LoongArch: Add writecombine support for DMW-based ioremap()

Currently, only TLB-based ioremap() support writecombine, so add the
counterpart for DMW-based ioremap() with help of DMW2. The base address
(WRITECOMBINE_BASE) is configured as 0xa000000000000000.

DMW3 is unused by kernel now, however firmware may leave garbage in them
and interfere kernel's address mapping. So clear it as necessary.

BTW, centralize the DMW configuration to macro SETUP_DMWINS.

Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

diff --git a/arch/loongarch/include/asm/addrspace.h b/arch/loongarch/include/asm/addrspace.h
index 7bd47d6..fe198b4 100644 (file)
--- a/arch/loongarch/include/asm/addrspace.h
+++ b/arch/loongarch/include/asm/addrspace.h
@@ -37,6 +37,10 @@ extern unsigned long vm_map_base;
 #define UNCACHE_BASE           CSR_DMW0_BASE
 #endif
 
+#ifndef WRITECOMBINE_BASE
+#define WRITECOMBINE_BASE      CSR_DMW2_BASE
+#endif
+
 #define DMW_PABITS     48
 #define TO_PHYS_MASK   ((1ULL << DMW_PABITS) - 1)
 

diff --git a/arch/loongarch/include/asm/io.h b/arch/loongarch/include/asm/io.h
index c2f9979..5e95a60 100644 (file)
--- a/arch/loongarch/include/asm/io.h
+++ b/arch/loongarch/include/asm/io.h
@@ -25,10 +25,16 @@ extern void __init early_iounmap(void __iomem *addr, unsigned long size);
 static inline void __iomem *ioremap_prot(phys_addr_t offset, unsigned long size,
                                         unsigned long prot_val)
 {
-       if (prot_val & _CACHE_CC)
+       switch (prot_val & _CACHE_MASK) {
+       case _CACHE_CC:
                return (void __iomem *)(unsigned long)(CACHE_BASE + offset);
-       else
+       case _CACHE_SUC:
                return (void __iomem *)(unsigned long)(UNCACHE_BASE + offset);
+       case _CACHE_WUC:
+               return (void __iomem *)(unsigned long)(WRITECOMBINE_BASE + offset);
+       default:
+               return NULL;
+       }
 }
 
 #define ioremap(offset, size)          \

diff --git a/arch/loongarch/include/asm/loongarch.h b/arch/loongarch/include/asm/loongarch.h
index eb09add..c430df5 100644 (file)
--- a/arch/loongarch/include/asm/loongarch.h
+++ b/arch/loongarch/include/asm/loongarch.h
@@ -877,7 +877,7 @@
 #define LOONGARCH_CSR_DMWIN2           0x182   /* 64 direct map win2: MEM */
 #define LOONGARCH_CSR_DMWIN3           0x183   /* 64 direct map win3: MEM */
 
-/* Direct Map window 0/1 */
+/* Direct Map window 0/1/2/3 */
 #define CSR_DMW0_PLV0          _CONST64_(1 << 0)
 #define CSR_DMW0_VSEG          _CONST64_(0x8000)
 #define CSR_DMW0_BASE          (CSR_DMW0_VSEG << DMW_PABITS)
@@ -889,6 +889,14 @@
 #define CSR_DMW1_BASE          (CSR_DMW1_VSEG << DMW_PABITS)
 #define CSR_DMW1_INIT          (CSR_DMW1_BASE | CSR_DMW1_MAT | CSR_DMW1_PLV0)
 
+#define CSR_DMW2_PLV0          _CONST64_(1 << 0)
+#define CSR_DMW2_MAT           _CONST64_(2 << 4)
+#define CSR_DMW2_VSEG          _CONST64_(0xa000)
+#define CSR_DMW2_BASE          (CSR_DMW2_VSEG << DMW_PABITS)
+#define CSR_DMW2_INIT          (CSR_DMW2_BASE | CSR_DMW2_MAT | CSR_DMW2_PLV0)
+
+#define CSR_DMW3_INIT          0x0
+
 /* Performance Counter registers */
 #define LOONGARCH_CSR_PERFCTRL0                0x200   /* 32 perf event 0 config */
 #define LOONGARCH_CSR_PERFCNTR0                0x201   /* 64 perf event 0 count value */

diff --git a/arch/loongarch/include/asm/stackframe.h b/arch/loongarch/include/asm/stackframe.h
index d9eafd3..6673683 100644 (file)
--- a/arch/loongarch/include/asm/stackframe.h
+++ b/arch/loongarch/include/asm/stackframe.h
@@ -38,6 +38,17 @@
        cfi_restore \reg \offset \docfi
        .endm
 
+       .macro SETUP_DMWINS temp
+       li.d    \temp, CSR_DMW0_INIT    # WUC, PLV0, 0x8000 xxxx xxxx xxxx
+       csrwr   \temp, LOONGARCH_CSR_DMWIN0
+       li.d    \temp, CSR_DMW1_INIT    # CAC, PLV0, 0x9000 xxxx xxxx xxxx
+       csrwr   \temp, LOONGARCH_CSR_DMWIN1
+       li.d    \temp, CSR_DMW2_INIT    # WUC, PLV0, 0xa000 xxxx xxxx xxxx
+       csrwr   \temp, LOONGARCH_CSR_DMWIN2
+       li.d    \temp, CSR_DMW3_INIT    # 0x0, unused
+       csrwr   \temp, LOONGARCH_CSR_DMWIN3
+       .endm
+
 /* Jump to the runtime virtual address. */
        .macro JUMP_VIRT_ADDR temp1 temp2
        li.d    \temp1, CACHE_BASE

diff --git a/arch/loongarch/kernel/head.S b/arch/loongarch/kernel/head.S
index 4677ea8..506a99a 100644 (file)
--- a/arch/loongarch/kernel/head.S
+++ b/arch/loongarch/kernel/head.S
@@ -44,11 +44,7 @@ SYM_DATA(kernel_fsize, .long _kernel_fsize);
 SYM_CODE_START(kernel_entry)                   # kernel entry point
 
        /* Config direct window and set PG */
-       li.d            t0, CSR_DMW0_INIT       # UC, PLV0, 0x8000 xxxx xxxx xxxx
-       csrwr           t0, LOONGARCH_CSR_DMWIN0
-       li.d            t0, CSR_DMW1_INIT       # CA, PLV0, 0x9000 xxxx xxxx xxxx
-       csrwr           t0, LOONGARCH_CSR_DMWIN1
-
+       SETUP_DMWINS    t0
        JUMP_VIRT_ADDR  t0, t1
 
        /* Enable PG */
@@ -124,11 +120,8 @@ SYM_CODE_END(kernel_entry)
  * function after setting up the stack and tp registers.
  */
 SYM_CODE_START(smpboot_entry)
-       li.d            t0, CSR_DMW0_INIT       # UC, PLV0
-       csrwr           t0, LOONGARCH_CSR_DMWIN0
-       li.d            t0, CSR_DMW1_INIT       # CA, PLV0
-       csrwr           t0, LOONGARCH_CSR_DMWIN1
 
+       SETUP_DMWINS    t0
        JUMP_VIRT_ADDR  t0, t1
 
 #ifdef CONFIG_PAGE_SIZE_4KB

diff --git a/arch/loongarch/power/suspend_asm.S b/arch/loongarch/power/suspend_asm.S
index e2fc3b4..c28ad52 100644 (file)
--- a/arch/loongarch/power/suspend_asm.S
+++ b/arch/loongarch/power/suspend_asm.S
@@ -73,11 +73,7 @@ SYM_FUNC_START(loongarch_suspend_enter)
         * Reload all of the registers and return.
         */
 SYM_INNER_LABEL(loongarch_wakeup_start, SYM_L_GLOBAL)
-       li.d            t0, CSR_DMW0_INIT       # UC, PLV0
-       csrwr           t0, LOONGARCH_CSR_DMWIN0
-       li.d            t0, CSR_DMW1_INIT       # CA, PLV0
-       csrwr           t0, LOONGARCH_CSR_DMWIN1
-
+       SETUP_DMWINS    t0
        JUMP_VIRT_ADDR  t0, t1
 
        /* Enable PG */

diff --git a/drivers/firmware/efi/libstub/loongarch.c b/drivers/firmware/efi/libstub/loongarch.c
index d0ef935..3782d0a 100644 (file)
--- a/drivers/firmware/efi/libstub/loongarch.c
+++ b/drivers/firmware/efi/libstub/loongarch.c
@@ -74,6 +74,8 @@ efi_status_t efi_boot_kernel(void *handle, efi_loaded_image_t *image,
        /* Config Direct Mapping */
        csr_write64(CSR_DMW0_INIT, LOONGARCH_CSR_DMWIN0);
        csr_write64(CSR_DMW1_INIT, LOONGARCH_CSR_DMWIN1);
+       csr_write64(CSR_DMW2_INIT, LOONGARCH_CSR_DMWIN2);
+       csr_write64(CSR_DMW3_INIT, LOONGARCH_CSR_DMWIN3);
 
        real_kernel_entry = (void *)kernel_entry_address(kernel_addr, image);