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Message-Id: <1430705875-6990-3-git-send-email-pure.logic@nexus-software.ie>
Date: Mon, 4 May 2015 03:17:55 +0100
From: Bryan O'Donoghue <pure.logic@...us-software.ie>
To: tglx@...utronix.de, mingo@...hat.com, hpa@...or.com,
x86@...nel.org, dvhart@...radead.org, pure.logic@...us-software.ie,
andy.schevchenko@...il.com, boon.leong.ong@...el.com,
linux-kernel@...r.kernel.org, platform-driver-x86@...r.kernel.org
Cc: derek.browne@...el.com, josef.ahmad@...el.com,
erik.nyquist@...el.com
Subject: [PATCH 2/2] x86/quark: Add Quark embedded SRAM self-test
Quark X1000 contains an embedded SRAM (eSRAM) a fast access SRAM. This code
is a self-test routine to measure the performance of that SRAM for
different read-values. The tests are designed the performance gains
provided by eSRAM using different read-sizes and comparing the performance
of eSRAM overlayed DRAM to raw DRAM.
Signed-off-by: Bryan O'Donoghue <pure.logic@...us-software.ie>
---
arch/x86/Kconfig.debug | 13 ++
arch/x86/platform/intel-quark/Makefile | 1 +
arch/x86/platform/intel-quark/esram_selftest.c | 159 +++++++++++++++++++++++++
3 files changed, 173 insertions(+)
create mode 100644 arch/x86/platform/intel-quark/esram_selftest.c
diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index 72484a6..bb62174 100644
--- a/arch/x86/Kconfig.debug
+++ b/arch/x86/Kconfig.debug
@@ -322,6 +322,19 @@ config DEBUG_IMR_SELFTEST
If unsure say N here.
+config DEBUG_ESRAM_SELFTEST
+ bool "Embedded SRAM self test"
+ default n
+ depends on INTEL_ESRAM
+ ---help---
+ This option enables automated sanity testing of the eSRAM driver
+ on Quark X1000. A simple set of tests with performance metrics
+ measured a DRAM baseline are run. These tests show the measured
+ performance increase across a given memory size for a series of
+ incrementing read sizes.
+
+ If unsure say N here.
+
config X86_DEBUG_STATIC_CPU_HAS
bool "Debug alternatives"
depends on DEBUG_KERNEL
diff --git a/arch/x86/platform/intel-quark/Makefile b/arch/x86/platform/intel-quark/Makefile
index 94adb0b..dc466be 100644
--- a/arch/x86/platform/intel-quark/Makefile
+++ b/arch/x86/platform/intel-quark/Makefile
@@ -1,3 +1,4 @@
obj-$(CONFIG_INTEL_IMR) += imr.o
obj-$(CONFIG_INTEL_ESRAM) += esram.o
obj-$(CONFIG_DEBUG_IMR_SELFTEST) += imr_selftest.o
+obj-$(CONFIG_DEBUG_ESRAM_SELFTEST) += esram_selftest.o
diff --git a/arch/x86/platform/intel-quark/esram_selftest.c b/arch/x86/platform/intel-quark/esram_selftest.c
new file mode 100644
index 0000000..7849dac
--- /dev/null
+++ b/arch/x86/platform/intel-quark/esram_selftest.c
@@ -0,0 +1,159 @@
+/**
+ * esram_selftest.c
+ *
+ * Copyright(c) 2015 Bryan O'Donoghue <pure.logic@...us-software.ie>
+ *
+ * IMR self test. The purpose of this module is to run a set of tests on the
+ * IMR API to validate it's sanity. We check for overlapping, reserved
+ * addresses and setup/teardown sanity.
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <asm/cpu_device_id.h>
+#include <asm/esram.h>
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/sizes.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+/**
+ * esram_self_test_time
+ *
+ * This function is carefully constructed to measure and verify the
+ * performance boost provided by eSRAM. We invalidate the cache with a
+ * wbinvd() and then perform a series of reads - each of which will cause a
+ * cacheline miss. We measure the aggregate time it takes to complete the
+ * series of reads and return the delta in cycles. The calling function will
+ * pass either a pointer to DRAM or a pointer to eSRAM.
+ *
+ * @param walker: Pointer to RAM area to test.
+ * @return: Number of cycles to complete test.
+ */
+static cycles_t esram_self_test_time(char *walker, ssize_t step, ssize_t size)
+{
+ volatile u32 dummy = 0;
+ int i;
+ int j;
+ cycle_t t1;
+ cycle_t t2;
+ u32 page_count = size / PAGE_SIZE;
+
+ local_irq_disable();
+ t1 = get_cycles();
+ for (i = 0; i < page_count; i++) {
+ for (j = 0; j < PAGE_SIZE/step; j++) {
+ dummy += *(u32 *)walker;
+ walker += step;
+ }
+ }
+ t2 = get_cycles();
+ local_irq_enable();
+
+ return t2 > t1 ? t2 - t1 : ULLONG_MAX - t2 + t1;
+}
+
+/**
+ * __get_percent - the the percentage that min is of max.
+ *
+ * @max: The larger value.
+ * @min: The smaller value.
+ * @return: The % of the max that the min is.
+*/
+static inline u32 __get_percent(u32 max, u32 min)
+{
+ max = max/100UL;
+ return 100UL - (min/max);
+}
+
+/**
+ * esram_self_test
+ *
+ * Verify eSRAM self_test with some simple tests to verify overlap,
+ * zero sized allocations and 1 KiB sized areas.
+ *
+ * return:
+ */
+static void __init esram_self_test(void)
+{
+ bool pass;
+ size_t size = SZ_512K;
+ cycles_t t1;
+ cycles_t t2;
+ u32 percent;
+ char *dram_mem;
+ unsigned long esram_mem;
+ int i;
+ struct gen_pool *pool = esram_get_genpool();
+ size_t steps[] = { 8, 16, 32, 64, 128 };
+
+ if (pool == NULL) {
+ pr_err("unable to get esram_genpool pointer!\n");
+ return;
+ }
+
+ esram_mem = gen_pool_alloc(pool, size);
+ if (esram_mem == 0) {
+ pr_err("gen_pool_alloc of %d KiB fail!\n", size);
+ return;
+ }
+ dram_mem = kzalloc(GFP_KERNEL, size);
+ if (dram_mem == NULL)
+ goto err;
+
+ /* Cycle through a series of tests, measurng cycle times as we go. */
+ for (i = 0; i < sizeof(steps)/sizeof(size_t); i++) {
+ t1 = esram_self_test_time(dram_mem, steps[i], size);
+ t2 = esram_self_test_time((char *)esram_mem, steps[i], size);
+ pass = t2 < t1;
+ if (pass)
+ percent = __get_percent(t1, t2);
+ else
+ percent = __get_percent(t2, t1);
+ pr_info("%s, %d%% %s DRAM:%10llu cycles, eSRAM:%10llu cycles, step-size:%3d\n",
+ pass ? "pass" : "fail", percent, pass ? "better" : "worse",
+ t1, t2, steps[i]);
+ }
+err:
+ if (dram_mem != NULL)
+ kfree(dram_mem);
+ if (esram_mem != 0)
+ gen_pool_free(pool, esram_mem, size);
+}
+
+static const struct x86_cpu_id esram_ids[] __initconst = {
+ { X86_VENDOR_INTEL, 5, 9 }, /* Intel Quark SoC X1000. */
+ {}
+};
+MODULE_DEVICE_TABLE(x86cpu, esram_ids);
+
+/**
+ * esram_self_test_init - entry point for IMR driver.
+ *
+ * return: -ENODEV for no IMR support 0 if good to go.
+ */
+static int __init esram_self_test_init(void)
+{
+ if (x86_match_cpu(esram_ids))
+ esram_self_test();
+ return 0;
+}
+
+/**
+ * esram_self_test_exit - exit point for IMR code.
+ *
+ * return:
+ */
+static void __exit esram_self_test_exit(void)
+{
+}
+
+module_init(esram_self_test_init);
+module_exit(esram_self_test_exit);
+
+MODULE_AUTHOR("Bryan O'Donoghue <pure.logic@...us-software.ie>");
+MODULE_DESCRIPTION("Intel Quark eSRAM self-test driver");
+MODULE_LICENSE("Dual BSD/GPL");
--
1.9.1
--
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