From patchwork Fri Dec 11 12:42:31 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Dasgupta, Romit" X-Patchwork-Id: 66641 X-Patchwork-Delegate: khilman@deeprootsystems.com Received: from vger.kernel.org (vger.kernel.org [209.132.176.167]) by demeter.kernel.org (8.14.2/8.14.2) with ESMTP id nBBCgehx025593 for ; Fri, 11 Dec 2009 12:42:40 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754457AbZLKMmb (ORCPT ); Fri, 11 Dec 2009 07:42:31 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753732AbZLKMmb (ORCPT ); Fri, 11 Dec 2009 07:42:31 -0500 Received: from arroyo.ext.ti.com ([192.94.94.40]:36141 "EHLO arroyo.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754217AbZLKMma (ORCPT ); Fri, 11 Dec 2009 07:42:30 -0500 Received: from dbdp31.itg.ti.com ([172.24.170.98]) by arroyo.ext.ti.com (8.13.7/8.13.7) with ESMTP id nBBCgYMP007532 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Fri, 11 Dec 2009 06:42:37 -0600 Received: from [172.24.191.66] (localhost [127.0.0.1]) by dbdp31.itg.ti.com (8.13.8/8.13.8) with ESMTP id nBBCgVMe009911; Fri, 11 Dec 2009 18:12:31 +0530 (IST) Subject: [PATCH] OMAP3: PM: Dynamic calculation of SDRC clock stabilization delay From: Romit Dasgupta Reply-To: romit@ti.com To: linux-omap@vger.kernel.org Cc: teerth@ti.com, nm@ti.com Organization: Texas Instruments Date: Fri, 11 Dec 2009 18:12:31 +0530 Message-ID: <1260535351.18582.2.camel@boson> Mime-Version: 1.0 X-Mailer: Evolution 2.28.1 Sender: linux-omap-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org diff --git a/arch/arm/mach-omap2/clock34xx.c b/arch/arm/mach-omap2/clock34xx.c index da5bc1f..dd49938 100644 --- a/arch/arm/mach-omap2/clock34xx.c +++ b/arch/arm/mach-omap2/clock34xx.c @@ -37,6 +37,8 @@ #include #include +#include + #include #include "clock.h" #include "prm.h" @@ -46,6 +48,8 @@ static const struct clkops clkops_noncore_dpll_ops; +unsigned int delay_sram; + static void omap3430es2_clk_ssi_find_idlest(struct clk *clk, void __iomem **idlest_reg, u8 *idlest_bit); @@ -333,14 +337,9 @@ static struct omap_clk omap34xx_clks[] = { /* Scale factor for fixed-point arith in omap3_core_dpll_m2_set_rate() */ #define SDRC_MPURATE_SCALE 8 -/* 2^SDRC_MPURATE_BASE_SHIFT: MPU MHz that SDRC_MPURATE_LOOPS is defined for */ -#define SDRC_MPURATE_BASE_SHIFT 9 - -/* - * SDRC_MPURATE_LOOPS: Number of MPU loops to execute at - * 2^MPURATE_BASE_SHIFT MHz for SDRC to stabilize - */ -#define SDRC_MPURATE_LOOPS 96 +/* SDRC_TIME_STABILIZE: Time for SDRC to stabilize in us */ +/* hardcoded currently */ +#define SDRC_TIME_STABILIZE 6 /* * DPLL5_FREQ_FOR_USBHOST: USBHOST and USBTLL are the only clocks @@ -870,16 +869,10 @@ static int omap3_core_dpll_m2_set_rate(struct clk *clk, unsigned long rate) unlock_dll = 1; } - /* - * XXX This only needs to be done when the CPU frequency changes - */ + /* Calculate the number of MPU cycles to wait for SDRC to stabilize */ + mpurate = arm_fck.rate / CYCLES_PER_MHZ; - c = (mpurate << SDRC_MPURATE_SCALE) >> SDRC_MPURATE_BASE_SHIFT; - c += 1; /* for safety */ - c *= SDRC_MPURATE_LOOPS; - c >>= SDRC_MPURATE_SCALE; - if (c == 0) - c = 1; + c = ((SDRC_TIME_STABILIZE * mpurate) / (delay_sram * 2)); pr_debug("clock: changing CORE DPLL rate from %lu to %lu\n", clk->rate, validrate); @@ -1228,6 +1221,11 @@ int __init omap2_clk_init(void) vclk = clk_get(NULL, "virt_prcm_set"); sclk = clk_get(NULL, "sys_ck"); #endif + + /* Measure sram delay */ + delay_sram = measure_sram_delay(10000)/(10000*2); + pr_debug("SRAM delay: %d\n", delay_sram); + return 0; } diff --git a/arch/arm/mach-omap2/sram34xx.S b/arch/arm/mach-omap2/sram34xx.S index 82aa4a3..dc0ac72 100644 --- a/arch/arm/mach-omap2/sram34xx.S +++ b/arch/arm/mach-omap2/sram34xx.S @@ -298,3 +298,10 @@ core_m2_mask_val: ENTRY(omap3_sram_configure_core_dpll_sz) .word . - omap3_sram_configure_core_dpll +ENTRY(__sram_wait_delay) + subs r0, r0, #1 + bne __sram_wait_delay + bx lr + +ENTRY(__sram_wait_delay_sz) + .word . - __sram_wait_delay diff --git a/arch/arm/plat-omap/Makefile b/arch/arm/plat-omap/Makefile index 95f8413..aac43da 100644 --- a/arch/arm/plat-omap/Makefile +++ b/arch/arm/plat-omap/Makefile @@ -15,6 +15,7 @@ obj-$(CONFIG_ARCH_OMAP16XX) += ocpi.o # omap_device support (OMAP2+ only at the moment) obj-$(CONFIG_ARCH_OMAP2) += omap_device.o obj-$(CONFIG_ARCH_OMAP3) += omap_device.o +obj-$(CONFIG_ARCH_OMAP3) += pmc.o obj-$(CONFIG_OMAP_MCBSP) += mcbsp.o obj-$(CONFIG_OMAP_IOMMU) += iommu.o iovmm.o diff --git a/arch/arm/plat-omap/include/plat/pmc.h b/arch/arm/plat-omap/include/plat/pmc.h new file mode 100644 index 0000000..6d73782 --- /dev/null +++ b/arch/arm/plat-omap/include/plat/pmc.h @@ -0,0 +1,9 @@ +#ifndef __PMC_H__ +#define __PMC_H__ +extern void start_perf_counter(void); +extern void start_cycle_counter(void); +extern void stop_cycle_counter(void); +extern void stop_perf_counter(void); +extern unsigned int cycle_count(void); +extern unsigned int delay_sram; +#endif diff --git a/arch/arm/plat-omap/include/plat/sram.h b/arch/arm/plat-omap/include/plat/sram.h index 16a1b45..6019ed8 100644 --- a/arch/arm/plat-omap/include/plat/sram.h +++ b/arch/arm/plat-omap/include/plat/sram.h @@ -69,6 +69,12 @@ extern u32 omap3_sram_configure_core_dpll( u32 sdrc_actim_ctrl_b_1, u32 sdrc_mr_1); extern unsigned long omap3_sram_configure_core_dpll_sz; +extern unsigned int measure_sram_delay(unsigned int); + +extern u32 __sram_wait_delay( + unsigned int); +extern unsigned long __sram_wait_delay_sz; + #ifdef CONFIG_PM extern void omap_push_sram_idle(void); #else diff --git a/arch/arm/plat-omap/pmc.c b/arch/arm/plat-omap/pmc.c new file mode 100644 index 0000000..11acf42 --- /dev/null +++ b/arch/arm/plat-omap/pmc.c @@ -0,0 +1,47 @@ +#include + +void start_perf_counter(void) +{ + unsigned int r1 = 0; + asm("mrc p15, 0, %0, c9, c12, 0" : "=r" (r1)); + r1 |= 0x1; /* enable counters */ + asm("mcr p15, 0, %0, c9, c12, 0" : : "r" (r1)); + return; +} +EXPORT_SYMBOL(start_perf_counter); + +void start_cycle_counter(void) +{ + unsigned int r2 = 0; + r2 = 0x80000000; /* enable cycle counter only */ + asm("mcr p15, 0, %0, c9, c12, 1" : : "r" (r2)); + return; +} +EXPORT_SYMBOL(start_cycle_counter); + +unsigned int cycle_count(void) +{ + unsigned int rd = 0; + asm("mrc p15, 0, %0, c9, c13, 0" : "=r" (rd)); + return rd; +} +EXPORT_SYMBOL(cycle_count); + + +void stop_cycle_counter(void) +{ + unsigned int r3 = 0; + r3 = 0x0; /* disable cycle counter */ + asm("mcr p15, 0, %0, c9, c12, 1" : : "r" (r3)); + return; +} +EXPORT_SYMBOL(stop_cycle_counter); + +void stop_perf_counter(void) +{ + unsigned int r1 = 0; + r1 = 0x0; /* disable counters */ + asm("mcr p15, 0, %0, c9, c12, 0" : : "r" (r1)); + return; +} +EXPORT_SYMBOL(stop_perf_counter); diff --git a/arch/arm/plat-omap/sram.c b/arch/arm/plat-omap/sram.c index 3e92366..4ed6a48 100644 --- a/arch/arm/plat-omap/sram.c +++ b/arch/arm/plat-omap/sram.c @@ -29,6 +29,10 @@ #include #include +#ifdef CONFIG_ARCH_OMAP3 +#include +#endif + #include #if defined(CONFIG_ARCH_OMAP2) || defined(CONFIG_ARCH_OMAP3) @@ -423,6 +427,25 @@ static inline int omap34xx_sram_init(void) } #endif + +#ifdef CONFIG_ARCH_OMAP3 +unsigned int measure_sram_delay(unsigned int loop) +{ + unsigned int start = 0, end = 0; + void (*_omap3_sram_delay)(unsigned long); + _omap3_sram_delay = omap_sram_push(__sram_wait_delay, + __sram_wait_delay_sz); + start_perf_counter(); + start_cycle_counter(); + start = cycle_count(); + _omap3_sram_delay(loop); + end = cycle_count(); + stop_cycle_counter(); + stop_perf_counter(); + return end - start; +} +#endif + int __init omap_sram_init(void) { omap_detect_sram();