From f42344a38963cba10604901a6934c7842db42c4d Mon Sep 17 00:00:00 2001 From: Marshall Dawson Date: Thu, 2 May 2019 12:53:00 -0600 Subject: soc/amd/stoneyridge: Move I2C bus clear out of gpio.c Relocate the I2C bus reset code from gpio.c to i2c.c. When it first went in, gpio.c was a natural location due to the nature of the algorithm. This is preparation for moving most of gpio.c to common code. Change-Id: I3b2d8e1b54e7c5929220d763bd99fe01b0636aaa Signed-off-by: Marshall Dawson Reviewed-on: https://review.coreboot.org/c/coreboot/+/32650 Reviewed-by: Martin Roth Reviewed-by: Richard Spiegel Tested-by: build bot (Jenkins) --- src/soc/amd/stoneyridge/i2c.c | 99 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 99 insertions(+) (limited to 'src/soc/amd/stoneyridge/i2c.c') diff --git a/src/soc/amd/stoneyridge/i2c.c b/src/soc/amd/stoneyridge/i2c.c index e99f3509ff..c3e5539e19 100644 --- a/src/soc/amd/stoneyridge/i2c.c +++ b/src/soc/amd/stoneyridge/i2c.c @@ -13,12 +13,16 @@ * GNU General Public License for more details. */ +#include #include #include +#include #include +#include #include #include #include +#include #include "chip.h" #define I2C_BUS_ADDRESS(x) (I2C_BASE_ADDRESS + I2C_DEVICE_SIZE * (x)) @@ -140,3 +144,98 @@ struct device_operations stoneyridge_i2c_mmio_ops = { .acpi_name = i2c_acpi_name, .acpi_fill_ssdt_generator = dw_i2c_acpi_fill_ssdt, }; + +/* + * I2C pins are open drain with external pull up, so in order to bit bang them + * all, SCL pins must become GPIO inputs with no pull, then they need to be + * toggled between input-no-pull and output-low. This table is for the initial + * conversion of all SCL pins to input with no pull. + */ +static const struct soc_amd_gpio i2c_2_gpi[] = { + PAD_GPI(I2C0_SCL_PIN, PULL_NONE), + PAD_GPI(I2C1_SCL_PIN, PULL_NONE), + PAD_GPI(I2C2_SCL_PIN, PULL_NONE), + PAD_GPI(I2C3_SCL_PIN, PULL_NONE), +}; +#define saved_pins_count ARRAY_SIZE(i2c_2_gpi) + +/* + * To program I2C pins without destroying their programming, the registers + * that will be changed need to be saved first. + */ +static void save_i2c_pin_registers(uint8_t gpio, + struct soc_amd_i2c_save *save_table) +{ + uint32_t *gpio_ptr; + + gpio_ptr = (uint32_t *)gpio_get_address(gpio); + save_table->mux_value = iomux_read8(gpio); + save_table->control_value = read32(gpio_ptr); +} + +static void restore_i2c_pin_registers(uint8_t gpio, + struct soc_amd_i2c_save *save_table) +{ + uint32_t *gpio_ptr; + + gpio_ptr = (uint32_t *)gpio_get_address(gpio); + iomux_write8(gpio, save_table->mux_value); + iomux_read8(gpio); + write32(gpio_ptr, save_table->control_value); + read32(gpio_ptr); +} + +/* Slaves to be reset are controlled by devicetree register i2c_scl_reset */ +void sb_reset_i2c_slaves(void) +{ + const struct soc_amd_stoneyridge_config *cfg; + const struct device *dev = pcidev_path_on_root(GNB_DEVFN); + struct soc_amd_i2c_save save_table[saved_pins_count]; + uint8_t i, j, control; + + if (!dev || !dev->chip_info) + return; + cfg = dev->chip_info; + control = cfg->i2c_scl_reset & GPIO_I2C_MASK; + if (control == 0) + return; + + /* Save and reprogram I2C SCL pins */ + for (i = 0; i < saved_pins_count; i++) + save_i2c_pin_registers(i2c_2_gpi[i].gpio, &save_table[i]); + sb_program_gpios(i2c_2_gpi, saved_pins_count); + + /* + * Toggle SCL back and forth 9 times under 100KHz. A single read is + * needed after the writes to force the posted write to complete. + */ + for (j = 0; j < 9; j++) { + if (control & GPIO_I2C0_SCL) + write32((uint32_t *)GPIO_I2C0_ADDRESS, GPIO_SCL_LOW); + if (control & GPIO_I2C1_SCL) + write32((uint32_t *)GPIO_I2C1_ADDRESS, GPIO_SCL_LOW); + if (control & GPIO_I2C2_SCL) + write32((uint32_t *)GPIO_I2C2_ADDRESS, GPIO_SCL_LOW); + if (control & GPIO_I2C3_SCL) + write32((uint32_t *)GPIO_I2C3_ADDRESS, GPIO_SCL_LOW); + + read32((uint32_t *)GPIO_I2C3_ADDRESS); /* Flush posted write */ + udelay(4); /* 4usec gets 85KHz for 1 pin, 70KHz for 4 pins */ + + if (control & GPIO_I2C0_SCL) + write32((uint32_t *)GPIO_I2C0_ADDRESS, GPIO_SCL_HIGH); + if (control & GPIO_I2C1_SCL) + write32((uint32_t *)GPIO_I2C1_ADDRESS, GPIO_SCL_HIGH); + if (control & GPIO_I2C2_SCL) + write32((uint32_t *)GPIO_I2C2_ADDRESS, GPIO_SCL_HIGH); + if (control & GPIO_I2C3_SCL) + write32((uint32_t *)GPIO_I2C3_ADDRESS, GPIO_SCL_HIGH); + + read32((uint32_t *)GPIO_I2C3_ADDRESS); /* Flush posted write */ + udelay(4); + } + + /* Restore I2C pins. */ + for (i = 0; i < saved_pins_count; i++) + restore_i2c_pin_registers(i2c_2_gpi[i].gpio, &save_table[i]); +} -- cgit v1.2.3