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Subject[PATCH v2] ARC: [plat-hsdk]: allow to switch between AXI DMAC port configurations
Date
We want to use DW AXI DMAC on HSDK board in our automated verification
to test cache & dma kernel code changes. This is perfect candidate
as we don't depend on any external peripherals like MMC card / USB
storage / etc.
To increase test coverage we want to test both options:
* DW AXI DMAC is connected through IOC port & dma direct ops used
* DW AXI DMAC is connected to DDR port & dma noncoherent ops used

Introduce 'arc_hsdk_axi_dmac_coherent' global variable which can be
modified by debugger (same way as we patch 'ioc_enable') to switch
between these options without recompiling the kernel.
Depend on this value we tweak memory bridge configuration and
"dma-coherent" DTS property of DW AXI DMAC.

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
---
Changes v1->v2:
* Force putting arc_hsdk_axi_dmac_coherent to data section
* Add missed __init to hsdk_tweak_node_coherency

arch/arc/boot/dts/Makefile | 3 ++
arch/arc/plat-hsdk/platform.c | 87 ++++++++++++++++++++++++++++++-----
2 files changed, 78 insertions(+), 12 deletions(-)

diff --git a/arch/arc/boot/dts/Makefile b/arch/arc/boot/dts/Makefile
index a83c4f5e928b..8483a86c743d 100644
--- a/arch/arc/boot/dts/Makefile
+++ b/arch/arc/boot/dts/Makefile
@@ -12,3 +12,6 @@ dtb-y := $(builtindtb-y).dtb
# for CONFIG_OF_ALL_DTBS test
dtstree := $(srctree)/$(src)
dtb- := $(patsubst $(dtstree)/%.dts,%.dtb, $(wildcard $(dtstree)/*.dts))
+
+# board-specific dtc flags
+DTC_FLAGS_hsdk += --pad 20
diff --git a/arch/arc/plat-hsdk/platform.c b/arch/arc/plat-hsdk/platform.c
index 7dd2dd335cf6..0b961a2a10b8 100644
--- a/arch/arc/plat-hsdk/platform.c
+++ b/arch/arc/plat-hsdk/platform.c
@@ -6,11 +6,15 @@
*/

#include <linux/init.h>
+#include <linux/of_fdt.h>
+#include <linux/libfdt.h>
#include <linux/smp.h>
#include <asm/arcregs.h>
#include <asm/io.h>
#include <asm/mach_desc.h>

+int arc_hsdk_axi_dmac_coherent __section(.data) = 0;
+
#define ARC_CCM_UNUSED_ADDR 0x60000000

static void __init hsdk_init_per_cpu(unsigned int cpu)
@@ -97,6 +101,42 @@ static void __init hsdk_enable_gpio_intc_wire(void)
iowrite32(GPIO_INT_CONNECTED_MASK, (void __iomem *) GPIO_INTEN);
}

+static int __init hsdk_tweak_node_coherency(const char *path, bool coherent)
+{
+ void *fdt = initial_boot_params;
+ const void *prop;
+ int node, ret;
+ bool dt_coh_set;
+
+ node = fdt_path_offset(fdt, path);
+ if (node < 0)
+ goto tweak_fail;
+
+ prop = fdt_getprop(fdt, node, "dma-coherent", &ret);
+ if (!prop && ret != -FDT_ERR_NOTFOUND)
+ goto tweak_fail;
+
+ dt_coh_set = ret != -FDT_ERR_NOTFOUND;
+ ret = 0;
+
+ /* need to remove "dma-coherent" property */
+ if (dt_coh_set && !coherent)
+ ret = fdt_delprop(fdt, node, "dma-coherent");
+
+ /* need to set "dma-coherent" property */
+ if (!dt_coh_set && coherent)
+ ret = fdt_setprop(fdt, node, "dma-coherent", NULL, 0);
+
+ if (ret < 0)
+ goto tweak_fail;
+
+ return 0;
+
+tweak_fail:
+ pr_err("failed to tweak %s to %scoherent\n", path, coherent ? "" : "non");
+ return -EFAULT;
+}
+
enum hsdk_axi_masters {
M_HS_CORE = 0,
M_HS_RTT,
@@ -162,6 +202,39 @@ enum hsdk_axi_masters {
#define CREG_PAE ((void __iomem *)(CREG_BASE + 0x180))
#define CREG_PAE_UPDT ((void __iomem *)(CREG_BASE + 0x194))

+static void __init hsdk_init_memory_bridge_axi_dmac(void)
+{
+ bool coherent = !!arc_hsdk_axi_dmac_coherent;
+ u32 axi_m_slv1, axi_m_oft1;
+
+ /*
+ * Don't tweak memory bridge configuration if we failed to tweak DTB
+ * as we will end up in a inconsistent state.
+ */
+ if (hsdk_tweak_node_coherency("/soc/dmac@80000", coherent))
+ return;
+
+ if (coherent) {
+ axi_m_slv1 = 0x77999999;
+ axi_m_oft1 = 0x76DCBA98;
+ } else {
+ axi_m_slv1 = 0x77777777;
+ axi_m_oft1 = 0x76543210;
+ }
+
+ writel(0x77777777, CREG_AXI_M_SLV0(M_DMAC_0));
+ writel(0xFEDCBA98, CREG_AXI_M_OFT0(M_DMAC_0));
+ writel(axi_m_slv1, CREG_AXI_M_SLV1(M_DMAC_0));
+ writel(axi_m_oft1, CREG_AXI_M_OFT1(M_DMAC_0));
+ writel(UPDATE_VAL, CREG_AXI_M_UPDT(M_DMAC_0));
+
+ writel(0x77777777, CREG_AXI_M_SLV0(M_DMAC_1));
+ writel(0xFEDCBA98, CREG_AXI_M_OFT0(M_DMAC_1));
+ writel(axi_m_slv1, CREG_AXI_M_SLV1(M_DMAC_1));
+ writel(axi_m_oft1, CREG_AXI_M_OFT1(M_DMAC_1));
+ writel(UPDATE_VAL, CREG_AXI_M_UPDT(M_DMAC_1));
+}
+
static void __init hsdk_init_memory_bridge(void)
{
u32 reg;
@@ -227,24 +300,14 @@ static void __init hsdk_init_memory_bridge(void)
writel(0x76543210, CREG_AXI_M_OFT1(M_GPU));
writel(UPDATE_VAL, CREG_AXI_M_UPDT(M_GPU));

- writel(0x77777777, CREG_AXI_M_SLV0(M_DMAC_0));
- writel(0x77777777, CREG_AXI_M_SLV1(M_DMAC_0));
- writel(0xFEDCBA98, CREG_AXI_M_OFT0(M_DMAC_0));
- writel(0x76543210, CREG_AXI_M_OFT1(M_DMAC_0));
- writel(UPDATE_VAL, CREG_AXI_M_UPDT(M_DMAC_0));
-
- writel(0x77777777, CREG_AXI_M_SLV0(M_DMAC_1));
- writel(0x77777777, CREG_AXI_M_SLV1(M_DMAC_1));
- writel(0xFEDCBA98, CREG_AXI_M_OFT0(M_DMAC_1));
- writel(0x76543210, CREG_AXI_M_OFT1(M_DMAC_1));
- writel(UPDATE_VAL, CREG_AXI_M_UPDT(M_DMAC_1));
-
writel(0x00000000, CREG_AXI_M_SLV0(M_DVFS));
writel(0x60000000, CREG_AXI_M_SLV1(M_DVFS));
writel(0x00000000, CREG_AXI_M_OFT0(M_DVFS));
writel(0x00000000, CREG_AXI_M_OFT1(M_DVFS));
writel(UPDATE_VAL, CREG_AXI_M_UPDT(M_DVFS));

+ hsdk_init_memory_bridge_axi_dmac();
+
/*
* PAE remapping for DMA clients does not work due to an RTL bug, so
* CREG_PAE register must be programmed to all zeroes, otherwise it
--
2.21.0
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