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    Subject[PATCH V2 4/4] ARM64 LPC: support earlycon for UART connected to LPC
    Date
    From: "zhichang.yuan" <yuanzhichang@hisilicon.com>

    This patch support the earlycon for UART connected to LPC on Hip06.
    This patch is depended on the LPC driver.

    Signed-off-by: zhichang.yuan <yuanzhichang@hisilicon.com>
    ---
    drivers/bus/hisi_lpc.c | 129 +++++++++++++++++++++++++++++++++++++++++++++++++
    1 file changed, 129 insertions(+)

    diff --git a/drivers/bus/hisi_lpc.c b/drivers/bus/hisi_lpc.c
    index 7ac0551..1cc5581 100644
    --- a/drivers/bus/hisi_lpc.c
    +++ b/drivers/bus/hisi_lpc.c
    @@ -374,6 +374,135 @@ void hisilpc_comm_outb(void *devobj, unsigned long ptaddr,
    }


    +static struct extio_ops hisilpc_earlyop __initdata;
    +
    +/**
    + * hisilpc_early_in - read/input operation specific for hisi LPC earlycon.
    + * @devobj: pointer to device relevant information of the caller.
    + * @inbuf: the buffer where the read back data is populated.
    + * @ptaddr: the io address where read operation targets to.
    + * @dlen: data length in byte to be read each IO operation.
    + * @count: how many IO operations expected.
    + * for earlycon, dlen and count should be one.
    + *
    + * Returns 0 on success, non-zero on fail.
    + *
    + */
    +static u64 __init hisilpc_early_in(void *devobj, unsigned long ptaddr,
    + void *inbuf, size_t dlen,unsigned int count)
    +{
    + unsigned int ret = 0;
    + struct lpc_cycle_para para;
    + struct hisilpc_dev lpcdev;
    + struct uart_port *port;
    + unsigned int rd_data;
    +
    + port = (struct uart_port *)devobj;
    + if (!port->mapbase || !port->membase || inbuf ||
    + count != 1 || dlen !=1)
    + return -EINVAL;
    +
    + para.opflags = FG_EARLYCON_LPC;
    + para.csize = dlen;
    + lpcdev.membase = port->membase;
    +
    + ret = hisilpc_target_in(&lpcdev, &para, ptaddr,
    + (unsigned char *)&rd_data, count);
    +
    + return (ret) ? : rd_data;
    +}
    +
    +/**
    + * hisilpc_early_out - write/output operation specific for hisi LPC earlycon.
    + * @devobj: pointer to device relevant information of the caller.
    + * @outbuf: the buffer where the data to be written is stored.
    + * @ptaddr: the io address where write operation targets to.
    + * @dlen: data length in byte to be written each IO operation.
    + * @count: how many IO operations expected.
    + * for earlycon, dlen and count must be one.
    + *
    + */
    +static void __init hisilpc_early_out(void *devobj, unsigned long ptaddr,
    + const void *outbuf, size_t dlen,
    + unsigned int count)
    +{
    + struct lpc_cycle_para para;
    + struct hisilpc_dev lpcdev;
    + struct uart_port *port;
    +
    + port = (struct uart_port *)devobj;
    + if (!port->mapbase || !port->membase || !outbuf ||
    + dlen != 1 || count != 1)
    + return;
    +
    + para.opflags = FG_EARLYCON_LPC;
    + para.csize = dlen;
    + lpcdev.membase = port->membase;
    +
    + (void)hisilpc_target_out(&lpcdev, &para, ptaddr, outbuf, count);
    +}
    +
    +
    +/**
    + * early_hisilpc8250_setup - initilize the lpc earlycon
    + * @device: pointer to the elarycon device
    + * @options: a option string from earlycon kernel-parameter
    + *
    + * Returns 0 on success, non-zero on fail.
    + *
    + */
    +static int __init early_hisilpc8250_setup(struct earlycon_device *device,
    + const char *options)
    +{
    + char *p;
    + int ret;
    +
    + if (!device->port.membase)
    + return -ENODEV;
    +
    + if (device->port.iotype != UPIO_MEM)
    + return -EINVAL;
    +
    + if (device->options) {
    + p = strchr(device->options, ',');
    + if (p && (p + 1) != '\0') {
    + ret = kstrtoul(++p, 0,
    + (unsigned long *)&device->port.iobase);
    + if (ret || device->port.iobase == 0)
    + return ret ?: -EFAULT;
    + } else
    + device->port.iobase = 0x2f8;
    + } else {
    + device->port.iobase = 0x2f8;
    + device->baud = 0;
    + }
    +
    + /* must set iotype as UPIO_PORT for Hip06 indirect-io */
    + device->port.iotype = UPIO_PORT;
    +
    + hisilpc_earlyop.pfin = hisilpc_early_in;
    + hisilpc_earlyop.pfout = hisilpc_early_out;
    + hisilpc_earlyop.devpara = &device->port;
    +
    +
    + /* disable interrupts from LPC */
    + writel(LPC_IRQ_CLEAR, device->port.membase + LPC_REG_IRQ_ST);
    + /* ensure the LPC is available */
    + while (!(readl(device->port.membase + LPC_REG_OP_STATUS) &
    + LPC_STATUS_IDLE))
    + cpu_relax();
    +
    + arm64_set_simops(&hisilpc_earlyop);
    +
    + return early_serial8250_setup(device, options);
    +}
    +
    +
    +
    +EARLYCON_DECLARE(hisilpcuart, early_hisilpc8250_setup);
    +OF_EARLYCON_DECLARE(hisilpcuart, "hisi,rawlpc-uart",
    + early_hisilpc8250_setup);
    +
    /**
    * hisilpc_probe - the probe callback function for hisi lpc device,
    * will finish all the intialization.
    --
    1.9.1
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