Hi Simon,
On Mon, Nov 25, 2019 at 12:12 PM Simon Glass sjg@chromium.org wrote:
Add a driver for the Apollo Lake UART. It uses the standard ns16550 device but also sets up the input clock with LPSS and supports configuration via of-platdata.
Signed-off-by: Simon Glass sjg@chromium.org
Changes in v5: None Changes in v4:
- Add an extra comment to apl_uart_init()
- Tidy up header guards
- apollolake -> Apollo Lake
Changes in v3:
- Use the LPSS code from a separate file
Changes in v2: None
arch/x86/cpu/apollolake/Makefile | 1 + arch/x86/cpu/apollolake/uart.c | 141 ++++++++++++++++++++ arch/x86/include/asm/arch-apollolake/uart.h | 20 +++ 3 files changed, 162 insertions(+) create mode 100644 arch/x86/cpu/apollolake/uart.c create mode 100644 arch/x86/include/asm/arch-apollolake/uart.h
diff --git a/arch/x86/cpu/apollolake/Makefile b/arch/x86/cpu/apollolake/Makefile index 5e136b6515..fdda748ea3 100644 --- a/arch/x86/cpu/apollolake/Makefile +++ b/arch/x86/cpu/apollolake/Makefile @@ -3,3 +3,4 @@ # Copyright 2019 Google LLC
obj-y += pmc.o +obj-y += uart.o diff --git a/arch/x86/cpu/apollolake/uart.c b/arch/x86/cpu/apollolake/uart.c new file mode 100644 index 0000000000..1dc4d33e52 --- /dev/null +++ b/arch/x86/cpu/apollolake/uart.c @@ -0,0 +1,141 @@ +// 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 <ns16550.h> +#include <spl.h> +#include <asm/io.h> +#include <asm/pci.h> +#include <asm/lpss.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 ns16550_platdata.
- 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 ofdata_to_platdata routine.
- */
+static int apl_ns16550_probe(struct udevice *dev) +{
struct ns16550_platdata *plat = dev_get_platdata(dev);if (!CONFIG_IS_ENABLED(PCI))apl_uart_init(plat->bdf, plat->base);return ns16550_serial_probe(dev);+}
+static int apl_ns16550_ofdata_to_platdata(struct udevice *dev) +{
struct ns16550_platdata *plat;+#if CONFIG_IS_ENABLED(OF_PLATDATA)
struct dtd_intel_apl_ns16550 *dtplat = dev_get_platdata(dev);/** Convert our platdata to the ns16550's platdata, so we can just use* that driver*/plat = malloc(sizeof(*plat));if (!plat)return -ENOMEM;plat->base = dtplat->early_regs[0];plat->reg_width = 1;plat->reg_shift = dtplat->reg_shift;plat->reg_offset = 0;plat->clock = dtplat->clock_frequency;plat->fcr = UART_FCR_DEFVAL;plat->bdf = pci_ofplat_get_devfn(dtplat->reg[0]);dev->platdata = plat;+#else
int ret;ret = ns16550_serial_ofdata_to_platdata(dev);if (ret)return ret;if (!CONFIG_IS_ENABLED(OF_TRANSLATE)) {/** Without address translation we cannot get correct PCI* address, so just read the BAR manually.*/
Is this a bug in the DM PCI codes?
plat = dev_get_platdata(dev);plat->base = dm_pci_read_bar32(dev, 0);}+#endif /* OF_PLATDATA */
return 0;+}
+static const struct udevice_id apl_ns16550_serial_ids[] = {
{ .compatible = "intel,apl-ns16550" },{ },+};
+U_BOOT_DRIVER(apl_ns16550) = {
.name = "intel_apl_ns16550",.id = UCLASS_SERIAL,.of_match = apl_ns16550_serial_ids,.platdata_auto_alloc_size = sizeof(struct ns16550_platdata),.priv_auto_alloc_size = sizeof(struct NS16550),.ops = &ns16550_serial_ops,.ofdata_to_platdata = apl_ns16550_ofdata_to_platdata,.probe = apl_ns16550_probe,+}; diff --git a/arch/x86/include/asm/arch-apollolake/uart.h b/arch/x86/include/asm/arch-apollolake/uart.h new file mode 100644 index 0000000000..71006ccc74 --- /dev/null +++ b/arch/x86/include/asm/arch-apollolake/uart.h @@ -0,0 +1,20 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/*
- Copyright 2019 Google LLC
- */
+#ifndef _ASM_ARCH_UART_H +#define _ASM_ARCH_UART_H
+/**
- apl_uart_init() - Set up the APL UART device and clock
- This enables the PCI device, sets up the MMIO region and turns on the clock
- using LPSS.
- The UART won't actually work unless the GPIO settings are correct and the
- signals actually exit the SoC. See init_for_uart() for that.
Where is init_for_uart()?
- */
+int apl_uart_init(pci_dev_t bdf, ulong base);
+#endif
Regards, Bin