diff options
Diffstat (limited to 'src/soc/amd/stoneyridge/i2c.c')
| -rw-r--r-- | src/soc/amd/stoneyridge/i2c.c | 99 |
1 files changed, 99 insertions, 0 deletions
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 <device/mmio.h> #include <arch/acpi.h> #include <console/console.h> +#include <delay.h> #include <drivers/i2c/designware/dw_i2c.h> +#include <amdblocks/acpimmio.h> #include <soc/iomap.h> #include <soc/pci_devs.h> #include <soc/southbridge.h> +#include <soc/i2c.h> #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]); +} |