1 /* Copyright (C) 2012-2014 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library. If not, see
16 <http://www.gnu.org/licenses/>. */
24 #include <arch/spr_def.h>
27 /* The count of cores horizontally (X dimension) on the chip. */
28 static int chip_width;
30 /* Read the chip "width" from the /sys filesystem. */
32 initialize_chip_width (void)
37 fd = __open ("/sys/devices/system/cpu/chip_width", O_RDONLY);
44 n = __read (fd, buf, sizeof (buf));
47 for (i = 0; i < n; ++i)
49 if (buf[i] < '0' || buf[i] > '9')
51 w = (w * 10) + (buf[i] - '0');
55 /* Store a negative value so we don't try again. */
59 /* Using an atomic idempotent write here makes this thread-safe. */
70 if (__builtin_expect (w <= 0, 0))
73 w = initialize_chip_width ();
77 int r = INLINE_SYSCALL (getcpu, 3, &cpu, NULL, NULL);
78 return r == -1 ? r : cpu;
82 /* Assign 64-bit value to a 32-bit variable to ensure 32-bit multiply. */
83 coord = __insn_mfspr (SPR_TILE_COORD);
85 /* Extract Y coord from bits 7..10 and X coord from bits 18..21. */
86 return ((coord >> 7) & 0xf) * w + ((coord >> 18) & 0xf);