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>

diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index d1f1dd066600628887ed4ff22acde684a6d59c99..a1de0288de208985d16c087fd8422bd20d4b0796 100644 (file)
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -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

diff --git a/drivers/spi/spi-emul-uclass.c b/drivers/spi/spi-emul-uclass.c
new file mode 100644 (file)
index 0000000..b436a0e
--- /dev/null
+++ b/drivers/spi/spi-emul-uclass.c
@@ -0,0 +1,15 @@
+/*
+ * 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",
+};

diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
index 0afdc753869c398a330656a221a39fde631e8567..6e5638208b4917ce6b257675afdc2526e4b6bbdd 100644 (file)
--- a/include/dm/uclass-id.h
+++ b/include/dm/uclass-id.h
@@ -18,6 +18,7 @@ enum uclass_id {
        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 */

diff --git a/include/spi.h b/include/spi.h
index 89949b11b70cfb02f57424f131fa10fdc66d49f3..aa0a48ea62710dd019c77c75cc5350a9f61fb14d 100644 (file)
--- a/include/spi.h
+++ b/include/spi.h
@@ -456,6 +456,35 @@ struct dm_spi_ops {
        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_ofdata_to_platdata(const void *blob, int node, struct spi_slave *spi);
 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_ */