/* * Copyright (c) 2006 Dave Airlie * Copyright © 2006-2008,2010 Intel Corporation * Jesse Barnes * * 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. * * Authors: * Eric Anholt * Chris Wilson */ #include #include #include #include #include "i915_drv.h" #include "i915_irq.h" #include "i915_reg.h" #include "intel_de.h" #include "intel_display_types.h" #include "intel_gmbus.h" #include "intel_gmbus_regs.h" struct intel_gmbus { struct i2c_adapter adapter; #define GMBUS_FORCE_BIT_RETRY (1U << 31) u32 force_bit; u32 reg0; i915_reg_t gpio_reg; struct i2c_algo_bit_data bit_algo; struct drm_i915_private *i915; }; enum gmbus_gpio { GPIOA, GPIOB, GPIOC, GPIOD, GPIOE, GPIOF, GPIOG, GPIOH, __GPIOI_UNUSED, GPIOJ, GPIOK, GPIOL, GPIOM, GPION, GPIOO, }; struct gmbus_pin { const char *name; enum gmbus_gpio gpio; }; /* Map gmbus pin pairs to names and registers. */ static const struct gmbus_pin gmbus_pins[] = { [GMBUS_PIN_SSC] = { "ssc", GPIOB }, [GMBUS_PIN_VGADDC] = { "vga", GPIOA }, [GMBUS_PIN_PANEL] = { "panel", GPIOC }, [GMBUS_PIN_DPC] = { "dpc", GPIOD }, [GMBUS_PIN_DPB] = { "dpb", GPIOE }, [GMBUS_PIN_DPD] = { "dpd", GPIOF }, }; static const struct gmbus_pin gmbus_pins_bdw[] = { [GMBUS_PIN_VGADDC] = { "vga", GPIOA }, [GMBUS_PIN_DPC] = { "dpc", GPIOD }, [GMBUS_PIN_DPB] = { "dpb", GPIOE }, [GMBUS_PIN_DPD] = { "dpd", GPIOF }, }; static const struct gmbus_pin gmbus_pins_skl[] = { [GMBUS_PIN_DPC] = { "dpc", GPIOD }, [GMBUS_PIN_DPB] = { "dpb", GPIOE }, [GMBUS_PIN_DPD] = { "dpd", GPIOF }, }; static const struct gmbus_pin gmbus_pins_bxt[] = { [GMBUS_PIN_1_BXT] = { "dpb", GPIOB }, [GMBUS_PIN_2_BXT] = { "dpc", GPIOC }, [GMBUS_PIN_3_BXT] = { "misc", GPIOD }, }; static const struct gmbus_pin gmbus_pins_cnp[] = { [GMBUS_PIN_1_BXT] = { "dpb", GPIOB }, [GMBUS_PIN_2_BXT] = { "dpc", GPIOC }, [GMBUS_PIN_3_BXT] = { "misc", GPIOD }, [GMBUS_PIN_4_CNP] = { "dpd", GPIOE }, }; static const struct gmbus_pin gmbus_pins_icp[] = { [GMBUS_PIN_1_BXT] = { "dpa", GPIOB }, [GMBUS_PIN_2_BXT] = { "dpb", GPIOC }, [GMBUS_PIN_3_BXT] = { "dpc", GPIOD }, [GMBUS_PIN_9_TC1_ICP] = { "tc1", GPIOJ }, [GMBUS_PIN_10_TC2_ICP] = { "tc2", GPIOK }, [GMBUS_PIN_11_TC3_ICP] = { "tc3", GPIOL }, [GMBUS_PIN_12_TC4_ICP] = { "tc4", GPIOM }, [GMBUS_PIN_13_TC5_TGP] = { "tc5", GPION }, [GMBUS_PIN_14_TC6_TGP] = { "tc6", GPIOO }, }; static const struct gmbus_pin gmbus_pins_dg1[] = { [GMBUS_PIN_1_BXT] = { "dpa", GPIOB }, [GMBUS_PIN_2_BXT] = { "dpb", GPIOC }, [GMBUS_PIN_3_BXT] = { "dpc", GPIOD }, [GMBUS_PIN_4_CNP] = { "dpd", GPIOE }, }; static const struct gmbus_pin gmbus_pins_dg2[] = { [GMBUS_PIN_1_BXT] = { "dpa", GPIOB }, [GMBUS_PIN_2_BXT] = { "dpb", GPIOC }, [GMBUS_PIN_3_BXT] = { "dpc", GPIOD }, [GMBUS_PIN_4_CNP] = { "dpd", GPIOE }, [GMBUS_PIN_9_TC1_ICP] = { "tc1", GPIOJ }, }; static const struct gmbus_pin gmbus_pins_mtp[] = { [GMBUS_PIN_1_BXT] = { "dpa", GPIOB }, [GMBUS_PIN_2_BXT] = { "dpb", GPIOC }, [GMBUS_PIN_3_BXT] = { "dpc", GPIOD }, [GMBUS_PIN_4_CNP] = { "dpd", GPIOE }, [GMBUS_PIN_5_MTP] = { "dpe", GPIOF }, [GMBUS_PIN_9_TC1_ICP] = { "tc1", GPIOJ }, [GMBUS_PIN_10_TC2_ICP] = { "tc2", GPIOK }, [GMBUS_PIN_11_TC3_ICP] = { "tc3", GPIOL }, [GMBUS_PIN_12_TC4_ICP] = { "tc4", GPIOM }, }; static const struct gmbus_pin *get_gmbus_pin(struct drm_i915_private *i915, unsigned int pin) { const struct gmbus_pin *pins; size_t size; if (INTEL_PCH_TYPE(i915) >= PCH_DG2) { pins = gmbus_pins_dg2; size = ARRAY_SIZE(gmbus_pins_dg2); } else if (INTEL_PCH_TYPE(i915) >= PCH_DG1) { pins = gmbus_pins_dg1; size = ARRAY_SIZE(gmbus_pins_dg1); } else if (INTEL_PCH_TYPE(i915) >= PCH_MTP) { pins = gmbus_pins_mtp; size = ARRAY_SIZE(gmbus_pins_mtp); } else if (INTEL_PCH_TYPE(i915) >= PCH_ICP) { pins = gmbus_pins_icp; size = ARRAY_SIZE(gmbus_pins_icp); } else if (HAS_PCH_CNP(i915)) { pins = gmbus_pins_cnp; size = ARRAY_SIZE(gmbus_pins_cnp); } else if (IS_GEMINILAKE(i915) || IS_BROXTON(i915)) { pins = gmbus_pins_bxt; size = ARRAY_SIZE(gmbus_pins_bxt); } else if (DISPLAY_VER(i915) == 9) { pins = gmbus_pins_skl; size = ARRAY_SIZE(gmbus_pins_skl); } else if (IS_BROADWELL(i915)) { pins = gmbus_pins_bdw; size = ARRAY_SIZE(gmbus_pins_bdw); } else { pins = gmbus_pins; size = ARRAY_SIZE(gmbus_pins); } if (pin >= size || !pins[pin].name) return NULL; return &pins[pin]; } bool intel_gmbus_is_valid_pin(struct drm_i915_private *i915, unsigned int pin) { return get_gmbus_pin(i915, pin); } /* Intel GPIO access functions */ #define I2C_RISEFALL_TIME 10 static inline struct intel_gmbus * to_intel_gmbus(struct i2c_adapter *i2c) { return container_of(i2c, struct intel_gmbus, adapter); } void intel_gmbus_reset(struct drm_i915_private *i915) { intel_de_write(i915, GMBUS0(i915), 0); intel_de_write(i915, GMBUS4(i915), 0); } static void pnv_gmbus_clock_gating(struct drm_i915_private *i915, bool enable) { /* When using bit bashing for I2C, this bit needs to be set to 1 */ intel_de_rmw(i915, DSPCLK_GATE_D(i915), PNV_GMBUSUNIT_CLOCK_GATE_DISABLE, !enable ? PNV_GMBUSUNIT_CLOCK_GATE_DISABLE : 0); } static void pch_gmbus_clock_gating(struct drm_i915_private *i915, bool enable) { intel_de_rmw(i915, SOUTH_DSPCLK_GATE_D, PCH_GMBUSUNIT_CLOCK_GATE_DISABLE, !enable ? PCH_GMBUSUNIT_CLOCK_GATE_DISABLE : 0); } static void bxt_gmbus_clock_gating(struct drm_i915_private *i915, bool enable) { intel_de_rmw(i915, GEN9_CLKGATE_DIS_4, BXT_GMBUS_GATING_DIS, !enable ? BXT_GMBUS_GATING_DIS : 0); } static u32 get_reserved(struct intel_gmbus *bus) { struct drm_i915_private *i915 = bus->i915; u32 reserved = 0; /* On most chips, these bits must be preserved in software. */ if (!IS_I830(i915) && !IS_I845G(i915)) reserved = intel_de_read_notrace(i915, bus->gpio_reg) & (GPIO_DATA_PULLUP_DISABLE | GPIO_CLOCK_PULLUP_DISABLE); return reserved; } static int get_clock(void *data) { struct intel_gmbus *bus = data; struct drm_i915_private *i915 = bus->i915; u32 reserved = get_reserved(bus); intel_de_write_notrace(i915, bus->gpio_reg, reserved | GPIO_CLOCK_DIR_MASK); intel_de_write_notrace(i915, bus->gpio_reg, reserved); return (intel_de_read_notrace(i915, bus->gpio_reg) & GPIO_CLOCK_VAL_IN) != 0; } static int get_data(void *data) { struct intel_gmbus *bus = data; struct drm_i915_private *i915 = bus->i915; u32 reserved = get_reserved(bus); intel_de_write_notrace(i915, bus->gpio_reg, reserved | GPIO_DATA_DIR_MASK); intel_de_write_notrace(i915, bus->gpio_reg, reserved); return (intel_de_read_notrace(i915, bus->gpio_reg) & GPIO_DATA_VAL_IN) != 0; } static void set_clock(void *data, int state_high) { struct intel_gmbus *bus = data; struct drm_i915_private *i915 = bus->i915; u32 reserved = get_reserved(bus); u32 clock_bits; if (state_high) clock_bits = GPIO_CLOCK_DIR_IN | GPIO_CLOCK_DIR_MASK; else clock_bits = GPIO_CLOCK_DIR_OUT | GPIO_CLOCK_DIR_MASK | GPIO_CLOCK_VAL_MASK; intel_de_write_notrace(i915, bus->gpio_reg, reserved | clock_bits); intel_de_posting_read(i915, bus->gpio_reg); } static void set_data(void *data, int state_high) { struct intel_gmbus *bus = data; struct drm_i915_private *i915 = bus->i915; u32 reserved = get_reserved(bus); u32 data_bits; if (state_high) data_bits = GPIO_DATA_DIR_IN | GPIO_DATA_DIR_MASK; else data_bits = GPIO_DATA_DIR_OUT | GPIO_DATA_DIR_MASK | GPIO_DATA_VAL_MASK; intel_de_write_notrace(i915, bus->gpio_reg, reserved | data_bits); intel_de_posting_read(i915, bus->gpio_reg); } static int intel_gpio_pre_xfer(struct i2c_adapter *adapter) { struct intel_gmbus *bus = to_intel_gmbus(adapter); struct drm_i915_private *i915 = bus->i915; intel_gmbus_reset(i915); if (IS_PINEVIEW(i915)) pnv_gmbus_clock_gating(i915, false); set_data(bus, 1); set_clock(bus, 1); udelay(I2C_RISEFALL_TIME); return 0; } static void intel_gpio_post_xfer(struct i2c_adapter *adapter) { struct intel_gmbus *bus = to_intel_gmbus(adapter); struct drm_i915_private *i915 = bus->i915; set_data(bus, 1); set_clock(bus, 1); if (IS_PINEVIEW(i915)) pnv_gmbus_clock_gating(i915, true); } static void intel_gpio_setup(struct intel_gmbus *bus, i915_reg_t gpio_reg) { struct i2c_algo_bit_data *algo; algo = &bus->bit_algo; bus->gpio_reg = gpio_reg; bus->adapter.algo_data = algo; algo->setsda = set_data; algo->setscl = set_clock; algo->getsda = get_data; algo->getscl = get_clock; algo->pre_xfer = intel_gpio_pre_xfer; algo->post_xfer = intel_gpio_post_xfer; algo->udelay = I2C_RISEFALL_TIME; algo->timeout = usecs_to_jiffies(2200); algo->data = bus; } static bool has_gmbus_irq(struct drm_i915_private *i915) { /* * encoder->shutdown() may want to use GMBUS * after irqs have already been disabled. */ return HAS_GMBUS_IRQ(i915) && intel_irqs_enabled(i915); } static int gmbus_wait(struct drm_i915_private *i915, u32 status, u32 irq_en) { DEFINE_WAIT(wait); u32 gmbus2; int ret; /* Important: The hw handles only the first bit, so set only one! Since * we also need to check for NAKs besides the hw ready/idle signal, we * need to wake up periodically and check that ourselves. */ if (!has_gmbus_irq(i915)) irq_en = 0; add_wait_queue(&i915->display.gmbus.wait_queue, &wait); intel_de_write_fw(i915, GMBUS4(i915), irq_en); status |= GMBUS_SATOER; ret = wait_for_us((gmbus2 = intel_de_read_fw(i915, GMBUS2(i915))) & status, 2); if (ret) ret = wait_for((gmbus2 = intel_de_read_fw(i915, GMBUS2(i915))) & status, 50); intel_de_write_fw(i915, GMBUS4(i915), 0); remove_wait_queue(&i915->display.gmbus.wait_queue, &wait); if (gmbus2 & GMBUS_SATOER) return -ENXIO; return ret; } static int gmbus_wait_idle(struct drm_i915_private *i915) { DEFINE_WAIT(wait); u32 irq_enable; int ret; /* Important: The hw handles only the first bit, so set only one! */ irq_enable = 0; if (has_gmbus_irq(i915)) irq_enable = GMBUS_IDLE_EN; add_wait_queue(&i915->display.gmbus.wait_queue, &wait); intel_de_write_fw(i915, GMBUS4(i915), irq_enable); ret = intel_de_wait_for_register_fw(i915, GMBUS2(i915), GMBUS_ACTIVE, 0, 10); intel_de_write_fw(i915, GMBUS4(i915), 0); remove_wait_queue(&i915->display.gmbus.wait_queue, &wait); return ret; } static unsigned int gmbus_max_xfer_size(struct drm_i915_private *i915) { return DISPLAY_VER(i915) >= 9 ? GEN9_GMBUS_BYTE_COUNT_MAX : GMBUS_BYTE_COUNT_MAX; } static int gmbus_xfer_read_chunk(struct drm_i915_private *i915, unsigned short addr, u8 *buf, unsigned int len, u32 gmbus0_reg, u32 gmbus1_index) { unsigned int size = len; bool burst_read = len > gmbus_max_xfer_size(i915); bool extra_byte_added = false; if (burst_read) { /* * As per HW Spec, for 512Bytes need to read extra Byte and * Ignore the extra byte read. */ if (len == 512) { extra_byte_added = true; len++; } size = len % 256 + 256; intel_de_write_fw(i915, GMBUS0(i915), gmbus0_reg | GMBUS_BYTE_CNT_OVERRIDE); } intel_de_write_fw(i915, GMBUS1(i915), gmbus1_index | GMBUS_CYCLE_WAIT | (size << GMBUS_BYTE_COUNT_SHIFT) | (addr << GMBUS_SLAVE_ADDR_SHIFT) | GMBUS_SLAVE_READ | GMBUS_SW_RDY); while (len) { int ret; u32 val, loop = 0; ret = gmbus_wait(i915, GMBUS_HW_RDY, GMBUS_HW_RDY_EN); if (ret) return ret; val = intel_de_read_fw(i915, GMBUS3(i915)); do { if (extra_byte_added && len == 1) break; *buf++ = val & 0xff; val >>= 8; } while (--len && ++loop < 4); if (burst_read && len == size - 4) /* Reset the override bit */ intel_de_write_fw(i915, GMBUS0(i915), gmbus0_reg); } return 0; } /* * HW spec says that 512Bytes in Burst read need special treatment. * But it doesn't talk about other multiple of 256Bytes. And couldn't locate * an I2C slave, which supports such a lengthy burst read too for experiments. * * So until things get clarified on HW support, to avoid the burst read length * in fold of 256Bytes except 512, max burst read length is fixed at 767Bytes. */ #define INTEL_GMBUS_BURST_READ_MAX_LEN 767U static int gmbus_xfer_read(struct drm_i915_private *i915, struct i2c_msg *msg, u32 gmbus0_reg, u32 gmbus1_index) { u8 *buf = msg->buf; unsigned int rx_size = msg->len; unsigned int len; int ret; do { if (HAS_GMBUS_BURST_READ(i915)) len = min(rx_size, INTEL_GMBUS_BURST_READ_MAX_LEN); else len = min(rx_size, gmbus_max_xfer_size(i915)); ret = gmbus_xfer_read_chunk(i915, msg->addr, buf, len, gmbus0_reg, gmbus1_index); if (ret) return ret; rx_size -= len; buf += len; } while (rx_size != 0); return 0; } static int gmbus_xfer_write_chunk(struct drm_i915_private *i915, unsigned short addr, u8 *buf, unsigned int len, u32 gmbus1_index) { unsigned int chunk_size = len; u32 val, loop; val = loop = 0; while (len && loop < 4) { val |= *buf++ << (8 * loop++); len -= 1; } intel_de_write_fw(i915, GMBUS3(i915), val); intel_de_write_fw(i915, GMBUS1(i915), gmbus1_index | GMBUS_CYCLE_WAIT | (chunk_size << GMBUS_BYTE_COUNT_SHIFT) | (addr << GMBUS_SLAVE_ADDR_SHIFT) | GMBUS_SLAVE_WRITE | GMBUS_SW_RDY); while (len) { int ret; val = loop = 0; do { val |= *buf++ << (8 * loop); } while (--len && ++loop < 4); intel_de_write_fw(i915, GMBUS3(i915), val); ret = gmbus_wait(i915, GMBUS_HW_RDY, GMBUS_HW_RDY_EN); if (ret) return ret; } return 0; } static int gmbus_xfer_write(struct drm_i915_private *i915, struct i2c_msg *msg, u32 gmbus1_index) { u8 *buf = msg->buf; unsigned int tx_size = msg->len; unsigned int len; int ret; do { len = min(tx_size, gmbus_max_xfer_size(i915)); ret = gmbus_xfer_write_chunk(i915, msg->addr, buf, len, gmbus1_index); if (ret) return ret; buf += len; tx_size -= len; } while (tx_size != 0); return 0; } /* * The gmbus controller can combine a 1 or 2 byte write with another read/write * that immediately follows it by using an "INDEX" cycle. */ static bool gmbus_is_index_xfer(struct i2c_msg *msgs, int i, int num) { return (i + 1 < num && msgs[i].addr == msgs[i + 1].addr && !(msgs[i].flags & I2C_M_RD) && (msgs[i].len == 1 || msgs[i].len == 2) && msgs[i + 1].len > 0); } static int gmbus_index_xfer(struct drm_i915_private *i915, struct i2c_msg *msgs, u32 gmbus0_reg) { u32 gmbus1_index = 0; u32 gmbus5 = 0; int ret; if (msgs[0].len == 2) gmbus5 = GMBUS_2BYTE_INDEX_EN | msgs[0].buf[1] | (msgs[0].buf[0] << 8); if (msgs[0].len == 1) gmbus1_index = GMBUS_CYCLE_INDEX | (msgs[0].buf[0] << GMBUS_SLAVE_INDEX_SHIFT); /* GMBUS5 holds 16-bit index */ if (gmbus5) intel_de_write_fw(i915, GMBUS5(i915), gmbus5); if (msgs[1].flags & I2C_M_RD) ret = gmbus_xfer_read(i915, &msgs[1], gmbus0_reg, gmbus1_index); else ret = gmbus_xfer_write(i915, &msgs[1], gmbus1_index); /* Clear GMBUS5 after each index transfer */ if (gmbus5) intel_de_write_fw(i915, GMBUS5(i915), 0); return ret; } static int do_gmbus_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num, u32 gmbus0_source) { struct intel_gmbus *bus = to_intel_gmbus(adapter); struct drm_i915_private *i915 = bus->i915; int i = 0, inc, try = 0; int ret = 0; /* Display WA #0868: skl,bxt,kbl,cfl,glk */ if (IS_GEMINILAKE(i915) || IS_BROXTON(i915)) bxt_gmbus_clock_gating(i915, false); else if (HAS_PCH_SPT(i915) || HAS_PCH_CNP(i915)) pch_gmbus_clock_gating(i915, false); retry: intel_de_write_fw(i915, GMBUS0(i915), gmbus0_source | bus->reg0); for (; i < num; i += inc) { inc = 1; if (gmbus_is_index_xfer(msgs, i, num)) { ret = gmbus_index_xfer(i915, &msgs[i], gmbus0_source | bus->reg0); inc = 2; /* an index transmission is two msgs */ } else if (msgs[i].flags & I2C_M_RD) { ret = gmbus_xfer_read(i915, &msgs[i], gmbus0_source | bus->reg0, 0); } else { ret = gmbus_xfer_write(i915, &msgs[i], 0); } if (!ret) ret = gmbus_wait(i915, GMBUS_HW_WAIT_PHASE, GMBUS_HW_WAIT_EN); if (ret == -ETIMEDOUT) goto timeout; else if (ret) goto clear_err; } /* Generate a STOP condition on the bus. Note that gmbus can't generata * a STOP on the very first cycle. To simplify the code we * unconditionally generate the STOP condition with an additional gmbus * cycle. */ intel_de_write_fw(i915, GMBUS1(i915), GMBUS_CYCLE_STOP | GMBUS_SW_RDY); /* Mark the GMBUS interface as disabled after waiting for idle. * We will re-enable it at the start of the next xfer, * till then let it sleep. */ if (gmbus_wait_idle(i915)) { drm_dbg_kms(&i915->drm, "GMBUS [%s] timed out waiting for idle\n", adapter->name); ret = -ETIMEDOUT; } intel_de_write_fw(i915, GMBUS0(i915), 0); ret = ret ?: i; goto out; clear_err: /* * Wait for bus to IDLE before clearing NAK. * If we clear the NAK while bus is still active, then it will stay * active and the next transaction may fail. * * If no ACK is received during the address phase of a transaction, the * adapter must report -ENXIO. It is not clear what to return if no ACK * is received at other times. But we have to be careful to not return * spurious -ENXIO because that will prevent i2c and drm edid functions * from retrying. So return -ENXIO only when gmbus properly quiescents - * timing out seems to happen when there _is_ a ddc chip present, but * it's slow responding and only answers on the 2nd retry. */ ret = -ENXIO; if (gmbus_wait_idle(i915)) { drm_dbg_kms(&i915->drm, "GMBUS [%s] timed out after NAK\n", adapter->name); ret = -ETIMEDOUT; } /* Toggle the Software Clear Interrupt bit. This has the effect * of resetting the GMBUS controller and so clearing the * BUS_ERROR raised by the slave's NAK. */ intel_de_write_fw(i915, GMBUS1(i915), GMBUS_SW_CLR_INT); intel_de_write_fw(i915, GMBUS1(i915), 0); intel_de_write_fw(i915, GMBUS0(i915), 0); drm_dbg_kms(&i915->drm, "GMBUS [%s] NAK for addr: %04x %c(%d)\n", adapter->name, msgs[i].addr, (msgs[i].flags & I2C_M_RD) ? 'r' : 'w', msgs[i].len); /* * Passive adapters sometimes NAK the first probe. Retry the first * message once on -ENXIO for GMBUS transfers; the bit banging algorithm * has retries internally. See also the retry loop in * drm_do_probe_ddc_edid, which bails out on the first -ENXIO. */ if (ret == -ENXIO && i == 0 && try++ == 0) { drm_dbg_kms(&i915->drm, "GMBUS [%s] NAK on first message, retry\n", adapter->name); goto retry; } goto out; timeout: drm_dbg_kms(&i915->drm, "GMBUS [%s] timed out, falling back to bit banging on pin %d\n", bus->adapter.name, bus->reg0 & 0xff); intel_de_write_fw(i915, GMBUS0(i915), 0); /* * Hardware may not support GMBUS over these pins? Try GPIO bitbanging * instead. Use EAGAIN to have i2c core retry. */ ret = -EAGAIN; out: /* Display WA #0868: skl,bxt,kbl,cfl,glk */ if (IS_GEMINILAKE(i915) || IS_BROXTON(i915)) bxt_gmbus_clock_gating(i915, true); else if (HAS_PCH_SPT(i915) || HAS_PCH_CNP(i915)) pch_gmbus_clock_gating(i915, true); return ret; } static int gmbus_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num) { struct intel_gmbus *bus = to_intel_gmbus(adapter); struct drm_i915_private *i915 = bus->i915; intel_wakeref_t wakeref; int ret; wakeref = intel_display_power_get(i915, POWER_DOMAIN_GMBUS); if (bus->force_bit) { ret = i2c_bit_algo.master_xfer(adapter, msgs, num); if (ret < 0) bus->force_bit &= ~GMBUS_FORCE_BIT_RETRY; } else { ret = do_gmbus_xfer(adapter, msgs, num, 0); if (ret == -EAGAIN) bus->force_bit |= GMBUS_FORCE_BIT_RETRY; } intel_display_power_put(i915, POWER_DOMAIN_GMBUS, wakeref); return ret; } int intel_gmbus_output_aksv(struct i2c_adapter *adapter) { struct intel_gmbus *bus = to_intel_gmbus(adapter); struct drm_i915_private *i915 = bus->i915; u8 cmd = DRM_HDCP_DDC_AKSV; u8 buf[DRM_HDCP_KSV_LEN] = { 0 }; struct i2c_msg msgs[] = { { .addr = DRM_HDCP_DDC_ADDR, .flags = 0, .len = sizeof(cmd), .buf = &cmd, }, { .addr = DRM_HDCP_DDC_ADDR, .flags = 0, .len = sizeof(buf), .buf = buf, } }; intel_wakeref_t wakeref; int ret; wakeref = intel_display_power_get(i915, POWER_DOMAIN_GMBUS); mutex_lock(&i915->display.gmbus.mutex); /* * In order to output Aksv to the receiver, use an indexed write to * pass the i2c command, and tell GMBUS to use the HW-provided value * instead of sourcing GMBUS3 for the data. */ ret = do_gmbus_xfer(adapter, msgs, ARRAY_SIZE(msgs), GMBUS_AKSV_SELECT); mutex_unlock(&i915->display.gmbus.mutex); intel_display_power_put(i915, POWER_DOMAIN_GMBUS, wakeref); return ret; } static u32 gmbus_func(struct i2c_adapter *adapter) { return i2c_bit_algo.functionality(adapter) & (I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | /* I2C_FUNC_10BIT_ADDR | */ I2C_FUNC_SMBUS_READ_BLOCK_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL); } static const struct i2c_algorithm gmbus_algorithm = { .master_xfer = gmbus_xfer, .functionality = gmbus_func }; static void gmbus_lock_bus(struct i2c_adapter *adapter, unsigned int flags) { struct intel_gmbus *bus = to_intel_gmbus(adapter); struct drm_i915_private *i915 = bus->i915; mutex_lock(&i915->display.gmbus.mutex); } static int gmbus_trylock_bus(struct i2c_adapter *adapter, unsigned int flags) { struct intel_gmbus *bus = to_intel_gmbus(adapter); struct drm_i915_private *i915 = bus->i915; return mutex_trylock(&i915->display.gmbus.mutex); } static void gmbus_unlock_bus(struct i2c_adapter *adapter, unsigned int flags) { struct intel_gmbus *bus = to_intel_gmbus(adapter); struct drm_i915_private *i915 = bus->i915; mutex_unlock(&i915->display.gmbus.mutex); } static const struct i2c_lock_operations gmbus_lock_ops = { .lock_bus = gmbus_lock_bus, .trylock_bus = gmbus_trylock_bus, .unlock_bus = gmbus_unlock_bus, }; /** * intel_gmbus_setup - instantiate all Intel i2c GMBuses * @i915: i915 device private */ int intel_gmbus_setup(struct drm_i915_private *i915) { struct pci_dev *pdev = to_pci_dev(i915->drm.dev); unsigned int pin; int ret; if (IS_VALLEYVIEW(i915) || IS_CHERRYVIEW(i915)) i915->display.gmbus.mmio_base = VLV_DISPLAY_BASE; else if (!HAS_GMCH(i915)) /* * Broxton uses the same PCH offsets for South Display Engine, * even though it doesn't have a PCH. */ i915->display.gmbus.mmio_base = PCH_DISPLAY_BASE; mutex_init(&i915->display.gmbus.mutex); init_waitqueue_head(&i915->display.gmbus.wait_queue); for (pin = 0; pin < ARRAY_SIZE(i915->display.gmbus.bus); pin++) { const struct gmbus_pin *gmbus_pin; struct intel_gmbus *bus; gmbus_pin = get_gmbus_pin(i915, pin); if (!gmbus_pin) continue; bus = kzalloc(sizeof(*bus), GFP_KERNEL); if (!bus) { ret = -ENOMEM; goto err; } bus->adapter.owner = THIS_MODULE; bus->adapter.class = I2C_CLASS_DDC; snprintf(bus->adapter.name, sizeof(bus->adapter.name), "i915 gmbus %s", gmbus_pin->name); bus->adapter.dev.parent = &pdev->dev; bus->i915 = i915; bus->adapter.algo = &gmbus_algorithm; bus->adapter.lock_ops = &gmbus_lock_ops; /* * We wish to retry with bit banging * after a timed out GMBUS attempt. */ bus->adapter.retries = 1; /* By default use a conservative clock rate */ bus->reg0 = pin | GMBUS_RATE_100KHZ; /* gmbus seems to be broken on i830 */ if (IS_I830(i915)) bus->force_bit = 1; intel_gpio_setup(bus, GPIO(i915, gmbus_pin->gpio)); ret = i2c_add_adapter(&bus->adapter); if (ret) { kfree(bus); goto err; } i915->display.gmbus.bus[pin] = bus; } intel_gmbus_reset(i915); return 0; err: intel_gmbus_teardown(i915); return ret; } struct i2c_adapter *intel_gmbus_get_adapter(struct drm_i915_private *i915, unsigned int pin) { if (drm_WARN_ON(&i915->drm, pin >= ARRAY_SIZE(i915->display.gmbus.bus) || !i915->display.gmbus.bus[pin])) return NULL; return &i915->display.gmbus.bus[pin]->adapter; } void intel_gmbus_force_bit(struct i2c_adapter *adapter, bool force_bit) { struct intel_gmbus *bus = to_intel_gmbus(adapter); struct drm_i915_private *i915 = bus->i915; mutex_lock(&i915->display.gmbus.mutex); bus->force_bit += force_bit ? 1 : -1; drm_dbg_kms(&i915->drm, "%sabling bit-banging on %s. force bit now %d\n", force_bit ? "en" : "dis", adapter->name, bus->force_bit); mutex_unlock(&i915->display.gmbus.mutex); } bool intel_gmbus_is_forced_bit(struct i2c_adapter *adapter) { struct intel_gmbus *bus = to_intel_gmbus(adapter); return bus->force_bit; } void intel_gmbus_teardown(struct drm_i915_private *i915) { unsigned int pin; for (pin = 0; pin < ARRAY_SIZE(i915->display.gmbus.bus); pin++) { struct intel_gmbus *bus; bus = i915->display.gmbus.bus[pin]; if (!bus) continue; i2c_del_adapter(&bus->adapter); kfree(bus); i915->display.gmbus.bus[pin] = NULL; } }