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