On Fri, Oct 27, 2017 at 05:11:24PM +0100, Gabriele Paoloni wrote:
> From: "zhichang.yuan" <yuanzhich...@hisilicon.com>
> 
> The low-pin-count(LPC) interface of Hip06/Hip07 accesses the peripherals in
> I/O port addresses. This patch implements the LPC host controller driver
> which perform the I/O operations on the underlying hardware.
> We don't want to touch those existing peripherals' driver, such as ipmi-bt.
> So this driver applies the indirect-IO introduced in the previous patch
> after registering an indirect-IO node to the indirect-IO devices list which
> will be searched in the I/O accessors to retrieve the host-local I/O port.
> 
> Signed-off-by: Zou Rongrong <zourongr...@huawei.com>
> Signed-off-by: zhichang.yuan <yuanzhich...@hisilicon.com>
> Signed-off-by: Gabriele Paoloni <gabriele.paol...@huawei.com>
> Acked-by: Rob Herring <r...@kernel.org> #dts part
> ---
>  .../arm/hisilicon/hisilicon-low-pin-count.txt      |  33 ++
>  drivers/bus/Kconfig                                |   9 +
>  drivers/bus/Makefile                               |   1 +
>  drivers/bus/hisi_lpc.c                             | 526 
> +++++++++++++++++++++
>  4 files changed, 569 insertions(+)
>  create mode 100644 
> Documentation/devicetree/bindings/arm/hisilicon/hisilicon-low-pin-count.txt
>  create mode 100644 drivers/bus/hisi_lpc.c
> 
> diff --git 
> a/Documentation/devicetree/bindings/arm/hisilicon/hisilicon-low-pin-count.txt 
> b/Documentation/devicetree/bindings/arm/hisilicon/hisilicon-low-pin-count.txt
> new file mode 100644
> index 0000000..213181f
> --- /dev/null
> +++ 
> b/Documentation/devicetree/bindings/arm/hisilicon/hisilicon-low-pin-count.txt
> @@ -0,0 +1,33 @@
> +Hisilicon Hip06 low-pin-count device
> +  Hisilicon Hip06 SoCs implement a Low Pin Count (LPC) controller, which
> +  provides I/O access to some legacy ISA devices.
> +  Hip06 is based on arm64 architecture where there is no I/O space. So, the
> +  I/O ports here are not cpu addresses, and there is no 'ranges' property in
> +  LPC device node.
> +
> +Required properties:
> +- compatible:  value should be as follows:
> +     (a) "hisilicon,hip06-lpc"
> +     (b) "hisilicon,hip07-lpc"
> +- #address-cells: must be 2 which stick to the ISA/EISA binding doc.
> +- #size-cells: must be 1 which stick to the ISA/EISA binding doc.
> +- reg: base memory range where the LPC register set is mapped.
> +
> +Note:
> +  The node name before '@' must be "isa" to represent the binding stick to 
> the
> +  ISA/EISA binding specification.
> +
> +Example:
> +
> +isa@a01b0000 {
> +     compatible = "hisilicon,hip06-lpc";
> +     #address-cells = <2>;
> +     #size-cells = <1>;
> +     reg = <0x0 0xa01b0000 0x0 0x1000>;
> +
> +     ipmi0: bt@e4 {
> +             compatible = "ipmi-bt";
> +             device_type = "ipmi";
> +             reg = <0x01 0xe4 0x04>;
> +     };
> +};
> diff --git a/drivers/bus/Kconfig b/drivers/bus/Kconfig
> index 2408ea3..358eed3 100644
> --- a/drivers/bus/Kconfig
> +++ b/drivers/bus/Kconfig
> @@ -64,6 +64,15 @@ config BRCMSTB_GISB_ARB
>         arbiter. This driver provides timeout and target abort error handling
>         and internal bus master decoding.
>  
> +config HISILICON_LPC
> +     bool "Support for ISA I/O space on Hisilicon Hip0X"
> +     depends on (ARM64 && (ARCH_HISI || COMPILE_TEST))
> +     select LOGIC_PIO
> +     select INDIRECT_PIO
> +     help
> +       Driver needed for some legacy ISA devices attached to Low-Pin-Count
> +       on Hisilicon Hip0X SoC.
> +
>  config IMX_WEIM
>       bool "Freescale EIM DRIVER"
>       depends on ARCH_MXC
> diff --git a/drivers/bus/Makefile b/drivers/bus/Makefile
> index cc6364b..28e3862 100644
> --- a/drivers/bus/Makefile
> +++ b/drivers/bus/Makefile
> @@ -7,6 +7,7 @@ obj-$(CONFIG_ARM_CCI)         += arm-cci.o
>  obj-$(CONFIG_ARM_CCN)                += arm-ccn.o
>  
>  obj-$(CONFIG_BRCMSTB_GISB_ARB)       += brcmstb_gisb.o
> +obj-$(CONFIG_HISILICON_LPC)  += hisi_lpc.o
>  obj-$(CONFIG_IMX_WEIM)               += imx-weim.o
>  obj-$(CONFIG_MIPS_CDMM)              += mips_cdmm.o
>  obj-$(CONFIG_MVEBU_MBUS)     += mvebu-mbus.o
> diff --git a/drivers/bus/hisi_lpc.c b/drivers/bus/hisi_lpc.c
> new file mode 100644
> index 0000000..c885483
> --- /dev/null
> +++ b/drivers/bus/hisi_lpc.c
> @@ -0,0 +1,526 @@
> +/*
> + * Copyright (C) 2017 Hisilicon Limited, All Rights Reserved.
> + * Author: Zhichang Yuan <yuanzhich...@hisilicon.com>
> + * Author: Zou Rongrong <zourongr...@huawei.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * 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/acpi.h>
> +#include <linux/console.h>
> +#include <linux/delay.h>
> +#include <linux/io.h>
> +#include <linux/logic_pio.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/of_platform.h>
> +#include <linux/pci.h>
> +#include <linux/slab.h>
> +
> +#define LPC_MIN_BUS_RANGE    0x0
> +
> +/*
> + * The default maximal IO size for Hip06/Hip07 LPC bus.
> + * Defining the I/O range size as 0x4000 here should be sufficient for
> + * all peripherals under the bus.
> + */
> +#define LPC_BUS_IO_SIZE              0x4000
> +
> +/*
> + * Setting this bit means each IO operation will target to a
> + * different port address:
> + * 0 means repeatedly IO operations will stick on the same port,
> + * such as BT;
> + */
> +#define FG_INCRADDR_LPC              0x02
> +
> +struct lpc_cycle_para {
> +     unsigned int opflags;
> +     unsigned int csize; /* the data length of each operation */
> +};
> +
> +struct hisilpc_dev {
> +     spinlock_t cycle_lock;
> +     void __iomem  *membase;
> +     struct logic_pio_hwaddr *io_host;
> +};
> +
> +/* The maximum continuous cycles per burst */
> +#define LPC_MAX_BURST        16
> +/* The IO cycle counts supported is four per operation at maximum */
> +#define LPC_MAX_DULEN        4
> +#if LPC_MAX_DULEN > LPC_MAX_BURST
> +#error "LPC.. MAX_DULEN must be not bigger than MAX_OPCNT!"
> +#endif
> +
> +#if LPC_MAX_BURST % LPC_MAX_DULEN
> +#error "LPC.. LPC_MAX_BURST must be multiple of LPC_MAX_DULEN!"
> +#endif
> +
> +#define LPC_REG_START                0x00 /* start a new LPC cycle */
> +#define LPC_REG_OP_STATUS    0x04 /* the current LPC status */
> +#define LPC_REG_IRQ_ST               0x08 /* interrupt enable&status */
> +#define LPC_REG_OP_LEN               0x10 /* how many LPC cycles each start 
> */
> +#define LPC_REG_CMD          0x14 /* command for the required LPC cycle */
> +#define LPC_REG_ADDR         0x20 /* LPC target address */
> +#define LPC_REG_WDATA                0x24 /* data to be written */
> +#define LPC_REG_RDATA                0x28 /* data coming from peer */
> +
> +
> +/* The command register fields */
> +#define LPC_CMD_SAMEADDR     0x08
> +#define LPC_CMD_TYPE_IO              0x00
> +#define LPC_CMD_WRITE                0x01
> +#define LPC_CMD_READ         0x00
> +/* the bit attribute is W1C. 1 represents OK. */
> +#define LPC_STAT_BYIRQ               0x02
> +
> +#define LPC_STATUS_IDLE              0x01
> +#define LPC_OP_FINISHED              0x02
> +
> +#define START_WORK           0x01

Any reason not to put this in the LPC_ namespace as well?

> +/* The minimal nanosecond interval for each query on LPC cycle status. */
> +#define LPC_NSEC_PERWAIT     100
> +/*
> + * The maximum waiting time is about 128us.
> + * It is specific for stream I/O, such as ins.
> + * The fastest IO cycle time is about 390ns, but the worst case will wait
> + * for extra 256 lpc clocks, so (256 + 13) * 30ns = 8 us. The maximum
> + * burst cycles is 16. So, the maximum waiting time is about 128us under
> + * worst case.
> + * choose 1300 as the maximum.
> + */
> +#define LPC_MAX_WAITCNT              1300
> +/* About 10us. This is specific for single IO operation, such as inb. */
> +#define LPC_PEROP_WAITCNT    100
> +
> +static inline int wait_lpc_idle(unsigned char *mbase,
> +                             unsigned int waitcnt) {
> +     u32 opstatus;
> +
> +     while (waitcnt--) {
> +             ndelay(LPC_NSEC_PERWAIT);
> +             opstatus = readl(mbase + LPC_REG_OP_STATUS);
> +             if (opstatus & LPC_STATUS_IDLE)
> +                     return (opstatus & LPC_OP_FINISHED) ? 0 : (-EIO);
> +     }
> +     return -ETIME;
> +}
> +
> +/*
> + * hisilpc_target_in - trigger a series of lpc cycles to read required data
> + *                  from target peripheral.
> + * @pdev: pointer to hisi lpc device

It's now lpcdev

> + * @para: some parameters used to control the lpc I/O operations
> + * @ptaddr: the lpc I/O target port address
> + * @buf: where the read back data is stored
> + * @opcnt: how many I/O operations required in this calling
> + *
> + * Only one byte data is read each I/O operation.
> + *
> + * Returns 0 on success, non-zero on fail.
> + */
> +static int
> +hisilpc_target_in(struct hisilpc_dev *lpcdev, struct lpc_cycle_para *para,
> +               unsigned long ptaddr, unsigned char *buf,
> +               unsigned long opcnt)
> +{
> +     unsigned long cnt_per_trans;
> +     unsigned int cmd_word;
> +     unsigned int waitcnt;
> +     int ret;
> +
> +     if (!buf || !opcnt || !para || !para->csize || !lpcdev)
> +             return -EINVAL;
> +
> +     cmd_word = LPC_CMD_TYPE_IO | LPC_CMD_READ;
> +     waitcnt = LPC_PEROP_WAITCNT;
> +     if (!(para->opflags & FG_INCRADDR_LPC)) {
> +             cmd_word |= LPC_CMD_SAMEADDR;
> +             waitcnt = LPC_MAX_WAITCNT;
> +     }
> +
> +     ret = 0;
> +     cnt_per_trans = (para->csize == 1) ? opcnt : para->csize;
> +     for (; opcnt && !ret; cnt_per_trans = para->csize) {
> +             unsigned long flags;
> +
> +             /* whole operation must be atomic */
> +             spin_lock_irqsave(&lpcdev->cycle_lock, flags);
> +
> +             writel_relaxed(cnt_per_trans, lpcdev->membase + LPC_REG_OP_LEN);
> +
> +             writel_relaxed(cmd_word, lpcdev->membase + LPC_REG_CMD);
> +
> +             writel_relaxed(ptaddr, lpcdev->membase + LPC_REG_ADDR);
> +
> +             writel(START_WORK, lpcdev->membase + LPC_REG_START);
> +
> +             /* whether the operation is finished */
> +             ret = wait_lpc_idle(lpcdev->membase, waitcnt);
> +             if (!ret) {
> +                     opcnt -= cnt_per_trans;
> +                     for (cnt_per_trans--; cnt_per_trans--; buf++)
> +                             *buf = readb_relaxed(lpcdev->membase +
> +                                     LPC_REG_RDATA);
> +                     *buf = readb(lpcdev->membase + LPC_REG_RDATA);
> +             }
> +
> +             spin_unlock_irqrestore(&lpcdev->cycle_lock, flags);
> +     }
> +
> +     return ret;
> +}
> +
> +/*
> + * hisilpc_target_out - trigger a series of lpc cycles to write required
> + *                   data to target peripheral.
> + * @pdev: pointer to hisi lpc device
> + * @para: some parameters used to control the lpc I/O operations
> + * @ptaddr: the lpc I/O target port address
> + * @buf: where the data to be written is stored
> + * @opcnt: how many I/O operations required
> + *
> + * Only one byte data is read each I/O operation.
> + *
> + * Returns 0 on success, non-zero on fail.
> + *
> + */
> +static int
> +hisilpc_target_out(struct hisilpc_dev *lpcdev, struct lpc_cycle_para *para,
> +                unsigned long ptaddr, const unsigned char *buf,
> +                unsigned long opcnt)
> +{
> +     unsigned long cnt_per_trans;
> +     unsigned int cmd_word;
> +     unsigned int waitcnt;
> +     int ret;
> +
> +     if (!buf || !opcnt || !para || !lpcdev)
> +             return -EINVAL;
> +
> +     /* default is increasing address */
> +     cmd_word = LPC_CMD_TYPE_IO | LPC_CMD_WRITE;
> +     waitcnt = LPC_PEROP_WAITCNT;
> +     if (!(para->opflags & FG_INCRADDR_LPC)) {
> +             cmd_word |= LPC_CMD_SAMEADDR;
> +             waitcnt = LPC_MAX_WAITCNT;
> +     }
> +
> +     ret = 0;
> +     cnt_per_trans = (para->csize == 1) ? opcnt : para->csize;
> +     for (; opcnt && !ret; cnt_per_trans = para->csize) {
> +             unsigned long flags;
> +
> +             spin_lock_irqsave(&lpcdev->cycle_lock, flags);
> +
> +             writel_relaxed(cnt_per_trans, lpcdev->membase + LPC_REG_OP_LEN);
> +             writel_relaxed(cmd_word, lpcdev->membase + LPC_REG_CMD);
> +             writel_relaxed(ptaddr, lpcdev->membase + LPC_REG_ADDR);
> +
> +             opcnt -= cnt_per_trans;
> +             for (; cnt_per_trans--; buf++)
> +                     writeb_relaxed(*buf, lpcdev->membase + LPC_REG_WDATA);
> +
> +             writel(START_WORK, lpcdev->membase + LPC_REG_START);
> +
> +             /* whether the operation is finished */
> +             ret = wait_lpc_idle(lpcdev->membase, waitcnt);
> +
> +             spin_unlock_irqrestore(&lpcdev->cycle_lock, flags);
> +     }
> +
> +     return ret;
> +}
> +
> +static inline unsigned long
> +hisi_lpc_pio_to_addr(struct hisilpc_dev *lpcdev, unsigned long pio)
> +{
> +     return pio - lpcdev->io_host->io_start +
> +             lpcdev->io_host->hw_start;
> +}
> +
> +
> +/**
> + * hisilpc_comm_in - read/input the data from the I/O peripheral
> + *                through LPC.
> + * @devobj: pointer to the device information relevant to LPC controller.
> + * @pio: the target I/O port address.
> + * @dlen: the data length required to read from the target I/O port.
> + *
> + * when succeed, the data read back is stored in buffer pointed by inbuf.
> + * For inb, return the data read from I/O or -1 when error occur.
> + */
> +static u32 hisilpc_comm_in(void *devobj, unsigned long pio, size_t dlen)
> +{
> +     int ret = 0;
> +     unsigned char rd_data = 0;
> +     unsigned long ptaddr;
> +     struct lpc_cycle_para iopara;
> +     struct hisilpc_dev *lpcdev = devobj;
> +
> +     if (!lpcdev || !dlen || dlen > LPC_MAX_DULEN)
> +             return -1;
> +
> +     ptaddr = hisi_lpc_pio_to_addr(lpcdev, pio);
> +
> +     iopara.opflags = FG_INCRADDR_LPC;
> +     iopara.csize = dlen;
> +
> +     ret = hisilpc_target_in(lpcdev, &iopara, ptaddr, &rd_data, dlen);
> +     if (ret)
> +             return -1;
> +
> +     return le32_to_cpu((u32)rd_data);
> +}
> +
> +/**
> + * hisilpc_comm_out - output the data whose maximum length is four bytes
> +                   to the I/O peripheral through the LPC host.
> + * @devobj: pointer to the device information relevant to LPC controller.
> + * @outval: a value to be outputted from caller, maximum is four bytes.
> + * @pio: the target I/O port address.

@outval & @pio are in the opposite order of the actual function

> + * @dlen: the data length required writing to the target I/O port.
> + *
> + * This function is corresponding to out(b,w,l) only
> + *
> + */
> +static void hisilpc_comm_out(void *devobj, unsigned long pio,
> +                          u32 outval, size_t dlen)
> +{
> +     unsigned long ptaddr;
> +     struct hisilpc_dev *lpcdev = devobj;
> +     struct lpc_cycle_para iopara;
> +     const unsigned char *newbuf;
> +
> +     if (!lpcdev || !dlen || dlen > LPC_MAX_DULEN)
> +             return;
> +
> +     outval = cpu_to_le32(outval);
> +
> +     newbuf = (const unsigned char *)&outval;
> +     ptaddr = hisi_lpc_pio_to_addr(lpcdev, pio);
> +
> +     iopara.opflags = FG_INCRADDR_LPC;
> +     iopara.csize = dlen;
> +
> +     hisilpc_target_out(lpcdev, &iopara, ptaddr, newbuf, dlen);
> +}
> +
> +/*
> + * hisilpc_comm_ins - read/input the data in buffer to the I/O
> + *           peripheral through LPC, it corresponds to ins(b,w,l)
> + * @devobj: pointer to the device information relevant to LPC controller.
> + * @pio: the target I/O port address.
> + * @inbuf: a buffer where read/input data bytes are stored.
> + * @dlen: the data length required writing to the target I/O port.
> + * @count: how many data units whose length is dlen will be read.
> + *
> + * when succeed, the data read back is stored in buffer pointed by inbuf.
> + * Returns 0 on success, -errno otherwise
> + *
> + */
> +static u32
> +hisilpc_comm_ins(void *devobj, unsigned long pio, void *inbuf,
> +              size_t dlen, unsigned int count)
> +{
> +     struct hisilpc_dev *lpcdev = devobj;
> +     struct lpc_cycle_para iopara;
> +     unsigned char *newbuf;
> +     unsigned int loopcnt, cntleft;
> +     unsigned long ptaddr;
> +
> +     if (!lpcdev || !inbuf || !count || !dlen || dlen > LPC_MAX_DULEN ||
> +                     count % dlen)
> +             return -EINVAL;
> +
> +     iopara.opflags = 0;
> +     if (dlen > 1)
> +             iopara.opflags |= FG_INCRADDR_LPC;
> +     iopara.csize = dlen;
> +
> +     ptaddr = hisi_lpc_pio_to_addr(lpcdev, pio);
> +     newbuf = inbuf;
> +     /*
> +      * ensure data stream whose length is multiple of dlen to be processed
> +      * each IO input
> +      */
> +     cntleft = count * dlen;
> +     do {
> +             int ret;
> +
> +             loopcnt = min_t(unsigned int, LPC_MAX_BURST, cntleft);
> +             ret = hisilpc_target_in(lpcdev, &iopara, ptaddr,
> +                                     newbuf, loopcnt);
> +             if (ret)
> +                     return ret;
> +             newbuf += loopcnt;
> +             cntleft -= loopcnt;
> +     } while (cntleft);
> +
> +     return 0;
> +}
> +
> +/*
> + * hisilpc_comm_outs - write/output the data in buffer to the I/O
> + *           peripheral through LPC, it corresponds to outs(b,w,l)
> + * @devobj: pointer to the device information relevant to LPC controller.
> + * @pio: the target I/O port address.
> + * @outbuf: a buffer where write/output data bytes are stored.
> + * @dlen: the data length required writing to the target I/O port .
> + * @count: how many data units whose length is dlen will be written.
> + *
> + */
> +static void
> +hisilpc_comm_outs(void *devobj, unsigned long pio, const void *outbuf,
> +               size_t dlen, unsigned int count)
> +{
> +     struct hisilpc_dev *lpcdev = devobj;
> +     struct lpc_cycle_para iopara;
> +     const unsigned char *newbuf;
> +     unsigned int loopcnt, cntleft;
> +     unsigned long ptaddr;
> +
> +     if (!lpcdev || !outbuf || !count || !dlen || dlen > LPC_MAX_DULEN ||
> +                     count % dlen)
> +             return;
> +
> +     iopara.opflags = 0;
> +     if (dlen > 1)
> +             iopara.opflags |= FG_INCRADDR_LPC;
> +     iopara.csize = dlen;
> +
> +     ptaddr = hisi_lpc_pio_to_addr(lpcdev, pio);
> +     newbuf = outbuf;
> +     /*
> +      * ensure data stream whose length is multiple of dlen to be processed
> +      * each IO input
> +      */
> +     cntleft = count * dlen;
> +     do {
> +             loopcnt = min_t(unsigned int, LPC_MAX_BURST, cntleft);
> +             if (hisilpc_target_out(lpcdev, &iopara, ptaddr, newbuf,
> +                                             loopcnt))
> +                     break;
> +             newbuf += loopcnt;
> +             cntleft -= loopcnt;
> +     } while (cntleft);
> +}
> +
> +static struct hostio_ops hisi_lpc_ops = {
> +     .pfin = hisilpc_comm_in,
> +     .pfout = hisilpc_comm_out,
> +     .pfins = hisilpc_comm_ins,
> +     .pfouts = hisilpc_comm_outs,
> +};
> +
> +/**
> + * hisilpc_probe - the probe callback function for hisi lpc device,
> + *              will finish all the initialization.
> + * @pdev: the platform device corresponding to hisi lpc
> + *
> + * Returns 0 on success, non-zero on fail.
> + */
> +static int hisilpc_probe(struct platform_device *pdev)
> +{
> +     struct device *dev = &pdev->dev;
> +     struct resource *res;
> +     struct hisilpc_dev *lpcdev;
> +     struct logic_pio_hwaddr *range;
> +     int ret = 0;
> +
> +     lpcdev = devm_kzalloc(dev, sizeof(struct hisilpc_dev), GFP_KERNEL);
> +     if (!lpcdev)
> +             return -ENOMEM;
> +
> +     spin_lock_init(&lpcdev->cycle_lock);
> +
> +     res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +     if (!res) {
> +             dev_err(dev, "no MEM resource\n");
> +             return -ENODEV;
> +     }
> +
> +     lpcdev->membase = devm_ioremap_resource(dev, res);
> +     if (IS_ERR(lpcdev->membase)) {
> +             dev_err(dev, "remap failed\n");
> +             return PTR_ERR(lpcdev->membase);
> +     }
> +
> +     /* register the LPC host PIO resources */
> +     range = devm_kzalloc(dev, sizeof(*range), GFP_KERNEL);
> +     if (!range)
> +             return -ENOMEM;
> +     range->fwnode = dev->fwnode;
> +     range->flags = PIO_INDIRECT;
> +     range->size = LPC_BUS_IO_SIZE;
> +     range->hw_start = LPC_MIN_BUS_RANGE;
> +
> +     ret = logic_pio_register_range(range);
> +     if (ret) {
> +             kfree(range);
> +             dev_err(dev, "OF: register IO range FAIL!\n");
> +             return -ret;
> +     }
> +     lpcdev->io_host = range;
> +     lpcdev->io_host->devpara = lpcdev;
> +     lpcdev->io_host->ops = &hisi_lpc_ops;
> +
> +     /*
> +      * It is time to start the children scannings....
> +      * For ACPI children, the corresponding devices had been created
> +      * during the ACPI enumeration.
> +      * The OF scanning must be performed after initialization of 'lpcdev'
> +      * to avoid some children which complete the scanning trigger the
> +      * MMIO accesses which will probably cause panic.
> +      */
> +     dev_info(dev, " calling of_platform_populate");
> +     ret = of_platform_populate(dev->of_node, NULL, NULL, dev);
> +     if (ret) {
> +             /*
> +              * When LPC probing is not completely successful, set 'devpara'
> +              * as NULL. This will make all the LPC I/O return failure
> +              * directly without any hardware operations. It will prevent
> +              * some peripherals which had not finished the initialization to
> +              * manipulate I/O for safety.
> +              */
> +             lpcdev->io_host->devpara = NULL;
> +             dev_err(dev, "OF: scan hisilpc children got failed(%d)\n",
> +                     ret);

nit: Maybe "OF: scanning hisilpc children failed(%d)" ?

> +             return ret;
> +     }
> +
> +     dev_info(dev, "hslpc end probing. range[%pa - sz:%pa]\n",
> +             &lpcdev->io_host->io_start,
> +             &lpcdev->io_host->size);
> +
> +     return ret;
> +}


 -dann

Reply via email to