dm: sandbox: Add a SPI emulation uclass

U-Boot includes a SPI emulation driver already but it is not explicit, and is hidden in the SPI flash code. Conceptually with sandbox's SPI implementation we have a layer which creates SPI bus transitions and a layer which interprets them, currently only for SPI flash. The latter is actually an emulation, and it should be possible to add more than one emulation - not just SPI flash. Add a SPI emulation uclass so that other emulations can be plugged in to support different types of emulated devices on difference buses/chip selects. Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Jagannadha Sutradharudu Teki <jagannadh.teki@gmail.com>

dm: sandbox: Add a SPI emulation uclass
U-Boot includes a SPI emulation driver already but it is not explicit, and is hidden in the SPI flash code. Conceptually with sandbox's SPI implementation we have a layer which creates SPI bus transitions and a layer which interprets them, currently only for SPI flash. The latter is actually an emulation, and it should be possible to add more than one emulation - not just SPI flash. Add a SPI emulation uclass so that other emulations can be plugged in to support different types of emulated devices on difference buses/chip selects. Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Jagannadha Sutradharudu Teki <jagannadh.teki@gmail.com>
Simon Glass
1 parent d7af6a4851
Showing 4 changed files with 62 additions and 0 deletions Side-by-side Diff
drivers/spi/Makefile
drivers/spi/spi-emul-uclass.c
include/dm/uclass-id.h
include/spi.h
@@ -8,6 +8,7 @@
 # There are many options which enable SPI, so make this library available
 ifdef CONFIG_DM_SPI
 obj-y += spi-uclass.o
+obj-$(CONFIG_SANDBOX) += spi-emul-uclass.o
 else
 obj-y += spi.o
 endif
+/*
+ * Copyright (c) 2014 Google, Inc
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <spi.h>
+#include <spi_flash.h>
+
+UCLASS_DRIVER(spi_emul) = {
+	.id		= UCLASS_SPI_EMUL,
+	.name		= "spi_emul",
+};
@@ -18,6 +18,7 @@
 	UCLASS_TEST,
 	UCLASS_TEST_FDT,
 	UCLASS_TEST_BUS,
+	UCLASS_SPI_EMUL,	/* sandbox SPI device emulator */
  
 	/* U-Boot uclasses start here */
 	UCLASS_GPIO,		/* Bank of general-purpose I/O pins */
@@ -456,6 +456,35 @@
 	int (*cs_info)(struct udevice *bus, uint cs, struct spi_cs_info *info);
 };
  
+struct dm_spi_emul_ops {
+	/**
+	 * SPI transfer
+	 *
+	 * This writes "bitlen" bits out the SPI MOSI port and simultaneously
+	 * clocks "bitlen" bits in the SPI MISO port.  That's just the way SPI
+	 * works. Here the device is a slave.
+	 *
+	 * The source of the outgoing bits is the "dout" parameter and the
+	 * destination of the input bits is the "din" parameter.  Note that
+	 * "dout" and "din" can point to the same memory location, in which
+	 * case the input data overwrites the output data (since both are
+	 * buffered by temporary variables, this is OK).
+	 *
+	 * spi_xfer() interface:
+	 * @slave:	The SPI slave which will be sending/receiving the data.
+	 * @bitlen:	How many bits to write and read.
+	 * @dout:	Pointer to a string of bits sent to the device. The
+	 *		bits are held in a byte array and are sent MSB first.
+	 * @din:	Pointer to a string of bits that will be sent back to
+	 *		the master.
+	 * @flags:	A bitwise combination of SPI_XFER_* flags.
+	 *
+	 * Returns: 0 on success, not -1 on failure
+	 */
+	int (*xfer)(struct udevice *slave, unsigned int bitlen,
+		    const void *dout, void *din, unsigned long flags);
+};
+
 /**
  * spi_find_bus_and_cs() - Find bus and slave devices by number
  *
  
@@ -545,12 +574,28 @@
 int spi_cs_info(struct udevice *bus, uint cs, struct spi_cs_info *info);
  
 struct sandbox_state;
+
+/**
+ * sandbox_spi_get_emul() - get an emulator for a SPI slave
+ *
+ * This provides a way to attach an emulated SPI device to a particular SPI
+ * slave, so that xfer() operations on the slave will be handled by the
+ * emulator. If a emulator already exists on that chip select it is returned.
+ * Otherwise one is created.
+ *
+ * @state:	Sandbox state
+ * @bus:	SPI bus requesting the emulator
+ * @slave:	SPI slave device requesting the emulator
+ * @emuip:	Returns pointer to emulator
+ * @return 0 if OK, -ve on error
+ */
 int sandbox_spi_get_emul(struct sandbox_state *state,
 			 struct udevice *bus, struct udevice *slave,
 			 struct udevice **emulp);
  
 /* Access the serial operations for a device */
 #define spi_get_ops(dev)	((struct dm_spi_ops *)(dev)->driver->ops)
+#define spi_emul_get_ops(dev)	((struct dm_spi_emul_ops *)(dev)->driver->ops)
 #endif /* CONFIG_DM_SPI */
  
 #endif	/* _SPI_H_ */
...	...	@@ -8,6 +8,7 @@
8	8	# There are many options which enable SPI, so make this library available
9	9	ifdef CONFIG_DM_SPI
10	10	obj-y += spi-uclass.o
	11	+obj-$(CONFIG_SANDBOX) += spi-emul-uclass.o
11	12	else
12	13	obj-y += spi.o
13	14	endif
	1	+/*
	2	+ * Copyright (c) 2014 Google, Inc
	3	+ *
	4	+ * SPDX-License-Identifier: GPL-2.0+
	5	+ */
	6	+
	7	+#include <common.h>
	8	+#include <dm.h>
	9	+#include <spi.h>
	10	+#include <spi_flash.h>
	11	+
	12	+UCLASS_DRIVER(spi_emul) = {
	13	+ .id = UCLASS_SPI_EMUL,
	14	+ .name = "spi_emul",
	15	+};
...	...	@@ -18,6 +18,7 @@
18	18	UCLASS_TEST,
19	19	UCLASS_TEST_FDT,
20	20	UCLASS_TEST_BUS,
	21	+ UCLASS_SPI_EMUL, /* sandbox SPI device emulator */
21	22
22	23	/* U-Boot uclasses start here */
23	24	UCLASS_GPIO, /* Bank of general-purpose I/O pins */
...	...	@@ -456,6 +456,35 @@
456	456	int (cs_info)(struct udevice bus, uint cs, struct spi_cs_info *info);
457	457	};
458	458
	459	+struct dm_spi_emul_ops {
	460	+ /**
	461	+ * SPI transfer
	462	+ *
	463	+ * This writes "bitlen" bits out the SPI MOSI port and simultaneously
	464	+ * clocks "bitlen" bits in the SPI MISO port. That's just the way SPI
	465	+ * works. Here the device is a slave.
	466	+ *
	467	+ * The source of the outgoing bits is the "dout" parameter and the
	468	+ * destination of the input bits is the "din" parameter. Note that
	469	+ * "dout" and "din" can point to the same memory location, in which
	470	+ * case the input data overwrites the output data (since both are
	471	+ * buffered by temporary variables, this is OK).
	472	+ *
	473	+ * spi_xfer() interface:
	474	+ * @slave: The SPI slave which will be sending/receiving the data.
	475	+ * @bitlen: How many bits to write and read.
	476	+ * @dout: Pointer to a string of bits sent to the device. The
	477	+ * bits are held in a byte array and are sent MSB first.
	478	+ * @din: Pointer to a string of bits that will be sent back to
	479	+ * the master.
	480	+ * @flags: A bitwise combination of SPI_XFER_* flags.
	481	+ *
	482	+ * Returns: 0 on success, not -1 on failure
	483	+ */
	484	+ int (xfer)(struct udevice slave, unsigned int bitlen,
	485	+ const void dout, void din, unsigned long flags);
	486	+};
	487	+
459	488	/**
460	489	* spi_find_bus_and_cs() - Find bus and slave devices by number
461	490	*
462	491
...	...	@@ -545,12 +574,28 @@
545	574	int spi_cs_info(struct udevice bus, uint cs, struct spi_cs_info info);
546	575
547	576	struct sandbox_state;
	577	+
	578	+/**
	579	+ * sandbox_spi_get_emul() - get an emulator for a SPI slave
	580	+ *
	581	+ * This provides a way to attach an emulated SPI device to a particular SPI
	582	+ * slave, so that xfer() operations on the slave will be handled by the
	583	+ * emulator. If a emulator already exists on that chip select it is returned.
	584	+ * Otherwise one is created.
	585	+ *
	586	+ * @state: Sandbox state
	587	+ * @bus: SPI bus requesting the emulator
	588	+ * @slave: SPI slave device requesting the emulator
	589	+ * @emuip: Returns pointer to emulator
	590	+ * @return 0 if OK, -ve on error
	591	+ */
548	592	int sandbox_spi_get_emul(struct sandbox_state *state,
549	593	struct udevice bus, struct udevice slave,
550	594	struct udevice **emulp);
551	595
552	596	/* Access the serial operations for a device */
553	597	#define spi_get_ops(dev) ((struct dm_spi_ops *)(dev)->driver->ops)
	598	+#define spi_emul_get_ops(dev) ((struct dm_spi_emul_ops *)(dev)->driver->ops)
554	599	#endif /* CONFIG_DM_SPI */
555	600
556	601	#endif /* _SPI_H_ */