mfd: db8500-prcmu: add function to read reset status

This patch adds a function that returns the value of the reset
status register at startup. It also changes the read of the
(software) reset code, so that the saved value is only read at
startup.

ST Ericsson ID: 366664
ST Ericsson FOSS-OUT ID: trivial

Signed-off-by: Mattias Nilsson <mattias.i.nilsson@stericsson.com>

1 files changed, 32 insertions, 1 deletions

diff --git a/drivers/mfd/db8500-prcmu.c b/drivers/mfd/db8500-prcmu.c
index 536566a890d..186206daab7 100644
--- a/drivers/mfd/db8500-prcmu.c
+++ b/drivers/mfd/db8500-prcmu.c
@@ -426,6 +426,13 @@ static DEFINE_SPINLOCK(clkout_lock);
 /* Global var to runtime determine TCDM base for v2 or v1 */
 static __iomem void *tcdm_base;
 
+/*
+ * Copies of the startup values of the reset status register and the SW reset
+ * code.
+ */
+static u32 reset_status_copy;
+static u16 reset_code_copy;
+
 struct clk_mgt {
 	void __iomem *reg;
 	u32 pllsw;
@@ -2404,7 +2411,17 @@ void db8500_prcmu_system_reset(u16 reset_code)
  */
 u16 db8500_prcmu_get_reset_code(void)
 {
-	return readw(tcdm_base + PRCM_SW_RST_REASON);
+	return reset_code_copy;
+}
+
+/**
+ * db8500_prcmu_get_reset_status - Retrieve reset status
+ *
+ * Retrieves the value of the reset status register as read at startup.
+ */
+u32 db8500_prcmu_get_reset_status(void)
+{
+	return reset_status_copy;
 }
 
 /**
@@ -2689,6 +2706,7 @@ void __init db8500_prcmu_early_init(void)
 {
 	unsigned int i;
 	void *tcpm_base = ioremap_nocache(U8500_PRCMU_TCPM_BASE, SZ_4K);
+	void __iomem *sec_base;
 
 	if (tcpm_base != NULL) {
 		u32 version;
@@ -2707,6 +2725,19 @@ void __init db8500_prcmu_early_init(void)
 
 	tcdm_base = __io_address(U8500_PRCMU_TCDM_BASE);
 
+	/*
+	 * Copy the value of the reset status register and if needed also
+	 * the software reset code.
+	 */
+	sec_base = ioremap_nocache(U8500_PRCMU_SEC_BASE, SZ_4K);
+	if (sec_base != NULL) {
+		reset_status_copy = readl(sec_base +
+			DB8500_SEC_PRCM_RESET_STATUS);
+		iounmap(sec_base);
+	}
+	if (reset_status_copy & DB8500_SEC_PRCM_RESET_STATUS_APE_SOFTWARE_RESET)
+		reset_code_copy = readw(tcdm_base + PRCM_SW_RST_REASON);
+
 	spin_lock_init(&mb0_transfer.lock);
 	spin_lock_init(&mb0_transfer.dbb_irqs_lock);
 	mutex_init(&mb0_transfer.ac_wake_lock);