[PATCH 2/3] spi: meson: Add support for Amlogic Meson SPIFC
From: Beniamino Galvani
Date: Sun Nov 09 2014 - 04:28:04 EST
This is a driver for the Amlogic Meson SPIFC (SPI flash controller),
which is one of the two SPI controllers available on the SoC. It
doesn't support DMA and has a 64-byte unified transmit/receive buffer.
The device is optimized for interfacing with SPI NOR memories and
allows the execution of standard operations such as read, page
program, sector erase, etc. in a simplified way, basically toggling a
bit in a dedicated register. The driver doesn't use those predefined
commands and relies only on custom transfers.
Signed-off-by: Beniamino Galvani <b.galvani@xxxxxxxxx>
---
drivers/spi/Kconfig | 7 +
drivers/spi/Makefile | 1 +
drivers/spi/spi-meson-spifc.c | 411 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 419 insertions(+)
create mode 100644 drivers/spi/spi-meson-spifc.c
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 84e7c9e..3c98a9d 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -301,6 +301,13 @@ config SPI_FSL_ESPI
From MPC8536, 85xx platform uses the controller, and all P10xx,
P20xx, P30xx,P40xx, P50xx uses this controller.
+config SPI_MESON_SPIFC
+ bool "Amlogic Meson SPIFC controller"
+ depends on ARCH_MESON
+ help
+ This enables master mode support for the SPIFC (SPI flash
+ controller) available in Amlogic Meson SoCs.
+
config SPI_OC_TINY
tristate "OpenCores tiny SPI"
depends on GPIOLIB
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 78f24ca..9b8a747 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -42,6 +42,7 @@ obj-$(CONFIG_SPI_FSL_SPI) += spi-fsl-spi.o
obj-$(CONFIG_SPI_GPIO) += spi-gpio.o
obj-$(CONFIG_SPI_IMX) += spi-imx.o
obj-$(CONFIG_SPI_LM70_LLP) += spi-lm70llp.o
+obj-$(CONFIG_SPI_MESON_SPIFC) += spi-meson-spifc.o
obj-$(CONFIG_SPI_MPC512x_PSC) += spi-mpc512x-psc.o
obj-$(CONFIG_SPI_MPC52xx_PSC) += spi-mpc52xx-psc.o
obj-$(CONFIG_SPI_MPC52xx) += spi-mpc52xx.o
diff --git a/drivers/spi/spi-meson-spifc.c b/drivers/spi/spi-meson-spifc.c
new file mode 100644
index 0000000..a0ba5d8
--- /dev/null
+++ b/drivers/spi/spi-meson-spifc.c
@@ -0,0 +1,411 @@
+/*
+ * Driver for Amlogic Meson SPI flash controller (SPIFC)
+ *
+ * Copyright (C) 2014 Beniamino Galvani <b.galvani@xxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/spi/spi.h>
+#include <linux/types.h>
+
+/* register map */
+#define REG_CMD 0x00
+#define REG_ADDR 0x04
+#define REG_CTRL 0x08
+#define REG_CTRL1 0x0c
+#define REG_STATUS 0x10
+#define REG_CTRL2 0x14
+#define REG_CLOCK 0x18
+#define REG_USER 0x1c
+#define REG_USER1 0x20
+#define REG_USER2 0x24
+#define REG_USER3 0x28
+#define REG_USER4 0x2c
+#define REG_SLAVE 0x30
+#define REG_SLAVE1 0x34
+#define REG_SLAVE2 0x38
+#define REG_SLAVE3 0x3c
+#define REG_C0 0x40
+#define REG_B8 0x60
+
+/* register fields */
+#define CMD_USER BIT(18)
+#define CTRL_ENABLE_AHB BIT(17)
+#define CLOCK_SOURCE BIT(31)
+#define CLOCK_DIV_SHIFT 12
+#define CLOCK_DIV_MASK (0x3f << CLOCK_DIV_SHIFT)
+#define CLOCK_CNT_HIGH_SHIFT 6
+#define CLOCK_CNT_HIGH_MASK (0x3f << CLOCK_CNT_HIGH_SHIFT)
+#define CLOCK_CNT_LOW_SHIFT 0
+#define CLOCK_CNT_LOW_MASK (0x3f << CLOCK_CNT_LOW_SHIFT)
+#define USER_DIN_EN_MS BIT(0)
+#define USER_CMP_MODE BIT(2)
+#define USER_UC_DOUT_SEL BIT(27)
+#define USER_UC_DIN_SEL BIT(28)
+#define USER_UC_MASK ((BIT(5) - 1) << 27)
+#define USER1_BN_UC_DOUT_SHIFT 17
+#define USER1_BN_UC_DOUT_MASK (0xff << 16)
+#define USER1_BN_UC_DIN_SHIFT 8
+#define USER1_BN_UC_DIN_MASK (0xff << 8)
+#define USER4_CS_ACT BIT(30)
+#define SLAVE_TRST_DONE BIT(4)
+#define SLAVE_OP_MODE BIT(30)
+#define SLAVE_SW_RST BIT(31)
+
+#define SPIFC_BUFFER_SIZE 64
+
+/**
+ * struct meson_spifc
+ * @master: the SPI master
+ * @regmap: regmap for device registers
+ * @clk: input clock of the built-in baud rate generator
+ * @device: the device structure
+ */
+struct meson_spifc {
+ struct spi_master *master;
+ struct regmap *regmap;
+ struct clk *clk;
+ struct device *dev;
+};
+
+static struct regmap_config spifc_regmap_config = {
+ .reg_bits = 32,
+ .val_bits = 32,
+ .reg_stride = 4,
+};
+
+/**
+ * meson_spifc_wait_ready() - wait for the current operation to terminate
+ * @spifc: the Meson SPI device
+ * Return: 0 on success, a negative value on error
+ */
+static int meson_spifc_wait_ready(struct meson_spifc *spifc)
+{
+ unsigned long deadline = jiffies + msecs_to_jiffies(1000);
+ u32 data;
+
+ do {
+ regmap_read(spifc->regmap, REG_SLAVE, &data);
+ if (data & SLAVE_TRST_DONE)
+ return 0;
+ cond_resched();
+ } while (time_before(jiffies, deadline));
+
+ return -ETIMEDOUT;
+}
+
+/**
+ * meson_spifc_drain_buffer() - copy data from device buffer to memory
+ * @spifc: the Meson SPI device
+ * @buf: the destination buffer
+ * @len: number of bytes to copy
+ */
+static void meson_spifc_drain_buffer(struct meson_spifc *spifc, u8 *buf,
+ int len)
+{
+ u32 data;
+ int i = 0;
+
+ while (i < len) {
+ regmap_read(spifc->regmap, REG_C0 + i, &data);
+
+ if (len - i >= 4) {
+ *((u32 *)buf) = data;
+ buf += 4;
+ } else {
+ memcpy(buf, &data, len - i);
+ break;
+ }
+ i += 4;
+ }
+}
+
+/**
+ * meson_spifc_fill_buffer() - copy data from memory to device buffer
+ * @spifc: the Meson SPI device
+ * @buf: the source buffer
+ * @len: number of bytes to copy
+ */
+static void meson_spifc_fill_buffer(struct meson_spifc *spifc, const u8 *buf,
+ int len)
+{
+ u32 data;
+ int i = 0;
+
+ while (i < len) {
+ if (len - i >= 4)
+ data = *(u32 *)buf;
+ else
+ memcpy(&data, buf, len - i);
+
+ regmap_write(spifc->regmap, REG_C0 + i, data);
+
+ buf += 4;
+ i += 4;
+ }
+}
+
+/**
+ * meson_spifc_setup_speed() - program the clock divider
+ * @spifc: the Meson SPI device
+ * @speed: desired speed in Hz
+ */
+void meson_spifc_setup_speed(struct meson_spifc *spifc, u32 speed)
+{
+ unsigned long parent, value;
+ int n;
+
+ parent = clk_get_rate(spifc->clk);
+ n = max_t(int, parent / speed - 1, 1);
+
+ dev_dbg(spifc->dev, "parent %lu, speed %u, n %d\n", parent,
+ speed, n);
+
+ value = (n << CLOCK_DIV_SHIFT) & CLOCK_DIV_MASK;
+ value |= (n << CLOCK_CNT_LOW_SHIFT) & CLOCK_CNT_LOW_MASK;
+ value |= (((n + 1) / 2 - 1) << CLOCK_CNT_HIGH_SHIFT) &
+ CLOCK_CNT_HIGH_MASK;
+
+ regmap_write(spifc->regmap, REG_CLOCK, value);
+}
+
+/**
+ * meson_spifc_txrx() - transfer a chunk of data
+ * @spifc: the Meson SPI device
+ * @xfer: the current SPI transfer
+ * @offset: offset of the data to transfer
+ * @len: length of the data to transfer
+ * @last_xfer: whether this is the last transfer of the message
+ * @last_chunk: whether this is the last chunk of the transfer
+ * Return: 0 on success, a negative value on error
+ */
+static int meson_spifc_txrx(struct meson_spifc *spifc,
+ struct spi_transfer *xfer,
+ int offset, int len, bool last_xfer,
+ bool last_chunk)
+{
+ bool keep_cs = true;
+ int ret;
+
+ if (xfer->tx_buf)
+ meson_spifc_fill_buffer(spifc, xfer->tx_buf + offset, len);
+
+ /* enable DOUT stage */
+ regmap_update_bits(spifc->regmap, REG_USER, USER_UC_MASK,
+ USER_UC_DOUT_SEL);
+ regmap_write(spifc->regmap, REG_USER1,
+ (8 * len - 1) << USER1_BN_UC_DOUT_SHIFT);
+
+ /* enable data input during DOUT */
+ regmap_update_bits(spifc->regmap, REG_USER, USER_DIN_EN_MS,
+ USER_DIN_EN_MS);
+
+ if (last_chunk) {
+ if (last_xfer)
+ keep_cs = xfer->cs_change;
+ else
+ keep_cs = !xfer->cs_change;
+ }
+
+ regmap_update_bits(spifc->regmap, REG_USER4, USER4_CS_ACT,
+ keep_cs ? USER4_CS_ACT : 0);
+
+ /* clear transition done bit */
+ regmap_update_bits(spifc->regmap, REG_SLAVE, SLAVE_TRST_DONE, 0);
+ /* start transfer */
+ regmap_update_bits(spifc->regmap, REG_CMD, CMD_USER, CMD_USER);
+
+ ret = meson_spifc_wait_ready(spifc);
+
+ if (!ret && xfer->rx_buf)
+ meson_spifc_drain_buffer(spifc, xfer->rx_buf + offset, len);
+
+ return ret;
+}
+
+/**
+ * meson_spifc_transfer_one() - perform a single transfer
+ * @spifc: the Meson SPI device
+ * @xfer: the current SPI transfer
+ * @last_xfer: whether this is the last transfer of the message
+ * Return: 0 on success, a negative value on error
+ */
+static int meson_spifc_transfer_one(struct spi_device *spi,
+ struct spi_transfer *xfer,
+ bool last_xfer)
+{
+ struct meson_spifc *spifc = spi_master_get_devdata(spi->master);
+ int len, done = 0, ret = 0;
+
+ meson_spifc_setup_speed(spifc, xfer->speed_hz ? xfer->speed_hz :
+ spi->max_speed_hz);
+
+ regmap_update_bits(spifc->regmap, REG_CTRL, CTRL_ENABLE_AHB, 0);
+
+ while (done < xfer->len && !ret) {
+ len = min_t(int, xfer->len - done, SPIFC_BUFFER_SIZE);
+ ret = meson_spifc_txrx(spifc, xfer, done, len,
+ last_xfer, done + len >= xfer->len);
+ done += len;
+ }
+
+ regmap_update_bits(spifc->regmap, REG_CTRL, CTRL_ENABLE_AHB,
+ CTRL_ENABLE_AHB);
+
+ if (!ret && xfer->delay_usecs)
+ udelay(xfer->delay_usecs);
+
+ return ret;
+}
+
+/**
+ * meson_spifc_transfer_one_message() - transfer a single SPI message
+ * @master: the SPI master
+ * @msg: the message to transfer
+ * Return: 0 on success, a negative value on error
+ */
+static int meson_spifc_transfer_one_message(struct spi_master *master,
+ struct spi_message *msg)
+{
+ struct spi_transfer *xfer;
+ int ret = 0;
+ bool last;
+
+ list_for_each_entry(xfer, &msg->transfers, transfer_list) {
+ last = list_is_last(&xfer->transfer_list, &msg->transfers);
+ ret = meson_spifc_transfer_one(msg->spi, xfer, last);
+ if (ret)
+ break;
+ msg->actual_length += xfer->len;
+ }
+
+ msg->status = ret;
+ spi_finalize_current_message(master);
+
+ return ret;
+}
+
+static int meson_spifc_probe(struct platform_device *pdev)
+{
+ struct spi_master *master;
+ struct meson_spifc *spifc;
+ struct resource *res;
+ void __iomem *base;
+ unsigned int rate;
+ int ret = 0;
+
+ master = spi_alloc_master(&pdev->dev, sizeof(struct meson_spifc));
+ if (!master)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, master);
+
+ spifc = spi_master_get_devdata(master);
+ memset(spifc, 0, sizeof(struct meson_spifc));
+ spifc->dev = &pdev->dev;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ base = devm_ioremap_resource(spifc->dev, res);
+ if (IS_ERR(base)) {
+ ret = PTR_ERR(base);
+ goto out_err;
+ }
+
+ spifc_regmap_config.max_register = resource_size(res) - 4;
+ spifc_regmap_config.name = "amlogic,meson-spifc";
+ spifc->regmap = devm_regmap_init_mmio(spifc->dev, base,
+ &spifc_regmap_config);
+ if (IS_ERR(spifc->regmap)) {
+ ret = PTR_ERR(spifc->regmap);
+ goto out_err;
+ }
+
+ spifc->clk = devm_clk_get(spifc->dev, NULL);
+ if (IS_ERR(spifc->clk)) {
+ dev_err(spifc->dev, "missing clock\n");
+ ret = PTR_ERR(spifc->clk);
+ goto out_err;
+ }
+
+ ret = clk_prepare_enable(spifc->clk);
+ if (ret) {
+ dev_err(spifc->dev, "can't prepare clock\n");
+ goto out_err;
+ }
+
+ rate = clk_get_rate(spifc->clk);
+
+ master->bus_num = pdev->id;
+ master->num_chipselect = 1;
+ master->dev.of_node = pdev->dev.of_node;
+ master->bits_per_word_mask = SPI_BPW_MASK(8);
+ master->transfer_one_message = meson_spifc_transfer_one_message;
+ master->min_speed_hz = rate >> 6;
+ master->max_speed_hz = rate >> 1;
+
+ /* reset device */
+ regmap_update_bits(spifc->regmap, REG_SLAVE, SLAVE_SW_RST,
+ SLAVE_SW_RST);
+ /* disable compatible mode */
+ regmap_update_bits(spifc->regmap, REG_USER, USER_CMP_MODE, 0);
+ /* set master mode */
+ regmap_update_bits(spifc->regmap, REG_SLAVE, SLAVE_OP_MODE, 0);
+
+ ret = devm_spi_register_master(&pdev->dev, master);
+ if (ret) {
+ dev_err(spifc->dev, "failed to register spi master\n");
+ goto out_clk;
+ }
+
+ return 0;
+out_clk:
+ clk_disable_unprepare(spifc->clk);
+out_err:
+ spi_master_put(master);
+ return ret;
+}
+
+static int meson_spifc_remove(struct platform_device *pdev)
+{
+ struct spi_master *master = platform_get_drvdata(pdev);
+ struct meson_spifc *spifc = spi_master_get_devdata(master);
+
+ clk_disable_unprepare(spifc->clk);
+
+ return 0;
+}
+
+static const struct of_device_id meson_spifc_dt_match[] = {
+ { .compatible = "amlogic,meson6-spifc", },
+ { },
+};
+
+static struct platform_driver meson_spifc_driver = {
+ .probe = meson_spifc_probe,
+ .remove = meson_spifc_remove,
+ .driver = {
+ .name = "meson-spifc",
+ .of_match_table = of_match_ptr(meson_spifc_dt_match),
+ },
+};
+
+module_platform_driver(meson_spifc_driver);
+
+MODULE_AUTHOR("Beniamino Galvani <b.galvani@xxxxxxxxx>");
+MODULE_DESCRIPTION("Amlogic Meson SPIFC driver");
+MODULE_LICENSE("GPL v2");
--
1.9.1
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