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authorArnd Bergmann <arnd@arndb.de>2014-04-15 15:38:39 +0200
committerArnd Bergmann <arnd@arndb.de>2015-12-01 21:44:24 +0100
commitd33c43ac185e2921e0f541872719588c3d491c60 (patch)
treeda03c6f7cbc9c939d2ccc4c5f1a4bfe4ad8a7209
parent990f2f223cb479a15afda9eb8552582aa82e2404 (diff)
ARM: make xscale iwmmxt code multiplatform aware
In a multiplatform configuration, we may end up building a kernel for both Marvell PJ1 and an ARMv4 CPU implementation. In that case, the xscale-cp0 code is built with gcc -march=armv4{,t}, which results in a build error from the coprocessor instructions. Since we know this code will only have to run on an actual xscale processor, we can simply build the entire file for ARMv5TE. Related to this, we need to handle the iWMMXT initialization sequence differently during boot, to ensure we don't try to touch xscale specific registers on other CPUs from the xscale_cp0_init initcall. cpu_is_xscale() used to be hardcoded to '1' in any configuration that enables any XScale-compatible core, but this breaks once we can have a combined kernel with MMP1 and something else. In this patch, I replace the existing cpu_is_xscale() macro with a new cpu_is_xscale_family() macro that evaluates true for xscale, xsc3 and mohawk, which makes the behavior more deterministic. The two existing users of cpu_is_xscale() are modified accordingly, but slightly change behavior for kernels that enable CPU_MOHAWK without also enabling CPU_XSCALE or CPU_XSC3. Previously, these would leave leave PMD_BIT4 in the page tables untouched, now they clear it as we've always done for kernels that enable both MOHAWK and the support for the older CPU types. Since the previous behavior was inconsistent, I assume it was unintentional. Signed-off-by: Arnd Bergmann <arnd@arndb.de>
-rw-r--r--arch/arm/include/asm/cputype.h22
-rw-r--r--arch/arm/kernel/xscale-cp0.c7
-rw-r--r--arch/arm/mm/idmap.c2
-rw-r--r--arch/arm/mm/mmu.c2
4 files changed, 28 insertions, 5 deletions
diff --git a/arch/arm/include/asm/cputype.h b/arch/arm/include/asm/cputype.h
index 85e374f873ac..b23c6c81c9ad 100644
--- a/arch/arm/include/asm/cputype.h
+++ b/arch/arm/include/asm/cputype.h
@@ -228,10 +228,26 @@ static inline int cpu_is_xsc3(void)
}
#endif
-#if !defined(CONFIG_CPU_XSCALE) && !defined(CONFIG_CPU_XSC3)
-#define cpu_is_xscale() 0
+#if !defined(CONFIG_CPU_XSCALE) && !defined(CONFIG_CPU_XSC3) && \
+ !defined(CONFIG_CPU_MOHAWK)
+#define cpu_is_xscale_family() 0
#else
-#define cpu_is_xscale() 1
+static inline int cpu_is_xscale_family(void)
+{
+ unsigned int id;
+ id = read_cpuid_id() & 0xffffe000;
+
+ switch (id) {
+ case 0x69052000: /* Intel XScale 1 */
+ case 0x69054000: /* Intel XScale 2 */
+ case 0x69056000: /* Intel XScale 3 */
+ case 0x56056000: /* Marvell XScale 3 */
+ case 0x56158000: /* Marvell Mohawk */
+ return 1;
+ }
+
+ return 0;
+}
#endif
/*
diff --git a/arch/arm/kernel/xscale-cp0.c b/arch/arm/kernel/xscale-cp0.c
index bdbb8853a19b..77a2eef72115 100644
--- a/arch/arm/kernel/xscale-cp0.c
+++ b/arch/arm/kernel/xscale-cp0.c
@@ -15,6 +15,9 @@
#include <linux/init.h>
#include <linux/io.h>
#include <asm/thread_notify.h>
+#include <asm/cputype.h>
+
+asm(" .arch armv5te\n");
static inline void dsp_save_state(u32 *state)
{
@@ -152,6 +155,10 @@ static int __init xscale_cp0_init(void)
{
u32 cp_access;
+ /* do not attempt to probe iwmmxt on non-xscale family CPUs */
+ if (!cpu_is_xscale_family())
+ return 0;
+
cp_access = xscale_cp_access_read() & ~3;
xscale_cp_access_write(cp_access | 1);
diff --git a/arch/arm/mm/idmap.c b/arch/arm/mm/idmap.c
index e7a81cebbb2e..d65909697165 100644
--- a/arch/arm/mm/idmap.c
+++ b/arch/arm/mm/idmap.c
@@ -86,7 +86,7 @@ static void identity_mapping_add(pgd_t *pgd, const char *text_start,
prot |= PMD_TYPE_SECT | PMD_SECT_AP_WRITE | PMD_SECT_AF;
- if (cpu_architecture() <= CPU_ARCH_ARMv5TEJ && !cpu_is_xscale())
+ if (cpu_architecture() <= CPU_ARCH_ARMv5TEJ && !cpu_is_xscale_family())
prot |= PMD_BIT4;
pgd += pgd_index(addr);
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 4867f5daf82c..e0e911ea32e6 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -477,7 +477,7 @@ static void __init build_mem_type_table(void)
* "update-able on write" bit on ARM610). However, Xscale and
* Xscale3 require this bit to be cleared.
*/
- if (cpu_is_xscale() || cpu_is_xsc3()) {
+ if (cpu_is_xscale_family()) {
for (i = 0; i < ARRAY_SIZE(mem_types); i++) {
mem_types[i].prot_sect &= ~PMD_BIT4;
mem_types[i].prot_l1 &= ~PMD_BIT4;