[PATCH v4 1/4] spi: Add support for Armada 3700 SPI Controller
Romain Perier
romain.perier at free-electrons.com
Thu Dec 8 06:58:44 PST 2016
Marvell Armada 3700 SoC comprises an SPI Controller. This Controller
supports up to 4 SPI slave devices, with dedicated chip selects,supports
SPI mode 0/1/2 and 3, CPIO or Fifo mode with DMA transfers and different
SPI transfer mode (Single, Dual or Quad).
This commit adds basic driver support for FIFO mode. In this mode,
dedicated registers are used to store the instruction, the address, the
read mode and the data. Write and Read FIFO are used to store the
outcoming or incoming data. The data FIFOs are accessible via DMA or by
the CPU. Only the CPU is supported for now.
Signed-off-by: Romain Perier <romain.perier at free-electrons.com>
Tested-by: Gregory CLEMENT <gregory.clement at free-electrons.com>
---
Changes in v4:
- Added missing COMPILE_TEST in KConfig
- Replaced the busy wait for loop by a single busy wait in spi_init()
- Handle IRQ_NONE in the interrupt handler
- Assign pdev->id to master->cs_num directly (no conditionnal operator)
- Moved clock gating into prepare/unprepare callbacks
- Removed dev_info() in the end of the probe() function
- Added flag to the spi master for single duplex transfers
- Squashed patch 1/5 and 2/5 together: remove the non-fifo mode, just keep
the more efficient mode
- So removed the module parameter
Changes in v3:
- Don't enable the fifo mode based on the compatible string, we introduce
a module parameter "pio_mode". By default this option is set to zero, so
the fifo mode is enabled. Pass pio_mode=1 to the driver enables the PIO
mode.
- Added tag "Tested-by" by Gregory
- Fixed wrong variable passed as MODULE_DEVICE_TABLE
- Added missing null terminated entry in a3700_spi_dt_ids
Changes in v2:
- Removed a3700_spi_bytelen_set from the setup function, it was accidentally
let here and not required, as it is configured in the prepare callback now
(defaults to 4 for fifo mode). It solves unrecognized spi-nor flash memory
detection with jedec.
drivers/spi/Kconfig | 7 +
drivers/spi/Makefile | 1 +
drivers/spi/spi-armada-3700.c | 923 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 931 insertions(+)
create mode 100644 drivers/spi/spi-armada-3700.c
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index b799547..1faad2ce 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -67,6 +67,13 @@ config SPI_ATH79
This enables support for the SPI controller present on the
Atheros AR71XX/AR724X/AR913X SoCs.
+config SPI_ARMADA_3700
+ tristate "Marvell Armada 3700 SPI Controller"
+ depends on (ARCH_MVEBU && OF) || COMPILE_TEST
+ help
+ This enables support for the SPI controller present on the
+ Marvell Armada 3700 SoCs.
+
config SPI_ATMEL
tristate "Atmel SPI Controller"
depends on HAS_DMA
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index aa939d9..140ca45 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_SPI_LOOPBACK_TEST) += spi-loopback-test.o
# SPI master controller drivers (bus)
obj-$(CONFIG_SPI_ALTERA) += spi-altera.o
+obj-$(CONFIG_SPI_ARMADA_3700) += spi-armada-3700.o
obj-$(CONFIG_SPI_ATMEL) += spi-atmel.o
obj-$(CONFIG_SPI_ATH79) += spi-ath79.o
obj-$(CONFIG_SPI_AU1550) += spi-au1550.o
diff --git a/drivers/spi/spi-armada-3700.c b/drivers/spi/spi-armada-3700.c
new file mode 100644
index 0000000..e89da0a
--- /dev/null
+++ b/drivers/spi/spi-armada-3700.c
@@ -0,0 +1,923 @@
+/*
+ * Marvell Armada-3700 SPI controller driver
+ *
+ * Copyright (C) 2016 Marvell Ltd.
+ *
+ * Author: Wilson Ding <dingwei at marvell.com>
+ * Author: Romain Perier <romain.perier at free-electrons.com>
+ *
+ * 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.
+ */
+
+#include <linux/clk.h>
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/of_device.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/spi/spi.h>
+
+#define DRIVER_NAME "armada_3700_spi"
+
+#define A3700_SPI_TIMEOUT 10
+
+/* SPI Register Offest */
+#define A3700_SPI_IF_CTRL_REG 0x00
+#define A3700_SPI_IF_CFG_REG 0x04
+#define A3700_SPI_DATA_OUT_REG 0x08
+#define A3700_SPI_DATA_IN_REG 0x0C
+#define A3700_SPI_IF_INST_REG 0x10
+#define A3700_SPI_IF_ADDR_REG 0x14
+#define A3700_SPI_IF_RMODE_REG 0x18
+#define A3700_SPI_IF_HDR_CNT_REG 0x1C
+#define A3700_SPI_IF_DIN_CNT_REG 0x20
+#define A3700_SPI_IF_TIME_REG 0x24
+#define A3700_SPI_INT_STAT_REG 0x28
+#define A3700_SPI_INT_MASK_REG 0x2C
+
+/* A3700_SPI_IF_CTRL_REG */
+#define A3700_SPI_EN BIT(16)
+#define A3700_SPI_ADDR_NOT_CONFIG BIT(12)
+#define A3700_SPI_WFIFO_OVERFLOW BIT(11)
+#define A3700_SPI_WFIFO_UNDERFLOW BIT(10)
+#define A3700_SPI_RFIFO_OVERFLOW BIT(9)
+#define A3700_SPI_RFIFO_UNDERFLOW BIT(8)
+#define A3700_SPI_WFIFO_FULL BIT(7)
+#define A3700_SPI_WFIFO_EMPTY BIT(6)
+#define A3700_SPI_RFIFO_FULL BIT(5)
+#define A3700_SPI_RFIFO_EMPTY BIT(4)
+#define A3700_SPI_WFIFO_RDY BIT(3)
+#define A3700_SPI_RFIFO_RDY BIT(2)
+#define A3700_SPI_XFER_RDY BIT(1)
+#define A3700_SPI_XFER_DONE BIT(0)
+
+/* A3700_SPI_IF_CFG_REG */
+#define A3700_SPI_WFIFO_THRS BIT(28)
+#define A3700_SPI_RFIFO_THRS BIT(24)
+#define A3700_SPI_AUTO_CS BIT(20)
+#define A3700_SPI_DMA_RD_EN BIT(18)
+#define A3700_SPI_FIFO_MODE BIT(17)
+#define A3700_SPI_SRST BIT(16)
+#define A3700_SPI_XFER_START BIT(15)
+#define A3700_SPI_XFER_STOP BIT(14)
+#define A3700_SPI_INST_PIN BIT(13)
+#define A3700_SPI_ADDR_PIN BIT(12)
+#define A3700_SPI_DATA_PIN1 BIT(11)
+#define A3700_SPI_DATA_PIN0 BIT(10)
+#define A3700_SPI_FIFO_FLUSH BIT(9)
+#define A3700_SPI_RW_EN BIT(8)
+#define A3700_SPI_CLK_POL BIT(7)
+#define A3700_SPI_CLK_PHA BIT(6)
+#define A3700_SPI_BYTE_LEN BIT(5)
+#define A3700_SPI_CLK_PRESCALE BIT(0)
+#define A3700_SPI_CLK_PRESCALE_MASK (0x1f)
+
+#define A3700_SPI_WFIFO_THRS_BIT 28
+#define A3700_SPI_RFIFO_THRS_BIT 24
+#define A3700_SPI_FIFO_THRS_MASK 0x7
+
+#define A3700_SPI_DATA_PIN_MASK 0x3
+
+/* A3700_SPI_IF_HDR_CNT_REG */
+#define A3700_SPI_DUMMY_CNT_BIT 12
+#define A3700_SPI_DUMMY_CNT_MASK 0x7
+#define A3700_SPI_RMODE_CNT_BIT 8
+#define A3700_SPI_RMODE_CNT_MASK 0x3
+#define A3700_SPI_ADDR_CNT_BIT 4
+#define A3700_SPI_ADDR_CNT_MASK 0x7
+#define A3700_SPI_INSTR_CNT_BIT 0
+#define A3700_SPI_INSTR_CNT_MASK 0x3
+
+/* A3700_SPI_IF_TIME_REG */
+#define A3700_SPI_CLK_CAPT_EDGE BIT(7)
+
+/* Flags and macros for struct a3700_spi */
+#define A3700_INSTR_CNT 1
+#define A3700_ADDR_CNT 3
+#define A3700_DUMMY_CNT 1
+
+struct a3700_spi {
+ struct spi_master *master;
+ void __iomem *base;
+ struct clk *clk;
+ unsigned int irq;
+ unsigned int flags;
+ bool xmit_data;
+ const u8 *tx_buf;
+ u8 *rx_buf;
+ size_t buf_len;
+ u8 byte_len;
+ u32 wait_mask;
+ struct completion done;
+ u32 addr_cnt;
+ u32 instr_cnt;
+ size_t hdr_cnt;
+};
+
+static u32 spireg_read(struct a3700_spi *a3700_spi, u32 offset)
+{
+ return readl(a3700_spi->base + offset);
+}
+
+static void spireg_write(struct a3700_spi *a3700_spi, u32 offset, u32 data)
+{
+ writel(data, a3700_spi->base + offset);
+}
+
+static void a3700_spi_auto_cs_unset(struct a3700_spi *a3700_spi)
+{
+ u32 val;
+
+ val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+ val &= ~A3700_SPI_AUTO_CS;
+ spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+}
+
+static void a3700_spi_activate_cs(struct a3700_spi *a3700_spi, unsigned int cs)
+{
+ u32 val;
+
+ val = spireg_read(a3700_spi, A3700_SPI_IF_CTRL_REG);
+ val |= (A3700_SPI_EN << cs);
+ spireg_write(a3700_spi, A3700_SPI_IF_CTRL_REG, val);
+}
+
+static void a3700_spi_deactivate_cs(struct a3700_spi *a3700_spi,
+ unsigned int cs)
+{
+ u32 val;
+
+ val = spireg_read(a3700_spi, A3700_SPI_IF_CTRL_REG);
+ val &= ~(A3700_SPI_EN << cs);
+ spireg_write(a3700_spi, A3700_SPI_IF_CTRL_REG, val);
+}
+
+static int a3700_spi_pin_mode_set(struct a3700_spi *a3700_spi,
+ unsigned int pin_mode)
+{
+ u32 val;
+
+ val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+ val &= ~(A3700_SPI_INST_PIN | A3700_SPI_ADDR_PIN);
+ val &= ~(A3700_SPI_DATA_PIN0 | A3700_SPI_DATA_PIN1);
+
+ switch (pin_mode) {
+ case 1:
+ break;
+ case 2:
+ val |= A3700_SPI_DATA_PIN0;
+ break;
+ case 4:
+ val |= A3700_SPI_DATA_PIN1;
+ break;
+ default:
+ dev_err(&a3700_spi->master->dev, "wrong pin mode %u", pin_mode);
+ return -EINVAL;
+ }
+
+ spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+
+ return 0;
+}
+
+static void a3700_spi_fifo_mode_set(struct a3700_spi *a3700_spi)
+{
+ u32 val;
+
+ val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+ val |= A3700_SPI_FIFO_MODE;
+ spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+}
+
+static void a3700_spi_mode_set(struct a3700_spi *a3700_spi,
+ unsigned int mode_bits)
+{
+ u32 val;
+
+ val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+
+ if (mode_bits & SPI_CPOL)
+ val |= A3700_SPI_CLK_POL;
+ else
+ val &= ~A3700_SPI_CLK_POL;
+
+ if (mode_bits & SPI_CPHA)
+ val |= A3700_SPI_CLK_PHA;
+ else
+ val &= ~A3700_SPI_CLK_PHA;
+
+ spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+}
+
+static void a3700_spi_clock_set(struct a3700_spi *a3700_spi,
+ unsigned int speed_hz, u16 mode)
+{
+ u32 val;
+ u32 prescale;
+
+ prescale = DIV_ROUND_UP(clk_get_rate(a3700_spi->clk), speed_hz);
+
+ val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+ val = val & ~A3700_SPI_CLK_PRESCALE_MASK;
+
+ val = val | (prescale & A3700_SPI_CLK_PRESCALE_MASK);
+ spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+
+ if (prescale <= 2) {
+ val = spireg_read(a3700_spi, A3700_SPI_IF_TIME_REG);
+ val |= A3700_SPI_CLK_CAPT_EDGE;
+ spireg_write(a3700_spi, A3700_SPI_IF_TIME_REG, val);
+ }
+
+ val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+ val &= ~(A3700_SPI_CLK_POL | A3700_SPI_CLK_PHA);
+
+ if (mode & SPI_CPOL)
+ val |= A3700_SPI_CLK_POL;
+
+ if (mode & SPI_CPHA)
+ val |= A3700_SPI_CLK_PHA;
+
+ spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+}
+
+static void a3700_spi_bytelen_set(struct a3700_spi *a3700_spi, unsigned int len)
+{
+ u32 val;
+
+ val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+ if (len == 4)
+ val |= A3700_SPI_BYTE_LEN;
+ else
+ val &= ~A3700_SPI_BYTE_LEN;
+ spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+
+ a3700_spi->byte_len = len;
+}
+
+static int a3700_spi_fifo_flush(struct a3700_spi *a3700_spi)
+{
+ int timeout = A3700_SPI_TIMEOUT;
+ u32 val;
+
+ val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+ val |= A3700_SPI_FIFO_FLUSH;
+ spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+
+ while (--timeout) {
+ val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+ if (!(val & A3700_SPI_FIFO_FLUSH))
+ return 0;
+ udelay(1);
+ }
+
+ return -ETIMEDOUT;
+}
+
+static int a3700_spi_init(struct a3700_spi *a3700_spi)
+{
+ struct spi_master *master = a3700_spi->master;
+ u32 val;
+ int i, ret = 0;
+
+ /* Reset SPI unit */
+ val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+ val |= A3700_SPI_SRST;
+ spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+
+ udelay(A3700_SPI_TIMEOUT);
+
+ val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+ val &= ~A3700_SPI_SRST;
+ spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+
+ /* Disable AUTO_CS and deactivate all chip-selects */
+ a3700_spi_auto_cs_unset(a3700_spi);
+ for (i = 0; i < master->num_chipselect; i++)
+ a3700_spi_deactivate_cs(a3700_spi, i);
+
+ /* Enable FIFO mode */
+ a3700_spi_fifo_mode_set(a3700_spi);
+
+ /* Set SPI mode */
+ a3700_spi_mode_set(a3700_spi, master->mode_bits);
+
+ /* Reset counters */
+ spireg_write(a3700_spi, A3700_SPI_IF_HDR_CNT_REG, 0);
+ spireg_write(a3700_spi, A3700_SPI_IF_DIN_CNT_REG, 0);
+
+ /* Mask the interrupts and clear cause bits */
+ spireg_write(a3700_spi, A3700_SPI_INT_MASK_REG, 0);
+ spireg_write(a3700_spi, A3700_SPI_INT_STAT_REG, ~0U);
+
+ return ret;
+}
+
+static irqreturn_t a3700_spi_interrupt(int irq, void *dev_id)
+{
+ struct spi_master *master = dev_id;
+ struct a3700_spi *a3700_spi;
+ u32 cause;
+
+ a3700_spi = spi_master_get_devdata(master);
+
+ /* Get interrupt causes */
+ cause = spireg_read(a3700_spi, A3700_SPI_INT_STAT_REG);
+
+ if (!cause || !(a3700_spi->wait_mask & cause))
+ return IRQ_NONE;
+
+ /* mask and acknowledge the SPI interrupts */
+ spireg_write(a3700_spi, A3700_SPI_INT_MASK_REG, 0);
+ spireg_write(a3700_spi, A3700_SPI_INT_STAT_REG, cause);
+
+ /* Wake up the transfer */
+ if (a3700_spi->wait_mask & cause)
+ complete(&a3700_spi->done);
+
+ return IRQ_HANDLED;
+}
+
+static bool a3700_spi_wait_completion(struct spi_device *spi)
+{
+ struct a3700_spi *a3700_spi;
+ unsigned int timeout;
+ unsigned int ctrl_reg;
+ unsigned long timeout_jiffies;
+
+ a3700_spi = spi_master_get_devdata(spi->master);
+
+ /* SPI interrupt is edge-triggered, which means an interrupt will
+ * be generated only when detecting a specific status bit changed
+ * from '0' to '1'. So when we start waiting for a interrupt, we
+ * need to check status bit in control reg first, if it is already 1,
+ * then we do not need to wait for interrupt
+ */
+ ctrl_reg = spireg_read(a3700_spi, A3700_SPI_IF_CTRL_REG);
+ if (a3700_spi->wait_mask & ctrl_reg)
+ return true;
+
+ reinit_completion(&a3700_spi->done);
+
+ spireg_write(a3700_spi, A3700_SPI_INT_MASK_REG,
+ a3700_spi->wait_mask);
+
+ timeout_jiffies = msecs_to_jiffies(A3700_SPI_TIMEOUT);
+ timeout = wait_for_completion_timeout(&a3700_spi->done,
+ timeout_jiffies);
+
+ a3700_spi->wait_mask = 0;
+
+ if (timeout)
+ return true;
+
+ /* there might be the case that right after we checked the
+ * status bits in this routine and before start to wait for
+ * interrupt by wait_for_completion_timeout, the interrupt
+ * happens, to avoid missing it we need to double check
+ * status bits in control reg, if it is already 1, then
+ * consider that we have the interrupt successfully and
+ * return true.
+ */
+ ctrl_reg = spireg_read(a3700_spi, A3700_SPI_IF_CTRL_REG);
+ if (a3700_spi->wait_mask & ctrl_reg)
+ return true;
+
+ spireg_write(a3700_spi, A3700_SPI_INT_MASK_REG, 0);
+
+ return true;
+}
+
+static bool a3700_spi_transfer_wait(struct spi_device *spi,
+ unsigned int bit_mask)
+{
+ struct a3700_spi *a3700_spi;
+
+ a3700_spi = spi_master_get_devdata(spi->master);
+ a3700_spi->wait_mask = bit_mask;
+
+ return a3700_spi_wait_completion(spi);
+}
+
+static void a3700_spi_fifo_thres_set(struct a3700_spi *a3700_spi,
+ unsigned int bytes)
+{
+ u32 val;
+
+ val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+ val &= ~(A3700_SPI_FIFO_THRS_MASK << A3700_SPI_RFIFO_THRS_BIT);
+ val |= (bytes - 1) << A3700_SPI_RFIFO_THRS_BIT;
+ val &= ~(A3700_SPI_FIFO_THRS_MASK << A3700_SPI_WFIFO_THRS_BIT);
+ val |= (7 - bytes) << A3700_SPI_WFIFO_THRS_BIT;
+ spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+}
+
+static void a3700_spi_transfer_setup(struct spi_device *spi,
+ struct spi_transfer *xfer)
+{
+ struct a3700_spi *a3700_spi;
+ unsigned int byte_len;
+
+ a3700_spi = spi_master_get_devdata(spi->master);
+
+ a3700_spi_clock_set(a3700_spi, xfer->speed_hz, spi->mode);
+
+ byte_len = xfer->bits_per_word >> 3;
+
+ a3700_spi_fifo_thres_set(a3700_spi, byte_len);
+}
+
+static void a3700_spi_set_cs(struct spi_device *spi, bool enable)
+{
+ struct a3700_spi *a3700_spi = spi_master_get_devdata(spi->master);
+
+ if (!enable)
+ a3700_spi_activate_cs(a3700_spi, spi->chip_select);
+ else
+ a3700_spi_deactivate_cs(a3700_spi, spi->chip_select);
+}
+
+static void a3700_spi_header_set(struct a3700_spi *a3700_spi)
+{
+ u32 instr_cnt = 0, addr_cnt = 0, dummy_cnt = 0;
+ u32 val = 0;
+
+ /* Clear the header registers */
+ spireg_write(a3700_spi, A3700_SPI_IF_INST_REG, 0);
+ spireg_write(a3700_spi, A3700_SPI_IF_ADDR_REG, 0);
+ spireg_write(a3700_spi, A3700_SPI_IF_RMODE_REG, 0);
+
+ /* Set header counters */
+ if (a3700_spi->tx_buf) {
+ if (a3700_spi->buf_len <= a3700_spi->instr_cnt) {
+ instr_cnt = a3700_spi->buf_len;
+ } else if (a3700_spi->buf_len <= (a3700_spi->instr_cnt +
+ a3700_spi->addr_cnt)) {
+ instr_cnt = a3700_spi->instr_cnt;
+ addr_cnt = a3700_spi->buf_len - instr_cnt;
+ } else if (a3700_spi->buf_len <= a3700_spi->hdr_cnt) {
+ instr_cnt = a3700_spi->instr_cnt;
+ addr_cnt = a3700_spi->addr_cnt;
+ /* Need to handle the normal write case with 1 byte
+ * data
+ */
+ if (!a3700_spi->tx_buf[instr_cnt + addr_cnt])
+ dummy_cnt = a3700_spi->buf_len - instr_cnt -
+ addr_cnt;
+ }
+ val |= ((instr_cnt & A3700_SPI_INSTR_CNT_MASK)
+ << A3700_SPI_INSTR_CNT_BIT);
+ val |= ((addr_cnt & A3700_SPI_ADDR_CNT_MASK)
+ << A3700_SPI_ADDR_CNT_BIT);
+ val |= ((dummy_cnt & A3700_SPI_DUMMY_CNT_MASK)
+ << A3700_SPI_DUMMY_CNT_BIT);
+ }
+ spireg_write(a3700_spi, A3700_SPI_IF_HDR_CNT_REG, val);
+
+ /* Update the buffer length to be transferred */
+ a3700_spi->buf_len -= (instr_cnt + addr_cnt + dummy_cnt);
+
+ /* Set Instruction */
+ val = 0;
+ while (instr_cnt--) {
+ val = (val << 8) | a3700_spi->tx_buf[0];
+ a3700_spi->tx_buf++;
+ }
+ spireg_write(a3700_spi, A3700_SPI_IF_INST_REG, val);
+
+ /* Set Address */
+ val = 0;
+ while (addr_cnt--) {
+ val = (val << 8) | a3700_spi->tx_buf[0];
+ a3700_spi->tx_buf++;
+ }
+ spireg_write(a3700_spi, A3700_SPI_IF_ADDR_REG, val);
+}
+
+static int a3700_is_wfifo_full(struct a3700_spi *a3700_spi)
+{
+ u32 val;
+
+ val = spireg_read(a3700_spi, A3700_SPI_IF_CTRL_REG);
+ return (val & A3700_SPI_WFIFO_FULL);
+}
+
+static int a3700_spi_fifo_write(struct a3700_spi *a3700_spi)
+{
+ u32 val;
+ int i = 0;
+
+ while (!a3700_is_wfifo_full(a3700_spi) && a3700_spi->buf_len) {
+ val = 0;
+ if (a3700_spi->buf_len >= 4) {
+ val = cpu_to_le32(*(u32 *)a3700_spi->tx_buf);
+ spireg_write(a3700_spi, A3700_SPI_DATA_OUT_REG, val);
+
+ a3700_spi->buf_len -= 4;
+ a3700_spi->tx_buf += 4;
+ } else {
+ /*
+ * If the remained buffer length is less than 4-bytes,
+ * we should pad the write buffer with all ones. So that
+ * it avoids overwrite the unexpected bytes following
+ * the last one.
+ */
+ val = GENMASK(31, 0);
+ while (a3700_spi->buf_len) {
+ val &= ~(0xff << (8 * i));
+ val |= *a3700_spi->tx_buf++ << (8 * i);
+ i++;
+ a3700_spi->buf_len--;
+
+ spireg_write(a3700_spi, A3700_SPI_DATA_OUT_REG,
+ val);
+ }
+ break;
+ }
+ }
+
+ return 0;
+}
+
+static int a3700_is_rfifo_empty(struct a3700_spi *a3700_spi)
+{
+ u32 val = spireg_read(a3700_spi, A3700_SPI_IF_CTRL_REG);
+
+ return (val & A3700_SPI_RFIFO_EMPTY);
+}
+
+static int a3700_spi_fifo_read(struct a3700_spi *a3700_spi)
+{
+ u32 val;
+
+ while (!a3700_is_rfifo_empty(a3700_spi) && a3700_spi->buf_len) {
+ val = spireg_read(a3700_spi, A3700_SPI_DATA_IN_REG);
+ if (a3700_spi->buf_len >= 4) {
+ u32 data = le32_to_cpu(val);
+ memcpy(a3700_spi->rx_buf, &data, 4);
+
+ a3700_spi->buf_len -= 4;
+ a3700_spi->rx_buf += 4;
+ } else {
+ /*
+ * When remain bytes is not larger than 4, we should
+ * avoid memory overwriting and just write the left rx
+ * buffer bytes.
+ */
+ while (a3700_spi->buf_len) {
+ *a3700_spi->rx_buf = val & 0xff;
+ val >>= 8;
+
+ a3700_spi->buf_len--;
+ a3700_spi->rx_buf++;
+ }
+ }
+ }
+
+ return 0;
+}
+
+static void a3700_spi_transfer_abort_fifo(struct a3700_spi *a3700_spi)
+{
+ int timeout = A3700_SPI_TIMEOUT;
+ u32 val;
+
+ val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+ val |= A3700_SPI_XFER_STOP;
+ spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+
+ while (--timeout) {
+ val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+ if (!(val & A3700_SPI_XFER_START))
+ break;
+ udelay(1);
+ }
+
+ a3700_spi_fifo_flush(a3700_spi);
+
+ val &= ~A3700_SPI_XFER_STOP;
+ spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+}
+
+static int a3700_spi_prepare_message(struct spi_master *master,
+ struct spi_message *message)
+{
+ struct a3700_spi *a3700_spi = spi_master_get_devdata(master);
+ struct spi_device *spi = message->spi;
+ int ret;
+
+ ret = clk_enable(a3700_spi->clk);
+ if (ret) {
+ dev_err(&spi->dev, "failed to enable clk with error %d\n", ret);
+ return ret;
+ }
+
+ /* Flush the FIFOs */
+ ret = a3700_spi_fifo_flush(a3700_spi);
+ if (ret)
+ return ret;
+
+ a3700_spi_bytelen_set(a3700_spi, 4);
+
+ return 0;
+}
+
+static int a3700_spi_transfer_one(struct spi_master *master,
+ struct spi_device *spi,
+ struct spi_transfer *xfer)
+{
+ struct a3700_spi *a3700_spi = spi_master_get_devdata(master);
+ int ret = 0, timeout = A3700_SPI_TIMEOUT;
+ unsigned int nbits = 0;
+ u32 val;
+
+ a3700_spi_transfer_setup(spi, xfer);
+
+ a3700_spi->tx_buf = xfer->tx_buf;
+ a3700_spi->rx_buf = xfer->rx_buf;
+ a3700_spi->buf_len = xfer->len;
+
+ /* SPI transfer headers */
+ a3700_spi_header_set(a3700_spi);
+
+ if (xfer->tx_buf)
+ nbits = xfer->tx_nbits;
+ else if (xfer->rx_buf)
+ nbits = xfer->rx_nbits;
+
+ a3700_spi_pin_mode_set(a3700_spi, nbits);
+
+ if (xfer->rx_buf) {
+ /* Set read data length */
+ spireg_write(a3700_spi, A3700_SPI_IF_DIN_CNT_REG,
+ a3700_spi->buf_len);
+ /* Start READ transfer */
+ val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+ val &= ~A3700_SPI_RW_EN;
+ val |= A3700_SPI_XFER_START;
+ spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+ } else if (xfer->tx_buf) {
+ /* Start Write transfer */
+ val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+ val |= (A3700_SPI_XFER_START | A3700_SPI_RW_EN);
+ spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+
+ /*
+ * If there are data to be written to the SPI device, xmit_data
+ * flag is set true; otherwise the instruction in SPI_INSTR does
+ * not require data to be written to the SPI device, then
+ * xmit_data flag is set false.
+ */
+ a3700_spi->xmit_data = (a3700_spi->buf_len != 0);
+ }
+
+ while (a3700_spi->buf_len) {
+ if (a3700_spi->tx_buf) {
+ /* Wait wfifo ready */
+ if (!a3700_spi_transfer_wait(spi,
+ A3700_SPI_WFIFO_RDY)) {
+ dev_err(&spi->dev,
+ "wait wfifo ready timed out\n");
+ ret = -ETIMEDOUT;
+ goto error;
+ }
+ /* Fill up the wfifo */
+ ret = a3700_spi_fifo_write(a3700_spi);
+ if (ret)
+ goto error;
+ } else if (a3700_spi->rx_buf) {
+ /* Wait rfifo ready */
+ if (!a3700_spi_transfer_wait(spi,
+ A3700_SPI_RFIFO_RDY)) {
+ dev_err(&spi->dev,
+ "wait rfifo ready timed out\n");
+ ret = -ETIMEDOUT;
+ goto error;
+ }
+ /* Drain out the rfifo */
+ ret = a3700_spi_fifo_read(a3700_spi);
+ if (ret)
+ goto error;
+ }
+ }
+
+ /*
+ * Stop a write transfer in fifo mode:
+ * - wait all the bytes in wfifo to be shifted out
+ * - set XFER_STOP bit
+ * - wait XFER_START bit clear
+ * - clear XFER_STOP bit
+ * Stop a read transfer in fifo mode:
+ * - the hardware is to reset the XFER_START bit
+ * after the number of bytes indicated in DIN_CNT
+ * register
+ * - just wait XFER_START bit clear
+ */
+ if (a3700_spi->tx_buf) {
+ if (a3700_spi->xmit_data) {
+ /*
+ * If there are data written to the SPI device, wait
+ * until SPI_WFIFO_EMPTY is 1 to wait for all data to
+ * transfer out of write FIFO.
+ */
+ if (!a3700_spi_transfer_wait(spi,
+ A3700_SPI_WFIFO_EMPTY)) {
+ dev_err(&spi->dev, "wait wfifo empty timed out\n");
+ return -ETIMEDOUT;
+ }
+ } else {
+ /*
+ * If the instruction in SPI_INSTR does not require data
+ * to be written to the SPI device, wait until SPI_RDY
+ * is 1 for the SPI interface to be in idle.
+ */
+ if (!a3700_spi_transfer_wait(spi, A3700_SPI_XFER_RDY)) {
+ dev_err(&spi->dev, "wait xfer ready timed out\n");
+ return -ETIMEDOUT;
+ }
+ }
+
+ val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+ val |= A3700_SPI_XFER_STOP;
+ spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+ }
+
+ while (--timeout) {
+ val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+ if (!(val & A3700_SPI_XFER_START))
+ break;
+ udelay(1);
+ }
+
+ if (timeout == 0) {
+ dev_err(&spi->dev, "wait transfer start clear timed out\n");
+ ret = -ETIMEDOUT;
+ goto error;
+ }
+
+ val &= ~A3700_SPI_XFER_STOP;
+ spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+ goto out;
+
+error:
+ a3700_spi_transfer_abort_fifo(a3700_spi);
+out:
+ spi_finalize_current_transfer(master);
+
+ return ret;
+}
+
+static int a3700_spi_unprepare_message(struct spi_master *master,
+ struct spi_message *message)
+{
+ struct a3700_spi *a3700_spi = spi_master_get_devdata(master);
+
+ clk_disable(a3700_spi->clk);
+
+ return 0;
+}
+
+static const struct of_device_id a3700_spi_dt_ids[] = {
+ { .compatible = "marvell,armada-3700-spi", .data = NULL },
+ {},
+};
+
+MODULE_DEVICE_TABLE(of, a3700_spi_dt_ids);
+
+static int a3700_spi_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node *of_node = dev->of_node;
+ struct resource *res;
+ struct spi_master *master;
+ struct a3700_spi *spi;
+ u32 num_cs = 0;
+ int ret = 0;
+
+ master = spi_alloc_master(dev, sizeof(*spi));
+ if (!master) {
+ dev_err(dev, "master allocation failed\n");
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ if (of_property_read_u32(of_node, "num-cs", &num_cs)) {
+ dev_err(dev, "could not find num-cs\n");
+ ret = -ENXIO;
+ goto error;
+ }
+
+ master->bus_num = pdev->id;
+ master->dev.of_node = of_node;
+ master->mode_bits = SPI_MODE_3;
+ master->num_chipselect = num_cs;
+ master->bits_per_word_mask = SPI_BPW_MASK(8) | SPI_BPW_MASK(32);
+ master->prepare_message = a3700_spi_prepare_message;
+ master->transfer_one = a3700_spi_transfer_one;
+ master->unprepare_message = a3700_spi_unprepare_message;
+ master->set_cs = a3700_spi_set_cs;
+ master->flags = SPI_MASTER_HALF_DUPLEX;
+ master->mode_bits |= (SPI_RX_DUAL | SPI_RX_DUAL |
+ SPI_RX_QUAD | SPI_TX_QUAD);
+
+ platform_set_drvdata(pdev, master);
+
+ spi = spi_master_get_devdata(master);
+ memset(spi, 0, sizeof(struct a3700_spi));
+
+ spi->master = master;
+ spi->instr_cnt = A3700_INSTR_CNT;
+ spi->addr_cnt = A3700_ADDR_CNT;
+ spi->hdr_cnt = A3700_INSTR_CNT + A3700_ADDR_CNT +
+ A3700_DUMMY_CNT;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ spi->base = devm_ioremap_resource(dev, res);
+ if (IS_ERR(spi->base)) {
+ ret = PTR_ERR(spi->base);
+ goto error;
+ }
+
+ spi->irq = platform_get_irq(pdev, 0);
+ if (spi->irq < 0) {
+ dev_err(dev, "could not get irq: %d\n", spi->irq);
+ ret = -ENXIO;
+ goto error;
+ }
+
+ init_completion(&spi->done);
+
+ spi->clk = devm_clk_get(dev, NULL);
+ if (IS_ERR(spi->clk)) {
+ dev_err(dev, "could not find clk: %ld\n", PTR_ERR(spi->clk));
+ goto error;
+ }
+
+ ret = clk_prepare(spi->clk);
+ if (ret) {
+ dev_err(dev, "could not prepare clk: %d\n", ret);
+ goto error;
+ }
+
+ ret = a3700_spi_init(spi);
+ if (ret)
+ goto error_clk;
+
+ ret = devm_request_irq(dev, spi->irq, a3700_spi_interrupt, 0,
+ dev_name(dev), master);
+ if (ret) {
+ dev_err(dev, "could not request IRQ: %d\n", ret);
+ goto error_clk;
+ }
+
+ ret = devm_spi_register_master(dev, master);
+ if (ret) {
+ dev_err(dev, "Failed to register master\n");
+ goto error_clk;
+ }
+
+ return 0;
+
+error_clk:
+ clk_disable_unprepare(spi->clk);
+error:
+ spi_master_put(master);
+out:
+ return ret;
+}
+
+static int a3700_spi_remove(struct platform_device *pdev)
+{
+ struct spi_master *master = platform_get_drvdata(pdev);
+ struct a3700_spi *spi = spi_master_get_devdata(master);
+
+ clk_unprepare(spi->clk);
+ spi_master_put(master);
+
+ return 0;
+}
+
+static struct platform_driver a3700_spi_driver = {
+ .driver = {
+ .name = DRIVER_NAME,
+ .owner = THIS_MODULE,
+ .of_match_table = of_match_ptr(a3700_spi_dt_ids),
+ },
+ .probe = a3700_spi_probe,
+ .remove = a3700_spi_remove,
+};
+
+module_platform_driver(a3700_spi_driver);
+
+MODULE_DESCRIPTION("Armada-3700 SPI driver");
+MODULE_AUTHOR("Wilson Ding <dingwei at marvell.com>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" DRIVER_NAME);
--
2.9.3
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