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      1 /* $NetBSD: pci_smccc.c,v 1.1 2021/08/07 21:23:37 jmcneill Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 2021 Jared McNeill <jmcneill (at) invisible.ca>
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
     21  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     22  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     23  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     24  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  * SUCH DAMAGE.
     27  */
     28 
     29 #include <sys/cdefs.h>
     30 __KERNEL_RCSID(0, "$NetBSD: pci_smccc.c,v 1.1 2021/08/07 21:23:37 jmcneill Exp $");
     31 
     32 #include <sys/param.h>
     33 #include <sys/kernel.h>
     34 
     35 #include <arm/arm/smccc.h>
     36 #include <arm/pci/pci_smccc.h>
     37 
     38 /* Minimum SMCCC version required for PCI_VERSION call. */
     39 #define	SMCCC_VERSION_1_1	0x10001
     40 
     41 /* PCI Configuration Space Access ABI functions */
     42 #define	PCI_VERSION		0x84000130
     43 #define	PCI_FEATURES		0x84000131
     44 #define	PCI_READ		0x84000132
     45 #define	PCI_WRITE		0x84000133
     46 #define	PCI_GET_SEG_INFO	0x84000134
     47 #define	 GET_SEG_INFO_BUS_START		__BITS(7,0)
     48 #define	 GET_SEG_INFO_BUS_END		__BITS(15,8)
     49 
     50 static int
     51 pci_smccc_call(uint32_t fid,
     52     register_t arg1, register_t arg2, register_t arg3, register_t arg4,
     53     register_t *res0, register_t *res1, register_t *res2, register_t *res3)
     54 {
     55 	static int smccc_ver;
     56 
     57 	if (smccc_ver == 0) {
     58 		smccc_ver = smccc_version();
     59 	}
     60 	if (smccc_ver < SMCCC_VERSION_1_1) {
     61 		return SMCCC_NOT_SUPPORTED;
     62 	}
     63 
     64 	return smccc_call(fid, arg1, arg2, arg3, arg4,
     65 			  res0, res1, res2, res3);
     66 }
     67 
     68 int
     69 pci_smccc_version(void)
     70 {
     71 	return pci_smccc_call(PCI_VERSION, 0, 0, 0, 0,
     72 			      NULL, NULL, NULL, NULL);
     73 }
     74 
     75 int
     76 pci_smccc_features(uint32_t fid)
     77 {
     78 	return pci_smccc_call(PCI_FEATURES, fid, 0, 0, 0,
     79 			      NULL, NULL, NULL, NULL);
     80 }
     81 
     82 int
     83 pci_smccc_read(uint32_t sbdf, uint32_t offset, uint32_t access_size,
     84     uint32_t *data)
     85 {
     86 	register_t value;
     87 	int status;
     88 
     89 	status = pci_smccc_call(PCI_READ, sbdf, offset, access_size, 0,
     90 				NULL, &value, NULL, NULL);
     91 	if (status == SMCCC_SUCCESS) {
     92 		*data = value;
     93 	}
     94 
     95 	return status;
     96 }
     97 
     98 int
     99 pci_smccc_write(uint32_t sbdf, uint32_t offset, uint32_t access_size,
    100     uint32_t data)
    101 {
    102 	return pci_smccc_call(PCI_WRITE, sbdf, offset, access_size, data,
    103 			      NULL, NULL, NULL, NULL);
    104 }
    105 
    106 int
    107 pci_smccc_get_seg_info(uint16_t seg, uint8_t *bus_start, uint8_t *bus_end,
    108     uint16_t *next_seg)
    109 {
    110 	register_t res1, res2;
    111 	int status;
    112 
    113 	status = pci_smccc_call(PCI_GET_SEG_INFO, seg, 0, 0, 0,
    114 				NULL, &res1, &res2, NULL);
    115 	if (status == SMCCC_SUCCESS) {
    116 		*bus_start = __SHIFTOUT(res1, GET_SEG_INFO_BUS_START);
    117 		*bus_end = __SHIFTOUT(res1, GET_SEG_INFO_BUS_END);
    118 		*next_seg = (uint16_t)res2;
    119 	}
    120 
    121 	return status;
    122 }
    123