| Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2007 Freescale Semiconductor, Inc. All Rights Reserved. |
| 3 | * Copyright 2008 Juergen Beisert, kernel@pengutronix.de |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or |
| 6 | * modify it under the terms of the GNU General Public License |
| 7 | * as published by the Free Software Foundation; either version 2 |
| 8 | * of the License, or (at your option) any later version. |
| 9 | * This program 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 |
| 12 | * GNU General Public License for more details. |
| 13 | * |
| 14 | * You should have received a copy of the GNU General Public License |
| 15 | * along with this program; if not, write to the Free Software |
| 16 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, |
| 17 | * MA 02110-1301, USA. |
| 18 | */ |
| 19 | |
| 20 | /* |
| 21 | * i.MX27 specific CPU detection code |
| 22 | */ |
| 23 | |
| 24 | #include <linux/io.h> |
| 25 | #include <linux/module.h> |
| 26 | |
| 27 | #include "hardware.h" |
| 28 | |
| 29 | static int mx27_cpu_rev = -1; |
| 30 | static int mx27_cpu_partnumber; |
| 31 | |
| 32 | #define SYS_CHIP_ID 0x00 /* The offset of CHIP ID register */ |
| 33 | |
| 34 | static int mx27_read_cpu_rev(void) |
| 35 | { |
| 36 | u32 val; |
| 37 | /* |
| 38 | * now we have access to the IO registers. As we need |
| 39 | * the silicon revision very early we read it here to |
| 40 | * avoid any further hooks |
| 41 | */ |
| 42 | val = imx_readl(MX27_IO_ADDRESS(MX27_SYSCTRL_BASE_ADDR + SYS_CHIP_ID)); |
| 43 | |
| 44 | mx27_cpu_partnumber = (int)((val >> 12) & 0xFFFF); |
| 45 | |
| 46 | switch (val >> 28) { |
| 47 | case 0: |
| 48 | return IMX_CHIP_REVISION_1_0; |
| 49 | case 1: |
| 50 | return IMX_CHIP_REVISION_2_0; |
| 51 | case 2: |
| 52 | return IMX_CHIP_REVISION_2_1; |
| 53 | default: |
| 54 | return IMX_CHIP_REVISION_UNKNOWN; |
| 55 | } |
| 56 | } |
| 57 | |
| 58 | /* |
| 59 | * Returns: |
| 60 | * the silicon revision of the cpu |
| 61 | * -EINVAL - not a mx27 |
| 62 | */ |
| 63 | int mx27_revision(void) |
| 64 | { |
| 65 | if (mx27_cpu_rev == -1) |
| 66 | mx27_cpu_rev = mx27_read_cpu_rev(); |
| 67 | |
| 68 | if (mx27_cpu_partnumber != 0x8821) |
| 69 | return -EINVAL; |
| 70 | |
| 71 | return mx27_cpu_rev; |
| 72 | } |
| 73 | EXPORT_SYMBOL(mx27_revision); |