dfu: add DFU virtual backend

Add a virtual DFU backend to allow board specific read and write
(for OTP update for example).

Acked-by: Lukasz Majewski <lukma@denx.de>
Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>

doc/README.dfu

@@ -22,11 +22,18 @@ Overview:
   - RAM
   - SF (serial flash)
   - MTD (all MTD device: NAND, SPI-NOR, SPI-NAND,...)
+  - virtual
 
   These DFU backends are also used by
   - the dfutftp (see README.dfutftp)
   - the thordown command (cmd/thordown.c and gadget/f_thor.c)
 
+  The "virtual" backend is a generic DFU backend to support a board specific
+  target (for example OTP), only based on the weak functions:
+  - dfu_write_medium_virt
+  - dfu_get_medium_size_virt
+  - dfu_read_medium_virt
+
 Configuration Options:
   CONFIG_DFU
   CONFIG_DFU_OVER_USB
@@ -36,6 +43,7 @@ Configuration Options:
   CONFIG_DFU_RAM
   CONFIG_DFU_SF
   CONFIG_DFU_SF_PART
+  CONFIG_DFU_VIRTUAL
   CONFIG_CMD_DFU
 
 Environment variables:
@@ -117,6 +125,11 @@ Commands:
 
       with <partid> is the MTD partition index
 
+  "virt"
+    cmd: dfu 0 virt <dev>
+    each element in "dfu_alt_info" =
+      <name>
+
   <interface> and <dev> are absent:
     the dfu command to use multiple devices
     cmd: dfu 0 list
@@ -128,7 +141,7 @@ Commands:
        ram <dev>=<alt1>;....;<altN>
        sf <dev>=<alt1>;....;<altN>
        mtd <dev>=<alt1>;....;<altN>
-
+       virt <dev>=<alt1>;....;<altN>
 
 Host tools:
   When U-Boot runs the dfu stack, the DFU host tools can be used
@@ -230,3 +243,20 @@ Usage:
   dev: MTD alt: 1 name: u-boot layout: RAW_ADDR
   dev: MTD alt: 2 name: u-boot-env layout: RAW_ADDR
   dev: MTD alt: 3 name: UBI layout: RAW_ADDR
+
+  Example 3: firmware located in SD Card (mmc) and virtual partition on
+             OTP and PMIC not volatile memory
+  - alternate 1 (alt=1) for scard
+  - alternate 2 (alt=2) for OTP (virtual)
+  - alternate 3 (alt=3) for PMIC NVM (virtual)
+
+   U-Boot> env set dfu_alt_info \
+      "mmc 0=sdcard raw 0 0x100000&"\
+      "virt 0=otp" \
+      "virt 1=pmic"
+
+   U-Boot> dfu 0 list
+   DFU alt settings list:
+   dev: eMMC alt: 0 name: sdcard layout: RAW_ADDR
+   dev: VIRT alt: 1 name: otp layout: RAW_ADDR
+   dev: VIRT alt: 2 name: pmic layout: RAW_ADDR

drivers/dfu/Kconfig

@@ -60,5 +60,12 @@ config DFU_MTD
 	help
 	  This option enables using DFU to read and write to on any MTD device.
 
+config DFU_VIRT
+	bool "VIRTUAL flash back end for DFU"
+	help
+	  This option enables using DFU to read and write to VIRTUAL device
+	  used at board level to manage specific behavior
+	  (OTP update for example).
+
 endif
 endmenu

drivers/dfu/Makefile

@@ -10,3 +10,4 @@ obj-$(CONFIG_$(SPL_)DFU_NAND) += dfu_nand.o
 obj-$(CONFIG_$(SPL_)DFU_RAM) += dfu_ram.o
 obj-$(CONFIG_$(SPL_)DFU_SF) += dfu_sf.o
 obj-$(CONFIG_$(SPL_)DFU_TFTP) += dfu_tftp.o
+obj-$(CONFIG_$(SPL_)DFU_VIRT) += dfu_virt.o

drivers/dfu/dfu.c

@@ -474,6 +474,9 @@ static int dfu_fill_entity(struct dfu_entity *dfu, char *s, int alt,
 	} else if (strcmp(interface, "sf") == 0) {
 		if (dfu_fill_entity_sf(dfu, devstr, s))
 			return -1;
+	} else if (strcmp(interface, "virt") == 0) {
+		if (dfu_fill_entity_virt(dfu, devstr, s))
+			return -1;
 	} else {
 		printf("%s: Device %s not (yet) supported!\n",
 		       __func__,  interface);
@@ -569,7 +572,7 @@ int dfu_config_entities(char *env, char *interface, char *devstr)
 const char *dfu_get_dev_type(enum dfu_device_type t)
 {
 	const char *const dev_t[] = {NULL, "eMMC", "OneNAND", "NAND", "RAM",
-				     "SF", "MTD"};
+				     "SF", "MTD", "VIRT"};
 	return dev_t[t];
 }
 

drivers/dfu/dfu_virt.c

@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause
+/*
+ * Copyright (C) 2019, STMicroelectronics - All Rights Reserved
+ */
+#include <common.h>
+#include <dfu.h>
+#include <errno.h>
+#include <malloc.h>
+
+int __weak dfu_write_medium_virt(struct dfu_entity *dfu, u64 offset,
+				 void *buf, long *len)
+{
+	debug("%s: off=0x%llx, len=0x%x\n", __func__, offset, (u32)*len);
+
+	return 0;
+}
+
+int __weak dfu_get_medium_size_virt(struct dfu_entity *dfu, u64 *size)
+{
+	*size = 0;
+
+	return 0;
+}
+
+int __weak dfu_read_medium_virt(struct dfu_entity *dfu, u64 offset,
+				void *buf, long *len)
+{
+	debug("%s: off=0x%llx, len=0x%x\n", __func__, offset, (u32)*len);
+	*len = 0;
+
+	return 0;
+}
+
+int dfu_fill_entity_virt(struct dfu_entity *dfu, char *devstr, char *s)
+{
+	debug("%s: devstr = %s\n", __func__, devstr);
+
+	dfu->dev_type = DFU_DEV_VIRT;
+	dfu->layout = DFU_RAW_ADDR;
+	dfu->data.virt.dev_num = simple_strtoul(devstr, NULL, 10);
+
+	dfu->write_medium = dfu_write_medium_virt;
+	dfu->get_medium_size = dfu_get_medium_size_virt;
+	dfu->read_medium = dfu_read_medium_virt;
+
+	dfu->inited = 0;
+
+	return 0;
+}

include/dfu.h

@@ -23,6 +23,7 @@ enum dfu_device_type {
 	DFU_DEV_RAM,
 	DFU_DEV_SF,
 	DFU_DEV_MTD,
+	DFU_DEV_VIRT,
 };
 
 enum dfu_layout {
@@ -92,6 +93,10 @@ struct sf_internal_data {
 	unsigned int ubi;
 };
 
+struct virt_internal_data {
+	int dev_num;
+};
+
 #define DFU_NAME_SIZE			32
 #ifndef CONFIG_SYS_DFU_DATA_BUF_SIZE
 #define CONFIG_SYS_DFU_DATA_BUF_SIZE		(1024*1024*8)	/* 8 MiB */
@@ -120,6 +125,7 @@ struct dfu_entity {
 		struct nand_internal_data nand;
 		struct ram_internal_data ram;
 		struct sf_internal_data sf;
+		struct virt_internal_data virt;
 	} data;
 
 	int (*get_medium_size)(struct dfu_entity *dfu, u64 *size);
@@ -272,6 +278,22 @@ static inline int dfu_fill_entity_mtd(struct dfu_entity *dfu, char *devstr,
 }
 #endif
 
+#ifdef CONFIG_DFU_VIRT
+int dfu_fill_entity_virt(struct dfu_entity *dfu, char *devstr, char *s);
+int dfu_write_medium_virt(struct dfu_entity *dfu, u64 offset,
+			  void *buf, long *len);
+int dfu_get_medium_size_virt(struct dfu_entity *dfu, u64 *size);
+int dfu_read_medium_virt(struct dfu_entity *dfu, u64 offset,
+			 void *buf, long *len);
+#else
+static inline int dfu_fill_entity_virt(struct dfu_entity *dfu, char *devstr,
+				       char *s)
+{
+	puts("VIRT support not available!\n");
+	return -1;
+}
+#endif
+
 /**
  * dfu_tftp_write - Write TFTP data to DFU medium
  *