Hi Cyrille:
Thanks for your carefully review.
On 2017?08?25? 19:29, Cyrille Pitchen wrote:
> Hi Andy,
>
> I see many issues in this driver:
>
> Le 25/07/2017 ? 12:08, Andy Yan a ?crit :
>> From: Shawn Lin <shawn.lin at rock-chips.com>
>>
>> Add rockchip serial flash controller driver
>>
>> Signed-off-by: Shawn Lin <shawn.lin at rock-chips.com>
>> Signed-off-by: Andy Yan <andy.yan at rock-chips.com>
>> Acked-by: Marek Vasut <marek.vasut at gmail.com>
>>
>> ---
>>
>> Changes in v7:
>> - correct the fifo status check in pio read/write mode.
>> - copy data from user buffer to dma buffer
>>
>> Changes in v6:
>> - fold in Andy's improvement for checking fifo level
>> before pio read
>> - rename the controller to rv1108 since offically it's
>> renamed and acked by Rob.
>> - use dma_coerce_mask_and_coherent suggested by Andy.
>>
>> Changes in v5:
>> - check if the buf is aligned to 32bit
>> - check if the buf for dma comes from vmalloc
>> - fix to use 1-1-n according to the current framework
>> - avoid bytes cnt overflow
>>
>> Changes in v4:
>> - use uppercase DMA for description
>> - simplify the code of get_if_type
>> - use dma_dir to simplify the code
>> - simplify the rockchip_sfc_do_rd_wr
>> - some minor improvements
>> - add reset controller when doing resume
>>
>> Changes in v3:
>> - use io{read32,write32}_rep to simplify the corner cases
>> - remove more unnecessary bit definitions
>> - some minor comment fixes and improvement
>> - fix wrong unregister function
>> - unify more code
>> - use nor to avoid constantly replicating the whole
>> sfc->flash[sfc->num_chip].nor
>> - add email for MODULE_AUTHOR
>> - remove #if 1 --- #endif
>> - extract DMA code to imporve the code structure
>> - reset all when failing to do dma
>> - pass sfc to get_if_type
>> - rename sfc-no-dma to sfc-no-DMA
>>
>> Changes in v2:
>> - fix typos
>> - add some comment for buffer and others operations
>> - rename SFC_MAX_CHIP_NUM to MAX_CHIPSELECT_NUM
>> - use u8 for cs
>> - return -EINVAL for default case of get_if_type
>> - use readl_poll_*() to check timeout cases
>> - simplify and clarify some condition checks
>> - rework the bitshifts to simplify the code
>> - define SFC_CMD_DUMMY(x)
>> - fix ummap for dma read path and finish all the
>> cache maintenance.
>> - rename to rockchip_sfc_chip_priv and embed struct spi_nor
>> in it.
>> - add MODULE_AUTHOR
>> - add runtime PM and general PM support.
>> - Thanks for Marek's comments. Link:
>> http://lists.infradead.org/pipermail/linux-mtd/2016-November/070321.html
>>
>> MAINTAINERS | 8 +
>> drivers/mtd/spi-nor/Kconfig | 7 +
>> drivers/mtd/spi-nor/Makefile | 3 +-
>> drivers/mtd/spi-nor/rockchip-sfc.c | 942 +++++++++++++++++++++++++++++++++++++
>> 4 files changed, 959 insertions(+), 1 deletion(-)
>> create mode 100644 drivers/mtd/spi-nor/rockchip-sfc.c
>>
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index 205d397..257361b 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -11258,6 +11258,14 @@ L: linux-serial at vger.kernel.org
>> S: Odd Fixes
>> F: drivers/tty/serial/rp2.*
>>
>> +ROCKCHIP SERIAL FLASH CONTROLLER DRIVER
>> +M: Shawn Lin <shawn.lin at rock-chips.com>
>> +L: linux-mtd at lists.infradead.org
>> +L: linux-rockchip at lists.infradead.org
>> +S: Maintained
>> +F: Documentation/devicetree/bindings/mtd/rockchip-sfc.txt
>> +F: drivers/mtd/spi-nor/rockchip-sfc.c
>> +
>> ROSE NETWORK LAYER
>> M: Ralf Baechle <ralf at linux-mips.org>
>> L: linux-hams at vger.kernel.org
>> diff --git a/drivers/mtd/spi-nor/Kconfig b/drivers/mtd/spi-nor/Kconfig
>> index 293c8a4..dbbcff9 100644
>> --- a/drivers/mtd/spi-nor/Kconfig
>> +++ b/drivers/mtd/spi-nor/Kconfig
>> @@ -113,4 +113,11 @@ config SPI_STM32_QUADSPI
>> This enables support for the STM32 Quad SPI controller.
>> We only connect the NOR to this controller.
>>
>> +config SPI_ROCKCHIP_SFC
>> + tristate "Rockchip Serial Flash Controller(SFC)"
>> + depends on ARCH_ROCKCHIP || COMPILE_TEST
>> + depends on HAS_IOMEM && HAS_DMA
>> + help
>> + This enables support for rockchip serial flash controller.
>> +
>> endif # MTD_SPI_NOR
>> diff --git a/drivers/mtd/spi-nor/Makefile b/drivers/mtd/spi-nor/Makefile
>> index 285aab8..cbc65b8 100644
>> --- a/drivers/mtd/spi-nor/Makefile
>> +++ b/drivers/mtd/spi-nor/Makefile
>> @@ -8,4 +8,5 @@ obj-$(CONFIG_MTD_MT81xx_NOR) += mtk-quadspi.o
>> obj-$(CONFIG_SPI_NXP_SPIFI) += nxp-spifi.o
>> obj-$(CONFIG_SPI_INTEL_SPI) += intel-spi.o
>> obj-$(CONFIG_SPI_INTEL_SPI_PLATFORM) += intel-spi-platform.o
>> -obj-$(CONFIG_SPI_STM32_QUADSPI) += stm32-quadspi.o
>> \ No newline at end of file
>> +obj-$(CONFIG_SPI_STM32_QUADSPI) += stm32-quadspi.o
>> +obj-$(CONFIG_SPI_ROCKCHIP_SFC) += rockchip-sfc.o
>> diff --git a/drivers/mtd/spi-nor/rockchip-sfc.c b/drivers/mtd/spi-nor/rockchip-sfc.c
>> new file mode 100644
>> index 0000000..df7a918
>> --- /dev/null
>> +++ b/drivers/mtd/spi-nor/rockchip-sfc.c
>> @@ -0,0 +1,942 @@
>> +/*
>> + * Rockchip Serial Flash Controller Driver
>> + *
>> + * Copyright (c) 2017, Rockchip Inc.
>> + * Author: Shawn Lin <shawn.lin at rock-chips.com>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License as published by
>> + * the Free Software Foundation; either version 2 of the License, or
>> + * (at your option) any later version.
>> + *
>> + * This program is distributed in the hope that 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/bitops.h>
>> +#include <linux/clk.h>
>> +#include <linux/completion.h>
>> +#include <linux/dma-mapping.h>
>> +#include <linux/iopoll.h>
>> +#include <linux/mm.h>
>> +#include <linux/module.h>
>> +#include <linux/mtd/mtd.h>
>> +#include <linux/mtd/spi-nor.h>
>> +#include <linux/of.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/pm_runtime.h>
>> +#include <linux/slab.h>
>> +
>> +/* System control */
>> +#define SFC_CTRL 0x0
>> +#define SFC_CTRL_COMMON_BITS_1 0x0
>> +#define SFC_CTRL_COMMON_BITS_2 0x1
>> +#define SFC_CTRL_COMMON_BITS_4 0x2
>> +#define SFC_CTRL_DATA_BITS_SHIFT 12
>> +#define SFC_CTRL_ADDR_BITS_SHIFT 10
>> +#define SFC_CTRL_CMD_BITS_SHIFT 8
>> +#define SFC_CTRL_PHASE_SEL_NEGETIVE BIT(1)
>> +
>> +/* Interrupt mask */
>> +#define SFC_IMR 0x4
>> +#define SFC_IMR_RX_FULL BIT(0)
>> +#define SFC_IMR_RX_UFLOW BIT(1)
>> +#define SFC_IMR_TX_OFLOW BIT(2)
>> +#define SFC_IMR_TX_EMPTY BIT(3)
>> +#define SFC_IMR_TRAN_FINISH BIT(4)
>> +#define SFC_IMR_BUS_ERR BIT(5)
>> +#define SFC_IMR_NSPI_ERR BIT(6)
>> +#define SFC_IMR_DMA BIT(7)
>> +/* Interrupt clear */
>> +#define SFC_ICLR 0x8
>> +#define SFC_ICLR_RX_FULL BIT(0)
>> +#define SFC_ICLR_RX_UFLOW BIT(1)
>> +#define SFC_ICLR_TX_OFLOW BIT(2)
>> +#define SFC_ICLR_TX_EMPTY BIT(3)
>> +#define SFC_ICLR_TRAN_FINISH BIT(4)
>> +#define SFC_ICLR_BUS_ERR BIT(5)
>> +#define SFC_ICLR_NSPI_ERR BIT(6)
>> +#define SFC_ICLR_DMA BIT(7)
>> +/* FIFO threshold level */
>> +#define SFC_FTLR 0xc
>> +#define SFC_FTLR_TX_SHIFT 0
>> +#define SFC_FTLR_TX_MASK 0x1f
>> +#define SFC_FTLR_RX_SHIFT 8
>> +#define SFC_FTLR_RX_MASK 0x1f
>> +/* Reset FSM and FIFO */
>> +#define SFC_RCVR 0x10
>> +#define SFC_RCVR_RESET BIT(0)
>> +/* Enhanced mode */
>> +#define SFC_AX 0x14
>> +/* Address Bit number */
>> +#define SFC_ABIT 0x18
>> +/* Interrupt status */
>> +#define SFC_ISR 0x1c
>> +#define SFC_ISR_RX_FULL_SHIFT BIT(0)
>> +#define SFC_ISR_RX_UFLOW_SHIFT BIT(1)
>> +#define SFC_ISR_TX_OFLOW_SHIFT BIT(2)
>> +#define SFC_ISR_TX_EMPTY_SHIFT BIT(3)
>> +#define SFC_ISR_TX_FINISH_SHIFT BIT(4)
>> +#define SFC_ISR_BUS_ERR_SHIFT BIT(5)
>> +#define SFC_ISR_NSPI_ERR_SHIFT BIT(6)
>> +#define SFC_ISR_DMA_SHIFT BIT(7)
>> +/* FIFO status */
>> +#define SFC_FSR 0x20
>> +#define SFC_FSR_TX_IS_FULL BIT(0)
>> +#define SFC_FSR_TX_IS_EMPTY BIT(1)
>> +#define SFC_FSR_RX_IS_EMPTY BIT(2)
>> +#define SFC_FSR_RX_IS_FULL BIT(3)
>> +#define SFC_FSR_TXLV_MASK GENMASK(12, 8)
>> +#define SFC_FSR_TXLV_SHIFT 8
>> +#define SFC_FSR_RXLV_MASK GENMASK(20, 16)
>> +#define SFC_FSR_RXLV_SHIFT 16
>> +/* FSM status */
>> +#define SFC_SR 0x24
>> +#define SFC_SR_IS_IDLE 0x0
>> +#define SFC_SR_IS_BUSY 0x1
>> +/* Raw interrupt status */
>> +#define SFC_RISR 0x28
>> +#define SFC_RISR_RX_FULL BIT(0)
>> +#define SFC_RISR_RX_UNDERFLOW BIT(1)
>> +#define SFC_RISR_TX_OVERFLOW BIT(2)
>> +#define SFC_RISR_TX_EMPTY BIT(3)
>> +#define SFC_RISR_TRAN_FINISH BIT(4)
>> +#define SFC_RISR_BUS_ERR BIT(5)
>> +#define SFC_RISR_NSPI_ERR BIT(6)
>> +#define SFC_RISR_DMA BIT(7)
>> +/* Master trigger */
>> +#define SFC_DMA_TRIGGER 0x80
>> +/* Src or Dst addr for master */
>> +#define SFC_DMA_ADDR 0x84
>> +/* Command */
>> +#define SFC_CMD 0x100
>> +#define SFC_CMD_IDX_SHIFT 0
>> +#define SFC_CMD_DUMMY_SHIFT 8
>> +#define SFC_CMD_DIR_RD 0
>> +#define SFC_CMD_DIR_WR 1
>> +#define SFC_CMD_DIR_SHIFT 12
>> +#define SFC_CMD_ADDR_ZERO (0x0 << 14)
>> +#define SFC_CMD_ADDR_24BITS (0x1 << 14)
>> +#define SFC_CMD_ADDR_32BITS (0x2 << 14)
>> +#define SFC_CMD_ADDR_FRS (0x3 << 14)
>> +#define SFC_CMD_TRAN_BYTES_SHIFT 16
>> +#define SFC_CMD_TRAN_BYTES_MASK 16
> strange value for a mask
This MASK is not used in the current version, so it will be removed
in next version.
>> +#define SFC_CMD_CS_SHIFT 30
>> +/* Address */
>> +#define SFC_ADDR 0x104
>> +/* Data */
>> +#define SFC_DATA 0x108
>> +
>> +#define SFC_MAX_CHIPSELECT_NUM 4
>> +#define SFC_DMA_MAX_LEN 0x4000
>> +#define SFC_MAX_TRANS_BYTES 0x3fff
>> +#define SFC_CMD_DUMMY(x) \
>> + ((x) << SFC_CMD_DUMMY_SHIFT)
>> +
>> +enum rockchip_sfc_iftype {
>> + IF_TYPE_STD,
>> + IF_TYPE_DUAL,
>> + IF_TYPE_QUAD,
>> +};
>> +
>> +struct rockchip_sfc;
>> +struct rockchip_sfc_chip_priv {
>> + u8 cs;
>> + u32 clk_rate;
>> + struct spi_nor nor;
>> + struct rockchip_sfc *sfc;
>> +};
>> +
>> +struct rockchip_sfc {
>> + struct device *dev;
>> + struct mutex lock;
>> + void __iomem *regbase;
>> + struct clk *hclk;
>> + struct clk *clk;
>> + /* virtual mapped addr for dma_buffer */
>> + void *buffer;
>> + dma_addr_t dma_buffer;
>> + struct completion cp;
>> + struct rockchip_sfc_chip_priv flash[SFC_MAX_CHIPSELECT_NUM];
>> + u32 num_chip;
>> + bool use_dma;
>> +};
>> +
>> +static int get_if_type(struct rockchip_sfc *sfc, enum spi_nor_protocol proto)
>> +{
>> + if (proto == SNOR_PROTO_1_1_2)
>> + return IF_TYPE_DUAL;
>> + else if (proto == SNOR_PROTO_1_1_4)
>> + return IF_TYPE_QUAD;
>> + else if (proto == SNOR_PROTO_1_1_1)
>> + return IF_TYPE_STD;
>> +
>> + dev_err(sfc->dev, "unsupported SPI read mode\n");
>> + return -EINVAL;
>> +}
>> +
>> +static int rockchip_sfc_reset(struct rockchip_sfc *sfc)
>> +{
>> + int err;
>> + u32 status;
>> +
>> + writel_relaxed(SFC_RCVR_RESET, sfc->regbase + SFC_RCVR);
>> +
>> + err = readl_poll_timeout(sfc->regbase + SFC_RCVR, status,
>> + !(status & SFC_RCVR_RESET), 20,
>> + jiffies_to_usecs(HZ));
>> + if (err)
>> + dev_err(sfc->dev, "SFC reset never finished\n");
>> +
>> + /* Still need to clear the masked interrupt from RISR */
>> + writel_relaxed(SFC_ICLR_RX_FULL | SFC_ICLR_RX_UFLOW |
>> + SFC_ICLR_TX_OFLOW | SFC_ICLR_TX_EMPTY |
>> + SFC_ICLR_TRAN_FINISH | SFC_ICLR_BUS_ERR |
>> + SFC_ICLR_NSPI_ERR | SFC_ICLR_DMA,
>> + sfc->regbase + SFC_ICLR);
>> + return err;
>> +}
>> +
>> +static int rockchip_sfc_init(struct rockchip_sfc *sfc)
>> +{
>> + int err;
>> +
>> + err = rockchip_sfc_reset(sfc);
>> + if (err)
>> + return err;
>> +
>> + /* Mask all eight interrupts */
>> + writel_relaxed(0xff, sfc->regbase + SFC_IMR);
>> +
>> + writel_relaxed(SFC_CTRL_PHASE_SEL_NEGETIVE, sfc->regbase + SFC_CTRL);
>> +
>> + return 0;
>> +}
>> +
>> +static int rockchip_sfc_prep(struct spi_nor *nor, enum spi_nor_ops ops)
>> +{
>> + struct rockchip_sfc_chip_priv *priv = nor->priv;
>> + struct rockchip_sfc *sfc = priv->sfc;
>> + int ret;
>> +
>> + mutex_lock(&sfc->lock);
>> + pm_runtime_get_sync(sfc->dev);
>> +
>> + ret = clk_set_rate(sfc->clk, priv->clk_rate);
>> + if (ret)
>> + goto out;
>> +
>> + ret = clk_prepare_enable(sfc->clk);
>> + if (ret)
>> + goto out;
>> +
>> + return 0;
>> +
>> +out:
>> + mutex_unlock(&sfc->lock);
>> + return ret;
>> +}
>> +
>> +static void rockchip_sfc_unprep(struct spi_nor *nor, enum spi_nor_ops ops)
>> +{
>> + struct rockchip_sfc_chip_priv *priv = nor->priv;
>> + struct rockchip_sfc *sfc = priv->sfc;
>> +
>> + clk_disable_unprepare(sfc->clk);
>> + mutex_unlock(&sfc->lock);
>> + pm_runtime_mark_last_busy(sfc->dev);
>> + pm_runtime_put_autosuspend(sfc->dev);
>> +}
>> +
>> +static int rockchip_sfc_get_fifo_level(struct rockchip_sfc *sfc, int wr, u32 timeout)
>> +{
>> + unsigned long deadline = jiffies + timeout;
>> + int level;
>> + u32 fsr;
>> +
>> + do {
>> + fsr = readl_relaxed(sfc->regbase + SFC_FSR);
>> + if (wr)
>> + level = (fsr & SFC_FSR_TXLV_MASK) >> SFC_FSR_TXLV_SHIFT;
>> + else
>> + level = (fsr & SFC_FSR_RXLV_MASK) >> SFC_FSR_RXLV_SHIFT;
>> + if (time_after_eq(jiffies, deadline))
>> + return -ETIMEDOUT;
>> + udelay(1);
> if level != 0, is it needed to call udelay or check for time out?
I will give a better solution in next version.
>
>> + } while (!level);
>> +
>> + return level;
>> +}
>> +
>> +static int rockchip_sfc_wait_op_finish(struct rockchip_sfc *sfc)
>> +{
>> + int err;
>> + u32 status;
>> +
>> + /*
>> + * Note: tx and rx share the same fifo, so the rx's water level
>> + * is the same as rx's, which means this function could be reused
>> + * for checking the read operations as well.
>> + */
>> + err = readl_poll_timeout(sfc->regbase + SFC_FSR, status,
>> + status & SFC_FSR_TX_IS_EMPTY,
>> + 20, jiffies_to_usecs(2 * HZ));
>> + if (err)
>> + dev_err(sfc->dev, "SFC fifo never empty\n");
>> +
>> + return err;
>> +}
>> +
>> +static int rockchip_sfc_op_reg(struct spi_nor *nor,
>> + u8 opcode, int len, u8 optype)
>> +{
>> + struct rockchip_sfc_chip_priv *priv = nor->priv;
>> + struct rockchip_sfc *sfc = priv->sfc;
>> + bool tx_no_empty, rx_no_empty, is_busy;
>> + int err;
>> + u32 reg;
>> +
>> + reg = readl_relaxed(sfc->regbase + SFC_FSR);
>> + tx_no_empty = !(reg & SFC_FSR_TX_IS_EMPTY);
>> + rx_no_empty = !(reg & SFC_FSR_RX_IS_EMPTY);
>> +
>> + is_busy = readl_relaxed(sfc->regbase + SFC_SR);
>> +
>> + if (tx_no_empty || rx_no_empty || is_busy) {
>> + err = rockchip_sfc_reset(sfc);
>> + if (err)
>> + return err;
>> + }
>> +
>> + reg = IF_TYPE_STD << SFC_CTRL_DATA_BITS_SHIFT;
>> + reg |= IF_TYPE_STD << SFC_CTRL_ADDR_BITS_SHIFT;
>> + reg |= IF_TYPE_STD << SFC_CTRL_CMD_BITS_SHIFT;
>> + reg |= SFC_CTRL_PHASE_SEL_NEGETIVE;
>> + writel_relaxed(reg, sfc->regbase + SFC_CTRL);
>> + reg = opcode << SFC_CMD_IDX_SHIFT;
>> + reg |= len << SFC_CMD_TRAN_BYTES_SHIFT;
>> + reg |= priv->cs << SFC_CMD_CS_SHIFT;
>> + reg |= optype << SFC_CMD_DIR_SHIFT;
>> + writel_relaxed(reg, sfc->regbase + SFC_CMD);
>> +
>> + return 0;
>> +}
>> +
>> +static int rockchip_sfc_write_fifo(struct rockchip_sfc *sfc, u8 *buf, int len)
>> +{
> The 'len' arguement of rockchip_sfc_read_fifo() seems to be in bytes
> whereas here 'len' is a number of DWORDS.
> This is not consistant.
>
OK, I will make them be consistent .
>> + u8 tx_level;
>> + u32 dwords;
>> +
>> + while (len) {
>> + tx_level = rockchip_sfc_get_fifo_level(sfc, SFC_CMD_DIR_WR, HZ);
>> + if (tx_level <= 0)
> As far as I understand, rockchip_sfc_get_fifo_level() can't return 0, so
> tx_level can't be 0. The test should be if (tx_level < 0)
>
> Besides, if tx_level could be 0 here, this function would retrun 0 as if
> it succeeded whereas it has actually failed.
Got it.
>> + return tx_level;
>> + dwords = min_t(u32, tx_level, len);
>> + iowrite32_rep(sfc->regbase + SFC_DATA, buf, dwords);
>> + buf += dwords << 2;
>> + len -= dwords;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static int rockchip_sfc_read_fifo(struct rockchip_sfc *sfc, u8 *buf, int len)
>> +{
>> + u32 tmp;
>> + u8 read_words;
>> + u8 rx_level;
>> + u32 dwords;
>> +
>> + /* 32-bit access only */
>> + if (len >= sizeof(u32)) {
>> + dwords = len >> 2;
>> + while (dwords) {
>> + rx_level = rockchip_sfc_get_fifo_level(sfc, SFC_CMD_DIR_RD, HZ);
>> + if (rx_level <= 0)
> if (rx_level < 0)
Got it.
>> + return rx_level;
>> + read_words = min_t(u32, rx_level, dwords);
>> + ioread32_rep(sfc->regbase + SFC_DATA, buf, read_words);
>> + buf += read_words << 2;
>> + dwords -= read_words;
>> + }
>> + len %= 4;
>> + }
>> +
>> + /* read the rest none word aligned bytes */
>> + if (len) {
>> + rx_level = rockchip_sfc_get_fifo_level(sfc, SFC_CMD_DIR_RD, HZ);
>> + if (rx_level <= 0)
> if (rx_level < 0)
Got it.
>> + return rx_level;
>> + tmp = readl_relaxed(sfc->regbase + SFC_DATA);
>> + memcpy(buf, &tmp, len);
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static int rockchip_sfc_read_reg(struct spi_nor *nor, u8 opcode,
>> + u8 *buf, int len)
>> +{
>> + struct rockchip_sfc_chip_priv *priv = nor->priv;
>> + struct rockchip_sfc *sfc = priv->sfc;
>> + int ret;
>> + int trans;
>> +
>> + while (len > 0) {
>> + trans = min_t(int, len, SFC_MAX_TRANS_BYTES);
>> + ret = rockchip_sfc_op_reg(nor, opcode, trans, SFC_CMD_DIR_RD);
> You simply cannot split a single SPI command into many smallers SPI
> commands like that.
>
> Unlike _read(), _read_reg() doesn't send an address or offset after the
> instruction byte in the SPI command. Then let's take the example of the
> Read JEDEC ID command (9Fh), if you send this command many times in this
> loop, you would read always the same bytes starting from offset 0.
The max bytes can be transferred by the SFC is 16kb - 1, I don't
think the length will exceed the max limitation(16kb - 1).
So can we directly remove the check of by min_t(int, len,
SFC_MAX_TRANS_BYYTES) here, just read the fifo in one time?
>
>
>> + if (ret)
>> + return ret;
>> +
>> + ret = rockchip_sfc_read_fifo(sfc, buf, trans);
> Why rockchip_sfc_write_reg() cares about the alignment of its 'buf'
> argument but not rockchip_sfr_read_reg() here?
>
>> + if (ret < 0)
>> + return ret;
>> + buf += trans;
>> + len -= trans;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static int rockchip_sfc_write_reg(struct spi_nor *nor, u8 opcode,
>> + u8 *buf, int len)
>> +{
>> + struct rockchip_sfc_chip_priv *priv = nor->priv;
>> + struct rockchip_sfc *sfc = priv->sfc;
>> + u32 dwords;
>> + int ret;
>> + u8 *pbuf = buf;
>> + u8 *tmpbuf = NULL;
>> +
>> + /* Align bytes to dwords */
>> + dwords = DIV_ROUND_UP(len, sizeof(u32));
>> + if (!IS_ALIGNED((u32)buf, sizeof(u32))) {
>> + dev_dbg(sfc->dev, "write_reg buf is not aligned to u32\n");
>> + tmpbuf = kzalloc(sizeof(*tmpbuf), len);
>> + if (!tmpbuf)
>> + return -ENOMEM;
>> + memcpy(tmpbuf, buf, len);
>> + pbuf = tmpbuf;
>> + }
>> +
>> + ret = rockchip_sfc_op_reg(nor, opcode, len, SFC_CMD_DIR_WR);
>> + if (ret)
>> + return ret;
>> + ret = rockchip_sfc_write_fifo(sfc, pbuf, dwords);
>> +
>> + kfree(tmpbuf);
>> +
>> + return ret;
>> +}
>> +
>> +static inline void rockchip_sfc_setup_transfer(struct spi_nor *nor,
>> + loff_t from_to,
>> + size_t len, u8 op_type)
>> +{
>> + struct rockchip_sfc_chip_priv *priv = nor->priv;
>> + struct rockchip_sfc *sfc = priv->sfc;
>> + u32 reg;
>> + u8 if_type = IF_TYPE_STD;
>> +
>> + if (op_type == SFC_CMD_DIR_RD)
>> + if_type = get_if_type(sfc, nor->read_proto);
>> + writel_relaxed((if_type << SFC_CTRL_DATA_BITS_SHIFT) |
>> + (IF_TYPE_STD << SFC_CTRL_ADDR_BITS_SHIFT) |
>> + (IF_TYPE_STD << SFC_CTRL_CMD_BITS_SHIFT) |
>> + SFC_CTRL_PHASE_SEL_NEGETIVE,
>> + sfc->regbase + SFC_CTRL);
>> +
>> + if (op_type == SFC_CMD_DIR_WR)
>> + reg = nor->program_opcode << SFC_CMD_IDX_SHIFT;
>> + else
>> + reg = nor->read_opcode << SFC_CMD_IDX_SHIFT;
>> +
>> + reg |= op_type << SFC_CMD_DIR_SHIFT;
>> + reg |= (nor->addr_width == 4) ?
>> + SFC_CMD_ADDR_32BITS : SFC_CMD_ADDR_24BITS;
>> +
>> + reg |= priv->cs << SFC_CMD_CS_SHIFT;
>> + reg |= len << SFC_CMD_TRAN_BYTES_SHIFT;
>> +
>> + if (op_type == SFC_CMD_DIR_RD)
>> + reg |= SFC_CMD_DUMMY(nor->read_dummy);
>> +
>> + /* Should minus one as 0x0 means 1 bit flash address */
>> + writel_relaxed(nor->addr_width * 8 - 1, sfc->regbase + SFC_ABIT);
>> + writel_relaxed(reg, sfc->regbase + SFC_CMD);
>> + writel_relaxed(from_to, sfc->regbase + SFC_ADDR);
>> +}
>> +
>> +static int rockchip_sfc_do_dma_transfer(struct spi_nor *nor, loff_t from_to,
>> + dma_addr_t dma_buf, size_t len,
>> + u8 op_type)
>> +{
>> + struct rockchip_sfc_chip_priv *priv = nor->priv;
>> + struct rockchip_sfc *sfc = priv->sfc;
>> + u32 reg;
>> + int err = 0;
>> +
>> + init_completion(&sfc->cp);
>> +
>> + writel_relaxed(SFC_ICLR_RX_FULL | SFC_ICLR_RX_UFLOW |
>> + SFC_ICLR_TX_OFLOW | SFC_ICLR_TX_EMPTY |
>> + SFC_ICLR_TRAN_FINISH | SFC_ICLR_BUS_ERR |
>> + SFC_ICLR_NSPI_ERR | SFC_ICLR_DMA,
>> + sfc->regbase + SFC_ICLR);
>> +
>> + /* Enable transfer complete interrupt */
>> + reg = readl_relaxed(sfc->regbase + SFC_IMR);
>> + reg &= ~SFC_IMR_TRAN_FINISH;
>> + writel_relaxed(reg, sfc->regbase + SFC_IMR);
>> +
>> + rockchip_sfc_setup_transfer(nor, from_to, len, op_type);
>> + writel_relaxed(dma_buf, sfc->regbase + SFC_DMA_ADDR);
>> +
>> + /*
>> + * Start dma but note that the sfc->dma_buffer is derived from
>> + * dmam_alloc_coherent so we don't actually need any sync operations
>> + * for coherent dma memory.
>> + */
>> + writel_relaxed(0x1, sfc->regbase + SFC_DMA_TRIGGER);
>> +
>> + /* Wait for the interrupt. */
>> + if (!wait_for_completion_timeout(&sfc->cp, msecs_to_jiffies(2000))) {
>> + dev_err(sfc->dev, "DMA wait for transfer finish timeout\n");
>> + err = -ETIMEDOUT;
>> + }
>> +
>> + /* Disable transfer finish interrupt */
>> + reg = readl_relaxed(sfc->regbase + SFC_IMR);
>> + reg |= SFC_IMR_TRAN_FINISH;
>> + writel_relaxed(reg, sfc->regbase + SFC_IMR);
>> +
>> + if (err) {
>> + rockchip_sfc_reset(sfc);
>> + return err;
>> + }
>> +
>> + return rockchip_sfc_wait_op_finish(sfc);
>> +}
>> +
>> +static inline int rockchip_sfc_pio_write(struct rockchip_sfc *sfc, u_char *buf,
>> + size_t len)
>> +{
>> + u32 dwords;
>> + u8 *tmpbuf;
>> +
>> + /*
>> + * Align bytes to dwords, although we will write some extra
>> + * bytes to fifo but the transfer bytes number in SFC_CMD
>> + * register will make sure we just send out the expected
>> + * byte numbers and the extra bytes will be clean before
>> + * setting up the next transfer. We should always round up
>> + * to align to DWORD as the ahb for Rockchip Socs won't
>> + * support non-aligned-to-DWORD transfer.
>> + */
>> + dwords = DIV_ROUND_UP(len, sizeof(u32));
>> + if (!IS_ALIGNED((u32)buf, sizeof(u32))) {
>> + dev_dbg(sfc->dev, "pio_write buf is not aligned to u32\n");
>> + tmpbuf = kmalloc(sizeof(*tmpbuf), len);
>> + if (!tmpbuf)
>> + return -ENOMEM;
>> + memcpy((u32 *)tmpbuf, (u32 *)buf, dwords);
>> + }
>> +
>> + iowrite32_rep(sfc->regbase + SFC_DATA,
>> + !IS_ALIGNED((u32)buf, sizeof(u32)) ? tmpbuf : buf,
> You could introduce a pbuf variable like you did in
> rockchip_sfc_write_reg(), hence the last argument of iowrite32_rep()
> would simply be pbuf.
>
> Also, why don't you care about the FIFO level, here?
>
> rockchip_sfc_pio_read == rockchip_sfc_read_fifo
>
> but
>
> rockchip_sfc_pio_write != rockchip_sfc_write_fifo
>
> ?
>
> Please, try to do something more consistant between read_reg(),
> write_reg(), read() and write() about data transfers and dealing with
> alignment issues.
>
>> + dwords);
>> +
>> + if (!IS_ALIGNED((u32)buf, sizeof(u32)))
>> + kfree(tmpbuf);
>> +
>> + return rockchip_sfc_wait_op_finish(sfc);
>> +}
>> +
>> +static inline int rockchip_sfc_pio_read(struct rockchip_sfc *sfc, u_char *buf,
>> + size_t len)
>> +{
>> + return rockchip_sfc_read_fifo(sfc, buf, len);
>> +}
>> +
>> +static int rockchip_sfc_pio_transfer(struct spi_nor *nor, loff_t from_to,
>> + size_t len, u_char *buf, u8 op_type)
>> +{
>> + struct rockchip_sfc_chip_priv *priv = nor->priv;
>> + struct rockchip_sfc *sfc = priv->sfc;
>> + size_t trans;
>> + int ret;
>> +
>> + while (len > 0) {
>> + trans = min_t(size_t, SFC_MAX_TRANS_BYTES, len);
>> + rockchip_sfc_setup_transfer(nor, from_to, trans, op_type);
>> +
>> + if (op_type == SFC_CMD_DIR_WR) {
>> + ret = rockchip_sfc_pio_write(sfc, buf, trans);
>> + if (ret)
>> + return ret;
>> + } else {
>> + ret = rockchip_sfc_pio_read(sfc, buf, trans);
>> + if (ret)
>> + return ret;
>> + }
>> + len -= trans;
>> + buf += trans;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static int rockchip_sfc_dma_transfer(struct spi_nor *nor, loff_t from_to,
>> + size_t len, u_char *buf, u8 op_type)
>> +{
>> + struct rockchip_sfc_chip_priv *priv = nor->priv;
>> + struct rockchip_sfc *sfc = priv->sfc;
>> + size_t offset;
>> + int ret;
>> + size_t aligned_trans;
>> + size_t padding_len;
>> +
>> + for (offset = 0; offset < len; offset += SFC_DMA_MAX_LEN) {
>> + size_t trans = min_t(size_t, SFC_DMA_MAX_LEN, len - offset);
>> +
>> + aligned_trans = ALIGN(trans, 4);
>> + padding_len = aligned_trans - trans;
> This is all wrong, you cannot split SPI commands into smaller SPI
> commands nor you can add padding bytes to align the length of the
> transfer data.
I think we have to check whether the requested transferred length
is exceed the SFC_DMA_MAX_LEN, especially
for the spi_nor_read() operation.
> 'aligned_trans' only (not 'len') is passed to
> rockchip_sfc_do_dma_transfer() so rockchip_sfc_setup_transfer() will
> write the wrong value into the SFC_CMD register.
>
> If the driver is asked to write 9 bytes, it must write 9 bytes, not 12.
According to the IC design, the DMA transfer bytes must 4bytes aligned.
>
> Even worse, you cannot split a Page Program command into smaller Page
> Program commands. Indeed, you can't send a Page Program command
> immediately after another Page Program command, like this function can
> do. Actually, spi-nor.c checks the Status Register for write completion
> after having called nor->write() and no SPI command can be sent to the
> memory until the BUSY bit is cleared.
As for the spi_nor_write, maybe we can start the transfer with
requested length directly without the
need to check if it exceed the SFC_DMA_MAX_LEN, because the spi-nor
framework will split the transfer packages by pages size.
> Please, don't try to duplicate here what spi-nor.c already does.
>
>
> Best regards,
>
> Cyrille
>
>> +
>> + if (op_type == SFC_CMD_DIR_WR) {
>> + memcpy(sfc->buffer, buf + offset, trans);
>> + /* padding the package to 4 byte aligned */
>> + memset(sfc->buffer + trans, 0xff, padding_len);
>> + }
>> +
>> + ret = rockchip_sfc_do_dma_transfer(nor, from_to + offset,
>> + sfc->dma_buffer,
>> + aligned_trans, op_type);
>> + if (ret) {
>> + dev_warn(nor->dev, "DMA timeout\n");
>> + return ret;
>> + }
>> +
>> + if (op_type == SFC_CMD_DIR_RD)
>> + memcpy(buf + offset, sfc->buffer, trans);
>> + }
>> +
>> + return len;
>> +}
>> +
>> +static ssize_t rockchip_sfc_do_rd_wr(struct spi_nor *nor, loff_t from_to,
>> + size_t len, u_char *buf, u32 op_type)
>> +{
>> + struct rockchip_sfc_chip_priv *priv = nor->priv;
>> + struct rockchip_sfc *sfc = priv->sfc;
>> + int ret;
>> +
>> + if (likely(sfc->use_dma))
>> + return rockchip_sfc_dma_transfer(nor, from_to, len,
>> + buf, op_type);
>> +
>> + /* Fall back to PIO mode if DMA isn't present */
>> + ret = rockchip_sfc_pio_transfer(nor, from_to, len,
>> + (u_char *)buf, op_type);
>> + if (ret) {
>> + dev_warn(nor->dev, "PIO %s timeout\n",
>> + (op_type == SFC_CMD_DIR_RD) ? "read" : "write");
>> + return ret;
>> + }
>> +
>> + return len;
>> +}
>> +
>> +static ssize_t rockchip_sfc_read(struct spi_nor *nor, loff_t from,
>> + size_t len, u_char *read_buf)
>> +{
>> + return rockchip_sfc_do_rd_wr(nor, from, len,
>> + read_buf, SFC_CMD_DIR_RD);
>> +}
>> +
>> +static ssize_t rockchip_sfc_write(struct spi_nor *nor, loff_t to,
>> + size_t len, const u_char *write_buf)
>> +{
>> + return rockchip_sfc_do_rd_wr(nor, to, len,
>> + (u_char *)write_buf,
>> + SFC_CMD_DIR_WR);
>> +}
>> +
>> +static int rockchip_sfc_register(struct device_node *np,
>> + struct rockchip_sfc *sfc)
>> +{
>> + const struct spi_nor_hwcaps hwcaps = {
>> + .mask = SNOR_HWCAPS_READ |
>> + SNOR_HWCAPS_READ_FAST |
>> + SNOR_HWCAPS_READ_1_1_2 |
>> + SNOR_HWCAPS_READ_1_1_4 |
>> + SNOR_HWCAPS_PP,
>> + };
>> + struct device *dev = sfc->dev;
>> + struct mtd_info *mtd;
>> + struct spi_nor *nor;
>> + int ret;
>> +
>> + nor = &sfc->flash[sfc->num_chip].nor;
>> + nor->dev = dev;
>> + spi_nor_set_flash_node(nor, np);
>> +
>> + ret = of_property_read_u8(np, "reg", &sfc->flash[sfc->num_chip].cs);
>> + if (ret) {
>> + dev_err(dev, "No reg property for %s\n",
>> + np->full_name);
>> + return ret;
>> + }
>> +
>> + ret = of_property_read_u32(np, "spi-max-frequency",
>> + &sfc->flash[sfc->num_chip].clk_rate);
>> + if (ret) {
>> + dev_err(dev, "No spi-max-frequency property for %s\n",
>> + np->full_name);
>> + return ret;
>> + }
>> +
>> + sfc->flash[sfc->num_chip].sfc = sfc;
>> + nor->priv = &sfc->flash[sfc->num_chip];
>> +
>> + nor->prepare = rockchip_sfc_prep;
>> + nor->unprepare = rockchip_sfc_unprep;
>> + nor->read_reg = rockchip_sfc_read_reg;
>> + nor->write_reg = rockchip_sfc_write_reg;
>> + nor->read = rockchip_sfc_read;
>> + nor->write = rockchip_sfc_write;
>> + nor->erase = NULL;
>> + ret = spi_nor_scan(nor, NULL, &hwcaps);
>> + if (ret)
>> + return ret;
>> +
>> + mtd = &nor->mtd;
>> + mtd->name = np->name;
>> + ret = mtd_device_register(mtd, NULL, 0);
>> + if (ret)
>> + return ret;
>> +
>> + sfc->num_chip++;
>> + return 0;
>> +}
>> +
>> +static void rockchip_sfc_unregister_all(struct rockchip_sfc *sfc)
>> +{
>> + int i;
>> +
>> + for (i = 0; i < sfc->num_chip; i++)
>> + mtd_device_unregister(&sfc->flash[i].nor.mtd);
>> +}
>> +
>> +static int rockchip_sfc_register_all(struct rockchip_sfc *sfc)
>> +{
>> + struct device *dev = sfc->dev;
>> + struct device_node *np;
>> + int ret;
>> +
>> + for_each_available_child_of_node(dev->of_node, np) {
>> + ret = rockchip_sfc_register(np, sfc);
>> + if (ret)
>> + goto fail;
>> +
>> + if (sfc->num_chip == SFC_MAX_CHIPSELECT_NUM) {
>> + dev_warn(dev, "Exceeds the max cs limitation\n");
>> + break;
>> + }
>> + }
>> +
>> + return 0;
>> +
>> +fail:
>> + dev_err(dev, "Failed to register all chips\n");
>> + /* Unregister all the _registered_ nor flash */
>> + rockchip_sfc_unregister_all(sfc);
>> + return ret;
>> +}
>> +
>> +static irqreturn_t rockchip_sfc_irq_handler(int irq, void *dev_id)
>> +{
>> + struct rockchip_sfc *sfc = dev_id;
>> + u32 reg;
>> +
>> + reg = readl_relaxed(sfc->regbase + SFC_RISR);
>> + dev_dbg(sfc->dev, "Get irq: 0x%x\n", reg);
>> +
>> + /* Clear interrupt */
>> + writel_relaxed(reg, sfc->regbase + SFC_ICLR);
>> +
>> + if (reg & SFC_RISR_TRAN_FINISH)
>> + complete(&sfc->cp);
>> +
>> + return IRQ_HANDLED;
>> +}
>> +
>> +static int rockchip_sfc_probe(struct platform_device *pdev)
>> +{
>> + struct device *dev = &pdev->dev;
>> + struct resource *res;
>> + struct rockchip_sfc *sfc;
>> + int ret;
>> +
>> + sfc = devm_kzalloc(dev, sizeof(*sfc), GFP_KERNEL);
>> + if (!sfc)
>> + return -ENOMEM;
>> +
>> + platform_set_drvdata(pdev, sfc);
>> + sfc->dev = dev;
>> +
>> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> + sfc->regbase = devm_ioremap_resource(dev, res);
>> + if (IS_ERR(sfc->regbase))
>> + return PTR_ERR(sfc->regbase);
>> +
>> + sfc->clk = devm_clk_get(&pdev->dev, "sfc");
>> + if (IS_ERR(sfc->clk)) {
>> + dev_err(&pdev->dev, "Failed to get sfc interface clk\n");
>> + return PTR_ERR(sfc->clk);
>> + }
>> +
>> + sfc->hclk = devm_clk_get(&pdev->dev, "hsfc");
>> + if (IS_ERR(sfc->hclk)) {
>> + dev_err(&pdev->dev, "Failed to get sfc ahp clk\n");
>> + return PTR_ERR(sfc->hclk);
>> + }
>> +
>> + ret = dma_coerce_mask_and_coherent(dev, DMA_BIT_MASK(32));
>> + if (ret) {
>> + dev_warn(dev, "Unable to set dma mask\n");
>> + return ret;
>> + }
>> +
>> + sfc->buffer = dmam_alloc_coherent(dev, SFC_DMA_MAX_LEN,
>> + &sfc->dma_buffer,
>> + GFP_KERNEL);
>> + if (!sfc->buffer)
>> + return -ENOMEM;
>> +
>> + mutex_init(&sfc->lock);
>> +
>> + ret = clk_prepare_enable(sfc->hclk);
>> + if (ret) {
>> + dev_err(&pdev->dev, "Failed to enable hclk\n");
>> + goto err_hclk;
>> + }
>> +
>> + ret = clk_prepare_enable(sfc->clk);
>> + if (ret) {
>> + dev_err(&pdev->dev, "Failed to enable clk\n");
>> + goto err_clk;
>> + }
>> +
>> + sfc->use_dma = !of_property_read_bool(sfc->dev->of_node,
>> + "rockchip,sfc-no-dma");
>> +
>> + /* Find the irq */
>> + ret = platform_get_irq(pdev, 0);
>> + if (ret < 0) {
>> + dev_err(dev, "Failed to get the irq\n");
>> + goto err_irq;
>> + }
>> +
>> + ret = devm_request_irq(dev, ret, rockchip_sfc_irq_handler,
>> + 0, pdev->name, sfc);
>> + if (ret) {
>> + dev_err(dev, "Failed to request irq\n");
>> + goto err_irq;
>> + }
>> +
>> + sfc->num_chip = 0;
>> + ret = rockchip_sfc_init(sfc);
>> + if (ret)
>> + goto err_irq;
>> +
>> + pm_runtime_get_noresume(&pdev->dev);
>> + pm_runtime_set_active(&pdev->dev);
>> + pm_runtime_enable(&pdev->dev);
>> + pm_runtime_set_autosuspend_delay(&pdev->dev, 50);
>> + pm_runtime_use_autosuspend(&pdev->dev);
>> +
>> + ret = rockchip_sfc_register_all(sfc);
>> + if (ret)
>> + goto err_register;
>> +
>> + clk_disable_unprepare(sfc->clk);
>> + pm_runtime_put_autosuspend(&pdev->dev);
>> + return 0;
>> +
>> +err_register:
>> + pm_runtime_disable(&pdev->dev);
>> + pm_runtime_set_suspended(&pdev->dev);
>> + pm_runtime_put_noidle(&pdev->dev);
>> +err_irq:
>> + clk_disable_unprepare(sfc->clk);
>> +err_clk:
>> + clk_disable_unprepare(sfc->hclk);
>> +err_hclk:
>> + mutex_destroy(&sfc->lock);
>> + return ret;
>> +}
>> +
>> +static int rockchip_sfc_remove(struct platform_device *pdev)
>> +{
>> + struct rockchip_sfc *sfc = platform_get_drvdata(pdev);
>> +
>> + pm_runtime_get_sync(&pdev->dev);
>> + pm_runtime_disable(&pdev->dev);
>> + pm_runtime_put_noidle(&pdev->dev);
>> +
>> + rockchip_sfc_unregister_all(sfc);
>> + mutex_destroy(&sfc->lock);
>> + clk_disable_unprepare(sfc->clk);
>> + clk_disable_unprepare(sfc->hclk);
>> + return 0;
>> +}
>> +
>> +#ifdef CONFIG_PM
>> +int rockchip_sfc_runtime_suspend(struct device *dev)
>> +{
>> + struct rockchip_sfc *sfc = dev_get_drvdata(dev);
>> +
>> + clk_disable_unprepare(sfc->hclk);
>> + return 0;
>> +}
>> +
>> +int rockchip_sfc_runtime_resume(struct device *dev)
>> +{
>> + struct rockchip_sfc *sfc = dev_get_drvdata(dev);
>> +
>> + clk_prepare_enable(sfc->hclk);
>> + return rockchip_sfc_reset(sfc);
>> +}
>> +#endif /* CONFIG_PM */
>> +
>> +static const struct of_device_id rockchip_sfc_dt_ids[] = {
>> + { .compatible = "rockchip,sfc"},
>> + { /* sentinel */ }
>> +};
>> +MODULE_DEVICE_TABLE(of, rockchip_sfc_dt_ids);
>> +
>> +static const struct dev_pm_ops rockchip_sfc_dev_pm_ops = {
>> + SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
>> + pm_runtime_force_resume)
>> + SET_RUNTIME_PM_OPS(rockchip_sfc_runtime_suspend,
>> + rockchip_sfc_runtime_resume, NULL)
>> +};
>> +
>> +static struct platform_driver rockchip_sfc_driver = {
>> + .driver = {
>> + .name = "rockchip-sfc",
>> + .of_match_table = rockchip_sfc_dt_ids,
>> + .pm = &rockchip_sfc_dev_pm_ops,
>> + },
>> + .probe = rockchip_sfc_probe,
>> + .remove = rockchip_sfc_remove,
>> +};
>> +module_platform_driver(rockchip_sfc_driver);
>> +
>> +MODULE_LICENSE("GPL v2");
>> +MODULE_DESCRIPTION("Rockchip Serial Flash Controller Driver");
>> +MODULE_AUTHOR("Shawn Lin <shawn.lin at rock-chips.com>");
>>
>
>
>
