x86: spi: Add helper functions for Intel Fast SPI

Most x86 CPUs use a mechanism where the SPI flash is mapped into the very
top of 32-bit address space, so that it can be executed in place and read
simply by copying from memory. For an 8MB ROM the mapping starts at
0xff800000.

However some recent Intel CPUs do not use a simple 1:1 memory map. Instead
the map starts at a different address and not all of the SPI flash is
accessible through the map. This 'Fast SPI' feature requires that U-Boot
check the location of the map. It is also possible (optionally) to read
from the SPI flash using a driver.

Add support for booting from Fast SPI. The memory-mapped version is used
by both TPL and SPL on Apollo Lake.

In respect of a SPI flash driver, the actual SPI driver is ich.c - this
just adds a few helper functions and definitions.

This is used by Apollo Lake.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

4 files changed, 143 insertions, 0 deletions

diff --git a/arch/x86/cpu/intel_common/Makefile b/arch/x86/cpu/intel_common/Makefile
index 07f27c29ec..dfbc29f047 100644
--- a/arch/x86/cpu/intel_common/Makefile
+++ b/arch/x86/cpu/intel_common/Makefile
@@ -9,6 +9,7 @@ obj-$(CONFIG_$(SPL_TPL_)X86_32BIT_INIT) += report_platform.o
 obj-$(CONFIG_$(SPL_TPL_)X86_32BIT_INIT) += mrc.o
 endif
 obj-y += cpu.o
+obj-y += fast_spi.o
 obj-y += lpc.o
 ifndef CONFIG_TARGET_EFI_APP
 obj-$(CONFIG_$(SPL_TPL_)X86_32BIT_INIT) += microcode.o
diff --git a/arch/x86/cpu/intel_common/fast_spi.c b/arch/x86/cpu/intel_common/fast_spi.c
new file mode 100644
index 0000000000..a6e3d0a5bf
--- /dev/null
+++ b/arch/x86/cpu/intel_common/fast_spi.c
@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2019 Google LLC
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <asm/cpu_common.h>
+#include <asm/fast_spi.h>
+#include <asm/pci.h>
+
+/*
+ * Returns bios_start and fills in size of the BIOS region.
+ */
+static ulong fast_spi_get_bios_region(struct fast_spi_regs *regs,
+				      uint *bios_size)
+{
+	ulong bios_start, bios_end;
+
+	/*
+	 * BIOS_BFPREG provides info about BIOS-Flash Primary Region Base and
+	 * Limit. Base and Limit fields are in units of 4K.
+	 */
+	u32 val = readl(&regs->bfp);
+
+	bios_start = (val & SPIBAR_BFPREG_PRB_MASK) << 12;
+	bios_end = (((val & SPIBAR_BFPREG_PRL_MASK) >>
+		     SPIBAR_BFPREG_PRL_SHIFT) + 1) << 12;
+	*bios_size = bios_end - bios_start;
+
+	return bios_start;
+}
+
+int fast_spi_get_bios_mmap(pci_dev_t pdev, ulong *map_basep, uint *map_sizep,
+			   uint *offsetp)
+{
+	struct fast_spi_regs *regs;
+	ulong bar, base, mmio_base;
+
+	/* Special case to find mapping without probing the device */
+	pci_x86_read_config(pdev, PCI_BASE_ADDRESS_0, &bar, PCI_SIZE_32);
+	mmio_base = bar & PCI_BASE_ADDRESS_MEM_MASK;
+	regs = (struct fast_spi_regs *)mmio_base;
+	base = fast_spi_get_bios_region(regs, map_sizep);
+	*map_basep = (u32)-*map_sizep - base;
+	*offsetp = base;
+
+	return 0;
+}
+
+int fast_spi_early_init(pci_dev_t pdev, ulong mmio_base)
+{
+	/* Program Temporary BAR for SPI */
+	pci_x86_write_config(pdev, PCI_BASE_ADDRESS_0,
+			     mmio_base | PCI_BASE_ADDRESS_SPACE_MEMORY,
+			     PCI_SIZE_32);
+
+	/* Enable Bus Master and MMIO Space */
+	pci_x86_clrset_config(pdev, PCI_COMMAND, 0, PCI_COMMAND_MASTER |
+			      PCI_COMMAND_MEMORY, PCI_SIZE_8);
+
+	/*
+	 * Disable the BIOS write protect so write commands are allowed.
+	 * Enable Prefetching and caching.
+	 */
+	pci_x86_clrset_config(pdev, SPIBAR_BIOS_CONTROL,
+			      SPIBAR_BIOS_CONTROL_EISS |
+			      SPIBAR_BIOS_CONTROL_CACHE_DISABLE,
+			      SPIBAR_BIOS_CONTROL_WPD |
+			      SPIBAR_BIOS_CONTROL_PREFETCH_ENABLE, PCI_SIZE_8);
+
+	return 0;
+}
diff --git a/arch/x86/include/asm/fast_spi.h b/arch/x86/include/asm/fast_spi.h
new file mode 100644
index 0000000000..6894298526
--- /dev/null
+++ b/arch/x86/include/asm/fast_spi.h
@@ -0,0 +1,68 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (C) 2017 Intel Corporation.
+ */
+
+#ifndef ASM_FAST_SPI_H
+#define ASM_FAST_SPI_H
+
+/* Register offsets from the MMIO region base (PCI_BASE_ADDRESS_0) */
+struct fast_spi_regs {
+	u32 bfp;
+	u32 hsfsts_ctl;
+	u32 faddr;
+	u32 dlock;
+
+	u32 fdata[0x10];
+
+	u32 fracc;
+	u32 freg[12];
+	u32 fpr[5];
+	u32 gpr0;
+	u32 spare2;
+	u32 sts_ctl;
+	u16 preop;
+	u16 optype;
+	u8 opmenu[8];
+
+	u32 spare3;
+	u32 fdoc;
+	u32 fdod;
+	u32 spare4;
+	u32 afc;
+	u32 vscc[2];
+	u32 ptinx;
+	u32 ptdata;
+};
+check_member(fast_spi_regs, ptdata, 0xd0);
+
+/* Bit definitions for BFPREG (0x00) register */
+#define SPIBAR_BFPREG_PRB_MASK		0x7fff
+#define SPIBAR_BFPREG_PRL_SHIFT		16
+#define SPIBAR_BFPREG_PRL_MASK		(0x7fff << SPIBAR_BFPREG_PRL_SHIFT)
+
+/* PCI configuration registers */
+#define SPIBAR_BIOS_CONTROL			0xdc
+#define SPIBAR_BIOS_CONTROL_WPD			BIT(0)
+#define SPIBAR_BIOS_CONTROL_LOCK_ENABLE		BIT(1)
+#define SPIBAR_BIOS_CONTROL_CACHE_DISABLE	BIT(2)
+#define SPIBAR_BIOS_CONTROL_PREFETCH_ENABLE	BIT(3)
+#define SPIBAR_BIOS_CONTROL_EISS		BIT(5)
+#define SPIBAR_BIOS_CONTROL_BILD		BIT(7)
+
+/**
+ * fast_spi_get_bios_mmap() - Get memory map for SPI flash
+ *
+ * @pdev:	PCI device to use (this is the Fast SPI device)
+ * @map_basep:	Returns base memory address for mapped SPI
+ * @map_sizep:	Returns size of mapped SPI
+ * @offsetp:	Returns start offset of SPI flash where the map works
+ *	correctly (offsets before this are not visible)
+ * @return 0 (always)
+ */
+int fast_spi_get_bios_mmap(pci_dev_t pdev, ulong *map_basep, uint *map_sizep,
+			   uint *offsetp);
+
+int fast_spi_early_init(pci_dev_t pdev, ulong mmio_base);
+
+#endif	/* ASM_FAST_SPI_H */
diff --git a/arch/x86/include/asm/spl.h b/arch/x86/include/asm/spl.h
index 1bef4877eb..cc6cac08f2 100644
--- a/arch/x86/include/asm/spl.h
+++ b/arch/x86/include/asm/spl.h
@@ -11,6 +11,7 @@
 
 enum {
 	BOOT_DEVICE_SPI_MMAP	= 10,
+	BOOT_DEVICE_FAST_SPI,
 	BOOT_DEVICE_CROS_VBOOT,
 };