More low-level flash interface cleanup

Setting at-boot protection always used the same start/range
(RO+PSTATE), so no point in passing that to the physical layer as
params.

flash_dataptr() should take a pointer to const data.

No functional changes; just rearranging code.

BUG=chrome-os-partner:15613
BRANCH=none
TEST=build pit, link, spring

     - flashinfo -> (no flags)
     - enable WP (via screw or dut-control)
     - flashinfo -> wp_gpio_asserted
     - flashwp enable
     - flashinfo -> wp_gpio_asserted ro_at_boot
     - flashwp now
     - flashinfo -> wp_gpio_asserted ro_at_boot all_now (and possibly ro_now)
     - flashwp disable -> fails
     - flashinfo -> wp_gpio_asserted ro_at_boot all_now
     - reboot ap-off
     - flashinfo -> wp_gpio_asserted ro_at_boot ro_now
     - disable WP (via screw or dut-control)
     - reboot
     - flashinfo -> ro_at_boot
     - flashwp disable
     - flashinfo -> (no flags)

Change-Id: Ifd6553dc907fa6fafce81b56af0c648ac6d6bee1
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/56628

5 files changed, 51 insertions, 49 deletions

diff --git a/chip/lm4/flash.c b/chip/lm4/flash.c
index 2c5e0f9127..e7b4064665 100644
--- a/chip/lm4/flash.c
+++ b/chip/lm4/flash.c
@@ -225,7 +225,7 @@ int flash_pre_init(void)
 	if (reset_flags & RESET_FLAG_SYSJUMP)
 		return EC_SUCCESS;
 
-	if ((prot_flags & EC_FLASH_PROTECT_GPIO_ASSERTED)) {
+	if (prot_flags & EC_FLASH_PROTECT_GPIO_ASSERTED) {
 		/*
 		 * Write protect is asserted.  If we want RO flash protected,
 		 * protect it now.
diff --git a/chip/stm32/flash-stm32f100.c b/chip/stm32/flash-stm32f100.c
index 1c22ed4f0b..ff6e01e8e0 100644
--- a/chip/stm32/flash-stm32f100.c
+++ b/chip/stm32/flash-stm32f100.c
@@ -47,6 +47,10 @@ static int entire_flash_locked;
 #define FLASH_SYSJUMP_TAG 0x5750 /* "WP" - Write Protect */
 #define FLASH_HOOK_VERSION 1
 /* The previous write protect state before sys jump */
+/*
+ * TODO: check if STM32L code works here too - that is, check if entire flash
+ * is locked by attempting to lock it rather than keeping a global variable.
+ */
 struct flash_wp_state {
 	int entire_flash_locked;
 };
@@ -359,8 +363,7 @@ uint32_t flash_physical_get_protect_flags(void)
 	return flags;
 }
 
-int flash_physical_set_protect_at_boot(int start_bank, int bank_count,
-				       int enable)
+int flash_physical_protect_ro_at_boot(int enable)
 {
 	int block;
 	int i;
@@ -369,7 +372,9 @@ int flash_physical_set_protect_at_boot(int start_bank, int bank_count,
 	for (i = 0; i < 4; ++i)
 		original_val[i] = val[i] = read_optb(i * 2 + 8);
 
-	for (block = start_bank; block < start_bank + bank_count; block++) {
+	for (block = RO_BANK_OFFSET;
+	     block < RO_BANK_OFFSET + RO_BANK_COUNT + PSTATE_BANK_COUNT;
+	     block++) {
 		int byte_off = STM32_OPTB_WRP_OFF(block/8) / 2 - 4;
 		if (enable)
 			val[byte_off] = val[byte_off] & (~(1 << (block % 8)));
@@ -466,7 +471,7 @@ int flash_pre_init(void)
 			 * update to the write protect register and reboot so
 			 * it takes effect.
 			 */
-			flash_protect_ro_at_boot(1);
+			flash_physical_protect_ro_at_boot(1);
 			need_reset = 1;
 		}
 
diff --git a/chip/stm32/flash-stm32l15x.c b/chip/stm32/flash-stm32l15x.c
index 04ca0eddd3..51453d4198 100644
--- a/chip/stm32/flash-stm32l15x.c
+++ b/chip/stm32/flash-stm32l15x.c
@@ -312,11 +312,11 @@ int flash_physical_get_protect(int block)
 	return STM32_FLASH_WRPR & (1 << block);
 }
 
-int flash_physical_set_protect_at_boot(int start_bank, int bank_count,
-				       int enable)
+int flash_physical_protect_ro_at_boot(int enable)
 {
 	uint32_t prot;
-	uint32_t mask = ((1 << bank_count) - 1) << start_bank;
+	uint32_t mask = ((1 << (RO_BANK_COUNT + PSTATE_BANK_COUNT)) - 1)
+			<< RO_BANK_OFFSET;
 	int rv;
 
 	/* Read the current protection status */
diff --git a/common/flash_common.c b/common/flash_common.c
index 15f8fac3d1..430bcaead8 100644
--- a/common/flash_common.c
+++ b/common/flash_common.c
@@ -30,6 +30,22 @@ struct persist_state {
 #define PERSIST_FLAG_PROTECT_RO 0x02
 
 /**
+ * Get the physical memory address of a flash offset
+ *
+ * This is used for direct flash access. We assume that the flash is
+ * contiguous from this start address through to the end of the usable
+ * flash.
+ *
+ * @param offset	Flash offset to get address of
+ * @param dataptrp	Returns pointer to memory address of flash offset
+ * @return pointer to flash memory offset, if ok, else NULL
+ */
+static const char *flash_physical_dataptr(int offset)
+{
+	return (char *)((uintptr_t)CONFIG_FLASH_BASE + offset);
+}
+
+/**
  * Read persistent state into pstate.
  *
  * @param pstate	Destination for persistent state
@@ -77,7 +93,7 @@ static int flash_write_pstate(const struct persist_state *pstate)
 				    (const char *)pstate);
 }
 
-int flash_dataptr(int offset, int size_req, int align, char **ptrp)
+int flash_dataptr(int offset, int size_req, int align, const char **ptrp)
 {
 	if (offset < 0 || size_req < 0 ||
 			offset + size_req > CONFIG_FLASH_SIZE ||
@@ -93,9 +109,10 @@ int flash_dataptr(int offset, int size_req, int align, char **ptrp)
 #ifndef CHIP_VARIANT_stm32l15x
 int flash_is_erased(uint32_t offset, int size)
 {
-	uint32_t *ptr;
+	const uint32_t *ptr;
 
-	if (flash_dataptr(offset, size, sizeof(uint32_t), (char **)&ptr) < 0)
+	if (flash_dataptr(offset, size, sizeof(uint32_t),
+			  (const char **)&ptr) < 0)
 		return 0;
 
 	for (size /= sizeof(uint32_t); size > 0; size -= 4, ptr++)
@@ -167,9 +184,7 @@ int flash_protect_ro_at_boot(int enable)
 	 * This assumes PSTATE immediately follows RO, which it does on
 	 * all STM32 platforms (which are the only ones with this config).
 	 */
-	flash_physical_set_protect_at_boot(RO_BANK_OFFSET,
-					   RO_BANK_COUNT + PSTATE_BANK_COUNT,
-					   new_flags);
+	flash_physical_protect_ro_at_boot(new_flags);
 #endif
 
 	return EC_SUCCESS;
@@ -469,7 +484,8 @@ static int flash_command_read(struct host_cmd_handler_args *args)
 {
 	const struct ec_params_flash_read *p = args->params;
 
-	if (flash_dataptr(p->offset, p->size, 1, (char **)&args->response) < 0)
+	if (flash_dataptr(p->offset, p->size, 1,
+			  (const char **)&args->response) < 0)
 		return EC_RES_ERROR;
 
 	args->response_size = p->size;
diff --git a/include/flash.h b/include/flash.h
index 55f0b0fba8..4bcbb8eb8f 100644
--- a/include/flash.h
+++ b/include/flash.h
@@ -32,33 +32,6 @@
 /* Low-level methods, for use by flash_common. */
 
 /**
- * Get the physical memory address of a flash offset
- *
- * This is used for direct flash access. We assume that the flash is
- * contiguous from this start address through to the end of the usable
- * flash.
- *
- * @param offset	Flash offset to get address of
- * @param dataptrp	Returns pointer to memory address of flash offset
- * @return pointer to flash memory offset, if ok, else NULL
- */
-static inline char *flash_physical_dataptr(int offset)
-{
-	return (char *)((uintptr_t)CONFIG_FLASH_BASE + offset);
-}
-
-/**
- * Check if a region of flash is erased
- *
- * It is assumed that an erased region has all bits set to 1.
- *
- * @param offset	Flash offset to check
- * @param size		Number of bytes to check (word-aligned)
- * @return 1 if erased, 0 if not erased
- */
-int flash_is_erased(uint32_t offset, int size);
-
-/**
  * Write to physical flash.
  *
  * Offset and size must be a multiple of CONFIG_FLASH_WRITE_SIZE.
@@ -97,15 +70,12 @@ int flash_physical_get_protect(int bank);
 uint32_t flash_physical_get_protect_flags(void);
 
 /**
- * Set physical write protect status for the next boot.
+ * Enable/disable protecting RO firmware and pstate at boot.
  *
- * @param start_bank	Start bank
- * @param bank_count	Number of banks to protect
  * @param enable	Enable (non-zero) or disable (zero) protection
  * @return non-zero if error.
  */
-int flash_physical_set_protect_at_boot(int start_bank, int bank_count,
-				       int enable);
+int flash_physical_protect_ro_at_boot(int enable);
 
 /**
  * Protect flash now.
@@ -127,7 +97,18 @@ int flash_physical_protect_now(int all);
 int flash_physical_force_reload(void);
 
 /*****************************************************************************/
-/* Low-level persistent state code for use by flash modules. */
+/* Low-level common code for use by flash modules. */
+
+/**
+ * Check if a region of flash is erased
+ *
+ * It is assumed that an erased region has all bits set to 1.
+ *
+ * @param offset	Flash offset to check
+ * @param size		Number of bytes to check (word-aligned)
+ * @return 1 if erased, 0 if not erased
+ */
+int flash_is_erased(uint32_t offset, int size);
 
 /**
  * Enable write protect for the read-only code.
@@ -177,7 +158,7 @@ int flash_get_size(void);
  *			in memory, unless function fails, iwc it is unset.
  * @return size of flash region available at *ptrp, or -1 on error
  */
-int flash_dataptr(int offset, int size_req, int align, char **ptrp);
+int flash_dataptr(int offset, int size_req, int align, const char **ptrp);
 
 /**
  * Write to flash.