From ac0d98cd557e0939bd0f10ff68e2e648a74bbea6 Mon Sep 17 00:00:00 2001 From: Akshay Saraswat Date: Fri, 20 Feb 2015 13:27:12 +0530 Subject: Exynos542x: CPU: Power down all secondary cores This patch adds code to shutdown secondary cores. When U-boot comes up, all secondary cores appear powered on, which is undesirable and causes side effects while initializing these cores in kernel. Secondary core power down happens in following steps: Step-1: After Exynos power-on, primary core starts executing first. Step-2: In iROM code every core has to check 2 flags i.e. addresses 0x02020028 & 0x02020004. Step-3: Initially 0x02020028 is 0 for all cores and 0x02020004 has a jump address for primary core and 0 for all secondary cores. Step-4: Therefore, primary core follows normal iROM execution and jumps to BL1 eventually, whereas all secondary cores enter WFE. Step-5: When primary core comes into function secondary_cores_configure, it puts pointer to function power_down_core into 0x02020004 and provides DSB and SEV for all cores so that they may come out of WFE and jump to power_down_core function. Step-6: And ultimately because of power_down_core all secondary cores shut-down. Signed-off-by: Kimoon Kim Signed-off-by: Akshay Saraswat Signed-off-by: Minkyu Kang --- arch/arm/include/asm/arch-exynos/system.h | 87 +++++++++++++++++++++++++++++++ 1 file changed, 87 insertions(+) (limited to 'arch/arm/include/asm/arch-exynos/system.h') diff --git a/arch/arm/include/asm/arch-exynos/system.h b/arch/arm/include/asm/arch-exynos/system.h index 4968d3dd2e..86903c3696 100644 --- a/arch/arm/include/asm/arch-exynos/system.h +++ b/arch/arm/include/asm/arch-exynos/system.h @@ -37,6 +37,93 @@ struct exynos5_sysreg { #define USB20_PHY_CFG_HOST_LINK_EN (1 << 0) +#ifdef CONFIG_EXYNOS5420 +/* + * Data Synchronization Barrier acts as a special kind of memory barrier. + * No instruction in program order after this instruction executes until + * this instruction completes. This instruction completes when: + * - All explicit memory accesses before this instruction complete. + * - All Cache, Branch predictor and TLB maintenance operations before + * this instruction complete. + */ +#define dsb() __asm__ __volatile__ ("dsb\n\t" : : ); + +/* + * This instruction causes an event to be signaled to all cores + * within a multiprocessor system. If SEV is implemented, + * WFE must also be implemented. + */ +#define sev() __asm__ __volatile__ ("sev\n\t" : : ); +/* + * If the Event Register is not set, WFE suspends execution until + * one of the following events occurs: + * - an IRQ interrupt, unless masked by the CPSR I-bit + * - an FIQ interrupt, unless masked by the CPSR F-bit + * - an Imprecise Data abort, unless masked by the CPSR A-bit + * - a Debug Entry request, if Debug is enabled + * - an Event signaled by another processor using the SEV instruction. + * If the Event Register is set, WFE clears it and returns immediately. + * If WFE is implemented, SEV must also be implemented. + */ +#define wfe() __asm__ __volatile__ ("wfe\n\t" : : ); + +/* Move 0xd3 value to CPSR register to enable SVC mode */ +#define svc32_mode_en() __asm__ __volatile__ \ + ("@ I&F disable, Mode: 0x13 - SVC\n\t" \ + "msr cpsr_c, #0x13|0xC0\n\t" : : ) + +/* Set program counter with the given value */ +#define set_pc(x) __asm__ __volatile__ ("mov pc, %0\n\t" : : "r"(x)) + +/* Read Main Id register */ +#define mrc_midr(x) __asm__ __volatile__ \ + ("mrc p15, 0, %0, c0, c0, 0\n\t" : "=r"(x) : ) + +/* Read Multiprocessor Affinity Register */ +#define mrc_mpafr(x) __asm__ __volatile__ \ + ("mrc p15, 0, %0, c0, c0, 5\n\t" : "=r"(x) : ) + +/* Read System Control Register */ +#define mrc_sctlr(x) __asm__ __volatile__ \ + ("mrc p15, 0, %0, c1, c0, 0\n\t" : "=r"(x) : ) + +/* Read Auxiliary Control Register */ +#define mrc_auxr(x) __asm__ __volatile__ \ + ("mrc p15, 0, %0, c1, c0, 1\n\t" : "=r"(x) : ) + +/* Read L2 Control register */ +#define mrc_l2_ctlr(x) __asm__ __volatile__ \ + ("mrc p15, 1, %0, c9, c0, 2\n\t" : "=r"(x) : ) + +/* Read L2 Auxilliary Control register */ +#define mrc_l2_aux_ctlr(x) __asm__ __volatile__ \ + ("mrc p15, 1, %0, c15, c0, 0\n\t" : "=r"(x) : ) + +/* Write System Control Register */ +#define mcr_sctlr(x) __asm__ __volatile__ \ + ("mcr p15, 0, %0, c1, c0, 0\n\t" : : "r"(x)) + +/* Write Auxiliary Control Register */ +#define mcr_auxr(x) __asm__ __volatile__ \ + ("mcr p15, 0, %0, c1, c0, 1\n\t" : : "r"(x)) + +/* Invalidate all instruction caches to PoU */ +#define mcr_icache(x) __asm__ __volatile__ \ + ("mcr p15, 0, %0, c7, c5, 0\n\t" : : "r"(x)) + +/* Invalidate unified TLB */ +#define mcr_tlb(x) __asm__ __volatile__ \ + ("mcr p15, 0, %0, c8, c7, 0\n\t" : : "r"(x)) + +/* Write L2 Control register */ +#define mcr_l2_ctlr(x) __asm__ __volatile__ \ + ("mcr p15, 1, %0, c9, c0, 2\n\t" : : "r"(x)) + +/* Write L2 Auxilliary Control register */ +#define mcr_l2_aux_ctlr(x) __asm__ __volatile__ \ + ("mcr p15, 1, %0, c15, c0, 0\n\t" : : "r"(x)) +#endif + void set_usbhost_mode(unsigned int mode); void set_system_display_ctrl(void); int exynos_lcd_early_init(const void *blob); -- cgit v1.2.1 From cecf2db23b256d84ed54e1442b646f07373e5caa Mon Sep 17 00:00:00 2001 From: Akshay Saraswat Date: Fri, 20 Feb 2015 13:27:18 +0530 Subject: Exynos542x: Fix secondary core booting for thumb When compiled SPL for Thumb secondary cores failed to boot at the kernel boot up. Only one core came up out of 4. This was happening because the code relocated to the address 0x02073000 by the primary core was an ARM asm code which was executed by the secondary cores as if it was a thumb code. This patch fixes the issue of secondary cores considering relocated code as Thumb instructions and not ARM instructions by jumping to the relocated with the help of "bx" ARM instruction. "bx" instruction changes the 5th bit of CPSR which allows execution unit to consider the following instructions as ARM instructions. Signed-off-by: Akshay Saraswat Reviewed-by: Simon Glass Tested-by: Simon Glass Signed-off-by: Minkyu Kang --- arch/arm/include/asm/arch-exynos/system.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'arch/arm/include/asm/arch-exynos/system.h') diff --git a/arch/arm/include/asm/arch-exynos/system.h b/arch/arm/include/asm/arch-exynos/system.h index 86903c3696..a9fd5e6aa4 100644 --- a/arch/arm/include/asm/arch-exynos/system.h +++ b/arch/arm/include/asm/arch-exynos/system.h @@ -75,6 +75,9 @@ struct exynos5_sysreg { /* Set program counter with the given value */ #define set_pc(x) __asm__ __volatile__ ("mov pc, %0\n\t" : : "r"(x)) +/* Branch to the given location */ +#define branch_bx(x) __asm__ __volatile__ ("bx %0\n\t" : : "r"(x)) + /* Read Main Id register */ #define mrc_midr(x) __asm__ __volatile__ \ ("mrc p15, 0, %0, c0, c0, 0\n\t" : "=r"(x) : ) -- cgit v1.2.1 From 306f527eff269e48a98c9d83016df6d6877dbb6a Mon Sep 17 00:00:00 2001 From: Doug Anderson Date: Fri, 20 Feb 2015 13:27:20 +0530 Subject: Exynos: Fix L2 cache timings on Exynos5420 and Exynos5800 It was found that the L2 cache timings that we had before could cause freezes and hangs. We should make things more robust with better timings. Currently the production ChromeOS kernel applies these timings, but it's nice to fixup firmware too (and upstream probably won't take our kernel hacks). This also provides a big cleanup of the L2 cache init code avoiding some duplication. The way things used to work: * low_power_start() was installed by the SPL (both at boot and resume time) and left resident in iRAM for the kernel to use when bringing up additional CPUs. It used configure_l2_ctlr() and configure_l2_actlr() when it detected it was on an A15. This was needed (despite the L2 cache registers being shared among all A15s) because we might have been the first man in after the whole A15 cluster was shutdown. * secondary_cores_configure() was called on at boot time and at resume time. Strangely this called configure_l2_ctlr() but not configure_l2_actlr() which was almost certainly wrong. Given that we'll call both (see next bullet) later in the boot process it didn't matter for normal boot, but I guess this is how L2 cache settings got set on 5420/5800 (but not 5250?) at resume time. * exynos5_set_l2cache_params() was called as part of cache enablement. This should happen at boot time (normally in the SPL except for USB boot where it happens in main U-Boot). Note that the old code wasn't setting ECC/parity in the cache enablement code but we happened to get it anyway because we'd call secondary_cores_configure() at boot time. For resume time we'd get it anyway when the 2nd A15 core came up. Let's make this a whole lot simpler. Now we always set these parameters in the same place for all boots and use the same code for setting up secondary CPUs. Intended net effects of this change (other than cleanup): * Timings go from before: data: 0 cycle setup, 3 cycles (0x2) latency tag: 0 cycle setup, 3 cycles (0x2) latency after: data: 1 cycle setup, 4 cycles (0x3) latency tag: 1 cycle setup, 4 cycles (0x3) latency * L2ACTLR is properly initted on 5420/5800 in all cases. One note is that we're still relying on luck to keep low_power_start() working. The compiler is being nice and not storing anything on the stack. Another note is that on its own this patch won't help to fix cache settings in an RW U-Boot update where we still have the RO SPL. The plan for that is: * Have RW U-Boot re-init the cache right before calling the kernel (after it has turned the L2 cache off). This is why the functions are in a header file instead of lowlevel_init.c. * Have the kernel save the L2 cache settings of the boot CPU and apply them to all other CPUs. We get a little lucky here because the old code was using "|=" to modify the registers and all of the bits that it's setting are also present in the new settings (!). That means that when the 2nd CPU in the A15 cluster comes up it doesn't actually mess up the settings of the 1st CPU in the A15 cluster. An alternative option is to have the kernel write its own low_power_start() code. Signed-off-by: Doug Anderson Signed-off-by: Akshay Saraswat Signed-off-by: Minkyu Kang --- arch/arm/include/asm/arch-exynos/system.h | 2 -- 1 file changed, 2 deletions(-) (limited to 'arch/arm/include/asm/arch-exynos/system.h') diff --git a/arch/arm/include/asm/arch-exynos/system.h b/arch/arm/include/asm/arch-exynos/system.h index a9fd5e6aa4..3ffb296a57 100644 --- a/arch/arm/include/asm/arch-exynos/system.h +++ b/arch/arm/include/asm/arch-exynos/system.h @@ -37,7 +37,6 @@ struct exynos5_sysreg { #define USB20_PHY_CFG_HOST_LINK_EN (1 << 0) -#ifdef CONFIG_EXYNOS5420 /* * Data Synchronization Barrier acts as a special kind of memory barrier. * No instruction in program order after this instruction executes until @@ -125,7 +124,6 @@ struct exynos5_sysreg { /* Write L2 Auxilliary Control register */ #define mcr_l2_aux_ctlr(x) __asm__ __volatile__ \ ("mcr p15, 1, %0, c15, c0, 0\n\t" : : "r"(x)) -#endif void set_usbhost_mode(unsigned int mode); void set_system_display_ctrl(void); -- cgit v1.2.1