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https://github.com/brain-hackers/u-boot-brain
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41575d8e4c
This construct is quite long-winded. In earlier days it made some sense since auto-allocation was a strange concept. But with driver model now used pretty universally, we can shorten this to 'auto'. This reduces verbosity and makes it easier to read. Coincidentally it also ensures that every declaration is on one line, thus making dtoc's job easier. Signed-off-by: Simon Glass <sjg@chromium.org>
183 lines
3.7 KiB
C
183 lines
3.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* (C) 2018 NXP
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* (C) 2020 EPAM Systems Inc.
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*/
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#include <common.h>
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#include <cpu_func.h>
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#include <dm.h>
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#include <serial.h>
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#include <watchdog.h>
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#include <linux/bug.h>
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#include <xen/hvm.h>
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#include <xen/events.h>
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#include <xen/interface/sched.h>
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#include <xen/interface/hvm/hvm_op.h>
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#include <xen/interface/hvm/params.h>
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#include <xen/interface/io/console.h>
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#include <xen/interface/io/ring.h>
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DECLARE_GLOBAL_DATA_PTR;
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u32 console_evtchn;
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/*
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* struct xen_uart_priv - Structure representing a Xen UART info
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* @intf: Console I/O interface for Xen guest OSes
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* @evtchn: Console event channel
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*/
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struct xen_uart_priv {
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struct xencons_interface *intf;
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u32 evtchn;
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};
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int xen_serial_setbrg(struct udevice *dev, int baudrate)
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{
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return 0;
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}
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static int xen_serial_probe(struct udevice *dev)
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{
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struct xen_uart_priv *priv = dev_get_priv(dev);
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u64 val = 0;
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unsigned long gfn;
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int ret;
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ret = hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &val);
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if (ret < 0 || val == 0)
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return ret;
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priv->evtchn = val;
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console_evtchn = val;
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ret = hvm_get_parameter(HVM_PARAM_CONSOLE_PFN, &val);
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if (ret < 0)
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return ret;
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if (!val)
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return -EINVAL;
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gfn = val;
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priv->intf = (struct xencons_interface *)(gfn << XEN_PAGE_SHIFT);
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return 0;
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}
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static int xen_serial_pending(struct udevice *dev, bool input)
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{
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struct xen_uart_priv *priv = dev_get_priv(dev);
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struct xencons_interface *intf = priv->intf;
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if (!input || intf->in_cons == intf->in_prod)
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return 0;
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return 1;
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}
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static int xen_serial_getc(struct udevice *dev)
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{
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struct xen_uart_priv *priv = dev_get_priv(dev);
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struct xencons_interface *intf = priv->intf;
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XENCONS_RING_IDX cons;
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char c;
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while (intf->in_cons == intf->in_prod)
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mb(); /* wait */
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cons = intf->in_cons;
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mb(); /* get pointers before reading ring */
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c = intf->in[MASK_XENCONS_IDX(cons++, intf->in)];
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mb(); /* read ring before consuming */
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intf->in_cons = cons;
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notify_remote_via_evtchn(priv->evtchn);
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return c;
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}
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static int __write_console(struct udevice *dev, const char *data, int len)
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{
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struct xen_uart_priv *priv = dev_get_priv(dev);
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struct xencons_interface *intf = priv->intf;
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XENCONS_RING_IDX cons, prod;
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int sent = 0;
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cons = intf->out_cons;
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prod = intf->out_prod;
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mb(); /* Update pointer */
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WARN_ON((prod - cons) > sizeof(intf->out));
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while ((sent < len) && ((prod - cons) < sizeof(intf->out)))
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intf->out[MASK_XENCONS_IDX(prod++, intf->out)] = data[sent++];
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mb(); /* Update data before pointer */
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intf->out_prod = prod;
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if (sent)
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notify_remote_via_evtchn(priv->evtchn);
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return sent;
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}
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static int write_console(struct udevice *dev, const char *data, int len)
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{
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/*
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* Make sure the whole buffer is emitted, polling if
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* necessary. We don't ever want to rely on the hvc daemon
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* because the most interesting console output is when the
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* kernel is crippled.
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*/
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while (len) {
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int sent = __write_console(dev, data, len);
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data += sent;
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len -= sent;
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if (unlikely(len))
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HYPERVISOR_sched_op(SCHEDOP_yield, NULL);
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}
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return 0;
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}
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static int xen_serial_putc(struct udevice *dev, const char ch)
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{
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write_console(dev, &ch, 1);
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return 0;
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}
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static const struct dm_serial_ops xen_serial_ops = {
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.putc = xen_serial_putc,
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.getc = xen_serial_getc,
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.pending = xen_serial_pending,
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};
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#if CONFIG_IS_ENABLED(OF_CONTROL)
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static const struct udevice_id xen_serial_ids[] = {
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{ .compatible = "xen,xen" },
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{ }
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};
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#endif
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U_BOOT_DRIVER(serial_xen) = {
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.name = "serial_xen",
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.id = UCLASS_SERIAL,
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#if CONFIG_IS_ENABLED(OF_CONTROL)
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.of_match = xen_serial_ids,
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#endif
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.priv_auto = sizeof(struct xen_uart_priv),
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.probe = xen_serial_probe,
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.ops = &xen_serial_ops,
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#if !CONFIG_IS_ENABLED(OF_CONTROL)
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.flags = DM_FLAG_PRE_RELOC,
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#endif
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};
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