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Diffstat (limited to 'drivers/gpu/drm/i915/intel_i2c.c')
-rw-r--r--drivers/gpu/drm/i915/intel_i2c.c932
1 files changed, 932 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/intel_i2c.c b/drivers/gpu/drm/i915/intel_i2c.c
new file mode 100644
index 000000000..bef32b7c2
--- /dev/null
+++ b/drivers/gpu/drm/i915/intel_i2c.c
@@ -0,0 +1,932 @@
+/*
+ * Copyright (c) 2006 Dave Airlie <airlied@linux.ie>
+ * Copyright © 2006-2008,2010 Intel Corporation
+ * Jesse Barnes <jesse.barnes@intel.com>
+ *
+ * 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 <eric@anholt.net>
+ * Chris Wilson <chris@chris-wilson.co.uk>
+ */
+#include <linux/i2c.h>
+#include <linux/i2c-algo-bit.h>
+#include <linux/export.h>
+#include <drm/drmP.h>
+#include <drm/drm_hdcp.h>
+#include "intel_drv.h"
+#include <drm/i915_drm.h>
+#include "i915_drv.h"
+
+struct gmbus_pin {
+ const char *name;
+ i915_reg_t reg;
+};
+
+/* 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_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 },
+};
+
+/* pin is expected to be valid */
+static const struct gmbus_pin *get_gmbus_pin(struct drm_i915_private *dev_priv,
+ unsigned int pin)
+{
+ if (HAS_PCH_ICP(dev_priv))
+ return &gmbus_pins_icp[pin];
+ else if (HAS_PCH_CNP(dev_priv))
+ return &gmbus_pins_cnp[pin];
+ else if (IS_GEN9_LP(dev_priv))
+ return &gmbus_pins_bxt[pin];
+ else if (IS_GEN9_BC(dev_priv))
+ return &gmbus_pins_skl[pin];
+ else if (IS_BROADWELL(dev_priv))
+ return &gmbus_pins_bdw[pin];
+ else
+ return &gmbus_pins[pin];
+}
+
+bool intel_gmbus_is_valid_pin(struct drm_i915_private *dev_priv,
+ unsigned int pin)
+{
+ unsigned int size;
+
+ if (HAS_PCH_ICP(dev_priv))
+ size = ARRAY_SIZE(gmbus_pins_icp);
+ else if (HAS_PCH_CNP(dev_priv))
+ size = ARRAY_SIZE(gmbus_pins_cnp);
+ else if (IS_GEN9_LP(dev_priv))
+ size = ARRAY_SIZE(gmbus_pins_bxt);
+ else if (IS_GEN9_BC(dev_priv))
+ size = ARRAY_SIZE(gmbus_pins_skl);
+ else if (IS_BROADWELL(dev_priv))
+ size = ARRAY_SIZE(gmbus_pins_bdw);
+ else
+ size = ARRAY_SIZE(gmbus_pins);
+
+ return pin < size &&
+ i915_mmio_reg_valid(get_gmbus_pin(dev_priv, pin)->reg);
+}
+
+/* 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_i2c_reset(struct drm_i915_private *dev_priv)
+{
+ I915_WRITE(GMBUS0, 0);
+ I915_WRITE(GMBUS4, 0);
+}
+
+static void pnv_gmbus_clock_gating(struct drm_i915_private *dev_priv,
+ bool enable)
+{
+ u32 val;
+
+ /* When using bit bashing for I2C, this bit needs to be set to 1 */
+ val = I915_READ(DSPCLK_GATE_D);
+ if (!enable)
+ val |= PNV_GMBUSUNIT_CLOCK_GATE_DISABLE;
+ else
+ val &= ~PNV_GMBUSUNIT_CLOCK_GATE_DISABLE;
+ I915_WRITE(DSPCLK_GATE_D, val);
+}
+
+static void pch_gmbus_clock_gating(struct drm_i915_private *dev_priv,
+ bool enable)
+{
+ u32 val;
+
+ val = I915_READ(SOUTH_DSPCLK_GATE_D);
+ if (!enable)
+ val |= PCH_GMBUSUNIT_CLOCK_GATE_DISABLE;
+ else
+ val &= ~PCH_GMBUSUNIT_CLOCK_GATE_DISABLE;
+ I915_WRITE(SOUTH_DSPCLK_GATE_D, val);
+}
+
+static void bxt_gmbus_clock_gating(struct drm_i915_private *dev_priv,
+ bool enable)
+{
+ u32 val;
+
+ val = I915_READ(GEN9_CLKGATE_DIS_4);
+ if (!enable)
+ val |= BXT_GMBUS_GATING_DIS;
+ else
+ val &= ~BXT_GMBUS_GATING_DIS;
+ I915_WRITE(GEN9_CLKGATE_DIS_4, val);
+}
+
+static u32 get_reserved(struct intel_gmbus *bus)
+{
+ struct drm_i915_private *dev_priv = bus->dev_priv;
+ u32 reserved = 0;
+
+ /* On most chips, these bits must be preserved in software. */
+ if (!IS_I830(dev_priv) && !IS_I845G(dev_priv))
+ reserved = I915_READ_NOTRACE(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 *dev_priv = bus->dev_priv;
+ u32 reserved = get_reserved(bus);
+ I915_WRITE_NOTRACE(bus->gpio_reg, reserved | GPIO_CLOCK_DIR_MASK);
+ I915_WRITE_NOTRACE(bus->gpio_reg, reserved);
+ return (I915_READ_NOTRACE(bus->gpio_reg) & GPIO_CLOCK_VAL_IN) != 0;
+}
+
+static int get_data(void *data)
+{
+ struct intel_gmbus *bus = data;
+ struct drm_i915_private *dev_priv = bus->dev_priv;
+ u32 reserved = get_reserved(bus);
+ I915_WRITE_NOTRACE(bus->gpio_reg, reserved | GPIO_DATA_DIR_MASK);
+ I915_WRITE_NOTRACE(bus->gpio_reg, reserved);
+ return (I915_READ_NOTRACE(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 *dev_priv = bus->dev_priv;
+ 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;
+
+ I915_WRITE_NOTRACE(bus->gpio_reg, reserved | clock_bits);
+ POSTING_READ(bus->gpio_reg);
+}
+
+static void set_data(void *data, int state_high)
+{
+ struct intel_gmbus *bus = data;
+ struct drm_i915_private *dev_priv = bus->dev_priv;
+ 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;
+
+ I915_WRITE_NOTRACE(bus->gpio_reg, reserved | data_bits);
+ POSTING_READ(bus->gpio_reg);
+}
+
+static int
+intel_gpio_pre_xfer(struct i2c_adapter *adapter)
+{
+ struct intel_gmbus *bus = container_of(adapter,
+ struct intel_gmbus,
+ adapter);
+ struct drm_i915_private *dev_priv = bus->dev_priv;
+
+ intel_i2c_reset(dev_priv);
+
+ if (IS_PINEVIEW(dev_priv))
+ pnv_gmbus_clock_gating(dev_priv, 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 = container_of(adapter,
+ struct intel_gmbus,
+ adapter);
+ struct drm_i915_private *dev_priv = bus->dev_priv;
+
+ set_data(bus, 1);
+ set_clock(bus, 1);
+
+ if (IS_PINEVIEW(dev_priv))
+ pnv_gmbus_clock_gating(dev_priv, true);
+}
+
+static void
+intel_gpio_setup(struct intel_gmbus *bus, unsigned int pin)
+{
+ struct drm_i915_private *dev_priv = bus->dev_priv;
+ struct i2c_algo_bit_data *algo;
+
+ algo = &bus->bit_algo;
+
+ bus->gpio_reg = _MMIO(dev_priv->gpio_mmio_base +
+ i915_mmio_reg_offset(get_gmbus_pin(dev_priv, pin)->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 int gmbus_wait(struct drm_i915_private *dev_priv, 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(dev_priv))
+ irq_en = 0;
+
+ add_wait_queue(&dev_priv->gmbus_wait_queue, &wait);
+ I915_WRITE_FW(GMBUS4, irq_en);
+
+ status |= GMBUS_SATOER;
+ ret = wait_for_us((gmbus2 = I915_READ_FW(GMBUS2)) & status, 2);
+ if (ret)
+ ret = wait_for((gmbus2 = I915_READ_FW(GMBUS2)) & status, 50);
+
+ I915_WRITE_FW(GMBUS4, 0);
+ remove_wait_queue(&dev_priv->gmbus_wait_queue, &wait);
+
+ if (gmbus2 & GMBUS_SATOER)
+ return -ENXIO;
+
+ return ret;
+}
+
+static int
+gmbus_wait_idle(struct drm_i915_private *dev_priv)
+{
+ 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(dev_priv))
+ irq_enable = GMBUS_IDLE_EN;
+
+ add_wait_queue(&dev_priv->gmbus_wait_queue, &wait);
+ I915_WRITE_FW(GMBUS4, irq_enable);
+
+ ret = intel_wait_for_register_fw(dev_priv,
+ GMBUS2, GMBUS_ACTIVE, 0,
+ 10);
+
+ I915_WRITE_FW(GMBUS4, 0);
+ remove_wait_queue(&dev_priv->gmbus_wait_queue, &wait);
+
+ return ret;
+}
+
+static inline
+unsigned int gmbus_max_xfer_size(struct drm_i915_private *dev_priv)
+{
+ return INTEL_GEN(dev_priv) >= 9 ? GEN9_GMBUS_BYTE_COUNT_MAX :
+ GMBUS_BYTE_COUNT_MAX;
+}
+
+static int
+gmbus_xfer_read_chunk(struct drm_i915_private *dev_priv,
+ 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(dev_priv);
+ 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;
+ I915_WRITE_FW(GMBUS0, gmbus0_reg | GMBUS_BYTE_CNT_OVERRIDE);
+ }
+
+ I915_WRITE_FW(GMBUS1,
+ 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(dev_priv, GMBUS_HW_RDY, GMBUS_HW_RDY_EN);
+ if (ret)
+ return ret;
+
+ val = I915_READ_FW(GMBUS3);
+ 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 */
+ I915_WRITE_FW(GMBUS0, 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 *dev_priv, 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(dev_priv))
+ len = min(rx_size, INTEL_GMBUS_BURST_READ_MAX_LEN);
+ else
+ len = min(rx_size, gmbus_max_xfer_size(dev_priv));
+
+ ret = gmbus_xfer_read_chunk(dev_priv, 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 *dev_priv,
+ 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;
+ }
+
+ I915_WRITE_FW(GMBUS3, val);
+ I915_WRITE_FW(GMBUS1,
+ 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);
+
+ I915_WRITE_FW(GMBUS3, val);
+
+ ret = gmbus_wait(dev_priv, GMBUS_HW_RDY, GMBUS_HW_RDY_EN);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
+static int
+gmbus_xfer_write(struct drm_i915_private *dev_priv, 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(dev_priv));
+
+ ret = gmbus_xfer_write_chunk(dev_priv, 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 *dev_priv, 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)
+ I915_WRITE_FW(GMBUS5, gmbus5);
+
+ if (msgs[1].flags & I2C_M_RD)
+ ret = gmbus_xfer_read(dev_priv, &msgs[1], gmbus0_reg,
+ gmbus1_index);
+ else
+ ret = gmbus_xfer_write(dev_priv, &msgs[1], gmbus1_index);
+
+ /* Clear GMBUS5 after each index transfer */
+ if (gmbus5)
+ I915_WRITE_FW(GMBUS5, 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 = container_of(adapter,
+ struct intel_gmbus,
+ adapter);
+ struct drm_i915_private *dev_priv = bus->dev_priv;
+ int i = 0, inc, try = 0;
+ int ret = 0;
+
+ /* Display WA #0868: skl,bxt,kbl,cfl,glk,cnl */
+ if (IS_GEN9_LP(dev_priv))
+ bxt_gmbus_clock_gating(dev_priv, false);
+ else if (HAS_PCH_SPT(dev_priv) ||
+ HAS_PCH_KBP(dev_priv) || HAS_PCH_CNP(dev_priv))
+ pch_gmbus_clock_gating(dev_priv, false);
+
+retry:
+ I915_WRITE_FW(GMBUS0, gmbus0_source | bus->reg0);
+
+ for (; i < num; i += inc) {
+ inc = 1;
+ if (gmbus_is_index_xfer(msgs, i, num)) {
+ ret = gmbus_index_xfer(dev_priv, &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(dev_priv, &msgs[i],
+ gmbus0_source | bus->reg0, 0);
+ } else {
+ ret = gmbus_xfer_write(dev_priv, &msgs[i], 0);
+ }
+
+ if (!ret)
+ ret = gmbus_wait(dev_priv,
+ 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. */
+ I915_WRITE_FW(GMBUS1, 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(dev_priv)) {
+ DRM_DEBUG_KMS("GMBUS [%s] timed out waiting for idle\n",
+ adapter->name);
+ ret = -ETIMEDOUT;
+ }
+ I915_WRITE_FW(GMBUS0, 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(dev_priv)) {
+ DRM_DEBUG_KMS("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.
+ */
+ I915_WRITE_FW(GMBUS1, GMBUS_SW_CLR_INT);
+ I915_WRITE_FW(GMBUS1, 0);
+ I915_WRITE_FW(GMBUS0, 0);
+
+ DRM_DEBUG_KMS("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_DEBUG_KMS("GMBUS [%s] NAK on first message, retry\n",
+ adapter->name);
+ goto retry;
+ }
+
+ goto out;
+
+timeout:
+ DRM_DEBUG_KMS("GMBUS [%s] timed out, falling back to bit banging on pin %d\n",
+ bus->adapter.name, bus->reg0 & 0xff);
+ I915_WRITE_FW(GMBUS0, 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,cnl */
+ if (IS_GEN9_LP(dev_priv))
+ bxt_gmbus_clock_gating(dev_priv, true);
+ else if (HAS_PCH_SPT(dev_priv) ||
+ HAS_PCH_KBP(dev_priv) || HAS_PCH_CNP(dev_priv))
+ pch_gmbus_clock_gating(dev_priv, true);
+
+ return ret;
+}
+
+static int
+gmbus_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num)
+{
+ struct intel_gmbus *bus = container_of(adapter, struct intel_gmbus,
+ adapter);
+ struct drm_i915_private *dev_priv = bus->dev_priv;
+ int ret;
+
+ intel_display_power_get(dev_priv, 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(dev_priv, POWER_DOMAIN_GMBUS);
+
+ return ret;
+}
+
+int intel_gmbus_output_aksv(struct i2c_adapter *adapter)
+{
+ struct intel_gmbus *bus = container_of(adapter, struct intel_gmbus,
+ adapter);
+ struct drm_i915_private *dev_priv = bus->dev_priv;
+ int ret;
+ 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_display_power_get(dev_priv, POWER_DOMAIN_GMBUS);
+ mutex_lock(&dev_priv->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(&dev_priv->gmbus_mutex);
+ intel_display_power_put(dev_priv, POWER_DOMAIN_GMBUS);
+
+ 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 *dev_priv = bus->dev_priv;
+
+ mutex_lock(&dev_priv->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 *dev_priv = bus->dev_priv;
+
+ return mutex_trylock(&dev_priv->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 *dev_priv = bus->dev_priv;
+
+ mutex_unlock(&dev_priv->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
+ * @dev_priv: i915 device private
+ */
+int intel_setup_gmbus(struct drm_i915_private *dev_priv)
+{
+ struct pci_dev *pdev = dev_priv->drm.pdev;
+ struct intel_gmbus *bus;
+ unsigned int pin;
+ int ret;
+
+ if (INTEL_INFO(dev_priv)->num_pipes == 0)
+ return 0;
+
+ if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))
+ dev_priv->gpio_mmio_base = VLV_DISPLAY_BASE;
+ else if (!HAS_GMCH_DISPLAY(dev_priv))
+ dev_priv->gpio_mmio_base =
+ i915_mmio_reg_offset(PCH_GPIOA) -
+ i915_mmio_reg_offset(GPIOA);
+
+ mutex_init(&dev_priv->gmbus_mutex);
+ init_waitqueue_head(&dev_priv->gmbus_wait_queue);
+
+ for (pin = 0; pin < ARRAY_SIZE(dev_priv->gmbus); pin++) {
+ if (!intel_gmbus_is_valid_pin(dev_priv, pin))
+ continue;
+
+ bus = &dev_priv->gmbus[pin];
+
+ bus->adapter.owner = THIS_MODULE;
+ bus->adapter.class = I2C_CLASS_DDC;
+ snprintf(bus->adapter.name,
+ sizeof(bus->adapter.name),
+ "i915 gmbus %s",
+ get_gmbus_pin(dev_priv, pin)->name);
+
+ bus->adapter.dev.parent = &pdev->dev;
+ bus->dev_priv = dev_priv;
+
+ 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(dev_priv))
+ bus->force_bit = 1;
+
+ intel_gpio_setup(bus, pin);
+
+ ret = i2c_add_adapter(&bus->adapter);
+ if (ret)
+ goto err;
+ }
+
+ intel_i2c_reset(dev_priv);
+
+ return 0;
+
+err:
+ while (pin--) {
+ if (!intel_gmbus_is_valid_pin(dev_priv, pin))
+ continue;
+
+ bus = &dev_priv->gmbus[pin];
+ i2c_del_adapter(&bus->adapter);
+ }
+ return ret;
+}
+
+struct i2c_adapter *intel_gmbus_get_adapter(struct drm_i915_private *dev_priv,
+ unsigned int pin)
+{
+ if (WARN_ON(!intel_gmbus_is_valid_pin(dev_priv, pin)))
+ return NULL;
+
+ return &dev_priv->gmbus[pin].adapter;
+}
+
+void intel_gmbus_set_speed(struct i2c_adapter *adapter, int speed)
+{
+ struct intel_gmbus *bus = to_intel_gmbus(adapter);
+
+ bus->reg0 = (bus->reg0 & ~(0x3 << 8)) | speed;
+}
+
+void intel_gmbus_force_bit(struct i2c_adapter *adapter, bool force_bit)
+{
+ struct intel_gmbus *bus = to_intel_gmbus(adapter);
+ struct drm_i915_private *dev_priv = bus->dev_priv;
+
+ mutex_lock(&dev_priv->gmbus_mutex);
+
+ bus->force_bit += force_bit ? 1 : -1;
+ DRM_DEBUG_KMS("%sabling bit-banging on %s. force bit now %d\n",
+ force_bit ? "en" : "dis", adapter->name,
+ bus->force_bit);
+
+ mutex_unlock(&dev_priv->gmbus_mutex);
+}
+
+void intel_teardown_gmbus(struct drm_i915_private *dev_priv)
+{
+ struct intel_gmbus *bus;
+ unsigned int pin;
+
+ for (pin = 0; pin < ARRAY_SIZE(dev_priv->gmbus); pin++) {
+ if (!intel_gmbus_is_valid_pin(dev_priv, pin))
+ continue;
+
+ bus = &dev_priv->gmbus[pin];
+ i2c_del_adapter(&bus->adapter);
+ }
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-25 02:11:43 +0000