mpc85xx: add SPI kernel loader for TP-Link TL-WDR4900 v1

Similar to the lzma-loader on our MIPS targets, the spi-loader acts as
a second-stage loader that will then load and start the actual kernel.
As the TL-WDR4900 uses SPI-NOR and the P1010 family does not have support
for memory mapping of this type of flash, this loader needs to contain a
basic driver for the FSL ESPI controller.

Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>
(cherry picked from commit a296055b82fbb20457273492069ce9d62009e2a1)

1 files changed, 43 insertions, 0 deletions

diff --git a/target/linux/mpc85xx/image/spi-loader/include/spi.h b/target/linux/mpc85xx/image/spi-loader/include/spi.h
new file mode 100644
index 0000000000..98e799ccaf
--- /dev/null
+++ b/target/linux/mpc85xx/image/spi-loader/include/spi.h
@@ -0,0 +1,43 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Common SPI Interface: Controller-specific definitions
+ *
+ * Copyright (c) 2022 Matthias Schiffer <mschiffer@universe-factory.net>
+ *
+ * Based on U-boot's spi.h:
+ *
+ * (C) Copyright 2001
+ * Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com.
+ */
+
+#pragma once
+
+#include <types.h>
+
+/* SPI mode flags */
+#define SPI_CPHA	BIT(0)	/* clock phase (1 = SPI_CLOCK_PHASE_SECOND) */
+#define SPI_CPOL	BIT(1)	/* clock polarity (1 = SPI_POLARITY_HIGH) */
+#define SPI_MODE_0	(0|0)			/* (original MicroWire) */
+#define SPI_MODE_1	(0|SPI_CPHA)
+#define SPI_MODE_2	(SPI_CPOL|0)
+#define SPI_MODE_3	(SPI_CPOL|SPI_CPHA)
+
+struct spi_transfer {
+	const void *tx_buf;
+	void *rx_buf;
+	size_t len;
+};
+
+static inline size_t spi_message_len(const struct spi_transfer *msg, int n) {
+	size_t total = 0;
+	for (int i = 0; i < n; i++) {
+		total += msg[i].len;
+	}
+	return total;
+}
+
+int spi_init(unsigned int cs, unsigned int max_hz, unsigned int mode);
+int spi_claim_bus(void);
+void spi_release_bus(void);
+int spi_xfer(const struct spi_transfer *msg, int n);
+size_t spi_max_xfer(void);