From: Philip Oberfichtner Date: Fri, 2 Aug 2024 09:25:39 +0000 (+0200) Subject: net: dwc_eth_qos: Add glue driver for Intel MAC X-Git-Url: http://git.dujemihanovic.xyz/%22http:/www.sics.se/static/git-logo.png?a=commitdiff_plain;h=49d8fe07f997439171387e9dba4e4561e7846d90;p=u-boot.git net: dwc_eth_qos: Add glue driver for Intel MAC Add dwc_eth_qos glue driver for the Intel Elkhart-Lake SOC. Signed-off-by: Philip Oberfichtner --- diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig index 69ae7c0750..6ed325517c 100644 --- a/drivers/net/Kconfig +++ b/drivers/net/Kconfig @@ -243,6 +243,13 @@ config DWC_ETH_QOS_IMX The Synopsys Designware Ethernet QOS IP block with the specific configuration used in IMX soc. +config DWC_ETH_QOS_INTEL + bool "Synopsys DWC Ethernet QOS device support for Intel" + depends on DWC_ETH_QOS + help + The Synopsys Designware Ethernet QOS IP block with the specific + configuration used in the Intel Elkhart-Lake soc. + config DWC_ETH_QOS_ROCKCHIP bool "Synopsys DWC Ethernet QOS device support for Rockchip SoCs" depends on DWC_ETH_QOS diff --git a/drivers/net/Makefile b/drivers/net/Makefile index 425dd721f9..4946a63f80 100644 --- a/drivers/net/Makefile +++ b/drivers/net/Makefile @@ -20,6 +20,7 @@ obj-$(CONFIG_DRIVER_DM9000) += dm9000x.o obj-$(CONFIG_DSA_SANDBOX) += dsa_sandbox.o obj-$(CONFIG_DWC_ETH_QOS) += dwc_eth_qos.o obj-$(CONFIG_DWC_ETH_QOS_IMX) += dwc_eth_qos_imx.o +obj-$(CONFIG_DWC_ETH_QOS_INTEL) += dwc_eth_qos_intel.o obj-$(CONFIG_DWC_ETH_QOS_ROCKCHIP) += dwc_eth_qos_rockchip.o obj-$(CONFIG_DWC_ETH_QOS_QCOM) += dwc_eth_qos_qcom.o obj-$(CONFIG_DWC_ETH_XGMAC) += dwc_eth_xgmac.o diff --git a/drivers/net/dwc_eth_qos.c b/drivers/net/dwc_eth_qos.c index f6cec32021..3415c418a9 100644 --- a/drivers/net/dwc_eth_qos.c +++ b/drivers/net/dwc_eth_qos.c @@ -1434,6 +1434,18 @@ int eqos_get_base_addr_dt(struct udevice *dev) return eqos_get_base_addr_common(dev, addr); } +int eqos_get_base_addr_pci(struct udevice *dev) +{ + fdt_addr_t addr; + void *paddr; + + paddr = dm_pci_map_bar(dev, PCI_BASE_ADDRESS_0, 0, 0, PCI_REGION_TYPE, + PCI_REGION_MEM); + addr = paddr ? (fdt_addr_t)paddr : FDT_ADDR_T_NONE; + + return eqos_get_base_addr_common(dev, addr); +} + static int eqos_probe(struct udevice *dev) { struct eqos_priv *eqos = dev_get_priv(dev); diff --git a/drivers/net/dwc_eth_qos.h b/drivers/net/dwc_eth_qos.h index b37d3d2f5d..ce57e22a81 100644 --- a/drivers/net/dwc_eth_qos.h +++ b/drivers/net/dwc_eth_qos.h @@ -290,6 +290,7 @@ void eqos_flush_desc_generic(void *desc); void eqos_inval_buffer_generic(void *buf, size_t size); void eqos_flush_buffer_generic(void *buf, size_t size); int eqos_get_base_addr_dt(struct udevice *dev); +int eqos_get_base_addr_pci(struct udevice *dev); int eqos_null_ops(struct udevice *dev); void *eqos_get_driver_data(struct udevice *dev); diff --git a/drivers/net/dwc_eth_qos_intel.c b/drivers/net/dwc_eth_qos_intel.c new file mode 100644 index 0000000000..a2c6825732 --- /dev/null +++ b/drivers/net/dwc_eth_qos_intel.c @@ -0,0 +1,449 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2023-2024 DENX Software Engineering GmbH + * Philip Oberfichtner + * + * Based on linux v6.6.39, especially drivers/net/ethernet/stmicro/stmmac + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +#include "dwc_eth_qos.h" +#include "dwc_eth_qos_intel.h" + +static struct pci_device_id intel_pci_ids[] = { + { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_EHL_RGMII1G) }, + { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_EHL_SGMII1) }, + { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_EHL_SGMII2G5) }, + { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_EHL_PSE0_RGMII1G) }, + { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_EHL_PSE0_SGMII1G) }, + { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_EHL_PSE0_SGMII2G5) }, + { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_EHL_PSE1_RGMII1G) }, + { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_EHL_PSE1_SGMII1G) }, + { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_EHL_PSE1_SGMII2G5) }, + {} +}; + +static int pci_config(struct udevice *dev) +{ + u32 val; + + /* Try to enable I/O accesses and bus-mastering */ + dm_pci_read_config32(dev, PCI_COMMAND, &val); + val |= PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER; + dm_pci_write_config32(dev, PCI_COMMAND, val); + + /* Make sure it worked */ + dm_pci_read_config32(dev, PCI_COMMAND, &val); + if (!(val & PCI_COMMAND_MEMORY)) { + dev_err(dev, "%s: Can't enable I/O memory\n", __func__); + return -ENOSPC; + } + + if (!(val & PCI_COMMAND_MASTER)) { + dev_err(dev, "%s: Can't enable bus-mastering\n", __func__); + return -EPERM; + } + + return 0; +} + +static void limit_fifo_size(struct udevice *dev) +{ + /* + * As described in Intel Erratum EHL22, Document Number: 636674-2.1, + * the PSE GbE Controllers advertise a wrong RX and TX fifo size. + * Software should limit this value to 64KB. + */ + struct eqos_priv *eqos = dev_get_priv(dev); + + eqos->tx_fifo_sz = 0x8000; + eqos->rx_fifo_sz = 0x8000; +} + +static int serdes_status_poll(struct udevice *dev, + unsigned char phyaddr, unsigned char phyreg, + unsigned short mask, unsigned short val) +{ + struct eqos_priv *eqos = dev_get_priv(dev); + unsigned int retries = 10; + unsigned short val_rd; + + do { + miiphy_read(eqos->mii->name, phyaddr, phyreg, &val_rd); + if ((val_rd & mask) == (val & mask)) + return 0; + udelay(POLL_DELAY_US); + } while (--retries); + + return -ETIMEDOUT; +} + + /* Returns -ve if MAC is unknown and 0 on success */ +static int mac_check_pse(const struct udevice *dev, bool *is_pse) +{ + struct pci_child_plat *plat = dev_get_parent_plat(dev); + + if (!plat || plat->vendor != PCI_VENDOR_ID_INTEL) + return -ENXIO; + + switch (plat->device) { + case PCI_DEVICE_ID_INTEL_EHL_PSE0_RGMII1G: + case PCI_DEVICE_ID_INTEL_EHL_PSE1_RGMII1G: + case PCI_DEVICE_ID_INTEL_EHL_PSE0_SGMII1G: + case PCI_DEVICE_ID_INTEL_EHL_PSE1_SGMII1G: + case PCI_DEVICE_ID_INTEL_EHL_PSE0_SGMII2G5: + case PCI_DEVICE_ID_INTEL_EHL_PSE1_SGMII2G5: + *is_pse = 1; + return 0; + + case PCI_DEVICE_ID_INTEL_EHL_RGMII1G: + case PCI_DEVICE_ID_INTEL_EHL_SGMII1: + case PCI_DEVICE_ID_INTEL_EHL_SGMII2G5: + *is_pse = 0; + return 0; + }; + + return -ENXIO; +} + +/* Check if we're in 2G5 mode */ +static bool serdes_link_mode_2500(struct udevice *dev) +{ + const unsigned char phyad = INTEL_MGBE_ADHOC_ADDR; + struct eqos_priv *eqos = dev_get_priv(dev); + unsigned short data; + + miiphy_read(eqos->mii->name, phyad, SERDES_GCR, &data); + if (FIELD_GET(SERDES_LINK_MODE_MASK, data) == SERDES_LINK_MODE_2G5) + return true; + + return false; +} + +static int serdes_powerup(struct udevice *dev) +{ + /* Based on linux/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c */ + + const unsigned char phyad = INTEL_MGBE_ADHOC_ADDR; + struct eqos_priv *eqos = dev_get_priv(dev); + unsigned short data; + int ret; + bool is_pse; + + /* Set the serdes rate and the PCLK rate */ + miiphy_read(eqos->mii->name, phyad, SERDES_GCR0, &data); + + data &= ~SERDES_RATE_MASK; + data &= ~SERDES_PCLK_MASK; + + if (serdes_link_mode_2500(dev)) + data |= SERDES_RATE_PCIE_GEN2 << SERDES_RATE_PCIE_SHIFT | + SERDES_PCLK_37p5MHZ << SERDES_PCLK_SHIFT; + else + data |= SERDES_RATE_PCIE_GEN1 << SERDES_RATE_PCIE_SHIFT | + SERDES_PCLK_70MHZ << SERDES_PCLK_SHIFT; + + miiphy_write(eqos->mii->name, phyad, SERDES_GCR0, data); + + /* assert clk_req */ + miiphy_read(eqos->mii->name, phyad, SERDES_GCR0, &data); + data |= SERDES_PLL_CLK; + miiphy_write(eqos->mii->name, phyad, SERDES_GCR0, data); + + /* check for clk_ack assertion */ + ret = serdes_status_poll(dev, phyad, SERDES_GSR0, + SERDES_PLL_CLK, SERDES_PLL_CLK); + + if (ret) { + dev_err(dev, "Serdes PLL clk request timeout\n"); + return ret; + } + + /* assert lane reset*/ + miiphy_read(eqos->mii->name, phyad, SERDES_GCR0, &data); + data |= SERDES_RST; + miiphy_write(eqos->mii->name, phyad, SERDES_GCR0, data); + + /* check for assert lane reset reflection */ + ret = serdes_status_poll(dev, phyad, SERDES_GSR0, + SERDES_RST, SERDES_RST); + + if (ret) { + dev_err(dev, "Serdes assert lane reset timeout\n"); + return ret; + } + + /* move power state to P0 */ + miiphy_read(eqos->mii->name, phyad, SERDES_GCR0, &data); + data &= ~SERDES_PWR_ST_MASK; + data |= SERDES_PWR_ST_P0 << SERDES_PWR_ST_SHIFT; + miiphy_write(eqos->mii->name, phyad, SERDES_GCR0, data); + + /* Check for P0 state */ + ret = serdes_status_poll(dev, phyad, SERDES_GSR0, + SERDES_PWR_ST_MASK, + SERDES_PWR_ST_P0 << SERDES_PWR_ST_SHIFT); + + if (ret) { + dev_err(dev, "Serdes power state P0 timeout.\n"); + return ret; + } + + /* PSE only - ungate SGMII PHY Rx Clock*/ + ret = mac_check_pse(dev, &is_pse); + if (ret) { + dev_err(dev, "Failed to determine MAC type.\n"); + return ret; + } + + if (is_pse) { + miiphy_read(eqos->mii->name, phyad, SERDES_GCR0, &data); + data |= SERDES_PHY_RX_CLK; + miiphy_write(eqos->mii->name, phyad, SERDES_GCR0, data); + } + + return 0; +} + +static int xpcs_access(struct udevice *dev, int reg, int v) +{ + /* + * Common read/write helper function + * + * It may seem a bit odd at a first glance that we use bus->read() + * directly insetad of one of the wrapper functions. But: + * + * (1) phy_read() can't be used because we do not access an acutal PHY, + * but a MAC-internal submodule. + * + * (2) miiphy_read() can't be used because it assumes MDIO_DEVAD_NONE. + */ + + int port = INTEL_MGBE_XPCS_ADDR; + int devad = 0x1f; + u16 val; + struct eqos_priv *eqos; + struct mii_dev *bus; + + eqos = dev_get_priv(dev); + bus = eqos->mii; + + if (v < 0) + return bus->read(bus, port, devad, reg); + + val = v; + return bus->write(bus, port, devad, reg, val); +} + +static int xpcs_read(struct udevice *dev, int reg) +{ + return xpcs_access(dev, reg, -1); +} + +static int xpcs_write(struct udevice *dev, int reg, u16 val) +{ + return xpcs_access(dev, reg, val); +} + +static int xpcs_clr_bits(struct udevice *dev, int reg, u16 bits) +{ + int ret; + + ret = xpcs_read(dev, reg); + if (ret < 0) + return ret; + + ret &= ~bits; + + return xpcs_write(dev, reg, ret); +} + +static int xpcs_set_bits(struct udevice *dev, int reg, u16 bits) +{ + int ret; + + ret = xpcs_read(dev, reg); + if (ret < 0) + return ret; + + ret |= bits; + + return xpcs_write(dev, reg, ret); +} + +static int xpcs_init(struct udevice *dev) +{ + /* Based on linux/drivers/net/pcs/pcs-xpcs.c */ + struct eqos_priv *eqos = dev_get_priv(dev); + phy_interface_t interface = eqos->config->interface(dev); + + if (interface != PHY_INTERFACE_MODE_SGMII) + return 0; + + if (xpcs_clr_bits(dev, VR_MII_MMD_CTRL, XPCS_AN_CL37_EN) || + xpcs_set_bits(dev, VR_MII_AN_CTRL, XPCS_MODE_SGMII) || + xpcs_set_bits(dev, VR_MII_DIG_CTRL1, XPCS_MAC_AUTO_SW) || + xpcs_set_bits(dev, VR_MII_MMD_CTRL, XPCS_AN_CL37_EN)) + return -EIO; + + return 0; +} + +static int eqos_probe_ressources_intel(struct udevice *dev) +{ + int ret; + + ret = eqos_get_base_addr_pci(dev); + if (ret) { + dev_err(dev, "eqos_get_base_addr_pci failed: %d\n", ret); + return ret; + } + + limit_fifo_size(dev); + + ret = pci_config(dev); + if (ret) { + dev_err(dev, "pci_config failed: %d\n", ret); + return ret; + } + + return 0; +} + +struct eqos_config eqos_intel_config; + +/* + * overwrite __weak function from eqos_intel.c + * + * For PCI devices the devcie tree is optional. Choose driver data based on PCI + * IDs instead. + */ +void *eqos_get_driver_data(struct udevice *dev) +{ + const struct pci_device_id *id; + const struct pci_child_plat *plat; + + plat = dev_get_parent_plat(dev); + + if (!plat) + return NULL; + + /* last intel_pci_ids element is zero initialized */ + for (id = intel_pci_ids; id->vendor != 0; id++) { + if (id->vendor == plat->vendor && id->device == plat->device) + return &eqos_intel_config; + } + + return NULL; +} + +static int eqos_start_resets_intel(struct udevice *dev) +{ + int ret; + + ret = xpcs_init(dev); + if (ret) { + dev_err(dev, "xpcs init failed.\n"); + return ret; + } + + ret = serdes_powerup(dev); + if (ret) { + dev_err(dev, "Failed to power up serdes.\n"); + return ret; + } + + return 0; +} + +static ulong eqos_get_tick_clk_rate_intel(struct udevice *dev) +{ + return 0; +} + +static int eqos_get_enetaddr_intel(struct udevice *dev) +{ + /* Assume MAC address is programmed by previous boot stage */ + struct eth_pdata *plat = dev_get_plat(dev); + struct eqos_priv *eqos = dev_get_priv(dev); + u8 *lo = (u8 *)&eqos->mac_regs->address0_low; + u8 *hi = (u8 *)&eqos->mac_regs->address0_high; + + plat->enetaddr[0] = lo[0]; + plat->enetaddr[1] = lo[1]; + plat->enetaddr[2] = lo[2]; + plat->enetaddr[3] = lo[3]; + plat->enetaddr[4] = hi[0]; + plat->enetaddr[5] = hi[1]; + + return 0; +} + +static phy_interface_t eqos_get_interface_intel(const struct udevice *dev) +{ + struct pci_child_plat *plat = dev_get_parent_plat(dev); + + if (!plat || plat->vendor != PCI_VENDOR_ID_INTEL) + return PHY_INTERFACE_MODE_NA; + + switch (plat->device) { + /* The GbE Host Controller has no RGMII interface */ + case PCI_DEVICE_ID_INTEL_EHL_RGMII1G: + return PHY_INTERFACE_MODE_NA; + + case PCI_DEVICE_ID_INTEL_EHL_PSE0_RGMII1G: + case PCI_DEVICE_ID_INTEL_EHL_PSE1_RGMII1G: + return PHY_INTERFACE_MODE_RGMII; + + /* Host SGMII and Host SGMII2G5 share the same device id */ + case PCI_DEVICE_ID_INTEL_EHL_SGMII1: + case PCI_DEVICE_ID_INTEL_EHL_SGMII2G5: + case PCI_DEVICE_ID_INTEL_EHL_PSE0_SGMII2G5: + case PCI_DEVICE_ID_INTEL_EHL_PSE0_SGMII1G: + case PCI_DEVICE_ID_INTEL_EHL_PSE1_SGMII1G: + case PCI_DEVICE_ID_INTEL_EHL_PSE1_SGMII2G5: + return PHY_INTERFACE_MODE_SGMII; + }; + + return PHY_INTERFACE_MODE_NA; +} + +static struct eqos_ops eqos_intel_ops = { + .eqos_inval_desc = eqos_inval_desc_generic, + .eqos_flush_desc = eqos_flush_desc_generic, + .eqos_inval_buffer = eqos_inval_buffer_generic, + .eqos_flush_buffer = eqos_flush_buffer_generic, + .eqos_probe_resources = eqos_probe_ressources_intel, + .eqos_remove_resources = eqos_null_ops, + .eqos_stop_resets = eqos_null_ops, + .eqos_start_resets = eqos_start_resets_intel, + .eqos_stop_clks = eqos_null_ops, + .eqos_start_clks = eqos_null_ops, + .eqos_calibrate_pads = eqos_null_ops, + .eqos_disable_calibration = eqos_null_ops, + .eqos_set_tx_clk_speed = eqos_null_ops, + .eqos_get_enetaddr = eqos_get_enetaddr_intel, + .eqos_get_tick_clk_rate = eqos_get_tick_clk_rate_intel, +}; + +struct eqos_config eqos_intel_config = { + .reg_access_always_ok = false, + .mdio_wait = 10, + .swr_wait = 50, + .config_mac = EQOS_MAC_RXQ_CTRL0_RXQ0EN_ENABLED_DCB, + .config_mac_mdio = EQOS_MAC_MDIO_ADDRESS_CR_250_300, + .axi_bus_width = EQOS_AXI_WIDTH_64, + .interface = eqos_get_interface_intel, + .ops = &eqos_intel_ops +}; + +extern U_BOOT_DRIVER(eth_eqos); +U_BOOT_PCI_DEVICE(eth_eqos, intel_pci_ids); diff --git a/drivers/net/dwc_eth_qos_intel.h b/drivers/net/dwc_eth_qos_intel.h new file mode 100644 index 0000000000..847c75ede5 --- /dev/null +++ b/drivers/net/dwc_eth_qos_intel.h @@ -0,0 +1,57 @@ +/* SPDX-License-Identifier: GPL-2.0 + * + * Copyright (c) 2023-2024 DENX Software Engineering GmbH + * Philip Oberfichtner + * + * This header is based on linux v6.6.39, + * + * drivers/net/pcs/pcs-xpcs.h + * drivers/net/ethernet/stmicro/stmmac/dwmac-intel.h, + * + * Copyright (c) 2020 Synopsys, Inc. and/or its affiliates + * Copyright (c) 2020 Intel Corporation + */ + +#ifndef __DWMAC_INTEL_H__ +#define __DWMAC_INTEL_H__ + +#define POLL_DELAY_US 8 + +/* SERDES Register */ +#define SERDES_GCR 0x0 /* Global Conguration */ +#define SERDES_GSR0 0x5 /* Global Status Reg0 */ +#define SERDES_GCR0 0xb /* Global Configuration Reg0 */ + +/* SERDES defines */ +#define SERDES_PLL_CLK BIT(0) /* PLL clk valid signal */ +#define SERDES_PHY_RX_CLK BIT(1) /* PSE SGMII PHY rx clk */ +#define SERDES_RST BIT(2) /* Serdes Reset */ +#define SERDES_PWR_ST_MASK GENMASK(6, 4) /* Serdes Power state*/ +#define SERDES_RATE_MASK GENMASK(9, 8) +#define SERDES_PCLK_MASK GENMASK(14, 12) /* PCLK rate to PHY */ +#define SERDES_LINK_MODE_MASK GENMASK(2, 1) +#define SERDES_PWR_ST_SHIFT 4 +#define SERDES_PWR_ST_P0 0x0 +#define SERDES_PWR_ST_P3 0x3 +#define SERDES_LINK_MODE_2G5 0x3 +#define SERSED_LINK_MODE_1G 0x2 +#define SERDES_PCLK_37p5MHZ 0x0 +#define SERDES_PCLK_70MHZ 0x1 +#define SERDES_RATE_PCIE_GEN1 0x0 +#define SERDES_RATE_PCIE_GEN2 0x1 +#define SERDES_RATE_PCIE_SHIFT 8 +#define SERDES_PCLK_SHIFT 12 + +#define INTEL_MGBE_ADHOC_ADDR 0x15 +#define INTEL_MGBE_XPCS_ADDR 0x16 + +/* XPCS defines */ +#define XPCS_MODE_SGMII BIT(2) +#define XPCS_MAC_AUTO_SW BIT(9) +#define XPCS_AN_CL37_EN BIT(12) + +#define VR_MII_MMD_CTRL 0x0000 +#define VR_MII_DIG_CTRL1 0x8000 +#define VR_MII_AN_CTRL 0x8001 + +#endif /* __DWMAC_INTEL_H__ */ diff --git a/include/pci_ids.h b/include/pci_ids.h index 191d277bc8..a8939b105f 100644 --- a/include/pci_ids.h +++ b/include/pci_ids.h @@ -2600,6 +2600,15 @@ #define PCI_DEVICE_ID_DCI_PCCOM2 0x0004 #define PCI_VENDOR_ID_INTEL 0x8086 +#define PCI_DEVICE_ID_INTEL_EHL_RGMII1G 0x4b30 +#define PCI_DEVICE_ID_INTEL_EHL_SGMII1 0x4b31 +#define PCI_DEVICE_ID_INTEL_EHL_SGMII2G5 0x4b32 +#define PCI_DEVICE_ID_INTEL_EHL_PSE0_RGMII1G 0x4ba0 +#define PCI_DEVICE_ID_INTEL_EHL_PSE0_SGMII1G 0x4ba1 +#define PCI_DEVICE_ID_INTEL_EHL_PSE0_SGMII2G5 0x4ba2 +#define PCI_DEVICE_ID_INTEL_EHL_PSE1_RGMII1G 0x4bb0 +#define PCI_DEVICE_ID_INTEL_EHL_PSE1_SGMII1G 0x4bb1 +#define PCI_DEVICE_ID_INTEL_EHL_PSE1_SGMII2G5 0x4bb2 #define PCI_DEVICE_ID_INTEL_EESSC 0x0008 #define PCI_DEVICE_ID_INTEL_SNB_IMC 0x0100 #define PCI_DEVICE_ID_INTEL_IVB_IMC 0x0154