On 23.09.2016 14:53, Jagan Teki wrote:
On Fri, Sep 23, 2016 at 5:47 PM, Stefan Roese <s...@denx.de> wrote:
The SPI IP core in the Marvell Armada 3700 is similar to the one in the
other Armada SoCs. But the differences are big enough that it makes
sense to introduce a new driver instead of cluttering the old
kirkwood driver with #ifdef's.

Signed-off-by: Stefan Roese <s...@denx.de>
Cc: Nadav Haklai <nad...@marvell.com>
Cc: Kostya Porotchkin <kos...@marvell.com>
Cc: Wilson Ding <ding...@marvell.com>
Cc: Victor Gu <x...@marvell.com>
Cc: Hua Jing <jing...@marvell.com>
Cc: Terry Zhou <bjz...@marvell.com>
Cc: Hanna Hawa <han...@marvell.com>
Cc: Haim Boot <ha...@marvell.com>
Cc: Jagan Teki <jt...@openedev.com>
---
v2:
- Evaluated hz and used values provided by the DT in mvebu_spi_set_speed()
  as suggested by Jagan

 drivers/spi/Kconfig           |   7 +
 drivers/spi/Makefile          |   1 +
 drivers/spi/mvebu_a3700_spi.c | 289 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 297 insertions(+)
 create mode 100644 drivers/spi/mvebu_a3700_spi.c

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 5da66a6..8724f87 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -68,6 +68,13 @@ config ICH_SPI
          access the SPI NOR flash on platforms embedding this Intel
          ICH IP core.

+config MVEBU_A3700_SPI
+       bool "Marvell Armada 3700 SPI driver"
+       help
+         Enable the Marvell Armada 3700 SPI driver. This driver can be
+         used to access the SPI NOR flash on platforms embedding this
+         Marvell IP core.
+
 config PIC32_SPI
        bool "Microchip PIC32 SPI driver"
        depends on MACH_PIC32
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index b1d9e20..247c5f6 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -37,6 +37,7 @@ obj-$(CONFIG_KIRKWOOD_SPI) += kirkwood_spi.o
 obj-$(CONFIG_LPC32XX_SSP) += lpc32xx_ssp.o
 obj-$(CONFIG_MPC52XX_SPI) += mpc52xx_spi.o
 obj-$(CONFIG_MPC8XXX_SPI) += mpc8xxx_spi.o
+obj-$(CONFIG_MVEBU_A3700_SPI) += mvebu_a3700_spi.o
 obj-$(CONFIG_MXC_SPI) += mxc_spi.o
 obj-$(CONFIG_MXS_SPI) += mxs_spi.o
 obj-$(CONFIG_OMAP3_SPI) += omap3_spi.o
diff --git a/drivers/spi/mvebu_a3700_spi.c b/drivers/spi/mvebu_a3700_spi.c
new file mode 100644
index 0000000..b566e03
--- /dev/null
+++ b/drivers/spi/mvebu_a3700_spi.c
@@ -0,0 +1,289 @@
+/*
+ * Copyright (C) 2015 Marvell International Ltd.
+ *
+ * Copyright (C) 2016 Stefan Roese <s...@denx.de>
+ *
+ * SPDX-License-Identifier:    GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <malloc.h>
+#include <spi.h>
+#include <wait_bit.h>
+#include <asm/io.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+#define SPI_TIMEOUT                            10000
+
+#define MVEBU_SPI_A3700_XFER_RDY               BIT(1)
+#define MVEBU_SPI_A3700_FIFO_FLUSH             BIT(9)
+#define MVEBU_SPI_A3700_BYTE_LEN               BIT(5)
+#define MVEBU_SPI_A3700_CLK_PHA                        BIT(6)
+#define MVEBU_SPI_A3700_CLK_POL                        BIT(7)
+#define MVEBU_SPI_A3700_FIFO_EN                        BIT(17)
+#define MVEBU_SPI_A3700_SPI_EN_0               BIT(16)
+#define MVEBU_SPI_A3700_CLK_PRESCALE_BIT       0
+#define MVEBU_SPI_A3700_CLK_PRESCALE_MASK      \
+       (0x1f << MVEBU_SPI_A3700_CLK_PRESCALE_BIT)
+
+/* SPI registers */
+struct spi_reg {
+       u32 ctrl;       /* 0x10600 */
+       u32 cfg;        /* 0x10604 */
+       u32 dout;       /* 0x10608 */
+       u32 din;        /* 0x1060c */
+};
+
+struct mvebu_spi_platdata {
+       struct spi_reg *spireg;
+       unsigned int frequency;
+       unsigned int clock;
+};
+
+static void spi_cs_activate(struct spi_reg *reg, int cs)
+{
+       setbits_le32(&reg->ctrl, MVEBU_SPI_A3700_SPI_EN_0 << cs);
+}
+
+static void spi_cs_deactivate(struct spi_reg *reg, int cs)
+{
+       clrbits_le32(&reg->ctrl, MVEBU_SPI_A3700_SPI_EN_0 << cs);
+}
+
+/**
+ * spi_legacy_shift_byte() - triggers the real SPI transfer
+ * @bytelen:   Indicate how many bytes to transfer.
+ * @dout:      Buffer address of what to send.
+ * @din:       Buffer address of where to receive.
+ *
+ * This function triggers the real SPI transfer in legacy mode. It
+ * will shift out char buffer from @dout, and shift in char buffer to
+ * @din, if necessary.
+ *
+ * This function assumes that only one byte is shifted at one time.
+ * However, it is not its responisbility to set the transfer type to
+ * one-byte. Also, it does not guarantee that it will work if transfer
+ * type becomes two-byte. See spi_set_legacy() for details.
+ *
+ * In legacy mode, simply write to the SPI_DOUT register will trigger
+ * the transfer.
+ *
+ * If @dout == NULL, which means no actual data needs to be sent out,
+ * then the function will shift out 0x00 in order to shift in data.
+ * The XFER_RDY flag is checked every time before accessing SPI_DOUT
+ * and SPI_DIN register.
+ *
+ * The number of transfers to be triggerred is decided by @bytelen.
+ *
+ * Return:     0 - cool
+ *             -ETIMEDOUT - XFER_RDY flag timeout
+ */
+static int spi_legacy_shift_byte(struct spi_reg *reg, unsigned int bytelen,
+                                const void *dout, void *din)
+{
+       const u8 *dout_8;
+       u8 *din_8;
+       int ret;
+
+       /* Use 0x00 as dummy dout */
+       const u8 dummy_dout = 0x0;
+       u32 pending_dout = 0x0;
+
+       /* dout_8: pointer of current dout */
+       dout_8 = dout;
+       /* din_8: pointer of current din */
+       din_8 = din;
+
+       while (bytelen) {
+               ret = wait_for_bit(__func__, &reg->ctrl,
+                                  MVEBU_SPI_A3700_XFER_RDY, true, 100, false);
+               if (ret)
+                       return ret;
+
+               if (dout)
+                       pending_dout = (u32)*dout_8;
+               else
+                       pending_dout = (u32)dummy_dout;
+
+               /* Trigger the xfer */
+               writel(pending_dout, &reg->dout);
+
+               if (din) {
+                       ret = wait_for_bit(__func__, &reg->ctrl,
+                                          MVEBU_SPI_A3700_XFER_RDY,
+                                          true, 100, false);
+                       if (ret)
+                               return ret;
+
+                       /* Read what is transferred in */
+                       *din_8 = (u8)readl(&reg->din);
+               }
+
+               /* Don't increment the current pointer if NULL */
+               if (dout)
+                       dout_8++;
+               if (din)
+                       din_8++;
+
+               bytelen--;
+       }
+
+       return 0;
+}
+
+static int mvebu_spi_xfer(struct udevice *dev, unsigned int bitlen,
+                         const void *dout, void *din, unsigned long flags)
+{
+       struct udevice *bus = dev->parent;
+       struct mvebu_spi_platdata *plat = dev_get_platdata(bus);
+       struct spi_reg *reg = plat->spireg;
+       unsigned int bytelen;
+       int ret;
+
+       bytelen = bitlen / 8;
+
+       if (dout && din)
+               debug("This is a duplex transfer.\n");
+
+       /* Activate CS */
+       if (flags & SPI_XFER_BEGIN) {
+               debug("SPI: activate cs.\n");
+               spi_cs_activate(reg, spi_chip_select(dev));
+       }
+
+       /* Send and/or receive */
+       if (dout || din) {
+               ret = spi_legacy_shift_byte(reg, bytelen, dout, din);
+               if (ret)
+                       return ret;
+       }
+
+       /* Deactivate CS */
+       if (flags & SPI_XFER_END) {
+               ret = wait_for_bit(__func__, &reg->ctrl,
+                                  MVEBU_SPI_A3700_XFER_RDY, true, 100, false);
+               if (ret)
+                       return ret;
+
+               debug("SPI: deactivate cs.\n");
+               spi_cs_deactivate(reg, spi_chip_select(dev));
+       }
+
+       return 0;
+}
+
+static int mvebu_spi_set_speed(struct udevice *bus, uint hz)
+{
+       struct mvebu_spi_platdata *plat = dev_get_platdata(bus);
+       struct spi_reg *reg = plat->spireg;
+       u32 data;
+
+       data = readl(&reg->cfg);
+
+       /* Set Prescaler */
+       data &= ~MVEBU_SPI_A3700_CLK_PRESCALE_MASK;
+
+       /* Calculate Prescaler = (spi_input_freq / spi_max_freq) */
+       if (hz > plat->frequency)
+               hz = plat->frequency;
+       data |= plat->clock / plat->frequency;

Need to use the hz to compute here.

Yes, hz should be used instead of plat->frequency here. Will fix
in v3. Thanks for noticing.

+
+       writel(data, &reg->cfg);
+
+       return 0;
+}
+
+static int mvebu_spi_set_mode(struct udevice *bus, uint mode)
+{
+       struct mvebu_spi_platdata *plat = dev_get_platdata(bus);
+       struct spi_reg *reg = plat->spireg;
+
+       /*
+        * Set SPI polarity
+        * 0: Serial interface clock is low when inactive
+        * 1: Serial interface clock is high when inactive
+        */
+       if (mode & SPI_CPOL)
+               setbits_le32(&reg->cfg, MVEBU_SPI_A3700_CLK_POL);
+       else
+               clrbits_le32(&reg->cfg, MVEBU_SPI_A3700_CLK_POL);
+       if (mode & SPI_CPHA)
+               setbits_le32(&reg->cfg, MVEBU_SPI_A3700_CLK_PHA);
+       else
+               clrbits_le32(&reg->cfg, MVEBU_SPI_A3700_CLK_PHA);
+
+       return 0;
+}
+
+static int mvebu_spi_probe(struct udevice *bus)
+{
+       struct mvebu_spi_platdata *plat = dev_get_platdata(bus);
+       struct spi_reg *reg = plat->spireg;
+       u32 data;
+       int ret;
+
+       /*
+        * Settings SPI controller to be working in legacy mode, which
+        * means use only DO pin (I/O 1) for Data Out, and DI pin (I/O 0)
+        * for Data In.
+        */
+
+       /* Flush read/write FIFO */
+       data = readl(&reg->cfg);
+       writel(data | MVEBU_SPI_A3700_FIFO_FLUSH, &reg->cfg);
+       ret = wait_for_bit(__func__, &reg->cfg, MVEBU_SPI_A3700_FIFO_FLUSH,
+                          false, 1000, false);
+       if (ret)
+               return ret;
+
+       /* Disable FIFO mode */
+       data &= ~MVEBU_SPI_A3700_FIFO_EN;
+
+       /* Always shift 1 byte at a time */
+       data &= ~MVEBU_SPI_A3700_BYTE_LEN;
+
+       writel(data, &reg->cfg);
+
+       return 0;
+}
+
+static int mvebu_spi_ofdata_to_platdata(struct udevice *bus)
+{
+       struct mvebu_spi_platdata *plat = dev_get_platdata(bus);
+
+       plat->spireg = (struct spi_reg *)dev_get_addr(bus);
+
+       plat->clock = fdtdec_get_int(gd->fdt_blob, bus->of_offset,
+                                    "clock-frequency", 160000);

I think this is not related to spi, global clock is it? usually we
can't use clock-frequency we set the clock with the help of
spi-max-frequency.

This is the input clock to the SPI IP core in the SoC. And
in most drivers I've seen so far, this frequency is configured
via some macros / defines. E.g.:

CONFIG_SYS_TCLK
CONFIG_CQSPI_REF_CLK
...

Best would be if this SPI input clock could be read via some
clock driver infrastructure. But this is something that we
don't have for MVEBU in U-Boot yet. So I can either switch back
to some define for this value here or leave it as the DT property
for now.

Thanks,
Stefan
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