sunxi-fel: use RX DMA for FEL writes

The newer BROM FEL path copies received USB data byte-by-byte from the
MUSB FIFO. Even after switching the controller to high-speed mode, this
leaves large post-SPL DRAM writes far slower than the USB link can
support.

After SPL has initialized DRAM, install a parameterized RX DMA thunk for
writes into the known DRAM window. The thunk builds the MMU remap it
needs, hooks the BROM RX FIFO copy helper, and replaces it with a
MUSB/USBC endpoint-DMA receive path. It routes the active RX endpoint
DRQ through VEND0 before starting the internal DMA channel, so the FEL
wire protocol stays unchanged.

Put the common thunk code in fel_lib.c and install it from the shared
aw_fel_write_buffer() path. This makes normal writes and FIT image
loading use the same post-SPL DRAM write preparation path. Put the
SoC-specific hook, translation-table and shadow-page addresses in the
SoC table. Enable the path for SoCs whose BROM dumps contain the same
FIFO-copy helper ABI and compatible MUSB register layout: A33, A64, H3,
H5, A63, H6, H616, V853, V5, A523 and A133.

Coalesce full high-speed packets into bounded RX DMA requests and use
larger progress chunks once the RX DMA thunk is installed. This reduces
device-side FIFO-copy overhead and host-side progress overhead for
large DRAM writes. Use a 192 KiB DMA request cap; 256 KiB requests can
time out while the host is writing.

Add the checked-in DMA thunk header to the sunxi-fel prerequisites and
thunk documentation. This makes the binary rebuild when the generated
header changes without making the sunxi-fel target regenerate thunk
headers.

Signed-off-by: James Hilliard <james.hilliard1@gmail.com>

Author: jameshilliard

Makefile

@@ -163,8 +163,10 @@ PROGRESS := progress.c progress.h
 SOC_INFO := soc_info.c soc_info.h
 FEL_LIB  := fel_lib.c fel_lib.h
 SPI_FLASH:= fel-spiflash.c fel-spiflash.h fel-remotefunc-spi-data-transfer.h
+FEL_THUNKS := thunks/fel-to-spl-thunk.h thunks/fel-to-secure-svc-smc-thunk.h
+FEL_THUNKS += thunks/fel-rx-dma-thunk.h
 
-sunxi-fel: fel.c fit_image.c thunks/fel-to-spl-thunk.h thunks/fel-to-secure-svc-smc-thunk.h $(PROGRESS) $(SOC_INFO) $(FEL_LIB) $(SPI_FLASH)
+sunxi-fel: fel.c fit_image.c $(FEL_THUNKS) $(PROGRESS) $(SOC_INFO) $(FEL_LIB) $(SPI_FLASH)
 	$(CC) $(HOST_CFLAGS) $(LIBUSB_CFLAGS) $(ZLIB_CFLAGS) $(LIBFDT_CFLAGS) $(LDFLAGS) -o $@ \
 		$(filter %.c,$^) $(LIBS) $(LIBUSB_LIBS) $(ZLIB_LIBS) $(LIBFDT_LIBS)
 

fel.c

@@ -36,7 +36,6 @@ bool verbose = false; /* If set, makes the 'fel' tool more talkative */
 static uint32_t uboot_entry = 0; /* entry point (address) of U-Boot */
 static uint32_t uboot_size  = 0; /* size of U-Boot binary */
 static bool enter_in_aarch64 = false;
-static bool fel_usb_high_speed_enabled = false;
 
 #define FEL_REENUM_TIMEOUT_MS		5000
 #define FEL_REENUM_RETRY_MS		100
@@ -1118,6 +1117,7 @@ uint32_t aw_fel_write_and_execute_spl(feldev_handle *dev, uint8_t *buf, size_t l
 	/* re-enable the MMU if it was enabled by BROM */
 	if (tt != NULL)
 		aw_restore_and_enable_mmu(dev, soc_info, tt);
+	dev->dram_ready = true;
 
 	return spl_len;
 }
@@ -1650,7 +1650,7 @@ void usage(const char *cmd) {
 		"	-h, --help			Print this usage summary and exit\n"
 		"	-v, --verbose			Verbose logging\n"
 		"	-p, --progress			\"write\" transfers show a progress bar\n"
-		"	    --no-high-speed		Disable high-speed USB\n"
+		"	    --no-high-speed		Disable high-speed USB and fast writes\n"
 		"	-l, --list			Enumerate all (USB) FEL devices and exit\n"
 		"	-d, --dev bus:devnum		Use specific USB bus and device number\n"
 		"	    --sid SID			Select device by SID key (exact match)\n"
@@ -1790,10 +1790,11 @@ int main(int argc, char **argv)
 	 */
 	handle = feldev_open(busnum, devnum, AW_USB_VENDOR_ID, AW_USB_PRODUCT_ID);
 
-	fel_usb_high_speed_enabled = high_speed &&
-				     handle->soc_info->usb_musb_base != 0;
+	handle->verbose = verbose;
+	handle->usb_high_speed = high_speed &&
+				 handle->soc_info->usb_musb_base != 0;
 	reenum_sid_arg = sid_arg;
-	if (fel_usb_high_speed_enabled && !reenum_sid_arg &&
+	if (handle->usb_high_speed && !reenum_sid_arg &&
 	    read_device_sid(handle, reenum_sid)) {
 		reenum_sid_arg = reenum_sid;
 		pr_info("Tracking FEL device by SID %s\n", reenum_sid_arg);
@@ -1820,8 +1821,9 @@ int main(int argc, char **argv)
 
 		handle = feldev_open(busnum, devnum, AW_USB_VENDOR_ID,
 				     AW_USB_PRODUCT_ID);
-		fel_usb_high_speed_enabled = high_speed &&
-					     handle->soc_info->usb_musb_base != 0;
+		handle->verbose = verbose;
+		handle->usb_high_speed = high_speed &&
+					 handle->soc_info->usb_musb_base != 0;
 	}
 
 	/* Some SoCs need the SMC workaround to enter secure state. */

fel_lib.c

@@ -22,6 +22,7 @@
  **********************************************************************/
 
 #include "portable_endian.h"
+#include "common.h"
 #include "fel_lib.h"
 #include <libusb.h>
 
@@ -70,19 +71,25 @@ static void usb_error(int rc, const char *caption, int exitcode)
  * timeout, and "slow" transfers take place at approx. 64 KiB/sec - so we can
  * expect the maximum chunk being transmitted within 8 seconds or less.
  */
-static const int AW_USB_MAX_BULK_SEND = 512 * 1024; /* 512 KiB per bulk request */
+static const int AW_USB_MAX_BULK_SEND = 512 * 1024;
+static const int AW_USB_PROGRESS_BULK_SEND = 128 * 1024;
+static const int AW_USB_FAST_PROGRESS_BULK_SEND = 1024 * 1024;
 
+#define	DRAM_BASE		0x40000000
+#define	DRAM_SIZE		0x80000000
+#define	DRAM_END		(DRAM_BASE + DRAM_SIZE)
+
+static uint32_t fel_rx_dma_thunk[] = {
+	#include "thunks/fel-rx-dma-thunk.h"
+};
+
+/*
+ * Keep progress updates frequent enough for slow BROM PIO transfers. Once an
+ * RX-DMA thunk is installed, 1 MiB chunks avoid host-side progress overhead.
+ */
 static void usb_bulk_send(libusb_device_handle *usb, int ep, const void *data,
-			  size_t length, bool progress)
+			  size_t length, size_t max_chunk, bool progress)
 {
-	/*
-	 * With no progress notifications, we'll use the maximum chunk size.
-	 * Otherwise, it's useful to lower the size (have more chunks) to get
-	 * more frequent status updates. 128 KiB per request seem suitable.
-	 * (Worst case of "slow" transfers -> one update every two seconds.)
-	 */
-	size_t max_chunk = progress ? 128 * 1024 : AW_USB_MAX_BULK_SEND;
-
 	size_t chunk;
 	int rc, sent;
 	while (length > 0) {
@@ -187,7 +194,7 @@ static void aw_send_usb_request(feldev_handle *dev, int type, int length)
 	};
 	req.length2 = req.length;
 	usb_bulk_send(dev->usb->handle, dev->usb->endpoint_out,
-		      &req, sizeof(req), false);
+		      &req, sizeof(req), AW_USB_MAX_BULK_SEND, false);
 }
 
 static bool aw_send_usb_request_may_disconnect(feldev_handle *dev, int type,
@@ -239,9 +246,18 @@ static bool aw_usb_read_may_disconnect(feldev_handle *dev, void *data,
 static void aw_usb_write(feldev_handle *dev, const void *data, size_t len,
 			 bool progress)
 {
+	size_t max_chunk = AW_USB_MAX_BULK_SEND;
+
+	if (progress) {
+		if (dev->rx_dma_patched)
+			max_chunk = AW_USB_FAST_PROGRESS_BULK_SEND;
+		else
+			max_chunk = AW_USB_PROGRESS_BULK_SEND;
+	}
+
 	aw_send_usb_request(dev, AW_USB_WRITE, len);
 	usb_bulk_send(dev->usb->handle, dev->usb->endpoint_out,
-		      data, len, progress);
+		      data, len, max_chunk, progress);
 	aw_read_usb_response(dev);
 }
 
@@ -363,6 +379,49 @@ void aw_fel_execute_may_disconnect(feldev_handle *dev, uint32_t offset)
 		(void)aw_read_fel_status_may_disconnect(dev);
 }
 
+static void aw_fel_install_rx_dma_thunk(feldev_handle *dev)
+{
+	const fel_rx_dma_info *dma = &dev->soc_info->fel_rx_dma;
+	uint32_t params[6], param_offset;
+	size_t i;
+
+	if (dev->rx_dma_patched || !dma->thunk_addr)
+		return;
+
+	param_offset = fel_rx_dma_thunk[1];
+	if (param_offset % sizeof(*fel_rx_dma_thunk) ||
+	    param_offset + sizeof(params) > sizeof(fel_rx_dma_thunk))
+		pr_fatal("RX DMA thunk: bad parameter offset 0x%x\n",
+			 param_offset);
+
+	uint32_t thunk_buf[ARRAY_SIZE(fel_rx_dma_thunk)];
+
+	if (dev->verbose)
+		printf("Patching BROM RX FIFO copy to use DMA.\n");
+	for (i = 0; i < sizeof(thunk_buf) / sizeof(*thunk_buf); i++)
+		thunk_buf[i] = htole32(fel_rx_dma_thunk[i]);
+	params[0] = htole32(dma->l1_tt_addr);
+	params[1] = htole32(dma->l2_tt_addr);
+	params[2] = htole32(dma->brom_hook_addr);
+	params[3] = htole32(dma->brom_hook_shadow_addr);
+	params[4] = htole32(dev->soc_info->usb_musb_base);
+	params[5] = htole32(dma->dma_max_len);
+	memcpy((uint8_t *)thunk_buf + param_offset, params, sizeof(params));
+
+	aw_fel_write(dev, thunk_buf, dma->thunk_addr, sizeof(thunk_buf));
+
+	aw_fel_execute(dev, dma->thunk_addr + fel_rx_dma_thunk[0]);
+	dev->rx_dma_patched = true;
+}
+
+static void aw_fel_prepare_fast_dram_write(feldev_handle *dev,
+					   uint32_t offset)
+{
+	if (dev->usb_high_speed && dev->dram_ready &&
+	    offset >= DRAM_BASE && offset < DRAM_END)
+		aw_fel_install_rx_dma_thunk(dev);
+}
+
 static void aw_disable_icache(feldev_handle *dev)
 {
 	soc_info_t *soc_info = dev->soc_info;
@@ -401,6 +460,7 @@ void aw_fel_write_buffer(feldev_handle *dev, const void *buf, uint32_t offset,
 	if (len == 0)
 		return;
 
+	aw_fel_prepare_fast_dram_write(dev, offset);
 	aw_send_fel_request(dev, AW_FEL_1_WRITE, offset, len);
 	aw_usb_write(dev, buf, len, progress);
 	aw_read_fel_status(dev);

fel_lib.h

@@ -35,6 +35,10 @@ typedef struct {
 	soc_name_t soc_name;
 	soc_info_t *soc_info;
 	bool disconnected;
+	bool verbose;
+	bool usb_high_speed;
+	bool dram_ready;
+	bool rx_dma_patched;
 } feldev_handle;
 
 /* list_fel_devices() will return an array of this type */

soc_info.c

@@ -25,6 +25,8 @@
 #include <stdio.h>
 #include <string.h>
 
+#define FEL_RX_DMA_MAX_LEN	0x00030000
+
 /*
  * The FEL code from BROM in A10/A13/A20 sets up two stacks for itself. One
  * at 0x2000 (and growing down) for the IRQ handler. And another one at 0x7000
@@ -390,6 +392,14 @@ soc_info_t soc_info_table[] = {
 		.sid_sections = generic_2k_sid_maps,
 		.usb_musb_base= 0x01c19000,
 		.fel_endpoint_table_addr = 0x00006ed8,
+		.fel_rx_dma = {
+			.thunk_addr = 0x0004e000,
+			.l1_tt_addr = 0x00048000,
+			.l2_tt_addr = 0x0004c000,
+			.brom_hook_addr = 0xffff2588,
+			.brom_hook_shadow_addr = 0x0004d000,
+			.dma_max_len = FEL_RX_DMA_MAX_LEN,
+		},
 		.watchdog     = &wd_h3_compat,
 	},{
 		.soc_id       = 0x1689, /* Allwinner A64 */
@@ -405,6 +415,14 @@ soc_info_t soc_info_table[] = {
 		.rvbar_reg    = 0x017000A0,
 		.usb_musb_base= 0x01c19000,
 		.fel_endpoint_table_addr = 0x00016ecc,
+		.fel_rx_dma = {
+			.thunk_addr = 0x00022000,
+			.l1_tt_addr = 0x0002c000,
+			.l2_tt_addr = 0x00031000,
+			.brom_hook_addr = 0x00002670,
+			.brom_hook_shadow_addr = 0x00030000,
+			.dma_max_len = FEL_RX_DMA_MAX_LEN,
+		},
 		/* Check L.NOP in the OpenRISC reset vector */
 		.needs_smc_workaround_if_zero_word_at_addr = 0x40004,
 		.smc_workaround = SMC_WORKAROUND_DIRECT_SMC,
@@ -456,6 +474,14 @@ soc_info_t soc_info_table[] = {
 		.sid_sections = h3_sid_maps,
 		.usb_musb_base= 0x01c19000,
 		.fel_endpoint_table_addr = 0x00006ecc,
+		.fel_rx_dma = {
+			.thunk_addr = 0x0000e000,
+			.l1_tt_addr = 0x00008000,
+			.l2_tt_addr = 0x0000c000,
+			.brom_hook_addr = 0xffff2680,
+			.brom_hook_shadow_addr = 0x0000d000,
+			.dma_max_len = FEL_RX_DMA_MAX_LEN,
+		},
 		/* Check L.NOP in the OpenRISC reset vector */
 		.needs_smc_workaround_if_zero_word_at_addr = 0x40004,
 		.smc_workaround = SMC_WORKAROUND_DIRECT_SMC,
@@ -497,6 +523,14 @@ soc_info_t soc_info_table[] = {
 		.rvbar_reg    = 0x017000A0,
 		.usb_musb_base= 0x01c19000,
 		.fel_endpoint_table_addr = 0x00016ecc,
+		.fel_rx_dma = {
+			.thunk_addr = 0x00022000,
+			.l1_tt_addr = 0x0002c000,
+			.l2_tt_addr = 0x00031000,
+			.brom_hook_addr = 0x0000205c,
+			.brom_hook_shadow_addr = 0x00030000,
+			.dma_max_len = FEL_RX_DMA_MAX_LEN,
+		},
 		/* Check L.NOP in the OpenRISC reset vector */
 		.needs_smc_workaround_if_zero_word_at_addr = 0x40004,
 		.smc_workaround = SMC_WORKAROUND_DIRECT_SMC,
@@ -526,6 +560,14 @@ soc_info_t soc_info_table[] = {
 		.rvbar_reg    = 0x09010040,
 		.usb_musb_base= 0x05100000,
 		.fel_endpoint_table_addr = 0x00026ecc,
+		.fel_rx_dma = {
+			.thunk_addr = 0x00022000,
+			.l1_tt_addr = 0x00038000,
+			.l2_tt_addr = 0x0003d000,
+			.brom_hook_addr = 0x000021ac,
+			.brom_hook_shadow_addr = 0x0003c000,
+			.dma_max_len = FEL_RX_DMA_MAX_LEN,
+		},
 		.watchdog     = &wd_h6_compat,
 	},{
 		.soc_id       = 0x1728, /* Allwinner H6 */
@@ -541,6 +583,14 @@ soc_info_t soc_info_table[] = {
 		.rvbar_reg    = 0x09010040,
 		.usb_musb_base= 0x05100000,
 		.fel_endpoint_table_addr = 0x00026ecc,
+		.fel_rx_dma = {
+			.thunk_addr = 0x00022000,
+			.l1_tt_addr = 0x00038000,
+			.l2_tt_addr = 0x0003d000,
+			.brom_hook_addr = 0x00002300,
+			.brom_hook_shadow_addr = 0x0003c000,
+			.dma_max_len = FEL_RX_DMA_MAX_LEN,
+		},
 		/* Check L.NOP in the OpenRISC reset vector */
 		.needs_smc_workaround_if_zero_word_at_addr = 0x100004,
 		.smc_workaround = SMC_WORKAROUND_DIRECT_SMC,
@@ -585,6 +635,14 @@ soc_info_t soc_info_table[] = {
 		.ver_reg      = 0x03000024,
 		.usb_musb_base= 0x05100000,
 		.fel_endpoint_table_addr = 0x000550f0,
+		.fel_rx_dma = {
+			.thunk_addr = 0x00022000,
+			.l1_tt_addr = 0x0004c000,
+			.l2_tt_addr = 0x00051000,
+			.brom_hook_addr = 0x0000a17c,
+			.brom_hook_shadow_addr = 0x00050000,
+			.dma_max_len = FEL_RX_DMA_MAX_LEN,
+		},
 		.needs_smc_workaround_if_zero_word_at_addr = 0x03006240,
 		.secure_boot_fuse_offset = 0xa0,
 		.smc_workaround = SMC_WORKAROUND_SECURE_SVC_SMC_THUNK,
@@ -617,6 +675,14 @@ soc_info_t soc_info_table[] = {
 		.sid_sections = generic_2k_sid_maps,
 		.usb_musb_base= 0x04100000,
 		.fel_endpoint_table_addr = 0x000402e8,
+		.fel_rx_dma = {
+			.thunk_addr = 0x00022000,
+			.l1_tt_addr = 0x00038000,
+			.l2_tt_addr = 0x0003d000,
+			.brom_hook_addr = 0x0000aff0,
+			.brom_hook_shadow_addr = 0x0003c000,
+			.dma_max_len = FEL_RX_DMA_MAX_LEN,
+		},
 		.icache_fix   = true,
 		.watchdog     = &wd_v853_compat,
 	},{
@@ -645,6 +711,14 @@ soc_info_t soc_info_table[] = {
 		.sid_sections = generic_2k_sid_maps,
 		.usb_musb_base= 0x05100000,
 		.fel_endpoint_table_addr = 0x00026efc,
+		.fel_rx_dma = {
+			.thunk_addr = 0x00022000,
+			.l1_tt_addr = 0x00038000,
+			.l2_tt_addr = 0x0003d000,
+			.brom_hook_addr = 0x000036ec,
+			.brom_hook_shadow_addr = 0x0003c000,
+			.dma_max_len = FEL_RX_DMA_MAX_LEN,
+		},
 		.watchdog     = &wd_h6_compat,
 	},{
 		.soc_id       = 0x1890, /* Allwinner A523 */
@@ -660,6 +734,14 @@ soc_info_t soc_info_table[] = {
 		.rvbar_reg    = 0x08000040,
 		.usb_musb_base= 0x04100000,
 		.fel_endpoint_table_addr = 0x0005e6ec,
+		.fel_rx_dma = {
+			.thunk_addr = 0x00041000,
+			.l1_tt_addr = 0x00050000,
+			.l2_tt_addr = 0x00055000,
+			.brom_hook_addr = 0x00017574,
+			.brom_hook_shadow_addr = 0x00054000,
+			.dma_max_len = FEL_RX_DMA_MAX_LEN,
+		},
 		.icache_fix   = true,
 		.watchdog     = &wd_a523_compat,
 	},{
@@ -676,6 +758,14 @@ soc_info_t soc_info_table[] = {
 		.rvbar_reg    = 0x08100040,
 		.usb_musb_base= 0x05100000,
 		.fel_endpoint_table_addr = 0x00041ff0,
+		.fel_rx_dma = {
+			.thunk_addr = 0x00022000,
+			.l1_tt_addr = 0x00038000,
+			.l2_tt_addr = 0x0003d000,
+			.brom_hook_addr = 0x0000b698,
+			.brom_hook_shadow_addr = 0x0003c000,
+			.dma_max_len = FEL_RX_DMA_MAX_LEN,
+		},
 		.needs_smc_workaround_if_zero_word_at_addr = 0x100004,
 		.smc_workaround = SMC_WORKAROUND_DIRECT_SMC,
 		.watchdog     = &wd_h6_compat,