From a3ce5f9f76a371e54eb51445720682a35d7fa8a2 Mon Sep 17 00:00:00 2001 From: Bernhard Nortmann Date: Tue, 20 Dec 2016 17:52:01 +0100 Subject: [PATCH] fel_lib: Implement thunk code for register-based retrieval of SID The new function fel_get_sid_registers() uses ARM code for register access to the SID root key. This is necessary to retrieve correct values for certain SoCs, e.g. when not using this approach the H3 has been observed to return 'mangled' values (when reading SID from memory). See https://groups.google.com/forum/#!topic/linux-sunxi/ynyIP8c61Qs The FEL library provides a uniform fel_get_sid_root_key() wrapper that will automatically use the workaround method for SoCs that are tagged accordingly - so the application program does not have to bother with selecting memory vs. register-based access. Signed-off-by: Bernhard Nortmann --- fel_lib.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++--- fel_lib.h | 4 +++ sid_read_root.S | 72 +++++++++++++++++++++++++++++++++++++++++++++++++ sid_read_root.h | 24 +++++++++++++++++ 4 files changed, 168 insertions(+), 4 deletions(-) create mode 100644 sid_read_root.S create mode 100644 sid_read_root.h diff --git a/fel_lib.c b/fel_lib.c index b67238e654..9a02a2da05 100644 --- a/fel_lib.c +++ b/fel_lib.c @@ -368,6 +368,73 @@ void fel_writel_n(feldev_handle *dev, uint32_t addr, uint32_t *src, size_t count } } +/* + * Memory access to the SID (root) keys proved to be unreliable for certain + * SoCs. This function uses an alternative, register-based approach to retrieve + * the values. + */ +static void fel_get_sid_registers(feldev_handle *dev, uint32_t *result) +{ + uint32_t arm_code[] = { + htole32(0xe59f0040), /* 0: ldr r0, [pc, #64] */ + htole32(0xe3a01000), /* 4: mov r1, #0 */ + htole32(0xe28f303c), /* 8: add r3, pc, #60 */ + /* : */ + htole32(0xe1a02801), /* c: lsl r2, r1, #16 */ + htole32(0xe3822b2b), /* 10: orr r2, r2, #44032 */ + htole32(0xe3822002), /* 14: orr r2, r2, #2 */ + htole32(0xe5802040), /* 18: str r2, [r0, #64] */ + /* : */ + htole32(0xe5902040), /* 1c: ldr r2, [r0, #64] */ + htole32(0xe3120002), /* 20: tst r2, #2 */ + htole32(0x1afffffc), /* 24: bne 1c */ + htole32(0xe5902060), /* 28: ldr r2, [r0, #96] */ + htole32(0xe7832001), /* 2c: str r2, [r3, r1] */ + htole32(0xe2811004), /* 30: add r1, r1, #4 */ + htole32(0xe3510010), /* 34: cmp r1, #16 */ + htole32(0x3afffff3), /* 38: bcc c */ + htole32(0xe3a02000), /* 3c: mov r2, #0 */ + htole32(0xe5802040), /* 40: str r2, [r0, #64] */ + htole32(0xe12fff1e), /* 44: bx lr */ + htole32(dev->soc_info->sid_base), /* SID base addr */ + /* retrieved SID values go here */ + }; + /* write and execute code */ + aw_fel_write(dev, arm_code, dev->soc_info->scratch_addr, sizeof(arm_code)); + aw_fel_execute(dev, dev->soc_info->scratch_addr); + /* read back the result */ + aw_fel_read(dev, dev->soc_info->scratch_addr + sizeof(arm_code), + result, 4 * sizeof(uint32_t)); + for (unsigned i = 0; i < 4; i++) + result[i] = le32toh(result[i]); +} + +/* Read the SID "root" key (128 bits). You need to pass the device handle, + * a pointer to a result array capable of receiving at least four 32-bit words, + * and a flag specifying if the register-access workaround should be enforced. + * Return value indicates whether the result is expected to be usable: + * The function will return `false` (and zero the result) if it cannot access + * the SID registers. + */ +bool fel_get_sid_root_key(feldev_handle *dev, uint32_t *result, + bool force_workaround) +{ + if (!dev->soc_info->sid_base) { + /* SID unavailable */ + for (unsigned i = 0; i < 4; i++) result[i] = 0; + return false; + } + + if (dev->soc_info->sid_fix || force_workaround) + /* Work around SID issues by using ARM thunk code */ + fel_get_sid_registers(dev, result); + else + /* Read SID directly from memory */ + fel_readl_n(dev, dev->soc_info->sid_base + + dev->soc_info->sid_offset, result, 4); + return true; +} + /* general functions, "FEL device" management */ static int feldev_get_endpoint(feldev_handle *dev) @@ -601,10 +668,7 @@ feldev_list_entry *list_fel_devices(size_t *count) strncpy(entry->soc_name, dev->soc_name, sizeof(soc_name_t)); /* retrieve SID bits */ - if (dev->soc_info->sid_base) - aw_fel_readl_n(dev, - dev->soc_info->sid_base + dev->soc_info->sid_offset, - entry->SID, 4); + fel_get_root_key(dev, entry->SID, false); feldev_close(dev); free(dev); diff --git a/fel_lib.h b/fel_lib.h index 28d0884175..ed43a82954 100644 --- a/fel_lib.h +++ b/fel_lib.h @@ -67,4 +67,8 @@ void aw_fel_execute(feldev_handle *dev, uint32_t offset); void fel_readl_n(feldev_handle *dev, uint32_t addr, uint32_t *dst, size_t count); void fel_writel_n(feldev_handle *dev, uint32_t addr, uint32_t *src, size_t count); +/* retrieve SID root key */ +bool fel_get_sid_root_key(feldev_handle *dev, uint32_t *result, + bool force_workaround); + #endif /* _SUNXI_TOOLS_FEL_LIB_H */ diff --git a/sid_read_root.S b/sid_read_root.S new file mode 100644 index 0000000000..9fd04b1d00 --- /dev/null +++ b/sid_read_root.S @@ -0,0 +1,72 @@ +/* + * Copyright (C) 2016 Bernhard Nortmann + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the "Software"), + * to deal in the Software without restriction, including without limitation + * the rights to use, copy, modify, merge, publish, distribute, sublicense, + * and/or sell copies of the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice (including the next + * paragraph) shall be included in all copies or substantial portions of the + * Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER + * DEALINGS IN THE SOFTWARE. + */ + +/* + * ARM thunk code to read the SID root key using register-based access. + * + * This is necessary for certain SoCs (e.g. H3), as the values read via + * memory mapping might not be consistent. For background information see + * https://groups.google.com/forum/#!topic/linux-sunxi/ynyIP8c61Qs + */ + +SID_BASE .req r0 +sid_key_index .req r1 + +.set SID_PRCTL, 0x40 /* SID program/read control register */ +.set SID_PRKEY, 0x50 /* SID program key value register */ +.set SID_RDKEY, 0x60 /* SID read key value register */ + +.set SID_OP_LOCK, 0xAC /* Efuse operation lock value */ +.set SID_READ_START, (1 << 1) /* bit 1 of SID_PRCTL, Software Read Start */ +.set SID_PG_START, (1 << 0) /* bit 0 of SID_PRCTL, Software Program Start */ + +sid_read_root_key: + ldr SID_BASE, sid_base + mov sid_key_index, #0 + adr r3, sid_result /* result pointer */ +sid_read_loop: + mov r2, sid_key_index, lsl #16 /* PG_INDEX value */ + orr r2, #SID_OP_LOCK << 8 /* OP_LOCK to enable SID_READ_START */ + orr r2, #SID_READ_START + str r2, [SID_BASE, #SID_PRCTL] /* write SID_PRCTL */ +sid_read_wait: + ldr r2, [SID_BASE, #SID_PRCTL] /* read SID_PRCTL */ + tst r2, #SID_READ_START /* check if read operation completed */ + bne sid_read_wait /* loop while bit 1 still set */ + + ldr r2, [SID_BASE, #SID_RDKEY] /* read SID key value */ + str r2, [r3, sid_key_index] /* store SID value */ + + add sid_key_index, #4 + cmp sid_key_index, #16 + blo sid_read_loop /* loop while (sid_key_index < 0x10) */ + + mov r2, #0 + str r2, [SID_BASE, #SID_PRCTL] /* clear SID_PRCTL */ + bx lr + +sid_base: .word 0 +sid_result: .word 0 /* receives the four "root key" 32-bit words */ + .word 0 + .word 0 + .word 0 diff --git a/sid_read_root.h b/sid_read_root.h new file mode 100644 index 0000000000..48596bbb02 --- /dev/null +++ b/sid_read_root.h @@ -0,0 +1,24 @@ + /* : */ + htole32(0xe59f0040), /* 0: ldr r0, [pc, #64] */ + htole32(0xe3a01000), /* 4: mov r1, #0 */ + htole32(0xe28f303c), /* 8: add r3, pc, #60 */ + /* : */ + htole32(0xe1a02801), /* c: lsl r2, r1, #16 */ + htole32(0xe3822b2b), /* 10: orr r2, r2, #44032 */ + htole32(0xe3822002), /* 14: orr r2, r2, #2 */ + htole32(0xe5802040), /* 18: str r2, [r0, #64] */ + /* : */ + htole32(0xe5902040), /* 1c: ldr r2, [r0, #64] */ + htole32(0xe3120002), /* 20: tst r2, #2 */ + htole32(0x1afffffc), /* 24: bne 1c */ + htole32(0xe5902060), /* 28: ldr r2, [r0, #96] */ + htole32(0xe7832001), /* 2c: str r2, [r3, r1] */ + htole32(0xe2811004), /* 30: add r1, r1, #4 */ + htole32(0xe3510010), /* 34: cmp r1, #16 */ + htole32(0x3afffff3), /* 38: bcc c */ + htole32(0xe3a02000), /* 3c: mov r2, #0 */ + htole32(0xe5802040), /* 40: str r2, [r0, #64] */ + htole32(0xe12fff1e), /* 44: bx lr */ + /* : */ + htole32(0x00000000), /* 48: .word 0x00000000 */ + /* : */