summaryrefslogtreecommitdiff
path: root/arch/arc/plat-hsdk/platform.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/arc/plat-hsdk/platform.c')
-rw-r--r--arch/arc/plat-hsdk/platform.c62
1 files changed, 62 insertions, 0 deletions
diff --git a/arch/arc/plat-hsdk/platform.c b/arch/arc/plat-hsdk/platform.c
index 2958aedb649a..2588b842407c 100644
--- a/arch/arc/plat-hsdk/platform.c
+++ b/arch/arc/plat-hsdk/platform.c
@@ -42,6 +42,66 @@ static void __init hsdk_init_per_cpu(unsigned int cpu)
#define SDIO_UHS_REG_EXT (SDIO_BASE + 0x108)
#define SDIO_UHS_REG_EXT_DIV_2 (2 << 30)
+#define HSDK_GPIO_INTC (ARC_PERIPHERAL_BASE + 0x3000)
+
+static void __init hsdk_enable_gpio_intc_wire(void)
+{
+ /*
+ * Peripherals on CPU Card are wired to cpu intc via intermediate
+ * DW APB GPIO blocks (mainly for debouncing)
+ *
+ * ---------------------
+ * | snps,archs-intc |
+ * ---------------------
+ * |
+ * ----------------------
+ * | snps,archs-idu-intc |
+ * ----------------------
+ * | | | | |
+ * | [eth] [USB] [... other peripherals]
+ * |
+ * -------------------
+ * | snps,dw-apb-intc |
+ * -------------------
+ * | | | |
+ * [Bt] [HAPS] [... other peripherals]
+ *
+ * Current implementation of "irq-dw-apb-ictl" driver doesn't work well
+ * with stacked INTCs. In particular problem happens if its master INTC
+ * not yet instantiated. See discussion here -
+ * https://lkml.org/lkml/2015/3/4/755
+ *
+ * So setup the first gpio block as a passive pass thru and hide it from
+ * DT hardware topology - connect intc directly to cpu intc
+ * The GPIO "wire" needs to be init nevertheless (here)
+ *
+ * One side adv is that peripheral interrupt handling avoids one nested
+ * intc ISR hop
+ *
+ * According to HSDK User's Manual [1], "Table 2 Interrupt Mapping"
+ * we have the following GPIO input lines used as sources of interrupt:
+ * - GPIO[0] - Bluetooth interrupt of RS9113 module
+ * - GPIO[2] - HAPS interrupt (on HapsTrak 3 connector)
+ * - GPIO[3] - Audio codec (MAX9880A) interrupt
+ * - GPIO[8-23] - Available on Arduino and PMOD_x headers
+ * For now there's no use of Arduino and PMOD_x headers in Linux
+ * use-case so we only enable lines 0, 2 and 3.
+ *
+ * [1] https://github.com/foss-for-synopsys-dwc-arc-processors/ARC-Development-Systems-Forum/wiki/docs/ARC_HSDK_User_Guide.pdf
+ */
+#define GPIO_INTEN (HSDK_GPIO_INTC + 0x30)
+#define GPIO_INTMASK (HSDK_GPIO_INTC + 0x34)
+#define GPIO_INTTYPE_LEVEL (HSDK_GPIO_INTC + 0x38)
+#define GPIO_INT_POLARITY (HSDK_GPIO_INTC + 0x3c)
+#define GPIO_INT_CONNECTED_MASK 0x0d
+
+ iowrite32(0xffffffff, (void __iomem *) GPIO_INTMASK);
+ iowrite32(~GPIO_INT_CONNECTED_MASK, (void __iomem *) GPIO_INTMASK);
+ iowrite32(0x00000000, (void __iomem *) GPIO_INTTYPE_LEVEL);
+ iowrite32(0xffffffff, (void __iomem *) GPIO_INT_POLARITY);
+ iowrite32(GPIO_INT_CONNECTED_MASK, (void __iomem *) GPIO_INTEN);
+}
+
static void __init hsdk_init_early(void)
{
/*
@@ -62,6 +122,8 @@ static void __init hsdk_init_early(void)
* minimum possible div-by-2.
*/
iowrite32(SDIO_UHS_REG_EXT_DIV_2, (void __iomem *) SDIO_UHS_REG_EXT);
+
+ hsdk_enable_gpio_intc_wire();
}
static const char *hsdk_compat[] __initconst = {