diff options
Diffstat (limited to 'drivers/thunderbolt/cap.c')
| -rw-r--r-- | drivers/thunderbolt/cap.c | 243 |
1 files changed, 243 insertions, 0 deletions
diff --git a/drivers/thunderbolt/cap.c b/drivers/thunderbolt/cap.c new file mode 100644 index 000000000..8ecd610c6 --- /dev/null +++ b/drivers/thunderbolt/cap.c @@ -0,0 +1,243 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Thunderbolt driver - capabilities lookup + * + * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com> + * Copyright (C) 2018, Intel Corporation + */ + +#include <linux/slab.h> +#include <linux/errno.h> + +#include "tb.h" + +#define CAP_OFFSET_MAX 0xff +#define VSE_CAP_OFFSET_MAX 0xffff +#define TMU_ACCESS_EN BIT(20) + +static int tb_port_enable_tmu(struct tb_port *port, bool enable) +{ + struct tb_switch *sw = port->sw; + u32 value, offset; + int ret; + + /* + * Legacy devices need to have TMU access enabled before port + * space can be fully accessed. + */ + if (tb_switch_is_light_ridge(sw)) + offset = 0x26; + else if (tb_switch_is_eagle_ridge(sw)) + offset = 0x2a; + else + return 0; + + ret = tb_sw_read(sw, &value, TB_CFG_SWITCH, offset, 1); + if (ret) + return ret; + + if (enable) + value |= TMU_ACCESS_EN; + else + value &= ~TMU_ACCESS_EN; + + return tb_sw_write(sw, &value, TB_CFG_SWITCH, offset, 1); +} + +static void tb_port_dummy_read(struct tb_port *port) +{ + /* + * When reading from next capability pointer location in port + * config space the read data is not cleared on LR. To avoid + * reading stale data on next read perform one dummy read after + * port capabilities are walked. + */ + if (tb_switch_is_light_ridge(port->sw)) { + u32 dummy; + + tb_port_read(port, &dummy, TB_CFG_PORT, 0, 1); + } +} + +/** + * tb_port_next_cap() - Return next capability in the linked list + * @port: Port to find the capability for + * @offset: Previous capability offset (%0 for start) + * + * Returns dword offset of the next capability in port config space + * capability list and returns it. Passing %0 returns the first entry in + * the capability list. If no next capability is found returns %0. In case + * of failure returns negative errno. + */ +int tb_port_next_cap(struct tb_port *port, unsigned int offset) +{ + struct tb_cap_any header; + int ret; + + if (!offset) + return port->config.first_cap_offset; + + ret = tb_port_read(port, &header, TB_CFG_PORT, offset, 1); + if (ret) + return ret; + + return header.basic.next; +} + +static int __tb_port_find_cap(struct tb_port *port, enum tb_port_cap cap) +{ + int offset = 0; + + do { + struct tb_cap_any header; + int ret; + + offset = tb_port_next_cap(port, offset); + if (offset < 0) + return offset; + + ret = tb_port_read(port, &header, TB_CFG_PORT, offset, 1); + if (ret) + return ret; + + if (header.basic.cap == cap) + return offset; + } while (offset > 0); + + return -ENOENT; +} + +/** + * tb_port_find_cap() - Find port capability + * @port: Port to find the capability for + * @cap: Capability to look + * + * Returns offset to start of capability or %-ENOENT if no such + * capability was found. Negative errno is returned if there was an + * error. + */ +int tb_port_find_cap(struct tb_port *port, enum tb_port_cap cap) +{ + int ret; + + ret = tb_port_enable_tmu(port, true); + if (ret) + return ret; + + ret = __tb_port_find_cap(port, cap); + + tb_port_dummy_read(port); + tb_port_enable_tmu(port, false); + + return ret; +} + +/** + * tb_switch_next_cap() - Return next capability in the linked list + * @sw: Switch to find the capability for + * @offset: Previous capability offset (%0 for start) + * + * Finds dword offset of the next capability in router config space + * capability list and returns it. Passing %0 returns the first entry in + * the capability list. If no next capability is found returns %0. In case + * of failure returns negative errno. + */ +int tb_switch_next_cap(struct tb_switch *sw, unsigned int offset) +{ + struct tb_cap_any header; + int ret; + + if (!offset) + return sw->config.first_cap_offset; + + ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, offset, 2); + if (ret) + return ret; + + switch (header.basic.cap) { + case TB_SWITCH_CAP_TMU: + ret = header.basic.next; + break; + + case TB_SWITCH_CAP_VSE: + if (!header.extended_short.length) + ret = header.extended_long.next; + else + ret = header.extended_short.next; + break; + + default: + tb_sw_dbg(sw, "unknown capability %#x at %#x\n", + header.basic.cap, offset); + ret = -EINVAL; + break; + } + + return ret >= VSE_CAP_OFFSET_MAX ? 0 : ret; +} + +/** + * tb_switch_find_cap() - Find switch capability + * @sw: Switch to find the capability for + * @cap: Capability to look + * + * Returns offset to start of capability or %-ENOENT if no such + * capability was found. Negative errno is returned if there was an + * error. + */ +int tb_switch_find_cap(struct tb_switch *sw, enum tb_switch_cap cap) +{ + int offset = 0; + + do { + struct tb_cap_any header; + int ret; + + offset = tb_switch_next_cap(sw, offset); + if (offset < 0) + return offset; + + ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, offset, 1); + if (ret) + return ret; + + if (header.basic.cap == cap) + return offset; + } while (offset); + + return -ENOENT; +} + +/** + * tb_switch_find_vse_cap() - Find switch vendor specific capability + * @sw: Switch to find the capability for + * @vsec: Vendor specific capability to look + * + * Functions enumerates vendor specific capabilities (VSEC) of a switch + * and returns offset when capability matching @vsec is found. If no + * such capability is found returns %-ENOENT. In case of error returns + * negative errno. + */ +int tb_switch_find_vse_cap(struct tb_switch *sw, enum tb_switch_vse_cap vsec) +{ + int offset = 0; + + do { + struct tb_cap_any header; + int ret; + + offset = tb_switch_next_cap(sw, offset); + if (offset < 0) + return offset; + + ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, offset, 1); + if (ret) + return ret; + + if (header.extended_short.cap == TB_SWITCH_CAP_VSE && + header.extended_short.vsec_id == vsec) + return offset; + } while (offset); + + return -ENOENT; +} |