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SubjectRE: [RFC PATCH 2/2] spi: spi-mem: Add support for Zynq QSPI controller
Date
Hi Vignesh,

Thanks for the review.

> -----Original Message-----
> From: Vignesh Raghavendra <vigneshr@ti.com>
> Sent: Friday, March 1, 2019 3:42 PM
> To: Naga Sureshkumar Relli <nagasure@xilinx.com>; broonie@kernel.org;
> bbrezillon@kernel.org
> Cc: linux-spi@vger.kernel.org; dwmw2@infradead.org; marek.vasut@gmail.com;
> richard@nod.at; linux-mtd@lists.infradead.org; linux-kernel@vger.kernel.org; Michal Simek
> <michals@xilinx.com>; nagasuresh12@gmail.com
> Subject: Re: [RFC PATCH 2/2] spi: spi-mem: Add support for Zynq QSPI controller
>
>
>
> On 28/02/19 12:32 PM, Naga Sureshkumar Relli wrote:
> > Add support for QSPI controller driver used by Xilinx Zynq SOC.
> >
> > Signed-off-by: Naga Sureshkumar Relli
> > <naga.sureshkumar.relli@xilinx.com>
> > ---
> > drivers/spi/Kconfig | 8 +
> > drivers/spi/Makefile | 1 +
> > drivers/spi/spi-zynq-qspi.c | 780
> > ++++++++++++++++++++++++++++++++++++++++++++
> > 3 files changed, 789 insertions(+)
> > create mode 100644 drivers/spi/spi-zynq-qspi.c
> >
> > diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig index
> > 9f89cb1..f12c880 100644
> > --- a/drivers/spi/Kconfig
> > +++ b/drivers/spi/Kconfig
> > @@ -816,6 +816,14 @@ config SPI_XTENSA_XTFPGA
> > 16 bit words in SPI mode 0, automatically asserting CS on transfer
> > start and deasserting on end.
> >
> > +config SPI_ZYNQ_QSPI
> > + tristate "Xilinx Zynq QSPI controller"
> > + depends on ARCH_ZYNQ
> > + help
> > + This enables support for the Zynq Quad SPI controller
> > + in master mode.
> > + This controller only supports SPI memory interface.
> > +
> > config SPI_ZYNQMP_GQSPI
> > tristate "Xilinx ZynqMP GQSPI controller"
> > depends on SPI_MASTER && HAS_DMA
> > diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile index
> > f296270..565db4d 100644
> > --- a/drivers/spi/Makefile
> > +++ b/drivers/spi/Makefile
> > @@ -115,6 +115,7 @@ obj-$(CONFIG_SPI_XCOMM) += spi-xcomm.o
> > obj-$(CONFIG_SPI_XILINX) += spi-xilinx.o
> > obj-$(CONFIG_SPI_XLP) += spi-xlp.o
> > obj-$(CONFIG_SPI_XTENSA_XTFPGA) += spi-xtensa-xtfpga.o
> > +obj-$(CONFIG_SPI_ZYNQ_QSPI) += spi-zynq-qspi.o
> > obj-$(CONFIG_SPI_ZYNQMP_GQSPI) += spi-zynqmp-gqspi.o
> >
> > # SPI slave protocol handlers
> > diff --git a/drivers/spi/spi-zynq-qspi.c b/drivers/spi/spi-zynq-qspi.c
> > new file mode 100644 index 0000000..87c9ec2
> > --- /dev/null
> > +++ b/drivers/spi/spi-zynq-qspi.c
> > @@ -0,0 +1,780 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * Copyright (C) 2019 Xilinx, Inc.
> > + *
> > + * Author: Naga Sureshkumar Relli <nagasure@xilinx.com> */
> > +
> > +#include <linux/clk.h>
> > +#include <linux/delay.h>
> > +#include <linux/gpio.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/io.h>
> > +#include <linux/module.h>
> > +#include <linux/of_irq.h>
> > +#include <linux/of_address.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/spi/spi.h>
> > +#include <linux/workqueue.h>
> > +#include <linux/spi/spi-mem.h>
> > +
> > +/* Register offset definitions */
> > +#define ZYNQ_QSPI_CONFIG_OFFSET 0x00 /* Configuration Register, RW
> */
> > +#define ZYNQ_QSPI_STATUS_OFFSET 0x04 /* Interrupt Status Register, RO
> */
> > +#define ZYNQ_QSPI_IEN_OFFSET 0x08 /* Interrupt Enable Register,
> WO */
> > +#define ZYNQ_QSPI_IDIS_OFFSET 0x0C /* Interrupt Disable Reg, WO
> */
> > +#define ZYNQ_QSPI_IMASK_OFFSET 0x10 /* Interrupt Enabled Mask
> Reg,RO */
> > +#define ZYNQ_QSPI_ENABLE_OFFSET 0x14 /* Enable/Disable Register, RW
> */
> > +#define ZYNQ_QSPI_DELAY_OFFSET 0x18 /* Delay Register, RW */
> > +#define ZYNQ_QSPI_TXD_00_00_OFFSET 0x1C /* Transmit 4-byte inst, WO */
> > +#define ZYNQ_QSPI_TXD_00_01_OFFSET 0x80 /* Transmit 1-byte inst, WO */
> > +#define ZYNQ_QSPI_TXD_00_10_OFFSET 0x84 /* Transmit 2-byte inst, WO */
> > +#define ZYNQ_QSPI_TXD_00_11_OFFSET 0x88 /* Transmit 3-byte inst, WO */
> > +#define ZYNQ_QSPI_RXD_OFFSET 0x20 /* Data Receive Register, RO */
> > +#define ZYNQ_QSPI_SIC_OFFSET 0x24 /* Slave Idle Count Register,
> RW */
> > +#define ZYNQ_QSPI_TX_THRESH_OFFSET 0x28 /* TX FIFO Watermark Reg,
> RW */
> > +#define ZYNQ_QSPI_RX_THRESH_OFFSET 0x2C /* RX FIFO Watermark Reg,
> RW */
> > +#define ZYNQ_QSPI_GPIO_OFFSET 0x30 /* GPIO Register, RW */
> > +#define ZYNQ_QSPI_LINEAR_CFG_OFFSET 0xA0 /* Linear Adapter Config Ref,
> RW */
> > +#define ZYNQ_QSPI_MOD_ID_OFFSET 0xFC /* Module ID Register, RO */
> > +
> > +/*
> > + * QSPI Configuration Register bit Masks
> > + *
> > + * This register contains various control bits that effect the
> > +operation
> > + * of the QSPI controller
> > + */
> > +#define ZYNQ_QSPI_CONFIG_IFMODE_MASK 0x80000000 /* Flash Memory
> Interface */
> > +#define ZYNQ_QSPI_CONFIG_MANSRT_MASK 0x00010000 /* Manual TX
> Start */
> > +#define ZYNQ_QSPI_CONFIG_MANSRTEN_MASK 0x00008000 /* Enable
> Manual TX Mode */
> > +#define ZYNQ_QSPI_CONFIG_SSFORCE_MASK 0x00004000 /* Manual Chip
> Select */
> > +#define ZYNQ_QSPI_CONFIG_BDRATE_MASK 0x00000038 /* Baud Rate Divisor
> Mask */
> > +#define ZYNQ_QSPI_CONFIG_CPHA_MASK 0x00000004 /* Clock Phase Control
> */
> > +#define ZYNQ_QSPI_CONFIG_CPOL_MASK 0x00000002 /* Clock Polarity Control
> */
> > +#define ZYNQ_QSPI_CONFIG_SSCTRL_MASK 0x00000400 /* Slave Select Mask */
> > +#define ZYNQ_QSPI_CONFIG_FWIDTH_MASK 0x000000C0 /* FIFO width
> */
> > +#define ZYNQ_QSPI_CONFIG_MSTREN_MASK 0x00000001 /* Master Mode
> */
> > +
>
> Convert to GENMASK() and BIT() macros
Ok, I will update it.
>
> > +/*
> > + * QSPI Configuration Register - Baud rate and slave select
> > + *
> > + * These are the values used in the calculation of baud rate divisor
> > +and
> > + * setting the slave select.
> > + */
> > +#define ZYNQ_QSPI_BAUD_DIV_MAX 7 /* Baud rate divisor maximum */
> > +#define ZYNQ_QSPI_BAUD_DIV_SHIFT 3 /* Baud rate divisor shift in CR */
> > +#define ZYNQ_QSPI_SS_SHIFT 10 /* Slave Select field shift in CR */
> > +
> > +/*
> > + * QSPI Interrupt Registers bit Masks
> > + *
> > + * All the four interrupt registers (Status/Mask/Enable/Disable) have
> > +the same
> > + * bit definitions.
> > + */
> > +#define ZYNQ_QSPI_IXR_RX_OVERFLOW_MASK 0x00000001 /* QSPI RX
> FIFO Overflow */
> > +#define ZYNQ_QSPI_IXR_TXNFULL_MASK 0x00000004 /* QSPI TX FIFO
> Overflow */
> > +#define ZYNQ_QSPI_IXR_TXFULL_MASK 0x00000008 /* QSPI TX FIFO is full
> */
> > +#define ZYNQ_QSPI_IXR_RXNEMTY_MASK 0x00000010 /* QSPI RX FIFO Not
> Empty */
> > +#define ZYNQ_QSPI_IXR_RXF_FULL_MASK 0x00000020 /* QSPI RX FIFO is full
> */
> > +#define ZYNQ_QSPI_IXR_TXF_UNDRFLOW_MASK 0x00000040 /* QSPI TX
> FIFO Underflow */
> > +#define ZYNQ_QSPI_IXR_ALL_MASK
> (ZYNQ_QSPI_IXR_RX_OVERFLOW_MASK | \
> > + ZYNQ_QSPI_IXR_TXNFULL_MASK | \
> > + ZYNQ_QSPI_IXR_TXFULL_MASK | \
> > + ZYNQ_QSPI_IXR_RXNEMTY_MASK | \
> > + ZYNQ_QSPI_IXR_RXF_FULL_MASK | \
> > + ZYNQ_QSPI_IXR_TXF_UNDRFLOW_MASK)
> > +#define ZYNQ_QSPI_IXR_RXTX_MASK
> (ZYNQ_QSPI_IXR_TXNFULL_MASK | \
> > + ZYNQ_QSPI_IXR_RXNEMTY_MASK)
> > +
>
> Convert to GENMASK() and BIT() macros
Ok, will change it.
>
> > +/*
> > + * QSPI Enable Register bit Masks
> > + *
> > + * This register is used to enable or disable the QSPI controller */
> > +#define ZYNQ_QSPI_ENABLE_ENABLE_MASK 0x00000001 /* QSPI Enable
> Bit Mask */
> > +
> > +/*
> > + * QSPI Linear Configuration Register
> > + *
> > + * It is named Linear Configuration but it controls other modes when
> > +not in
> > + * linear mode also.
> > + */
> > +#define ZYNQ_QSPI_LCFG_TWO_MEM_MASK 0x40000000 /* LQSPI Two
> memories Mask */
> > +#define ZYNQ_QSPI_LCFG_SEP_BUS_MASK 0x20000000 /* LQSPI Separate bus
> Mask */
> > +#define ZYNQ_QSPI_LCFG_U_PAGE_MASK 0x10000000 /* LQSPI Upper Page
> Mask */
> > +
>
> Convert to GENMASK() and BIT() macros
Ok, will change it
>
> > +#define ZYNQ_QSPI_LCFG_DUMMY_SHIFT 8
> > +
> > +#define ZYNQ_QSPI_FAST_READ_QOUT_CODE 0x6B /* read instruction code
> */
> > +#define ZYNQ_QSPI_FIFO_DEPTH 63 /* FIFO depth in words */
> > +#define ZYNQ_QSPI_RX_THRESHOLD 32 /* Rx FIFO threshold level */
> > +#define ZYNQ_QSPI_TX_THRESHOLD 1 /* Tx FIFO threshold level */
> > +
> > +/*
> > + * The modebits configurable by the driver to make the SPI support
> > +different
> > + * data formats
> > + */
> > +#define MODEBITS (SPI_CPOL | SPI_CPHA)
> > +
>
> Rename as ZYNQ_QSPI_MODEBITS to avoid namespace conflicts
Ok, will update.
>
> > +/* Default number of chip selects */
> > +#define ZYNQ_QSPI_DEFAULT_NUM_CS 1
> > +
> > +/**
> > + * struct zynq_qspi - Defines qspi driver instance
> > + * @regs: Virtual address of the QSPI controller registers
> > + * @refclk: Pointer to the peripheral clock
> > + * @pclk: Pointer to the APB clock
> > + * @irq: IRQ number
> > + * @txbuf: Pointer to the TX buffer
> > + * @rxbuf: Pointer to the RX buffer
> > + * @tx_bytes: Number of bytes left to transfer
> > + * @rx_bytes: Number of bytes left to receive
> > + * @data_completion: completion structure
> > + */
> > +struct zynq_qspi {
> > + struct device *dev;
> > + void __iomem *regs;
> > + struct clk *refclk;
> > + struct clk *pclk;
> > + int irq;
> > + u8 *txbuf;
> > + u8 *rxbuf;
> > + int tx_bytes;
> > + int rx_bytes;
> > + struct completion data_completion;
> > +};
> > +
> > +/*
> > + * Inline functions for the QSPI controller read/write */ static
> > +inline u32 zynq_qspi_read(struct zynq_qspi *xqspi, u32 offset) {
> > + return readl_relaxed(xqspi->regs + offset); }
> > +
> > +static inline void zynq_qspi_write(struct zynq_qspi *xqspi, u32 offset,
> > + u32 val)
> > +{
> > + writel_relaxed(val, xqspi->regs + offset); }
> > +
> > +/**
> > + * zynq_qspi_init_hw - Initialize the hardware
> > + * @xqspi: Pointer to the zynq_qspi structure
> > + *
> > + * The default settings of the QSPI controller's configurable
> > +parameters on
> > + * reset are
> > + * - Master mode
> > + * - Baud rate divisor is set to 2
> > + * - Tx threshold set to 1l Rx threshold set to 32
> > + * - Flash memory interface mode enabled
> > + * - Size of the word to be transferred as 8 bit
> > + * This function performs the following actions
> > + * - Disable and clear all the interrupts
> > + * - Enable manual slave select
> > + * - Enable manual start
> > + * - Deselect all the chip select lines
> > + * - Set the size of the word to be transferred as 32 bit
> > + * - Set the little endian mode of TX FIFO and
> > + * - Enable the QSPI controller
> > + */
> > +static void zynq_qspi_init_hw(struct zynq_qspi *xqspi) {
> > + u32 config_reg;
> > +
> > + zynq_qspi_write(xqspi, ZYNQ_QSPI_ENABLE_OFFSET, 0);
> > + zynq_qspi_write(xqspi, ZYNQ_QSPI_IDIS_OFFSET,
> > +ZYNQ_QSPI_IXR_ALL_MASK);
> > +
> > + /* Disable linear mode as the boot loader may have used it */
> > + zynq_qspi_write(xqspi, ZYNQ_QSPI_LINEAR_CFG_OFFSET, 0);
> > +
> > + /* Clear the RX FIFO */
> > + while (zynq_qspi_read(xqspi, ZYNQ_QSPI_STATUS_OFFSET) &
> > + ZYNQ_QSPI_IXR_RXNEMTY_MASK)
> > + zynq_qspi_read(xqspi, ZYNQ_QSPI_RXD_OFFSET);
> > +
> > + zynq_qspi_write(xqspi, ZYNQ_QSPI_STATUS_OFFSET,
> ZYNQ_QSPI_IXR_ALL_MASK);
> > + config_reg = zynq_qspi_read(xqspi, ZYNQ_QSPI_CONFIG_OFFSET);
> > + config_reg &= ~(ZYNQ_QSPI_CONFIG_MSTREN_MASK |
> > + ZYNQ_QSPI_CONFIG_CPOL_MASK |
> > + ZYNQ_QSPI_CONFIG_CPHA_MASK |
> > + ZYNQ_QSPI_CONFIG_BDRATE_MASK |
> > + ZYNQ_QSPI_CONFIG_SSFORCE_MASK |
> > + ZYNQ_QSPI_CONFIG_MANSRTEN_MASK |
> > + ZYNQ_QSPI_CONFIG_MANSRT_MASK);
> > + config_reg |= (ZYNQ_QSPI_CONFIG_MSTREN_MASK |
> > + ZYNQ_QSPI_CONFIG_SSFORCE_MASK |
> > + ZYNQ_QSPI_CONFIG_FWIDTH_MASK |
> > + ZYNQ_QSPI_CONFIG_IFMODE_MASK);
> > + zynq_qspi_write(xqspi, ZYNQ_QSPI_CONFIG_OFFSET, config_reg);
> > +
> > + zynq_qspi_write(xqspi, ZYNQ_QSPI_RX_THRESH_OFFSET,
> > + ZYNQ_QSPI_RX_THRESHOLD);
> > + zynq_qspi_write(xqspi, ZYNQ_QSPI_TX_THRESH_OFFSET,
> > + ZYNQ_QSPI_TX_THRESHOLD);
> > +
> > + zynq_qspi_write(xqspi, ZYNQ_QSPI_ENABLE_OFFSET,
> > + ZYNQ_QSPI_ENABLE_ENABLE_MASK);
> > +}
> > +
> > +static int zynq_qspi_check_buswidth(u8 width) {
> > + switch (width) {
> > + case 1:
> > + case 2:
> > + case 4:
> > + return 0;
> > + }
> > +
> > + return -ENOTSUPP;
> > +}
> > +
> > +static bool zynq_qspi_supports_op(struct spi_mem *mem,
> > + const struct spi_mem_op *op)
> > +{
> > + int ret;
> > +
> > + ret = zynq_qspi_check_buswidth(op->cmd.buswidth);
> > +
> > + if (op->addr.nbytes)
> > + ret |= zynq_qspi_check_buswidth(op->addr.buswidth);
> > +
> > + if (op->dummy.nbytes)
> > + ret |= zynq_qspi_check_buswidth(op->dummy.buswidth);
> > +
> > + if (op->data.nbytes)
> > + ret |= zynq_qspi_check_buswidth(op->data.buswidth);
> > +
> > + if (ret)
> > + return false;
> > +
>
> spi_mem_default_supports_op() already has this code.
> Could you change, spi_mem_supports_op() to call
> spi_mem_default_supports_op() first before controller specific
> ->supports_op()? So that, above code can be dropped.
Ok, I will update it.
>
> > + /*
> > + * The number of address bytes should be equal to or less than 3 bytes.
> > + */
> > + if (op->addr.nbytes > 3)
> > + return false;
> > +
>
> Hmm, how does the driver handle flash devices >16MB in size? Not supported?
Zynq QSPI controller doesn't support 4 byte addressing.
So to support > 16MB size, we have to use EAR(extended address register).
As it is initial version of driver, I haven't added this code. This needs to be added in spi-nor.c.
Previously I have sent an RFC patch to support all these.
But Boris suggested to upstream the basic one first under spi-mem frame work.
Not only this support, there are other features like dual parallel and dual stacked.
All these features require additional support from spi-nor framework.
We have another QSPI controller on ZynqMP SOC, which is also similar(but it supports 4Byte addressing).
So by consolidating all these, I sent this patch.

Please let me know your suggestion on this.
>
> > + return true;
> > +}
> > +
> > +/**
> > + * zynq_qspi_rxfifo_op - Read 1..4 bytes from RxFIFO to RX buffer
> > + * @xqspi: Pointer to the zynq_qspi structure
> > + * @size: Number of bytes to be read (1..4)
> > + */
> > +static void zynq_qspi_rxfifo_op(struct zynq_qspi *xqspi, unsigned int
> > +size) {
> > + u32 data;
> > +
> > + data = zynq_qspi_read(xqspi, ZYNQ_QSPI_RXD_OFFSET);
> > +
> > + if (xqspi->rxbuf) {
> > + memcpy(xqspi->rxbuf, ((u8 *)&data) + 4 - size, size);
> > + xqspi->rxbuf += size;
> > + }
> > +
> > + xqspi->rx_bytes -= size;
> > + if (xqspi->rx_bytes < 0)
> > + xqspi->rx_bytes = 0;
> > +}
> > +
> > +/**
> > + * zynq_qspi_txfifo_op - Write 1..4 bytes from TX buffer to TxFIFO
> > + * @xqspi: Pointer to the zynq_qspi structure
> > + * @size: Number of bytes to be written (1..4)
> > + */
> > +static void zynq_qspi_txfifo_op(struct zynq_qspi *xqspi, unsigned int
> > +size) {
> > + static const unsigned int offset[4] = {
> > + ZYNQ_QSPI_TXD_00_01_OFFSET, ZYNQ_QSPI_TXD_00_10_OFFSET,
> > + ZYNQ_QSPI_TXD_00_11_OFFSET, ZYNQ_QSPI_TXD_00_00_OFFSET
> };
> > + u32 data;
> > +
> > + if (xqspi->txbuf) {
> > + data = 0xffffffff;
> > + memcpy(&data, xqspi->txbuf, size);
> > + xqspi->txbuf += size;
> > + } else {
> > + data = 0;
> > + }
> > +
> > + xqspi->tx_bytes -= size;
> > + zynq_qspi_write(xqspi, offset[size - 1], data); }
> > +
> > +/**
> > + * zynq_qspi_chipselect - Select or deselect the chip select line
> > + * @spi: Pointer to the spi_device structure
> > + * @assert: 1 for select or 0 for deselect the chip select line
> > + */
> > +static void zynq_qspi_chipselect(struct spi_device *spi, bool assert)
> > +{
> > + struct spi_controller *ctrl = spi->master;
> > + struct zynq_qspi *xqspi = spi_controller_get_devdata(ctrl);
> > + u32 config_reg;
> > +
> > + config_reg = zynq_qspi_read(xqspi, ZYNQ_QSPI_CONFIG_OFFSET);
> > + if (assert) {
> > + /* Select the slave */
> > + config_reg &= ~ZYNQ_QSPI_CONFIG_SSCTRL_MASK;
> > + config_reg |= (((~(BIT(spi->chip_select))) <<
> > + ZYNQ_QSPI_SS_SHIFT) &
> > + ZYNQ_QSPI_CONFIG_SSCTRL_MASK);
> > + } else {
> > + config_reg |= ZYNQ_QSPI_CONFIG_SSCTRL_MASK;
> > + }
> > +
> > + zynq_qspi_write(xqspi, ZYNQ_QSPI_CONFIG_OFFSET, config_reg); }
> > +
> > +/**
> > + * zynq_qspi_config_op - Configure QSPI controller for specified transfer
> > + * @xqspi: Pointer to the zynq_qspi structure
> > + * @qspi: Pointer to the spi_device structure
> > + *
> > + * Sets the operational mode of QSPI controller for the next QSPI
> > +transfer and
> > + * sets the requested clock frequency.
> > + *
> > + * Return: 0 on success and -EINVAL on invalid input parameter
> > + *
> > + * Note: If the requested frequency is not an exact match with what
> > +can be
> > + * obtained using the prescalar value, the driver sets the clock
> > +frequency which
> > + * is lower than the requested frequency (maximum lower) for the
> > +transfer. If
> > + * the requested frequency is higher or lower than that is supported
> > +by the QSPI
> > + * controller the driver will set the highest or lowest frequency
> > +supported by
> > + * controller.
> > + */
> > +static int zynq_qspi_config_op(struct zynq_qspi *xqspi, struct
> > +spi_device *spi) {
> > + u32 config_reg, baud_rate_val = 0;
> > +
> > + /* Set the clock frequency */
> > + while ((baud_rate_val < ZYNQ_QSPI_BAUD_DIV_MAX) &&
> > + (clk_get_rate(xqspi->refclk) / (2 << baud_rate_val)) >
> > + spi->max_speed_hz)
> > + baud_rate_val++;
>
> This can be simplified by using DIV_ROUND_UP() to find baud_rate_val
Yes, I will modify it.

Thanks,
Naga Sureshkumar Relli
>
>
>
> Regards
> Vignesh
>
> > + config_reg = zynq_qspi_read(xqspi, ZYNQ_QSPI_CONFIG_OFFSET);
> > +
> > + /* Set the QSPI clock phase and clock polarity */
> > + config_reg &= (~ZYNQ_QSPI_CONFIG_CPHA_MASK) &
> > + (~ZYNQ_QSPI_CONFIG_CPOL_MASK);
> > + if (spi->mode & SPI_CPHA)
> > + config_reg |= ZYNQ_QSPI_CONFIG_CPHA_MASK;
> > + if (spi->mode & SPI_CPOL)
> > + config_reg |= ZYNQ_QSPI_CONFIG_CPOL_MASK;
> > +
> > + config_reg &= ~ZYNQ_QSPI_CONFIG_BDRATE_MASK;
> > + config_reg |= (baud_rate_val << ZYNQ_QSPI_BAUD_DIV_SHIFT);
> > + zynq_qspi_write(xqspi, ZYNQ_QSPI_CONFIG_OFFSET, config_reg);
> > +
> > + return 0;
> > +}
> > +
> > +/**
> > + * zynq_qspi_setup - Configure the QSPI controller
> > + * @spi: Pointer to the spi_device structure
> > + *
> > + * Sets the operational mode of QSPI controller for the next QSPI
> > +transfer, baud
> > + * rate and divisor value to setup the requested qspi clock.
> > + *
> > + * Return: 0 on success and error value on failure
> > + */
> > +static int zynq_qspi_setup_op(struct spi_device *spi) {
> > + struct spi_controller *ctrl = spi->master;
> > + struct zynq_qspi *qspi = spi_controller_get_devdata(ctrl);
> > +
> > + if (ctrl->busy)
> > + return -EBUSY;
> > +
> > + clk_enable(qspi->refclk);
> > + clk_enable(qspi->pclk);
> > + zynq_qspi_write(qspi, ZYNQ_QSPI_ENABLE_OFFSET,
> > + ZYNQ_QSPI_ENABLE_ENABLE_MASK);
> > +
> > + return 0;
> > +}
> > +
> > +/**
> > + * zynq_qspi_write_op - Fills the TX FIFO with as many bytes as possible
> > + * @xqspi: Pointer to the zynq_qspi structure
> > + * @txcount: Maximum number of words to write
> > + * @txempty: Indicates that TxFIFO is empty
> > + */
> > +static void zynq_qspi_write_op(struct zynq_qspi *xqspi, int txcount,
> > + bool txempty)
> > +{
> > + int count, len, k;
> > +
> > + len = xqspi->tx_bytes;
> > + if (len && len < 4) {
> > + /*
> > + * We must empty the TxFIFO between accesses to TXD0,
> > + * TXD1, TXD2, TXD3.
> > + */
> > + if (txempty)
> > + zynq_qspi_txfifo_op(xqspi, len);
> > +
> > + return;
> > + }
> > +
> > + count = len / 4;
> > + if (count > txcount)
> > + count = txcount;
> > +
> > + if (xqspi->txbuf) {
> > + writesl(xqspi->regs + ZYNQ_QSPI_TXD_00_00_OFFSET,
> > + xqspi->txbuf, count);
> > + xqspi->txbuf += count * 4;
> > + } else {
> > + for (k = 0; k < count; k++)
> > + writel_relaxed(0, xqspi->regs +
> > + ZYNQ_QSPI_TXD_00_00_OFFSET);
> > + }
> > +
> > + xqspi->tx_bytes -= count * 4;
> > +}
> > +
> > +/**
> > + * zynq_qspi_read_op - Drains the RX FIFO by as many bytes as possible
> > + * @xqspi: Pointer to the zynq_qspi structure
> > + * @rxcount: Maximum number of words to read
> > + */
> > +static void zynq_qspi_read_op(struct zynq_qspi *xqspi, int rxcount) {
> > + int count, len, k;
> > +
> > + len = xqspi->rx_bytes - xqspi->tx_bytes;
> > + count = len / 4;
> > + if (count > rxcount)
> > + count = rxcount;
> > + if (xqspi->rxbuf) {
> > + readsl(xqspi->regs + ZYNQ_QSPI_RXD_OFFSET,
> > + xqspi->rxbuf, count);
> > + xqspi->rxbuf += count * 4;
> > + } else {
> > + for (k = 0; k < count; k++)
> > + readl_relaxed(xqspi->regs + ZYNQ_QSPI_RXD_OFFSET);
> > + }
> > + xqspi->rx_bytes -= count * 4;
> > + len -= count * 4;
> > +
> > + if (len && len < 4 && count < rxcount)
> > + zynq_qspi_rxfifo_op(xqspi, len);
> > +}
> > +
> > +/**
> > + * zynq_qspi_irq - Interrupt service routine of the QSPI controller
> > + * @irq: IRQ number
> > + * @dev_id: Pointer to the xqspi structure
> > + *
> > + * This function handles TX empty only.
> > + * On TX empty interrupt this function reads the received data from
> > +RX FIFO and
> > + * fills the TX FIFO if there is any data remaining to be transferred.
> > + *
> > + * Return: IRQ_HANDLED when interrupt is handled; IRQ_NONE otherwise.
> > + */
> > +static irqreturn_t zynq_qspi_irq(int irq, void *dev_id) {
> > + u32 intr_status;
> > + bool txempty;
> > + struct zynq_qspi *xqspi = (struct zynq_qspi *)dev_id;
> > +
> > + intr_status = zynq_qspi_read(xqspi, ZYNQ_QSPI_STATUS_OFFSET);
> > + zynq_qspi_write(xqspi, ZYNQ_QSPI_STATUS_OFFSET, intr_status);
> > +
> > + if ((intr_status & ZYNQ_QSPI_IXR_TXNFULL_MASK) ||
> > + (intr_status & ZYNQ_QSPI_IXR_RXNEMTY_MASK)) {
> > + /*
> > + * This bit is set when Tx FIFO has < THRESHOLD entries.
> > + * We have the THRESHOLD value set to 1,
> > + * so this bit indicates Tx FIFO is empty.
> > + */
> > + txempty = !!(intr_status & ZYNQ_QSPI_IXR_TXNFULL_MASK);
> > + /* Read out the data from the RX FIFO */
> > + zynq_qspi_read_op(xqspi, ZYNQ_QSPI_RX_THRESHOLD);
> > + if (xqspi->tx_bytes) {
> > + /* There is more data to send */
> > + zynq_qspi_write_op(xqspi, ZYNQ_QSPI_RX_THRESHOLD,
> > + txempty);
> > + } else {
> > + /*
> > + * If transfer and receive is completed then only send
> > + * complete signal.
> > + */
> > + if (!xqspi->rx_bytes) {
> > + zynq_qspi_write(xqspi,
> > + ZYNQ_QSPI_IDIS_OFFSET,
> > + ZYNQ_QSPI_IXR_RXTX_MASK);
> > + complete(&xqspi->data_completion);
> > + }
> > + }
> > + return IRQ_HANDLED;
> > + }
> > +
> > + return IRQ_NONE;
> > +}
> > +
> > +/**
> > + * zynq_qspi_exec_mem_op() - Initiates the QSPI transfer
> > + * @mem: the SPI memory
> > + * @op: the memory operation to execute
> > + *
> > + * Executes a memory operation.
> > + *
> > + * This function first selects the chip and starts the memory operation.
> > + *
> > + * Return: 0 in case of success, a negative error code otherwise.
> > + */
> > +static int zynq_qspi_exec_mem_op(struct spi_mem *mem,
> > + const struct spi_mem_op *op)
> > +{
> > + struct zynq_qspi *xqspi = spi_controller_get_devdata(mem->spi->master);
> > + int err = 0, i;
> > + u8 *tmpbuf;
> > +
> > + dev_dbg(xqspi->dev, "cmd:%#x mode:%d.%d.%d.%d\n",
> > + op->cmd.opcode, op->cmd.buswidth, op->addr.buswidth,
> > + op->dummy.buswidth, op->data.buswidth);
> > +
> > + zynq_qspi_chipselect(mem->spi, true);
> > + zynq_qspi_config_op(xqspi, mem->spi);
> > +
> > + if (op->cmd.opcode) {
> > + reinit_completion(&xqspi->data_completion);
> > + xqspi->txbuf = (u8 *)&op->cmd.opcode;
> > + xqspi->rxbuf = NULL;
> > + xqspi->tx_bytes = sizeof(op->cmd.opcode);
> > + xqspi->rx_bytes = sizeof(op->cmd.opcode);
> > + zynq_qspi_write_op(xqspi, ZYNQ_QSPI_FIFO_DEPTH, true);
> > + zynq_qspi_write(xqspi, ZYNQ_QSPI_IEN_OFFSET,
> > + ZYNQ_QSPI_IXR_RXTX_MASK);
> > + if (!wait_for_completion_interruptible_timeout(&xqspi->data_completion,
> > + msecs_to_jiffies(1000))) {
> > + err = -ETIMEDOUT;
> > + }
> > + }
> > + zynq_qspi_config_op(xqspi, mem->spi);
> > + if (op->addr.nbytes) {
> > + for (i = 0; i < op->addr.nbytes; i++) {
> > + xqspi->txbuf[i] = op->addr.val >>
> > + (8 * (op->addr.nbytes - i - 1));
> > + }
> > +
> > + reinit_completion(&xqspi->data_completion);
> > + xqspi->rxbuf = NULL;
> > + xqspi->tx_bytes = op->addr.nbytes;
> > + xqspi->rx_bytes = op->addr.nbytes;
> > + zynq_qspi_write_op(xqspi, ZYNQ_QSPI_FIFO_DEPTH, true);
> > + zynq_qspi_write(xqspi, ZYNQ_QSPI_IEN_OFFSET,
> > + ZYNQ_QSPI_IXR_RXTX_MASK);
> > + if (!wait_for_completion_interruptible_timeout(&xqspi->data_completion,
> > + msecs_to_jiffies(1000))) {
> > + err = -ETIMEDOUT;
> > + }
> > + }
> > + zynq_qspi_config_op(xqspi, mem->spi);
> > + if (op->dummy.nbytes) {
> > + tmpbuf = kzalloc(op->dummy.nbytes, GFP_KERNEL);
> > + memset(tmpbuf, 0xff, op->dummy.nbytes);
> > + reinit_completion(&xqspi->data_completion);
> > + xqspi->txbuf = tmpbuf;
> > + xqspi->rxbuf = NULL;
> > + xqspi->tx_bytes = op->dummy.nbytes;
> > + xqspi->rx_bytes = op->dummy.nbytes;
> > + zynq_qspi_write_op(xqspi, ZYNQ_QSPI_FIFO_DEPTH, true);
> > + zynq_qspi_write(xqspi, ZYNQ_QSPI_IEN_OFFSET,
> > + ZYNQ_QSPI_IXR_RXTX_MASK);
> > + if (!wait_for_completion_interruptible_timeout(&xqspi->data_completion,
> > + msecs_to_jiffies(1000))) {
> > + err = -ETIMEDOUT;
> > + }
> > + kfree(tmpbuf);
> > + }
> > + zynq_qspi_config_op(xqspi, mem->spi);
> > + if (op->data.nbytes) {
> > + reinit_completion(&xqspi->data_completion);
> > + if (op->data.dir == SPI_MEM_DATA_OUT) {
> > + xqspi->txbuf = (u8 *)op->data.buf.out;
> > + xqspi->tx_bytes = op->data.nbytes;
> > + xqspi->rxbuf = NULL;
> > + xqspi->rx_bytes = op->data.nbytes;
> > + } else {
> > + xqspi->txbuf = NULL;
> > + xqspi->rxbuf = (u8 *)op->data.buf.in;
> > + xqspi->rx_bytes = op->data.nbytes;
> > + xqspi->tx_bytes = op->data.nbytes;
> > + }
> > +
> > + zynq_qspi_write_op(xqspi, ZYNQ_QSPI_FIFO_DEPTH, true);
> > + zynq_qspi_write(xqspi, ZYNQ_QSPI_IEN_OFFSET,
> > + ZYNQ_QSPI_IXR_RXTX_MASK);
> > + if (!wait_for_completion_interruptible_timeout(&xqspi->data_completion,
> > + msecs_to_jiffies(1000))) {
> > + err = -ETIMEDOUT;
> > + }
> > + }
> > + zynq_qspi_chipselect(mem->spi, false);
> > +
> > + return err;
> > +}
> > +
> > +static const struct spi_controller_mem_ops zynq_qspi_mem_ops = {
> > + .supports_op = zynq_qspi_supports_op,
> > + .exec_op = zynq_qspi_exec_mem_op,
> > +};
> > +
> > +/**
> > + * zynq_qspi_probe - Probe method for the QSPI driver
> > + * @pdev: Pointer to the platform_device structure
> > + *
> > + * This function initializes the driver data structures and the hardware.
> > + *
> > + * Return: 0 on success and error value on failure
> > + */
> > +static int zynq_qspi_probe(struct platform_device *pdev) {
> > + int ret = 0;
> > + struct spi_controller *ctlr;
> > + struct device *dev = &pdev->dev;
> > + struct device_node *np = dev->of_node;
> > + struct zynq_qspi *xqspi;
> > + struct resource *res;
> > + u32 num_cs;
> > +
> > + ctlr = spi_alloc_master(&pdev->dev, sizeof(*xqspi));
> > + if (!ctlr)
> > + return -ENOMEM;
> > +
> > + xqspi = spi_controller_get_devdata(ctlr);
> > + xqspi->dev = dev;
> > + platform_set_drvdata(pdev, xqspi);
> > + ctlr->mem_ops = &zynq_qspi_mem_ops;
> > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > + xqspi->regs = devm_ioremap_resource(&pdev->dev, res);
> > + if (IS_ERR(xqspi->regs)) {
> > + ret = PTR_ERR(xqspi->regs);
> > + goto remove_master;
> > + }
> > +
> > + xqspi->pclk = devm_clk_get(&pdev->dev, "pclk");
> > + if (IS_ERR(xqspi->pclk)) {
> > + dev_err(&pdev->dev, "pclk clock not found.\n");
> > + ret = PTR_ERR(xqspi->pclk);
> > + goto remove_master;
> > + }
> > +
> > + init_completion(&xqspi->data_completion);
> > +
> > + xqspi->refclk = devm_clk_get(&pdev->dev, "ref_clk");
> > + if (IS_ERR(xqspi->refclk)) {
> > + dev_err(&pdev->dev, "ref_clk clock not found.\n");
> > + ret = PTR_ERR(xqspi->refclk);
> > + goto remove_master;
> > + }
> > +
> > + ret = clk_prepare_enable(xqspi->pclk);
> > + if (ret) {
> > + dev_err(&pdev->dev, "Unable to enable APB clock.\n");
> > + goto remove_master;
> > + }
> > +
> > + ret = clk_prepare_enable(xqspi->refclk);
> > + if (ret) {
> > + dev_err(&pdev->dev, "Unable to enable device clock.\n");
> > + goto clk_dis_pclk;
> > + }
> > +
> > + /* QSPI controller initializations */
> > + zynq_qspi_init_hw(xqspi);
> > +
> > + xqspi->irq = platform_get_irq(pdev, 0);
> > + if (xqspi->irq <= 0) {
> > + ret = -ENXIO;
> > + dev_err(&pdev->dev, "irq resource not found\n");
> > + goto remove_master;
> > + }
> > + ret = devm_request_irq(&pdev->dev, xqspi->irq, zynq_qspi_irq,
> > + 0, pdev->name, xqspi);
> > + if (ret != 0) {
> > + ret = -ENXIO;
> > + dev_err(&pdev->dev, "request_irq failed\n");
> > + goto remove_master;
> > + }
> > +
> > + ret = of_property_read_u32(pdev->dev.of_node, "num-cs",
> > + &num_cs);
> > + if (ret < 0)
> > + ctlr->num_chipselect = ZYNQ_QSPI_DEFAULT_NUM_CS;
> > + else
> > + ctlr->num_chipselect = num_cs;
> > + ctlr->mode_bits = SPI_RX_DUAL | SPI_RX_QUAD |
> > + SPI_TX_DUAL | SPI_TX_QUAD;
> > + ctlr->mem_ops = &zynq_qspi_mem_ops;
> > + ctlr->setup = zynq_qspi_setup_op;
> > + ctlr->max_speed_hz = clk_get_rate(xqspi->refclk) / 2;
> > + ctlr->dev.of_node = np;
> > + ret = spi_register_controller(ctlr);
> > + if (ret) {
> > + dev_err(&pdev->dev, "spi_register_master failed\n");
> > + goto clk_dis_all;
> > + }
> > +
> > + return ret;
> > +
> > +clk_dis_all:
> > + clk_disable_unprepare(xqspi->refclk);
> > +clk_dis_pclk:
> > + clk_disable_unprepare(xqspi->pclk);
> > +remove_master:
> > + spi_controller_put(ctlr);
> > +
> > + return ret;
> > +}
> > +
> > +/**
> > + * zynq_qspi_remove - Remove method for the QSPI driver
> > + * @pdev: Pointer to the platform_device structure
> > + *
> > + * This function is called if a device is physically removed from the
> > +system or
> > + * if the driver module is being unloaded. It frees all resources
> > +allocated to
> > + * the device.
> > + *
> > + * Return: 0 on success and error value on failure
> > + */
> > +static int zynq_qspi_remove(struct platform_device *pdev) {
> > + struct zynq_qspi *xqspi = platform_get_drvdata(pdev);
> > +
> > + zynq_qspi_write(xqspi, ZYNQ_QSPI_ENABLE_OFFSET, 0);
> > +
> > + clk_disable_unprepare(xqspi->refclk);
> > + clk_disable_unprepare(xqspi->pclk);
> > +
> > + return 0;
> > +}
> > +
> > +static const struct of_device_id zynq_qspi_of_match[] = {
> > + { .compatible = "xlnx,zynq-qspi-1.0", },
> > + { /* end of table */ }
> > +};
> > +
> > +MODULE_DEVICE_TABLE(of, zynq_qspi_of_match);
> > +
> > +/*
> > + * zynq_qspi_driver - This structure defines the QSPI platform driver
> > +*/ static struct platform_driver zynq_qspi_driver = {
> > + .probe = zynq_qspi_probe,
> > + .remove = zynq_qspi_remove,
> > + .driver = {
> > + .name = "zynq-qspi",
> > + .of_match_table = zynq_qspi_of_match,
> > + },
> > +};
> > +
> > +module_platform_driver(zynq_qspi_driver);
> > +
> > +MODULE_AUTHOR("Xilinx, Inc.");
> > +MODULE_DESCRIPTION("Xilinx Zynq QSPI driver"); MODULE_LICENSE("GPL");
> >

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