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      1 /* $NetBSD: riscv_platform.c,v 1.4 2025/09/06 22:53:48 thorpej Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 2023 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Nick Hudson
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 /*
     33  * This is the default RISC-V FDT platform implementation. It assumes the
     34  * following:
     35  *
     36  *  - Console UART is pre-configured by firmware
     37  */
     38 
     39 #include <sys/cdefs.h>
     40 __KERNEL_RCSID(0, "$NetBSD: riscv_platform.c,v 1.4 2025/09/06 22:53:48 thorpej Exp $");
     41 
     42 #include <sys/param.h>
     43 #include <sys/bus.h>
     44 
     45 #include <dev/fdt/fdtvar.h>
     46 #include <dev/fdt/fdt_console.h>
     47 #include <dev/fdt/fdt_platform.h>
     48 
     49 #include <uvm/uvm_extern.h>
     50 #include <uvm/pmap/pmap_devmap.h>
     51 
     52 #include <riscv/fdt/riscv_fdtvar.h>
     53 
     54 static const struct pmap_devmap *
     55 riscv_platform_devmap(void)
     56 {
     57 	static const struct pmap_devmap devmap_empty[] = {
     58 		DEVMAP_ENTRY_END
     59 	};
     60 
     61 	static struct pmap_devmap devmap_uart[] = {
     62 		DEVMAP_ENTRY(VM_KERNEL_IO_BASE, 0, PAGE_SIZE),
     63 		DEVMAP_ENTRY_END
     64 	};
     65 	bus_addr_t uart_base;
     66 
     67 	const int phandle = fdtbus_get_stdout_phandle();
     68 	if (phandle <= 0)
     69 		return devmap_empty;
     70 
     71 	if (fdtbus_get_reg(phandle, 0, &uart_base, NULL) != 0)
     72 		return devmap_empty;
     73 
     74 	devmap_uart[0].pd_pa = DEVMAP_ALIGN(uart_base);
     75 
     76 	return devmap_uart;
     77 }
     78 
     79 
     80 static u_int
     81 riscv_platform_uart_freq(void)
     82 {
     83 	return 0;
     84 }
     85 
     86 static const struct fdt_platform riscv_platform = {
     87 	.fp_devmap = riscv_platform_devmap,
     88 	.fp_bootstrap = riscv_fdt_cpu_bootstrap,
     89 	.fp_uart_freq = riscv_platform_uart_freq,
     90 	.fp_mpstart = riscv_fdt_cpu_mpstart,
     91 };
     92 
     93 FDT_PLATFORM(rv, FDT_PLATFORM_DEFAULT, &riscv_platform);
     94