Re: [PATCH V4 2/2] mtd: spi-nor: Add driver for Cadence Quad SPI Flash Controller.

From: Brian Norris
Date: Wed May 20 2015 - 18:26:25 EST

On Mon, Mar 23, 2015 at 08:36:22AM -0500, Graham Moore wrote:
> Signed-off-by: Graham Moore <grmoore@xxxxxxxxxxxxxxxxxxxxx>
> ---
> V2: use NULL instead of modalias in spi_nor_scan call
> V3: Use existing property is-decoded-cs instead of creating duplicate.
> V4: Support Micron quad mode by snooping command stream for EVCR command
> and subsequently configuring Cadence controller for quad mode.
> ---
> drivers/mtd/spi-nor/Kconfig | 6 +
> drivers/mtd/spi-nor/Makefile | 1 +
> drivers/mtd/spi-nor/cadence-quadspi.c | 1297 +++++++++++++++++++++++++++++++++
> 3 files changed, 1304 insertions(+)
> create mode 100644 drivers/mtd/spi-nor/cadence-quadspi.c
>
> diff --git a/drivers/mtd/spi-nor/Kconfig b/drivers/mtd/spi-nor/Kconfig
> index 64a4f0e..9485481 100644
> --- a/drivers/mtd/spi-nor/Kconfig
> +++ b/drivers/mtd/spi-nor/Kconfig
> @@ -28,4 +28,10 @@ config SPI_FSL_QUADSPI
> This enables support for the Quad SPI controller in master mode.
> We only connect the NOR to this controller now.
>
> +config SPI_CADENCE_QUADSPI
> + tristate "Cadence Quad SPI controller"
> + depends on ARCH_SOCFPGA
> + help
> + This enables support for the Cadence Quad SPI controller and NOR flash.
> +
> endif # MTD_SPI_NOR
> diff --git a/drivers/mtd/spi-nor/Makefile b/drivers/mtd/spi-nor/Makefile
> index 6a7ce14..372628c 100644
> --- a/drivers/mtd/spi-nor/Makefile
> +++ b/drivers/mtd/spi-nor/Makefile
> @@ -1,2 +1,3 @@
> obj-$(CONFIG_MTD_SPI_NOR) += spi-nor.o
> +obj-$(CONFIG_SPI_CADENCE_QUADSPI) += cadence-quadspi.o
> obj-$(CONFIG_SPI_FSL_QUADSPI) += fsl-quadspi.o
> diff --git a/drivers/mtd/spi-nor/cadence-quadspi.c b/drivers/mtd/spi-nor/cadence-quadspi.c
> new file mode 100644
> index 0000000..fa7b421
> --- /dev/null
> +++ b/drivers/mtd/spi-nor/cadence-quadspi.c
> @@ -0,0 +1,1297 @@
> +/*
> + * Driver for Cadence QSPI Controller
> + *
> + * Copyright Altera Corporation (C) 2012-2014. All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
> + * more details.
> + *
> + * 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/completion.h>
> +#include <linux/delay.h>
> +#include <linux/err.h>
> +#include <linux/errno.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/jiffies.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/mtd/mtd.h>
> +#include <linux/mtd/partitions.h>
> +#include <linux/mtd/spi-nor.h>
> +#include <linux/of_device.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/sched.h>
> +#include <linux/spi/spi.h>
> +#include <linux/timer.h>
> +
> +#define CQSPI_NAME "cadence-qspi"
> +#define CQSPI_MAX_CHIPSELECT 16
> +
> +struct cqspi_flash_pdata {
> + struct mtd_info mtd;
> + struct spi_nor nor;
> + u32 clk_rate;
> + unsigned int page_size;
> + unsigned int block_size;
> + unsigned int read_delay;
> + unsigned int tshsl_ns;
> + unsigned int tsd2d_ns;
> + unsigned int tchsh_ns;
> + unsigned int tslch_ns;
> + int quad_mode_set;
> +};
> +
> +struct cqspi_st {
> + struct platform_device *pdev;
> +
> + struct clk *clk;
> + unsigned int sclk;
> +
> + void __iomem *iobase;
> + void __iomem *ahb_base;
> + struct completion transfer_complete;
> + unsigned int irq_mask;
> + int current_cs;
> + unsigned int ahb_phy_addr;
> + unsigned int master_ref_clk_hz;
> + u32 is_decoded_cs;
> + unsigned int fifo_depth;
> + struct cqspi_flash_pdata f_pdata[CQSPI_MAX_CHIPSELECT];
> +};
> +
> +/* Operation timeout value */
> +#define CQSPI_TIMEOUT_MS 500
> +#define CQSPI_READ_TIMEOUT_MS 10
> +#define CQSPI_POLL_IDLE_RETRY 3
> +
> +#define CQSPI_FIFO_WIDTH 4
> +
> +#define CQSPI_REG_SRAM_THRESHOLD_BYTES 50
> +
> +/* Instruction type */
> +#define CQSPI_INST_TYPE_SINGLE 0
> +#define CQSPI_INST_TYPE_DUAL 1
> +#define CQSPI_INST_TYPE_QUAD 2
> +
> +#define CQSPI_DUMMY_CLKS_PER_BYTE 8
> +#define CQSPI_DUMMY_BYTES_MAX 4
> +
> +#define CQSPI_STIG_DATA_LEN_MAX 8
> +
> +#define CQSPI_INDIRECTTRIGGER_ADDR_MASK 0xFFFFF
> +
> +/* Register map */
> +#define CQSPI_REG_CONFIG 0x00
> +#define CQSPI_REG_CONFIG_ENABLE_MASK BIT(0)
> +#define CQSPI_REG_CONFIG_DECODE_MASK BIT(9)
> +#define CQSPI_REG_CONFIG_CHIPSELECT_LSB 10
> +#define CQSPI_REG_CONFIG_DMA_MASK BIT(15)
> +#define CQSPI_REG_CONFIG_BAUD_LSB 19
> +#define CQSPI_REG_CONFIG_IDLE_LSB 31
> +#define CQSPI_REG_CONFIG_CHIPSELECT_MASK 0xF
> +#define CQSPI_REG_CONFIG_BAUD_MASK 0xF
> +
> +#define CQSPI_REG_RD_INSTR 0x04
> +#define CQSPI_REG_RD_INSTR_OPCODE_LSB 0
> +#define CQSPI_REG_RD_INSTR_TYPE_INSTR_LSB 8
> +#define CQSPI_REG_RD_INSTR_TYPE_ADDR_LSB 12
> +#define CQSPI_REG_RD_INSTR_TYPE_DATA_LSB 16
> +#define CQSPI_REG_RD_INSTR_MODE_EN_LSB 20
> +#define CQSPI_REG_RD_INSTR_DUMMY_LSB 24
> +#define CQSPI_REG_RD_INSTR_TYPE_INSTR_MASK 0x3
> +#define CQSPI_REG_RD_INSTR_TYPE_ADDR_MASK 0x3
> +#define CQSPI_REG_RD_INSTR_TYPE_DATA_MASK 0x3
> +#define CQSPI_REG_RD_INSTR_DUMMY_MASK 0x1F
> +
> +#define CQSPI_REG_WR_INSTR 0x08
> +#define CQSPI_REG_WR_INSTR_OPCODE_LSB 0
> +#define CQSPI_REG_WR_INSTR_TYPE_ADDR_LSB 12
> +#define CQSPI_REG_WR_INSTR_TYPE_DATA_LSB 16
> +
> +#define CQSPI_REG_DELAY 0x0C
> +#define CQSPI_REG_DELAY_TSLCH_LSB 0
> +#define CQSPI_REG_DELAY_TCHSH_LSB 8
> +#define CQSPI_REG_DELAY_TSD2D_LSB 16
> +#define CQSPI_REG_DELAY_TSHSL_LSB 24
> +#define CQSPI_REG_DELAY_TSLCH_MASK 0xFF
> +#define CQSPI_REG_DELAY_TCHSH_MASK 0xFF
> +#define CQSPI_REG_DELAY_TSD2D_MASK 0xFF
> +#define CQSPI_REG_DELAY_TSHSL_MASK 0xFF
> +
> +#define CQSPI_REG_READCAPTURE 0x10
> +#define CQSPI_REG_READCAPTURE_BYPASS_LSB 0
> +#define CQSPI_REG_READCAPTURE_DELAY_LSB 1
> +#define CQSPI_REG_READCAPTURE_DELAY_MASK 0xF
> +
> +#define CQSPI_REG_SIZE 0x14
> +#define CQSPI_REG_SIZE_ADDRESS_LSB 0
> +#define CQSPI_REG_SIZE_PAGE_LSB 4
> +#define CQSPI_REG_SIZE_BLOCK_LSB 16
> +#define CQSPI_REG_SIZE_ADDRESS_MASK 0xF
> +#define CQSPI_REG_SIZE_PAGE_MASK 0xFFF
> +#define CQSPI_REG_SIZE_BLOCK_MASK 0x3F
> +
> +#define CQSPI_REG_SRAMPARTITION 0x18
> +#define CQSPI_REG_INDIRECTTRIGGER 0x1C
> +
> +#define CQSPI_REG_DMA 0x20
> +#define CQSPI_REG_DMA_SINGLE_LSB 0
> +#define CQSPI_REG_DMA_BURST_LSB 8
> +#define CQSPI_REG_DMA_SINGLE_MASK 0xFF
> +#define CQSPI_REG_DMA_BURST_MASK 0xFF
> +
> +#define CQSPI_REG_REMAP 0x24
> +#define CQSPI_REG_MODE_BIT 0x28
> +
> +#define CQSPI_REG_SDRAMLEVEL 0x2C
> +#define CQSPI_REG_SDRAMLEVEL_RD_LSB 0
> +#define CQSPI_REG_SDRAMLEVEL_WR_LSB 16
> +#define CQSPI_REG_SDRAMLEVEL_RD_MASK 0xFFFF
> +#define CQSPI_REG_SDRAMLEVEL_WR_MASK 0xFFFF
> +
> +#define CQSPI_REG_IRQSTATUS 0x40
> +#define CQSPI_REG_IRQMASK 0x44
> +
> +#define CQSPI_REG_INDIRECTRD 0x60
> +#define CQSPI_REG_INDIRECTRD_START_MASK BIT(0)
> +#define CQSPI_REG_INDIRECTRD_CANCEL_MASK BIT(1)
> +#define CQSPI_REG_INDIRECTRD_DONE_MASK BIT(5)
> +
> +#define CQSPI_REG_INDIRECTRDWATERMARK 0x64
> +#define CQSPI_REG_INDIRECTRDSTARTADDR 0x68
> +#define CQSPI_REG_INDIRECTRDBYTES 0x6C
> +
> +#define CQSPI_REG_CMDCTRL 0x90
> +#define CQSPI_REG_CMDCTRL_EXECUTE_MASK BIT(0)
> +#define CQSPI_REG_CMDCTRL_INPROGRESS_MASK BIT(1)
> +#define CQSPI_REG_CMDCTRL_WR_BYTES_LSB 12
> +#define CQSPI_REG_CMDCTRL_WR_EN_LSB 15
> +#define CQSPI_REG_CMDCTRL_ADD_BYTES_LSB 16
> +#define CQSPI_REG_CMDCTRL_ADDR_EN_LSB 19
> +#define CQSPI_REG_CMDCTRL_RD_BYTES_LSB 20
> +#define CQSPI_REG_CMDCTRL_RD_EN_LSB 23
> +#define CQSPI_REG_CMDCTRL_OPCODE_LSB 24
> +#define CQSPI_REG_CMDCTRL_WR_BYTES_MASK 0x7
> +#define CQSPI_REG_CMDCTRL_ADD_BYTES_MASK 0x3
> +#define CQSPI_REG_CMDCTRL_RD_BYTES_MASK 0x7
> +
> +#define CQSPI_REG_INDIRECTWR 0x70
> +#define CQSPI_REG_INDIRECTWR_START_MASK BIT(0)
> +#define CQSPI_REG_INDIRECTWR_CANCEL_MASK BIT(1)
> +#define CQSPI_REG_INDIRECTWR_DONE_MASK BIT(5)
> +
> +#define CQSPI_REG_INDIRECTWRWATERMARK 0x74
> +#define CQSPI_REG_INDIRECTWRSTARTADDR 0x78
> +#define CQSPI_REG_INDIRECTWRBYTES 0x7C
> +
> +#define CQSPI_REG_CMDADDRESS 0x94
> +#define CQSPI_REG_CMDREADDATALOWER 0xA0
> +#define CQSPI_REG_CMDREADDATAUPPER 0xA4
> +#define CQSPI_REG_CMDWRITEDATALOWER 0xA8
> +#define CQSPI_REG_CMDWRITEDATAUPPER 0xAC
> +
> +/* Interrupt status bits */
> +#define CQSPI_REG_IRQ_MODE_ERR BIT(0)
> +#define CQSPI_REG_IRQ_UNDERFLOW BIT(1)
> +#define CQSPI_REG_IRQ_IND_COMP BIT(2)
> +#define CQSPI_REG_IRQ_IND_RD_REJECT BIT(3)
> +#define CQSPI_REG_IRQ_WR_PROTECTED_ERR BIT(4)
> +#define CQSPI_REG_IRQ_ILLEGAL_AHB_ERR BIT(5)
> +#define CQSPI_REG_IRQ_WATERMARK BIT(6)
> +#define CQSPI_REG_IRQ_IND_RD_OVERFLOW BIT(12)
> +
> +#define CQSPI_IRQ_STATUS_ERR (CQSPI_REG_IRQ_MODE_ERR | \
> + CQSPI_REG_IRQ_IND_RD_REJECT | \
> + CQSPI_REG_IRQ_WR_PROTECTED_ERR | \
> + CQSPI_REG_IRQ_ILLEGAL_AHB_ERR)
> +
> +#define CQSPI_IRQ_MASK_RD (CQSPI_REG_IRQ_WATERMARK | \
> + CQSPI_REG_IRQ_IND_RD_OVERFLOW | \
> + CQSPI_REG_IRQ_IND_COMP)
> +
> +#define CQSPI_IRQ_MASK_WR (CQSPI_REG_IRQ_IND_COMP | \
> + CQSPI_REG_IRQ_WATERMARK | \
> + CQSPI_REG_IRQ_UNDERFLOW)
> +
> +#define CQSPI_IRQ_STATUS_MASK 0x1FFFF
> +
> +#define CQSPI_REG_IS_IDLE(base) \
> + ((readl(base + CQSPI_REG_CONFIG) >> \
> + CQSPI_REG_CONFIG_IDLE_LSB) & 0x1)
> +
> +#define CQSPI_GET_RD_SRAM_LEVEL(reg_base) \
> + (((readl(reg_base + CQSPI_REG_SDRAMLEVEL)) >> \
> + CQSPI_REG_SDRAMLEVEL_RD_LSB) & CQSPI_REG_SDRAMLEVEL_RD_MASK)
> +
> +static unsigned int cqspi_init_timeout(unsigned long timeout_in_ms)
> +{
> + return jiffies + msecs_to_jiffies(timeout_in_ms);
> +}
> +
> +static unsigned int cqspi_check_timeout(unsigned long timeout)
> +{
> + return time_before(jiffies, timeout);
> +}
> +
> +static void cqspi_fifo_read(void *dest, const void *src_ahb_addr,
> + unsigned int bytes)
> +{
> + unsigned int temp;
> + int remaining = bytes;
> + unsigned int *dest_ptr = (unsigned int *)dest;
> + unsigned int *src_ptr = (unsigned int *)src_ahb_addr;
> +
> + while (remaining > CQSPI_FIFO_WIDTH) {
> + *dest_ptr = readl(src_ptr);

sparse has a lot of complaints:

drivers/mtd/spi-nor/cadence-quadspi.c:256:29: warning: incorrect type in argument 1 (different address spaces) [sparse]
drivers/mtd/spi-nor/cadence-quadspi.c:256:29: expected void const volatile [noderef] <asn:2>*addr [sparse]
drivers/mtd/spi-nor/cadence-quadspi.c:256:29: got unsigned int *src_ptr [sparse]
drivers/mtd/spi-nor/cadence-quadspi.c:262:24: warning: incorrect type in argument 1 (different address spaces) [sparse]
drivers/mtd/spi-nor/cadence-quadspi.c:262:24: expected void const volatile [noderef] <asn:2>*addr [sparse]
drivers/mtd/spi-nor/cadence-quadspi.c:262:24: got unsigned int *src_ptr [sparse]
drivers/mtd/spi-nor/cadence-quadspi.c:276:17: warning: incorrect type in argument 2 (different address spaces) [sparse]
drivers/mtd/spi-nor/cadence-quadspi.c:276:17: expected void volatile [noderef] <asn:2>*addr [sparse]
drivers/mtd/spi-nor/cadence-quadspi.c:276:17: got unsigned int *dest_ptr [sparse]
drivers/mtd/spi-nor/cadence-quadspi.c:283:17: warning: incorrect type in argument 2 (different address spaces) [sparse]
drivers/mtd/spi-nor/cadence-quadspi.c:283:17: expected void volatile [noderef] <asn:2>*addr [sparse]
drivers/mtd/spi-nor/cadence-quadspi.c:283:17: got unsigned int *dest_ptr [sparse]
drivers/mtd/spi-nor/cadence-quadspi.c:595:48: warning: incorrect type in argument 2 (different address spaces) [sparse]
drivers/mtd/spi-nor/cadence-quadspi.c:595:48: expected void const *src_ahb_addr [sparse]
drivers/mtd/spi-nor/cadence-quadspi.c:595:48: got void [noderef] <asn:2>*ahb_base [sparse]
drivers/mtd/spi-nor/cadence-quadspi.c:691:26: warning: incorrect type in argument 1 (different address spaces) [sparse]
drivers/mtd/spi-nor/cadence-quadspi.c:691:26: expected void *dest_ahb_addr [sparse]
drivers/mtd/spi-nor/cadence-quadspi.c:691:26: got void [noderef] <asn:2>*ahb_base [sparse]
drivers/mtd/spi-nor/cadence-quadspi.c:706:34: warning: incorrect type in argument 1 (different address spaces) [sparse]
drivers/mtd/spi-nor/cadence-quadspi.c:706:34: expected void *dest_ahb_addr [sparse]
drivers/mtd/spi-nor/cadence-quadspi.c:706:34: got void [noderef] <asn:2>*ahb_base [sparse]

You should keep the __iomem type annotation on the void* MMIO addresses.

> + dest_ptr++;
> + remaining -= CQSPI_FIFO_WIDTH;
> + }
> + if (remaining > 0) {
> + /* dangling bytes */
> + temp = readl(src_ptr);
> + memcpy(dest_ptr, &temp, remaining);
> + }
> +}
> +
> +static void cqspi_fifo_write(void *dest_ahb_addr,
> + const void *src, unsigned int bytes)
> +{
> + unsigned int temp;
> + int remaining = bytes;
> + unsigned int *dest_ptr = (unsigned int *)dest_ahb_addr;
> + unsigned int *src_ptr = (unsigned int *)src;
> +
> + while (remaining > CQSPI_FIFO_WIDTH) {
> + writel(*src_ptr, dest_ptr);
> + src_ptr++;
> + remaining -= CQSPI_FIFO_WIDTH;
> + }
> + if (remaining > 0) {
> + /* dangling bytes */
> + memcpy(&temp, src_ptr, remaining);
> + writel(temp, dest_ptr);
> + }
> +}
> +
> +static irqreturn_t cqspi_irq_handler(int this_irq, void *dev)
> +{
> + struct cqspi_st *cqspi = dev;
> + unsigned int irq_status;
> +
> + /* Read interrupt status */
> + irq_status = readl(cqspi->iobase + CQSPI_REG_IRQSTATUS);
> +
> + /* Clear interrupt */
> + writel(irq_status, cqspi->iobase + CQSPI_REG_IRQSTATUS);
> +
> + if (irq_status & cqspi->irq_mask)
> + complete(&cqspi->transfer_complete);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int cqspi_find_chipselect(struct spi_nor *nor)
> +{
> + int cs = -1;
> + struct cqspi_st *cqspi = nor->priv;
> +
> + for (cs = 0; cs < CQSPI_MAX_CHIPSELECT; cs++)
> + if (nor == &cqspi->f_pdata[cs].nor)
> + break;
> + return cs;
> +}
> +
> +static unsigned int cqspi_calc_rdreg(struct spi_nor *nor, u8 opcode)
> +{
> + unsigned int rdreg = 0;
> + struct cqspi_st *cqspi = nor->priv;
> + struct cqspi_flash_pdata *f_pdata;
> +
> + f_pdata = &cqspi->f_pdata[cqspi->current_cs];
> +
> + if (f_pdata->quad_mode_set)
> + rdreg |= (CQSPI_INST_TYPE_QUAD
> + << CQSPI_REG_RD_INSTR_TYPE_INSTR_LSB);
> + else if (nor->flash_read == SPI_NOR_QUAD)
> + rdreg |= (CQSPI_INST_TYPE_QUAD
> + << CQSPI_REG_RD_INSTR_TYPE_DATA_LSB);
> + return rdreg;
> +}
> +
> +static unsigned int cqspi_wait_idle(struct cqspi_st *cqspi)
> +{
> + void __iomem *reg_base = cqspi->iobase;
> + unsigned int count = 0;
> + unsigned timeout;
> +
> + timeout = cqspi_init_timeout(CQSPI_TIMEOUT_MS);
> + while (cqspi_check_timeout(timeout)) {
> + if (CQSPI_REG_IS_IDLE(reg_base)) {
> + /*
> + * Read few times in succession to ensure it does
> + * not transition low again
> + */
> + count++;
> + if (count >= CQSPI_POLL_IDLE_RETRY)
> + return 1;
> + } else {
> + count = 0;
> + }
> + cpu_relax();
> + }
> +
> + /* Timeout, in busy mode. */
> + dev_err(&cqspi->pdev->dev, "QSPI is still busy after %dms timeout.\n",
> + CQSPI_TIMEOUT_MS);
> + return 0;
> +}
> +
> +static int cqspi_exec_flash_cmd(struct cqspi_st *cqspi, unsigned int reg)
> +{
> + void __iomem *reg_base = cqspi->iobase;
> + unsigned int timeout;
> +
> + /* Write the CMDCTRL without start execution. */
> + writel(reg, reg_base + CQSPI_REG_CMDCTRL);
> + /* Start execute */
> + reg |= CQSPI_REG_CMDCTRL_EXECUTE_MASK;
> + writel(reg, reg_base + CQSPI_REG_CMDCTRL);
> +
> + /* Polling for completion. */
> + timeout = cqspi_init_timeout(CQSPI_TIMEOUT_MS);
> + while (cqspi_check_timeout(timeout)) {
> + reg = readl(reg_base + CQSPI_REG_CMDCTRL) &
> + CQSPI_REG_CMDCTRL_INPROGRESS_MASK;
> + if (!reg)
> + break;
> + }
> +
> + if (reg != 0) {
> + dev_err(&cqspi->pdev->dev, "flash cmd execute time out\n");
> + return -EIO;
> + }
> +
> + /* Polling QSPI idle status. */
> + if (!cqspi_wait_idle(cqspi))
> + return -EIO;
> +
> + return 0;
> +}
> +
> +static int cqspi_command_read(struct spi_nor *nor,
> + const u8 *txbuf, unsigned n_tx,
> + u8 *rxbuf, unsigned n_rx)
> +{
> + unsigned int reg;
> + unsigned int read_len;
> + int status;
> + struct cqspi_st *cqspi = nor->priv;
> + void __iomem *reg_base = cqspi->iobase;
> + unsigned int rdreg;
> +
> + if (!n_rx || n_rx > CQSPI_STIG_DATA_LEN_MAX || !rxbuf) {
> + dev_err(nor->dev,
> + "Invalid input argument, len %d rxbuf 0x%08x\n", n_rx,
> + (unsigned int)rxbuf);
> + return -EINVAL;
> + }
> +
> + reg = txbuf[0] << CQSPI_REG_CMDCTRL_OPCODE_LSB;
> +
> + rdreg = cqspi_calc_rdreg(nor, txbuf[0]);
> + writel(rdreg, reg_base + CQSPI_REG_RD_INSTR);
> +
> + reg |= (0x1 << CQSPI_REG_CMDCTRL_RD_EN_LSB);
> +
> + /* 0 means 1 byte. */
> + reg |= (((n_rx - 1) & CQSPI_REG_CMDCTRL_RD_BYTES_MASK)
> + << CQSPI_REG_CMDCTRL_RD_BYTES_LSB);
> + status = cqspi_exec_flash_cmd(cqspi, reg);
> + if (status != 0)
> + return status;
> +
> + reg = readl(reg_base + CQSPI_REG_CMDREADDATALOWER);
> +
> + /* Put the read value into rx_buf */
> + read_len = (n_rx > 4) ? 4 : n_rx;
> + memcpy(rxbuf, &reg, read_len);
> + rxbuf += read_len;
> +
> + if (n_rx > 4) {
> + reg = readl(reg_base + CQSPI_REG_CMDREADDATAUPPER);
> +
> + read_len = n_rx - read_len;
> + memcpy(rxbuf, &reg, read_len);
> + }
> +
> + return 0;
> +}
> +
> +static int cqspi_command_write(struct spi_nor *nor,
> + u8 opcode, const u8 *txbuf, unsigned n_tx)
> +{
> + unsigned int reg;
> + unsigned int data;
> + int ret;
> + struct cqspi_st *cqspi = nor->priv;
> + void __iomem *reg_base = cqspi->iobase;
> +
> + if (n_tx > 4 || (n_tx && !txbuf)) {
> + dev_err(nor->dev,
> + "Invalid input argument, cmdlen %d txbuf 0x%08x\n",
> + n_tx, (unsigned int)txbuf);
> + return -EINVAL;
> + }
> +
> + reg = opcode << CQSPI_REG_CMDCTRL_OPCODE_LSB;
> + if (n_tx) {
> + reg |= (0x1 << CQSPI_REG_CMDCTRL_WR_EN_LSB);
> + reg |= ((n_tx - 1) & CQSPI_REG_CMDCTRL_WR_BYTES_MASK)
> + << CQSPI_REG_CMDCTRL_WR_BYTES_LSB;
> + data = 0;
> + memcpy(&data, txbuf, n_tx);
> + writel(data, reg_base + CQSPI_REG_CMDWRITEDATALOWER);
> + }
> +
> + ret = cqspi_exec_flash_cmd(cqspi, reg);
> + /*
> + * Hack it up, watch for Micron quad mode command so that
> + * we use proper controller setup for next command
> + */
> + if (n_tx && opcode == SPINOR_OP_WD_EVCR &&
> + !(txbuf[0] & EVCR_QUAD_EN_MICRON)) {
> + struct cqspi_flash_pdata *f_pdata;
> +
> + f_pdata = &cqspi->f_pdata[cqspi->current_cs];
> + f_pdata->quad_mode_set = 1;

No, please don't do this. The whole point of the spi-nor layer is that
we don't want low-level drivers having to snoop every type of flash
command. We want to have proper feedback between spi-nor.c and your
driver, so you *know* when you're using a quad-enabled device.

Food for thought: what happens for a non-Micron SPI flash that uses quad
mode?

Is it sufficient to just check if nor->flash_read == SPI_NOR_QUAD?

> + }
> + return ret;
> +}
> +
> +static int cqspi_command_write_addr(struct spi_nor *nor,
> + u8 opcode, unsigned int addr)
> +{
> + unsigned int reg;
> + struct cqspi_st *cqspi = nor->priv;
> + void __iomem *reg_base = cqspi->iobase;
> +
> + reg = opcode << CQSPI_REG_CMDCTRL_OPCODE_LSB;
> + reg |= (0x1 << CQSPI_REG_CMDCTRL_ADDR_EN_LSB);
> + reg |= ((nor->addr_width - 1) & CQSPI_REG_CMDCTRL_ADD_BYTES_MASK)
> + << CQSPI_REG_CMDCTRL_ADD_BYTES_LSB;
> +
> + writel(addr, reg_base + CQSPI_REG_CMDADDRESS);
> +
> + return cqspi_exec_flash_cmd(cqspi, reg);
> +}
> +
> +static int cqspi_indirect_read_setup(struct spi_nor *nor,
> + unsigned int from_addr)
> +{
> + unsigned int reg;
> + unsigned int dummy_clk = 0;
> + unsigned int dummy_bytes;
> + struct cqspi_st *cqspi = nor->priv;
> + void __iomem *reg_base = cqspi->iobase;
> + unsigned int ahb_phy_addr = cqspi->ahb_phy_addr;
> +
> + writel((ahb_phy_addr & CQSPI_INDIRECTTRIGGER_ADDR_MASK),
> + reg_base + CQSPI_REG_INDIRECTTRIGGER);
> + writel(from_addr, reg_base + CQSPI_REG_INDIRECTRDSTARTADDR);
> +
> + reg = nor->read_opcode << CQSPI_REG_RD_INSTR_OPCODE_LSB;
> + reg |= cqspi_calc_rdreg(nor, nor->read_opcode);
> +
> + /* Setup dummy clock cycles */
> + dummy_bytes = nor->read_dummy / 8;
> + if (dummy_bytes) {
> + struct cqspi_flash_pdata *f_pdata;
> +
> + f_pdata = &cqspi->f_pdata[cqspi->current_cs];
> +
> + if (dummy_bytes > CQSPI_DUMMY_BYTES_MAX)
> + dummy_bytes = CQSPI_DUMMY_BYTES_MAX;
> +
> + reg |= (1 << CQSPI_REG_RD_INSTR_MODE_EN_LSB);
> + /* Set mode bits high to ensure chip doesn't enter XIP */
> + writel(0xFF, reg_base + CQSPI_REG_MODE_BIT);
> +
> + dummy_clk = dummy_bytes * CQSPI_DUMMY_CLKS_PER_BYTE;
> + if (!f_pdata->quad_mode_set) {
> + /* Need to subtract the mode byte (8 clocks). */
> + dummy_clk -= CQSPI_DUMMY_CLKS_PER_BYTE;
> + }

Why do you have to subtract? Is nor->read_dummy incorrect?

> +
> + if (dummy_clk)
> + reg |= (dummy_clk & CQSPI_REG_RD_INSTR_DUMMY_MASK)
> + << CQSPI_REG_RD_INSTR_DUMMY_LSB;
> + }
> +
> + writel(reg, reg_base + CQSPI_REG_RD_INSTR);
> +
> + /* Set address width */
> + reg = readl(reg_base + CQSPI_REG_SIZE);
> + reg &= ~CQSPI_REG_SIZE_ADDRESS_MASK;
> + reg |= (nor->addr_width - 1);
> + writel(reg, reg_base + CQSPI_REG_SIZE);
> + return 0;
> +}
> +
> +static int cqspi_indirect_read_execute(struct spi_nor *nor,
> + u8 *rxbuf, unsigned n_rx)
> +{
> + int ret = 0;
> + unsigned int reg = 0;
> + unsigned int bytes_to_read = 0;
> + unsigned int timeout;
> + unsigned int watermark;
> + struct cqspi_st *cqspi = nor->priv;
> + void __iomem *reg_base = cqspi->iobase;
> + void __iomem *ahb_base = cqspi->ahb_base;
> + int remaining = (int)n_rx;
> +
> + watermark = cqspi->fifo_depth * CQSPI_FIFO_WIDTH / 2;
> + writel(watermark, reg_base + CQSPI_REG_INDIRECTRDWATERMARK);
> + writel(remaining, reg_base + CQSPI_REG_INDIRECTRDBYTES);
> +
> + /* Clear all interrupts. */
> + writel(CQSPI_IRQ_STATUS_MASK, reg_base + CQSPI_REG_IRQSTATUS);
> +
> + cqspi->irq_mask = CQSPI_IRQ_MASK_RD;
> + writel(cqspi->irq_mask, reg_base + CQSPI_REG_IRQMASK);
> +
> + reinit_completion(&cqspi->transfer_complete);
> + writel(CQSPI_REG_INDIRECTRD_START_MASK,
> + reg_base + CQSPI_REG_INDIRECTRD);
> +
> + while (remaining > 0) {
> + ret = wait_for_completion_timeout(&cqspi->transfer_complete,
> + msecs_to_jiffies
> + (CQSPI_READ_TIMEOUT_MS));
> +
> + bytes_to_read = CQSPI_GET_RD_SRAM_LEVEL(reg_base);
> +
> + if (!ret && bytes_to_read == 0) {
> + dev_err(nor->dev, "Indirect read timeout, no bytes\n");
> + ret = -ETIMEDOUT;
> + goto failrd;
> + }
> +
> + while (bytes_to_read != 0) {
> + bytes_to_read *= CQSPI_FIFO_WIDTH;
> + bytes_to_read = bytes_to_read > remaining
> + ? remaining : bytes_to_read;
> + cqspi_fifo_read(rxbuf, ahb_base, bytes_to_read);
> + rxbuf += bytes_to_read;
> + remaining -= bytes_to_read;
> + bytes_to_read = CQSPI_GET_RD_SRAM_LEVEL(reg_base);
> + }
> + }
> +
> + /* Check indirect done status */
> + timeout = cqspi_init_timeout(CQSPI_TIMEOUT_MS);
> + while (cqspi_check_timeout(timeout)) {
> + reg = readl(reg_base + CQSPI_REG_INDIRECTRD);
> + if (reg & CQSPI_REG_INDIRECTRD_DONE_MASK)
> + break;
> + }
> +
> + if (!(reg & CQSPI_REG_INDIRECTRD_DONE_MASK)) {
> + dev_err(nor->dev,
> + "Indirect read completion error 0x%08x\n", reg);
> + ret = -ETIMEDOUT;
> + goto failrd;
> + }
> +
> + /* Disable interrupt */
> + writel(0, reg_base + CQSPI_REG_IRQMASK);
> +
> + /* Clear indirect completion status */
> + writel(CQSPI_REG_INDIRECTRD_DONE_MASK, reg_base + CQSPI_REG_INDIRECTRD);
> +
> + return 0;
> +
> + failrd:
> + /* Disable interrupt */
> + writel(0, reg_base + CQSPI_REG_IRQMASK);
> +
> + /* Cancel the indirect read */
> + writel(CQSPI_REG_INDIRECTWR_CANCEL_MASK,
> + reg_base + CQSPI_REG_INDIRECTRD);
> + return ret;
> +}
> +
> +static int cqspi_indirect_write_setup(struct spi_nor *nor, unsigned int to_addr)
> +{
> + unsigned int reg;
> + struct cqspi_st *cqspi = nor->priv;
> + void __iomem *reg_base = cqspi->iobase;
> +
> + /* Set opcode. */
> + reg = nor->program_opcode << CQSPI_REG_WR_INSTR_OPCODE_LSB;
> + writel(reg, reg_base + CQSPI_REG_WR_INSTR);
> + reg = cqspi_calc_rdreg(nor, nor->program_opcode);
> + writel(reg, reg_base + CQSPI_REG_RD_INSTR);
> +
> + writel(to_addr, reg_base + CQSPI_REG_INDIRECTWRSTARTADDR);
> +
> + reg = readl(reg_base + CQSPI_REG_SIZE);
> + reg &= ~CQSPI_REG_SIZE_ADDRESS_MASK;
> + reg |= (nor->addr_width - 1);
> + writel(reg, reg_base + CQSPI_REG_SIZE);
> + return 0;
> +}
> +
> +static int cqspi_indirect_write_execute(struct spi_nor *nor,
> + const u8 *txbuf, unsigned n_tx)
> +{
> + int ret;
> + unsigned int timeout;
> + unsigned int reg = 0;
> + struct cqspi_st *cqspi = nor->priv;
> + void __iomem *reg_base = cqspi->iobase;
> + void __iomem *ahb_base = cqspi->ahb_base;
> + int remaining = (int)n_tx;
> + struct cqspi_flash_pdata *f_pdata;
> + unsigned int page_size;
> + unsigned int write_bytes;
> +
> + f_pdata = &cqspi->f_pdata[cqspi->current_cs];
> + page_size = f_pdata->page_size;
> +
> + writel(remaining, reg_base + CQSPI_REG_INDIRECTWRBYTES);
> +
> + writel(CQSPI_REG_SRAM_THRESHOLD_BYTES, reg_base +
> + CQSPI_REG_INDIRECTWRWATERMARK);
> +
> + /* Clear all interrupts. */
> + writel(CQSPI_IRQ_STATUS_MASK, reg_base + CQSPI_REG_IRQSTATUS);
> +
> + cqspi->irq_mask = CQSPI_IRQ_MASK_WR;
> + writel(cqspi->irq_mask, reg_base + CQSPI_REG_IRQMASK);
> +
> + reinit_completion(&cqspi->transfer_complete);
> + writel(CQSPI_REG_INDIRECTWR_START_MASK,
> + reg_base + CQSPI_REG_INDIRECTWR);
> +
> + /* Write a page or remaining bytes. */
> + write_bytes = remaining > page_size ? page_size : remaining;
> + /* Fill up the data at the beginning */
> + cqspi_fifo_write(ahb_base, txbuf, write_bytes);
> + txbuf += write_bytes;
> + remaining -= write_bytes;
> +
> + while (remaining > 0) {
> + ret = wait_for_completion_timeout(&cqspi->transfer_complete,
> + msecs_to_jiffies
> + (CQSPI_TIMEOUT_MS));
> + if (!ret) {
> + dev_err(nor->dev, "Indirect write timeout\n");
> + ret = -ETIMEDOUT;
> + goto failwr;
> + }
> +
> + write_bytes = remaining > page_size ? page_size : remaining;
> + cqspi_fifo_write(ahb_base, txbuf, write_bytes);
> + txbuf += write_bytes;
> + remaining -= write_bytes;
> + }
> +
> + ret = wait_for_completion_timeout(&cqspi->transfer_complete,
> + msecs_to_jiffies(CQSPI_TIMEOUT_MS));
> + if (!ret) {
> + dev_err(nor->dev, "Indirect write timeout\n");
> + ret = -ETIMEDOUT;
> + goto failwr;
> + }
> +
> + /* Check indirect done status */
> + timeout = cqspi_init_timeout(CQSPI_TIMEOUT_MS);
> + while (cqspi_check_timeout(timeout)) {
> + reg = readl(reg_base + CQSPI_REG_INDIRECTWR);
> + if (reg & CQSPI_REG_INDIRECTWR_DONE_MASK)
> + break;
> + }
> +
> + if (!(reg & CQSPI_REG_INDIRECTWR_DONE_MASK)) {
> + dev_err(nor->dev,
> + "Indirect write completion error 0x%08x\n", reg);
> + ret = -ETIMEDOUT;
> + goto failwr;
> + }
> +
> + /* Disable interrupt. */
> + writel(0, reg_base + CQSPI_REG_IRQMASK);
> +
> + /* Clear indirect completion status */
> + writel(CQSPI_REG_INDIRECTWR_DONE_MASK, reg_base + CQSPI_REG_INDIRECTWR);
> +
> + cqspi_wait_idle(cqspi);
> +
> + return 0;
> +
> + failwr:
> + /* Disable interrupt. */
> + writel(0, reg_base + CQSPI_REG_IRQMASK);
> +
> + /* Cancel the indirect write */
> + writel(CQSPI_REG_INDIRECTWR_CANCEL_MASK,
> + reg_base + CQSPI_REG_INDIRECTWR);
> + return ret;
> +}
> +
> +static void cqspi_write(struct spi_nor *nor, loff_t to,
> + size_t len, size_t *retlen, const u_char *buf)
> +{
> + int ret;
> +
> + ret = cqspi_indirect_write_setup(nor, to);
> + if (ret == 0) {
> + ret = cqspi_indirect_write_execute(nor, buf, len);
> + if (ret == 0)
> + *retlen += len;
> + }
> +}
> +
> +static int cqspi_read(struct spi_nor *nor, loff_t from,
> + size_t len, size_t *retlen, u_char *buf)
> +{
> + int ret;
> +
> + ret = cqspi_indirect_read_setup(nor, from);
> + if (ret == 0) {
> + ret = cqspi_indirect_read_execute(nor, buf, len);
> + if (ret == 0)
> + *retlen += len;
> + }
> + return ret;
> +}
> +
> +static int cqspi_erase(struct spi_nor *nor, loff_t offs)
> +{
> + int ret;
> +
> + /* Send write enable, then erase commands. */
> + ret = nor->write_reg(nor, SPINOR_OP_WREN, NULL, 0, 0);
> + if (ret)
> + return ret;
> +
> + /* Set up command buffer. */
> + ret = cqspi_command_write_addr(nor, nor->erase_opcode, offs);
> + if (ret)
> + return ret;
> +
> + return 0;

drivers/mtd/spi-nor/cadence-quadspi.c:791:1-4: WARNING: end returns can be simpified [coccinelle]

> +}
> +
> +static unsigned int calculate_ticks_for_ns(unsigned int ref_clk_hz,
> + unsigned int ns_val)
> +{
> + unsigned int ticks;
> +
> + ticks = ref_clk_hz;
> + ticks /= 1000;
> + ticks *= ns_val;
> + ticks += 999999;
> + ticks /= 1000000;
> + return ticks;
> +}
> +
> +static void cqspi_delay(struct cqspi_st *cqspi,
> + unsigned int ref_clk_hz, unsigned int sclk_hz)
> +{
> + void __iomem *iobase = cqspi->iobase;
> + struct cqspi_flash_pdata *f_pdata;
> + unsigned int ref_clk_ns;
> + unsigned int sclk_ns;
> + unsigned int tshsl, tchsh, tslch, tsd2d;
> + unsigned int reg;
> + unsigned int tsclk;
> +
> + f_pdata = &cqspi->f_pdata[cqspi->current_cs];
> +
> + /* Convert to ns. */
> + ref_clk_ns = NSEC_PER_SEC / ref_clk_hz;

drivers/mtd/spi-nor/cadence-quadspi.c:816:15: warning: variable âref_clk_nsâ set but not used [-Wunused-but-set-variable]
unsigned int ref_clk_ns;
^

> +
> + /* Convert to ns. */
> + sclk_ns = NSEC_PER_SEC / sclk_hz;

drivers/mtd/spi-nor/cadence-quadspi.c: In function âcqspi_delayâ:
drivers/mtd/spi-nor/cadence-quadspi.c:817:15: warning: variable âsclk_nsâ set but not used [-Wunused-but-set-variable]
unsigned int sclk_ns;
^

> +
> + /* calculate the number of ref ticks for one sclk tick */
> + tsclk = (ref_clk_hz + sclk_hz - 1) / sclk_hz;
> +
> + tshsl = calculate_ticks_for_ns(ref_clk_hz, f_pdata->tshsl_ns);
> + /* this particular value must be at least one sclk */
> + if (tshsl < tsclk)
> + tshsl = tsclk;
> +
> + tchsh = calculate_ticks_for_ns(ref_clk_hz, f_pdata->tchsh_ns);
> + tslch = calculate_ticks_for_ns(ref_clk_hz, f_pdata->tslch_ns);
> + tsd2d = calculate_ticks_for_ns(ref_clk_hz, f_pdata->tsd2d_ns);
> +
> + reg = ((tshsl & CQSPI_REG_DELAY_TSHSL_MASK)
> + << CQSPI_REG_DELAY_TSHSL_LSB);
> + reg |= ((tchsh & CQSPI_REG_DELAY_TCHSH_MASK)
> + << CQSPI_REG_DELAY_TCHSH_LSB);
> + reg |= ((tslch & CQSPI_REG_DELAY_TSLCH_MASK)
> + << CQSPI_REG_DELAY_TSLCH_LSB);
> + reg |= ((tsd2d & CQSPI_REG_DELAY_TSD2D_MASK)
> + << CQSPI_REG_DELAY_TSD2D_LSB);
> + writel(reg, iobase + CQSPI_REG_DELAY);
> +}
> +
> +static void cqspi_config_baudrate_div(struct cqspi_st *cqspi,
> + unsigned int ref_clk_hz,
> + unsigned int sclk_hz)
> +{
> + void __iomem *reg_base = cqspi->iobase;
> + unsigned int reg;
> + unsigned int div;
> +
> + reg = readl(reg_base + CQSPI_REG_CONFIG);
> + reg &= ~(CQSPI_REG_CONFIG_BAUD_MASK << CQSPI_REG_CONFIG_BAUD_LSB);
> +
> + div = ref_clk_hz / sclk_hz;
> +
> + /* Recalculate the baudrate divisor based on QSPI specification. */
> + if (div > 32)
> + div = 32;
> +
> + /* Check if even number. */
> + if (div & 1)
> + div = (div / 2);
> + else
> + div = (div / 2) - 1;
> +
> + div = (div & CQSPI_REG_CONFIG_BAUD_MASK) << CQSPI_REG_CONFIG_BAUD_LSB;
> + reg |= div;
> + writel(reg, reg_base + CQSPI_REG_CONFIG);
> +}
> +
> +static void cqspi_readdata_capture(struct cqspi_st *cqspi,
> + unsigned int bypass, unsigned int delay)
> +{
> + void __iomem *reg_base = cqspi->iobase;
> + unsigned int reg;
> +
> + reg = readl(reg_base + CQSPI_REG_READCAPTURE);
> +
> + if (bypass)
> + reg |= (1 << CQSPI_REG_READCAPTURE_BYPASS_LSB);
> + else
> + reg &= ~(1 << CQSPI_REG_READCAPTURE_BYPASS_LSB);
> +
> + reg &= ~(CQSPI_REG_READCAPTURE_DELAY_MASK
> + << CQSPI_REG_READCAPTURE_DELAY_LSB);
> +
> + reg |= ((delay & CQSPI_REG_READCAPTURE_DELAY_MASK)
> + << CQSPI_REG_READCAPTURE_DELAY_LSB);
> +
> + writel(reg, reg_base + CQSPI_REG_READCAPTURE);
> +}
> +
> +static void cqspi_chipselect(struct cqspi_st *cqspi,
> + unsigned int chip_select,
> + unsigned int decoder_enable)
> +{
> + void __iomem *reg_base = cqspi->iobase;
> + unsigned int reg;
> +
> + reg = readl(reg_base + CQSPI_REG_CONFIG);
> + if (decoder_enable) {
> + reg |= CQSPI_REG_CONFIG_DECODE_MASK;
> + } else {
> + reg &= ~CQSPI_REG_CONFIG_DECODE_MASK;
> +
> + /* Convert CS if without decoder.
> + * CS0 to 4b'1110
> + * CS1 to 4b'1101
> + * CS2 to 4b'1011
> + * CS3 to 4b'0111
> + */
> + chip_select = 0xF & ~(1 << chip_select);
> + }
> +
> + reg &= ~(CQSPI_REG_CONFIG_CHIPSELECT_MASK
> + << CQSPI_REG_CONFIG_CHIPSELECT_LSB);
> + reg |= (chip_select & CQSPI_REG_CONFIG_CHIPSELECT_MASK)
> + << CQSPI_REG_CONFIG_CHIPSELECT_LSB;
> + writel(reg, reg_base + CQSPI_REG_CONFIG);
> +}
> +
> +static void cqspi_controller_enable(struct cqspi_st *cqspi)
> +{
> + void __iomem *reg_base = cqspi->iobase;
> + unsigned int reg;
> +
> + reg = readl(reg_base + CQSPI_REG_CONFIG);
> + reg |= CQSPI_REG_CONFIG_ENABLE_MASK;
> + writel(reg, reg_base + CQSPI_REG_CONFIG);
> +}
> +
> +static void cqspi_controller_disable(struct cqspi_st *cqspi)
> +{
> + void __iomem *reg_base = cqspi->iobase;
> + unsigned int reg;
> +
> + reg = readl(reg_base + CQSPI_REG_CONFIG);
> + reg &= ~CQSPI_REG_CONFIG_ENABLE_MASK;
> + writel(reg, reg_base + CQSPI_REG_CONFIG);
> +}
> +
> +static void cqspi_switch_cs(struct cqspi_st *cqspi, unsigned int cs)
> +{
> + unsigned int reg;
> + struct cqspi_flash_pdata *f_pdata = &cqspi->f_pdata[cs];
> + void __iomem *iobase = cqspi->iobase;
> + struct spi_nor *nor = &f_pdata->nor;
> +
> + cqspi_controller_disable(cqspi);
> +
> + /* configure page size and block size. */
> + reg = readl(iobase + CQSPI_REG_SIZE);
> + reg &= ~(CQSPI_REG_SIZE_PAGE_MASK << CQSPI_REG_SIZE_PAGE_LSB);
> + reg &= ~(CQSPI_REG_SIZE_BLOCK_MASK << CQSPI_REG_SIZE_BLOCK_LSB);
> + reg |= (f_pdata->page_size << CQSPI_REG_SIZE_PAGE_LSB);
> + reg |= (f_pdata->block_size << CQSPI_REG_SIZE_BLOCK_LSB);
> + reg &= ~CQSPI_REG_SIZE_ADDRESS_MASK;
> + reg |= (nor->addr_width - 1);
> + writel(reg, iobase + CQSPI_REG_SIZE);
> +
> + /* configure the chip select */
> + cqspi_chipselect(cqspi, cs, cqspi->is_decoded_cs);
> +
> + cqspi_controller_enable(cqspi);
> +}
> +
> +static int cqspi_prep(struct spi_nor *nor, enum spi_nor_ops ops)
> +{
> + struct cqspi_st *cqspi = nor->priv;
> + int cs = cqspi_find_chipselect(nor);
> + struct cqspi_flash_pdata *f_pdata;
> + unsigned int sclk;
> +
> + /* Switch chip select. */
> + if (cqspi->current_cs != cs) {
> + cqspi->current_cs = cs;
> + cqspi_switch_cs(cqspi, cs);
> + }
> +
> + /* Setup baudrate divisor and delays */
> + f_pdata = &cqspi->f_pdata[cqspi->current_cs];
> + sclk = f_pdata->clk_rate;
> + if (cqspi->sclk != sclk) {
> + cqspi->sclk = sclk;
> + cqspi_controller_disable(cqspi);
> + cqspi_config_baudrate_div(cqspi,
> + cqspi->master_ref_clk_hz, sclk);
> + cqspi_delay(cqspi, cqspi->master_ref_clk_hz, sclk);
> + cqspi_readdata_capture(cqspi, 1, f_pdata->read_delay);
> + cqspi_controller_enable(cqspi);
> + }
> + return 0;
> +}
> +
> +static void cqspi_unprep(struct spi_nor *nor, enum spi_nor_ops ops)
> +{
> +}

Do you really need the empty function?

> +
> +static int cqspi_read_reg(struct spi_nor *nor, u8 opcode, u8 *buf, int len)
> +{
> + int ret;
> +
> + cqspi_prep(nor, SPI_NOR_OPS_READ);
> +
> + ret = cqspi_command_read(nor, &opcode, 1, buf, len);
> + return ret;
> +}
> +
> +static int cqspi_write_reg(struct spi_nor *nor, u8 opcode, u8 *buf, int len,
> + int write_enable)
> +{
> + int ret = 0;
> +
> + cqspi_prep(nor, SPI_NOR_OPS_WRITE);
> +
> + ret = cqspi_command_write(nor, opcode, buf, len);
> + return ret;
> +}
> +
> +static int cqspi_of_get_flash_pdata(struct platform_device *pdev,
> + struct cqspi_flash_pdata *f_pdata,
> + struct device_node *np)
> +{
> + if (of_property_read_u32(np, "cdns,page-size", &f_pdata->page_size)) {

Do you really need this property? Can't you use nor->page_size?

> + dev_err(&pdev->dev, "couldn't determine page-size\n");
> + return -ENXIO;
> + }
> +
> + if (of_property_read_u32(np, "cdns,block-size", &f_pdata->block_size)) {

Same here (mtd->erasesize).

> + dev_err(&pdev->dev, "couldn't determine block-size\n");
> + return -ENXIO;
> + }
> +
> + if (of_property_read_u32(np, "cdns,read-delay", &f_pdata->read_delay)) {
> + dev_err(&pdev->dev, "couldn't determine read-delay\n");
> + return -ENXIO;
> + }
> +
> + if (of_property_read_u32(np, "cdns,tshsl-ns", &f_pdata->tshsl_ns)) {
> + dev_err(&pdev->dev, "couldn't determine tshsl-ns\n");
> + return -ENXIO;
> + }
> +
> + if (of_property_read_u32(np, "cdns,tsd2d-ns", &f_pdata->tsd2d_ns)) {
> + dev_err(&pdev->dev, "couldn't determine tsd2d-ns\n");
> + return -ENXIO;
> + }
> +
> + if (of_property_read_u32(np, "cdns,tchsh-ns", &f_pdata->tchsh_ns)) {
> + dev_err(&pdev->dev, "couldn't determine tchsh-ns\n");
> + return -ENXIO;
> + }
> +
> + if (of_property_read_u32(np, "cdns,tslch-ns", &f_pdata->tslch_ns)) {
> + dev_err(&pdev->dev, "couldn't determine tslch-ns\n");
> + return -ENXIO;
> + }
> +
> + if (of_property_read_u32(np, "spi-max-frequency", &f_pdata->clk_rate)) {
> + dev_err(&pdev->dev, "couldn't determine spi-max-frequency\n");
> + return -ENXIO;
> + }
> +
> + return 0;
> +}
> +
> +static int cqspi_of_get_pdata(struct platform_device *pdev)
> +{
> + struct device_node *np = pdev->dev.of_node;
> + struct cqspi_st *cqspi = platform_get_drvdata(pdev);
> +
> + if (of_property_read_u32(np, "is-decoded-cs", &cqspi->is_decoded_cs))
> + cqspi->is_decoded_cs = 0;
> +
> + if (of_property_read_u32(np, "fifo-depth", &cqspi->fifo_depth)) {
> + dev_err(&pdev->dev, "couldn't determine fifo-depth\n");
> + return -ENXIO;
> + }
> +
> + return 0;
> +}
> +
> +static void cqspi_controller_init(struct cqspi_st *cqspi)
> +{
> + cqspi_controller_disable(cqspi);
> +
> + /* Configure the remap address register, no remap */
> + writel(0, cqspi->iobase + CQSPI_REG_REMAP);
> +
> + /* Disable all interrupts. */
> + writel(0, cqspi->iobase + CQSPI_REG_IRQMASK);
> +
> + cqspi_controller_enable(cqspi);
> +}
> +
> +static int cqspi_probe(struct platform_device *pdev)
> +{
> + struct device_node *np = pdev->dev.of_node;
> + struct mtd_part_parser_data ppdata;
> + struct device *dev = &pdev->dev;
> + struct cqspi_st *cqspi;
> + struct spi_nor *nor;
> + struct mtd_info *mtd;
> + struct resource *res;
> + struct resource *res_ahb;
> + int ret;
> + int irq;
> +
> + cqspi = devm_kzalloc(dev, sizeof(*cqspi), GFP_KERNEL);
> + if (!cqspi)
> + return -ENOMEM;
> +
> + cqspi->pdev = pdev;
> + platform_set_drvdata(pdev, cqspi);
> +
> + ret = cqspi_of_get_pdata(pdev);
> + if (ret) {
> + dev_err(dev, "Get platform data failed.\n");
> + return -ENODEV;
> + }
> +
> + cqspi->clk = devm_clk_get(dev, NULL);
> + if (IS_ERR(cqspi->clk)) {
> + dev_err(dev, "cannot get qspi clk\n");
> + ret = PTR_ERR(cqspi->clk);
> + goto probe_failed;
> + }
> + cqspi->master_ref_clk_hz = clk_get_rate(cqspi->clk);
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + cqspi->iobase = devm_ioremap_resource(dev, res);
> + if (IS_ERR(cqspi->iobase)) {
> + dev_err(dev, "devm_ioremap_resource res 0 failed\n");
> + ret = PTR_ERR(cqspi->iobase);
> + goto probe_failed;
> + }
> +
> + res_ahb = platform_get_resource(pdev, IORESOURCE_MEM, 1);
> + cqspi->ahb_phy_addr = res_ahb->start;
> + cqspi->ahb_base = devm_ioremap_resource(dev, res_ahb);
> + if (IS_ERR(cqspi->ahb_base)) {
> + dev_err(dev, "devm_ioremap_resource res 1 failed\n");
> + ret = PTR_ERR(cqspi->ahb_base);
> + goto probe_failed;
> + }
> +
> + init_completion(&cqspi->transfer_complete);
> +
> + irq = platform_get_irq(pdev, 0);
> + if (irq < 0) {
> + dev_err(dev, "platform_get_irq failed\n");
> + ret = -ENXIO;
> + goto probe_failed;
> + }
> + ret = devm_request_irq(dev, irq,
> + cqspi_irq_handler, 0, pdev->name, cqspi);
> + if (ret) {
> + dev_err(dev, "devm_request_irq failed\n");
> + goto probe_failed;
> + }
> +
> + cqspi_wait_idle(cqspi);
> + cqspi_controller_init(cqspi);
> + cqspi->current_cs = -1;
> + cqspi->sclk = 0;
> +
> + /* Get flash device data */
> + for_each_available_child_of_node(dev->of_node, np) {
> + unsigned int cs;
> + struct cqspi_flash_pdata *f_pdata;
> +
> + if (of_property_read_u32(np, "reg", &cs)) {
> + dev_err(dev, "couldn't determine chip select\n");
> + return -ENXIO;
> + }
> + if (cs > CQSPI_MAX_CHIPSELECT) {
> + dev_err(dev, "chip select %d out of range\n", cs);
> + return -ENXIO;
> + }
> + f_pdata = &cqspi->f_pdata[cs];

smatch catches a tricky one here:

drivers/mtd/spi-nor/cadence-quadspi.c:1190 cqspi_probe() warn: buffer overflow 'cqspi->f_pdata' 16 <= 16 [smatch]

I think the problem is in the condition a few lines above:

if (cs > CQSPI_MAX_CHIPSELECT) {

which should actually be:

if (cs >= CQSPI_MAX_CHIPSELECT) {

> +
> + ret = cqspi_of_get_flash_pdata(pdev, f_pdata, np);
> + if (ret)
> + goto probe_failed;
> +
> + f_pdata->quad_mode_set = 0;
> +
> + nor = &f_pdata->nor;
> + mtd = &f_pdata->mtd;
> +
> + nor->mtd = mtd;
> + nor->dev = dev;
> + nor->priv = cqspi;
> + mtd->priv = nor;
> +
> + nor->read_reg = cqspi_read_reg;
> + nor->write_reg = cqspi_write_reg;
> + nor->read = cqspi_read;
> + nor->write = cqspi_write;
> + nor->erase = cqspi_erase;
> +
> + nor->prepare = cqspi_prep;
> + nor->unprepare = cqspi_unprep;
> +
> + ret = spi_nor_scan(nor, NULL, SPI_NOR_QUAD);
> + if (ret)
> + goto probe_failed;
> +
> + ppdata.of_node = np;
> + ret = mtd_device_parse_register(mtd, NULL, &ppdata, NULL, 0);
> + if (ret)
> + goto probe_failed;
> + }
> +
> + dev_info(dev, "Cadence QSPI NOR flash driver\n");
> + return 0;
> +
> + probe_failed:
> + dev_err(dev, "Cadence QSPI NOR probe failed\n");

If you're bothering to print here, you might as well include the error
code.

> + return ret;

If you have more than one chip, and the second one fails, you're not
really unwinding the first correctly.

> +}
> +
> +static int cqspi_remove(struct platform_device *pdev)
> +{
> + struct cqspi_st *cqspi = platform_get_drvdata(pdev);
> + int i;
> +
> + cqspi_controller_disable(cqspi);
> +
> + for (i = 0; i < CQSPI_MAX_CHIPSELECT; i++)
> + if (cqspi->f_pdata[i].mtd.name)
> + mtd_device_unregister(&cqspi->f_pdata[i].mtd);
> +
> + return 0;
> +}
> +
> +#ifdef CONFIG_PM

CONFIG_PM_SLEEP

> +static int cqspi_suspend(struct device *dev)
> +{
> + struct cqspi_st *cqspi = dev_get_drvdata(dev);
> +
> + cqspi_controller_disable(cqspi);
> + return 0;
> +}
> +
> +static int cqspi_resume(struct device *dev)
> +{
> + struct cqspi_st *cqspi = dev_get_drvdata(dev);
> +
> + cqspi_controller_enable(cqspi);
> + return 0;
> +}
> +
> +static const struct dev_pm_ops cqspi__dev_pm_ops = {
> + .suspend = cqspi_suspend,
> + .resume = cqspi_resume,
> +};
> +
> +#define CQSPI_DEV_PM_OPS (&cqspi__dev_pm_ops)
> +#else
> +#define CQSPI_DEV_PM_OPS NULL
> +#endif
> +
> +static struct of_device_id const cqspi_dt_ids[] = {
> + {.compatible = "cdns,qspi-nor",},
> + { /* end of table */ }
> +};
> +
> +MODULE_DEVICE_TABLE(of, cqspi_dt_ids);
> +
> +static struct platform_driver cqspi_platform_driver = {
> + .probe = cqspi_probe,
> + .remove = cqspi_remove,
> + .driver = {
> + .name = CQSPI_NAME,
> + .pm = CQSPI_DEV_PM_OPS,
> + .of_match_table = cqspi_dt_ids,
> + },

Your indentation is a little screwed up for the above 4 lines. Please
use only tabs, not spaces, and make sure the closing brace is aligned
with '.driver', not '.of_match_table'.

> +};
> +
> +module_platform_driver(cqspi_platform_driver);
> +
> +MODULE_DESCRIPTION("Cadence QSPI Controller Driver");
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("platform:" CQSPI_NAME);
> +MODULE_AUTHOR("Ley Foon Tan <lftan@xxxxxxxxxx>");
> +MODULE_AUTHOR("Graham Moore <grmoore@xxxxxxxxxxxxxxxxxxxxx>");

There's likely more to say, but that's all I've got for now...

Regards,
Brian
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