ goto spi_timeout;
+
+ /* Check status */
+ deadline = jiffies + timeout_ms * HZ / 1000;
+ do {
+ tmp = bcm53xxspi_read(b53spi, B53SPI_MSPI_MSPI_STATUS);
+ if (tmp & B53SPI_MSPI_MSPI_STATUS_SPIF) {
+ bcm53xxspi_write(b53spi, B53SPI_MSPI_MSPI_STATUS, 0);
+ return 0;
+ }
+
+ cpu_relax();
+ udelay(100);
+ } while (!time_after_eq(jiffies, deadline));
+
+spi_timeout:
+ bcm53xxspi_write(b53spi, B53SPI_MSPI_MSPI_STATUS, 0);
+
+ pr_err("Timeout waiting for SPI to be ready!\n");
+
+ return -EBUSY;
+}
+
+static void bcm53xxspi_buf_write(struct bcm53xxspi *b53spi, u8 *w_buf,
+ size_t len, bool cont)
+{
+ u32 tmp;
+ int i;
+
+ for (i = 0; i < len; i++) {
+ /* Transmit Register File MSB */
+ bcm53xxspi_write(b53spi, B53SPI_MSPI_TXRAM + 4 * (i * 2),
+ (unsigned int)w_buf[i]);
+ }
+
+ for (i = 0; i < len; i++) {
+ tmp = B53SPI_CDRAM_CONT | B53SPI_CDRAM_PCS_DISABLE_ALL |
+ B53SPI_CDRAM_PCS_DSCK;
+ if (!cont && i == len - 1)
+ tmp &= ~B53SPI_CDRAM_CONT;
+ tmp &= ~0x1;
+ /* Command Register File */
+ bcm53xxspi_write(b53spi, B53SPI_MSPI_CDRAM + 4 * i, tmp);
+ }
+
+ /* Set queue pointers */
+ bcm53xxspi_write(b53spi, B53SPI_MSPI_NEWQP, 0);
+ bcm53xxspi_write(b53spi, B53SPI_MSPI_ENDQP, len - 1);
+
+ if (cont)
+ bcm53xxspi_write(b53spi, B53SPI_MSPI_WRITE_LOCK, 1);
+
+ /* Start SPI transfer */
+ tmp = bcm53xxspi_read(b53spi, B53SPI_MSPI_SPCR2);
+ tmp |= B53SPI_MSPI_SPCR2_SPE;
+ if (cont)
+ tmp |= B53SPI_MSPI_SPCR2_CONT_AFTER_CMD;
+ bcm53xxspi_write(b53spi, B53SPI_MSPI_SPCR2, tmp);
+
+ /* Wait for SPI to finish */
+ bcm53xxspi_wait(b53spi, bcm53xxspi_calc_timeout(len));
+
+ if (!cont)
+ bcm53xxspi_write(b53spi, B53SPI_MSPI_WRITE_LOCK, 0);
+
+ b53spi->read_offset = len;
+}
+
+static void bcm53xxspi_buf_read(struct bcm53xxspi *b53spi, u8 *r_buf,
+ size_t len, bool cont)
+{
+ u32 tmp;
+ int i;
+
+ for (i = 0; i < b53spi->read_offset + len; i++) {
+ tmp = B53SPI_CDRAM_CONT | B53SPI_CDRAM_PCS_DISABLE_ALL |
+ B53SPI_CDRAM_PCS_DSCK;
+ if (!cont && i == b53spi->read_offset + len - 1)
+ tmp &= ~B53SPI_CDRAM_CONT;
+ tmp &= ~0x1;
+ /* Command Register File */
+ bcm53xxspi_write(b53spi, B53SPI_MSPI_CDRAM + 4 * i, tmp);
+ }
+
+ /* Set queue pointers */
+ bcm53xxspi_write(b53spi, B53SPI_MSPI_NEWQP, 0);
+ bcm53xxspi_write(b53spi, B53SPI_MSPI_ENDQP,
+ b53spi->read_offset + len - 1);
+
+ if (cont)
+ bcm53xxspi_write(b53spi, B53SPI_MSPI_WRITE_LOCK, 1);
+
+ /* Start SPI transfer */
+ tmp = bcm53xxspi_read(b53spi, B53SPI_MSPI_SPCR2);
+ tmp |= B53SPI_MSPI_SPCR2_SPE;
+ if (cont)
+ tmp |= B53SPI_MSPI_SPCR2_CONT_AFTER_CMD;
+ bcm53xxspi_write(b53spi, B53SPI_MSPI_SPCR2, tmp);
+
+ /* Wait for SPI to finish */
+ bcm53xxspi_wait(b53spi, bcm53xxspi_calc_timeout(len));
+
+ if (!cont)
+ bcm53xxspi_write(b53spi, B53SPI_MSPI_WRITE_LOCK, 0);
+
+ for (i = 0; i < len; ++i) {
+ int offset = b53spi->read_offset + i;
+
+ /* Data stored in the transmit register file LSB */
+ r_buf[i] = (u8)bcm53xxspi_read(b53spi, B53SPI_MSPI_RXRAM + 4 * (1 + offset * 2));
+ }
+
+ b53spi->read_offset = 0;
+}
+
+static int bcm53xxspi_transfer_one(struct spi_master *master,
+ struct spi_device *spi,
+ struct spi_transfer *t)
+{
+ struct bcm53xxspi *b53spi = spi_master_get_devdata(master);
+ u8 *buf;
+ size_t left;
+
+ if (t->tx_buf) {
+ buf = (u8 *)t->tx_buf;
+ left = t->len;
+ while (left) {
+ size_t to_write = min_t(size_t, 16, left);
+ bool cont = left - to_write > 0;
+
+ bcm53xxspi_buf_write(b53spi, buf, to_write, cont);
+ left -= to_write;
+ buf += to_write;
+ }
+ }
+
+ if (t->rx_buf) {
+ buf = (u8 *)t->rx_buf;
+ left = t->len;
+ while (left) {
+ size_t to_read = min_t(size_t, 16 - b53spi->read_offset,
+ left);
+ bool cont = left - to_read > 0;
+
+ bcm53xxspi_buf_read(b53spi, buf, to_read, cont);
+ left -= to_read;
+ buf += to_read;
+ }
+ }
+
+ return 0;
+}
+
+/**************************************************
+ * BCMA
+ **************************************************/
+
+struct spi_board_info bcm53xx_info = {
+ .modalias = "bcm53xxspiflash",
+};
+
+static const struct bcma_device_id bcm53xxspi_bcma_tbl[] = {
+ BCMA_CORE(BCMA_MANUF_BCM, BCMA_CORE_NS_QSPI, BCMA_ANY_REV, BCMA_ANY_CLASS),
+ BCMA_CORETABLE_END
+};
+MODULE_DEVICE_TABLE(bcma, bcm53xxspi_bcma_tbl);
+
+static int bcm53xxspi_bcma_probe(struct bcma_device *core)
+{
+ struct bcm53xxspi *b53spi;
+ struct spi_master *master;
+ int err;
+
+ if (core->bus->drv_cc.core->id.rev != 42) {
+ pr_err("SPI on SoC with unsupported ChipCommon rev\n");
+ return -ENOTSUPP;
+ }
+
+ master = spi_alloc_master(&core->dev, sizeof(*b53spi));
+ if (!master)
+ return -ENOMEM;
+
+ b53spi = spi_master_get_devdata(master);
+ b53spi->master = master;
+ b53spi->core = core;
+
+ master->transfer_one = bcm53xxspi_transfer_one;
+
+ bcma_set_drvdata(core, b53spi);
+
+ err = devm_spi_register_master(&core->dev, master);
+ if (err) {
+ spi_master_put(master);
+ bcma_set_drvdata(core, NULL);
+ goto out;
+ }
+
+ /* Broadcom SoCs (at least with the CC rev 42) use SPI for flash only */
+ spi_new_device(master, &bcm53xx_info);
+
+out:
+ return err;
+}
+
+static void bcm53xxspi_bcma_remove(struct bcma_device *core)
+{
+ struct bcm53xxspi *b53spi = bcma_get_drvdata(core);
+
+ spi_unregister_master(b53spi->master);
+}
+
+static struct bcma_driver bcm53xxspi_bcma_driver = {
+ .name = KBUILD_MODNAME,
+ .id_table = bcm53xxspi_bcma_tbl,
+ .probe = bcm53xxspi_bcma_probe,
+ .remove = bcm53xxspi_bcma_remove,
+};
+
+/**************************************************
+ * Init & exit
+ **************************************************/
+
+static int __init bcm53xxspi_module_init(void)
+{
+ int err = 0;
+
+ err = bcma_driver_register(&bcm53xxspi_bcma_driver);
+ if (err)
+ pr_err("Failed to register bcma driver: %d\n", err);
+
+ return err;
+}
+
+static void __exit bcm53xxspi_module_exit(void)
+{
+ bcma_driver_unregister(&bcm53xxspi_bcma_driver);
+}
+
+module_init(bcm53xxspi_module_init);
+module_exit(bcm53xxspi_module_exit);