diff options
Diffstat (limited to 'roms/u-boot/arch/x86/cpu/apollolake/uart.c')
| -rw-r--r-- | roms/u-boot/arch/x86/cpu/apollolake/uart.c | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/roms/u-boot/arch/x86/cpu/apollolake/uart.c b/roms/u-boot/arch/x86/cpu/apollolake/uart.c new file mode 100644 index 000000000..876fa592b --- /dev/null +++ b/roms/u-boot/arch/x86/cpu/apollolake/uart.c @@ -0,0 +1,142 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Special driver to handle of-platdata + * + * Copyright 2019 Google LLC + * + * Some code from coreboot lpss.c + */ + +#include <common.h> +#include <dm.h> +#include <dt-structs.h> +#include <malloc.h> +#include <ns16550.h> +#include <spl.h> +#include <asm/io.h> +#include <asm/pci.h> +#include <asm/lpss.h> +#include <dm/device-internal.h> +#include <asm/arch/uart.h> + +/* Low-power Subsystem (LPSS) clock register */ +enum { + LPSS_CLOCK_CTL_REG = 0x200, + LPSS_CNT_CLOCK_EN = 1, + LPSS_CNT_CLK_UPDATE = 1U << 31, + LPSS_CLOCK_DIV_N_SHIFT = 16, + LPSS_CLOCK_DIV_N_MASK = 0x7fff << LPSS_CLOCK_DIV_N_SHIFT, + LPSS_CLOCK_DIV_M_SHIFT = 1, + LPSS_CLOCK_DIV_M_MASK = 0x7fff << LPSS_CLOCK_DIV_M_SHIFT, + + /* These set the UART input clock speed */ + LPSS_UART_CLK_M_VAL = 0x25a, + LPSS_UART_CLK_N_VAL = 0x7fff, +}; + +static void lpss_clk_update(void *regs, u32 clk_m_val, u32 clk_n_val) +{ + u32 clk_sel; + + clk_sel = clk_n_val << LPSS_CLOCK_DIV_N_SHIFT | + clk_m_val << LPSS_CLOCK_DIV_M_SHIFT; + clk_sel |= LPSS_CNT_CLK_UPDATE | LPSS_CNT_CLOCK_EN; + + writel(clk_sel, regs + LPSS_CLOCK_CTL_REG); +} + +static void uart_lpss_init(void *regs) +{ + /* Take UART out of reset */ + lpss_reset_release(regs); + + /* Set M and N divisor inputs and enable clock */ + lpss_clk_update(regs, LPSS_UART_CLK_M_VAL, LPSS_UART_CLK_N_VAL); +} + +void apl_uart_init(pci_dev_t bdf, ulong base) +{ + /* Set UART base address */ + pci_x86_write_config(bdf, PCI_BASE_ADDRESS_0, base, PCI_SIZE_32); + + /* Enable memory access and bus master */ + pci_x86_write_config(bdf, PCI_COMMAND, PCI_COMMAND_MEMORY | + PCI_COMMAND_MASTER, PCI_SIZE_32); + + uart_lpss_init((void *)base); +} + +/* + * This driver uses its own compatible string but almost everything else from + * the standard ns16550 driver. This allows us to provide an of-platdata + * implementation, since the platdata produced by of-platdata does not match + * struct apl_ns16550_plat. + * + * When running with of-platdata (generally TPL), the platdata is converted to + * something that ns16550 expects. When running withoutof-platdata (SPL, U-Boot + * proper), we use ns16550's of_to_plat routine. + */ + +static int apl_ns16550_probe(struct udevice *dev) +{ + struct apl_ns16550_plat *plat = dev_get_plat(dev); + + if (!CONFIG_IS_ENABLED(PCI)) + apl_uart_init(plat->ns16550.bdf, plat->ns16550.base); + + return ns16550_serial_probe(dev); +} + +static int apl_ns16550_of_to_plat(struct udevice *dev) +{ +#if CONFIG_IS_ENABLED(OF_PLATDATA) + struct dtd_intel_apl_ns16550 *dtplat; + struct apl_ns16550_plat *plat = dev_get_plat(dev); + struct ns16550_plat ns; + + /* + * The device's plat uses struct apl_ns16550_plat which starts with the + * dtd struct, but the ns16550 driver expects it to be struct ns16550. + * Set up what that driver expects. Note that this means that the values + * cannot be read in this driver when using of-platdata. + * + * TODO(sjg@chromium.org): Consider having a separate plat pointer for + * of-platdata so that it is not necessary to overwrite this. + */ + dtplat = &plat->dtplat; + ns.base = dtplat->early_regs[0]; + ns.reg_width = 1; + ns.reg_shift = dtplat->reg_shift; + ns.reg_offset = 0; + ns.clock = dtplat->clock_frequency; + ns.fcr = UART_FCR_DEFVAL; + ns.bdf = pci_ofplat_get_devfn(dtplat->reg[0]); + memcpy(plat, &ns, sizeof(ns)); +#else + int ret; + + ret = ns16550_serial_of_to_plat(dev); + if (ret) + return ret; +#endif /* OF_PLATDATA */ + + return 0; +} + +#if !CONFIG_IS_ENABLED(OF_PLATDATA) +static const struct udevice_id apl_ns16550_serial_ids[] = { + { .compatible = "intel,apl-ns16550" }, + { }, +}; +#endif + +U_BOOT_DRIVER(intel_apl_ns16550) = { + .name = "intel_apl_ns16550", + .id = UCLASS_SERIAL, + .of_match = of_match_ptr(apl_ns16550_serial_ids), + .plat_auto = sizeof(struct apl_ns16550_plat), + .priv_auto = sizeof(struct ns16550), + .ops = &ns16550_serial_ops, + .of_to_plat = apl_ns16550_of_to_plat, + .probe = apl_ns16550_probe, +}; |