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List:       busybox
Subject:    [PATCH] devmem: Add COUNT support
From:       Marek Vasut <marex () denx ! de>
Date:       2016-06-27 18:39:26
Message-ID: 1467052766-5944-1-git-send-email-marex () denx ! de
[Download RAW message or body]

Add additional parameter to allow dumping subsequent addresses.

Signed-off-by: Marek Vasut <marex@denx.de>
---
 miscutils/devmem.c | 122 +++++++++++++++++++++++++++++------------------------
 1 file changed, 67 insertions(+), 55 deletions(-)

diff --git a/miscutils/devmem.c b/miscutils/devmem.c
index 786a21b..cbde0ef 100644
--- a/miscutils/devmem.c
+++ b/miscutils/devmem.c
@@ -5,12 +5,13 @@
  */
 
 //usage:#define devmem_trivial_usage
-//usage:	"ADDRESS [WIDTH [VALUE]]"
+//usage:	"ADDRESS [WIDTH [VALUE [COUNT]]]"
 //usage:#define devmem_full_usage "\n\n"
 //usage:       "Read/write from physical address\n"
 //usage:     "\n	ADDRESS	Address to act upon"
 //usage:     "\n	WIDTH	Width (8/16/...)"
 //usage:     "\n	VALUE	Data to be written"
+//usage:     "\n	COUNT	Number of elements"
 
 #include "libbb.h"
 
@@ -20,10 +21,12 @@ int devmem_main(int argc UNUSED_PARAM, char **argv)
 	void *map_base, *virt_addr;
 	uint64_t read_result;
 	uint64_t writeval = writeval; /* for compiler */
+	uint64_t count = 1;
 	off_t target;
 	unsigned page_size, mapped_size, offset_in_page;
 	int fd;
 	unsigned width = 8 * sizeof(int);
+	int write = 0;
 
 	/* devmem ADDRESS [WIDTH [VALUE]] */
 // TODO: options?
@@ -55,26 +58,32 @@ int devmem_main(int argc UNUSED_PARAM, char **argv)
 			width = sizes[width];
 		}
 		/* VALUE */
-		if (argv[3])
-			writeval = bb_strtoull(argv[3], NULL, 0);
-	} else { /* argv[2] == NULL */
-		/* make argv[3] to be a valid thing to fetch */
-		argv--;
+		if (argv[3]) {
+			if (strcmp(argv[3], "-")) {
+				write = 1;
+				writeval = bb_strtoull(argv[3], NULL, 0);
+			}
+
+			/* COUNT */
+			if (argv[4])
+				count = bb_strtoull(argv[4], NULL, 0);
+		}
 	}
 	if (errno)
 		bb_show_usage(); /* one of bb_strtouXX failed */
 
-	fd = xopen("/dev/mem", argv[3] ? (O_RDWR | O_SYNC) : (O_RDONLY | O_SYNC));
-	mapped_size = page_size = getpagesize();
+	fd = xopen("/dev/mem", write ? (O_RDWR | O_SYNC) : (O_RDONLY | O_SYNC));
+	page_size = getpagesize();
+	mapped_size = roundup(count, page_size);
 	offset_in_page = (unsigned)target & (page_size - 1);
 	if (offset_in_page + width > page_size) {
 		/* This access spans pages.
 		 * Must map two pages to make it possible: */
-		mapped_size *= 2;
+		mapped_size += page_size;
 	}
 	map_base = mmap(NULL,
 			mapped_size,
-			argv[3] ? (PROT_READ | PROT_WRITE) : PROT_READ,
+			write ? (PROT_READ | PROT_WRITE) : PROT_READ,
 			MAP_SHARED,
 			fd,
 			target & ~(off_t)(page_size - 1));
@@ -85,52 +94,55 @@ int devmem_main(int argc UNUSED_PARAM, char **argv)
 
 	virt_addr = (char*)map_base + offset_in_page;
 
-	if (!argv[3]) {
-		switch (width) {
-		case 8:
-			read_result = *(volatile uint8_t*)virt_addr;
-			break;
-		case 16:
-			read_result = *(volatile uint16_t*)virt_addr;
-			break;
-		case 32:
-			read_result = *(volatile uint32_t*)virt_addr;
-			break;
-		case 64:
-			read_result = *(volatile uint64_t*)virt_addr;
-			break;
-		default:
-			bb_error_msg_and_die("bad width");
-		}
-//		printf("Value at address 0x%"OFF_FMT"X (%p): 0x%llX\n",
-//			target, virt_addr,
-//			(unsigned long long)read_result);
-		/* Zero-padded output shows the width of access just done */
-		printf("0x%0*llX\n", (width >> 2), (unsigned long long)read_result);
-	} else {
-		switch (width) {
-		case 8:
-			*(volatile uint8_t*)virt_addr = writeval;
-//			read_result = *(volatile uint8_t*)virt_addr;
-			break;
-		case 16:
-			*(volatile uint16_t*)virt_addr = writeval;
-//			read_result = *(volatile uint16_t*)virt_addr;
-			break;
-		case 32:
-			*(volatile uint32_t*)virt_addr = writeval;
-//			read_result = *(volatile uint32_t*)virt_addr;
-			break;
-		case 64:
-			*(volatile uint64_t*)virt_addr = writeval;
-//			read_result = *(volatile uint64_t*)virt_addr;
-			break;
-		default:
-			bb_error_msg_and_die("bad width");
-		}
-//		printf("Written 0x%llX; readback 0x%llX\n",
-//				(unsigned long long)writeval,
+	while (count--) {
+		if (!write) {
+			switch (width) {
+			case 8:
+				read_result = *(volatile uint8_t*)virt_addr;
+				break;
+			case 16:
+				read_result = *(volatile uint16_t*)virt_addr;
+				break;
+			case 32:
+				read_result = *(volatile uint32_t*)virt_addr;
+				break;
+			case 64:
+				read_result = *(volatile uint64_t*)virt_addr;
+				break;
+			default:
+				bb_error_msg_and_die("bad width");
+			}
+//			printf("Value at address 0x%"OFF_FMT"X (%p): 0x%llX\n",
+//				target, virt_addr,
 //				(unsigned long long)read_result);
+			/* Zero-padded output shows the width of access just done */
+			printf("0x%0*llX\n", (width >> 2), (unsigned long long)read_result);
+		} else {
+			switch (width) {
+			case 8:
+				*(volatile uint8_t*)virt_addr = writeval;
+//				read_result = *(volatile uint8_t*)virt_addr;
+				break;
+			case 16:
+				*(volatile uint16_t*)virt_addr = writeval;
+//				read_result = *(volatile uint16_t*)virt_addr;
+				break;
+			case 32:
+				*(volatile uint32_t*)virt_addr = writeval;
+//				read_result = *(volatile uint32_t*)virt_addr;
+				break;
+			case 64:
+				*(volatile uint64_t*)virt_addr = writeval;
+//				read_result = *(volatile uint64_t*)virt_addr;
+				break;
+			default:
+				bb_error_msg_and_die("bad width");
+			}
+//			printf("Written 0x%llX; readback 0x%llX\n",
+//					(unsigned long long)writeval,
+//					(unsigned long long)read_result);
+		}
+		virt_addr += width / 8;
 	}
 
 	if (ENABLE_FEATURE_CLEAN_UP) {
-- 
2.7.0

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