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authorTakashi Iwai2013-12-04 12:40:59 +0100
committerTakashi Iwai2013-12-04 12:40:59 +0100
commitb0e6989c965dda2f2b65a2abb04f5337b497f4a2 (patch)
treeeb70ca5f8fc50688f879d1c851fa3f09a6c68850 /drivers/char/hw_random/msm-rng.c
parentALSA: hda - Fix missing ELD info when using jackpoll_ms parameter (diff)
parentMerge remote-tracking branches 'asoc/fix/arizona', 'asoc/fix/atmel', 'asoc/fi... (diff)
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Merge tag 'asoc-v3.13-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus
ASoC: Fixes for v3.13 A smattering of fixes here, some core ones for the rate combination issues for things other than simple bitmasks, for readback of byte controls and for updating the power of value muxes plus a bunch of driver fixes of varying severity. The warning fix in the i.MX FIQ driver is fixing a warning introduced by a previous fix.
Diffstat (limited to 'drivers/char/hw_random/msm-rng.c')
-rw-r--r--drivers/char/hw_random/msm-rng.c197
1 files changed, 197 insertions, 0 deletions
diff --git a/drivers/char/hw_random/msm-rng.c b/drivers/char/hw_random/msm-rng.c
new file mode 100644
index 000000000000..148521e51dc6
--- /dev/null
+++ b/drivers/char/hw_random/msm-rng.c
@@ -0,0 +1,197 @@
+/*
+ * Copyright (c) 2011-2013, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/hw_random.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+
+/* Device specific register offsets */
+#define PRNG_DATA_OUT 0x0000
+#define PRNG_STATUS 0x0004
+#define PRNG_LFSR_CFG 0x0100
+#define PRNG_CONFIG 0x0104
+
+/* Device specific register masks and config values */
+#define PRNG_LFSR_CFG_MASK 0x0000ffff
+#define PRNG_LFSR_CFG_CLOCKS 0x0000dddd
+#define PRNG_CONFIG_HW_ENABLE BIT(1)
+#define PRNG_STATUS_DATA_AVAIL BIT(0)
+
+#define MAX_HW_FIFO_DEPTH 16
+#define MAX_HW_FIFO_SIZE (MAX_HW_FIFO_DEPTH * 4)
+#define WORD_SZ 4
+
+struct msm_rng {
+ void __iomem *base;
+ struct clk *clk;
+ struct hwrng hwrng;
+};
+
+#define to_msm_rng(p) container_of(p, struct msm_rng, hwrng)
+
+static int msm_rng_enable(struct hwrng *hwrng, int enable)
+{
+ struct msm_rng *rng = to_msm_rng(hwrng);
+ u32 val;
+ int ret;
+
+ ret = clk_prepare_enable(rng->clk);
+ if (ret)
+ return ret;
+
+ if (enable) {
+ /* Enable PRNG only if it is not already enabled */
+ val = readl_relaxed(rng->base + PRNG_CONFIG);
+ if (val & PRNG_CONFIG_HW_ENABLE)
+ goto already_enabled;
+
+ val = readl_relaxed(rng->base + PRNG_LFSR_CFG);
+ val &= ~PRNG_LFSR_CFG_MASK;
+ val |= PRNG_LFSR_CFG_CLOCKS;
+ writel(val, rng->base + PRNG_LFSR_CFG);
+
+ val = readl_relaxed(rng->base + PRNG_CONFIG);
+ val |= PRNG_CONFIG_HW_ENABLE;
+ writel(val, rng->base + PRNG_CONFIG);
+ } else {
+ val = readl_relaxed(rng->base + PRNG_CONFIG);
+ val &= ~PRNG_CONFIG_HW_ENABLE;
+ writel(val, rng->base + PRNG_CONFIG);
+ }
+
+already_enabled:
+ clk_disable_unprepare(rng->clk);
+ return 0;
+}
+
+static int msm_rng_read(struct hwrng *hwrng, void *data, size_t max, bool wait)
+{
+ struct msm_rng *rng = to_msm_rng(hwrng);
+ size_t currsize = 0;
+ u32 *retdata = data;
+ size_t maxsize;
+ int ret;
+ u32 val;
+
+ /* calculate max size bytes to transfer back to caller */
+ maxsize = min_t(size_t, MAX_HW_FIFO_SIZE, max);
+
+ /* no room for word data */
+ if (maxsize < WORD_SZ)
+ return 0;
+
+ ret = clk_prepare_enable(rng->clk);
+ if (ret)
+ return ret;
+
+ /* read random data from hardware */
+ do {
+ val = readl_relaxed(rng->base + PRNG_STATUS);
+ if (!(val & PRNG_STATUS_DATA_AVAIL))
+ break;
+
+ val = readl_relaxed(rng->base + PRNG_DATA_OUT);
+ if (!val)
+ break;
+
+ *retdata++ = val;
+ currsize += WORD_SZ;
+
+ /* make sure we stay on 32bit boundary */
+ if ((maxsize - currsize) < WORD_SZ)
+ break;
+ } while (currsize < maxsize);
+
+ clk_disable_unprepare(rng->clk);
+
+ return currsize;
+}
+
+static int msm_rng_init(struct hwrng *hwrng)
+{
+ return msm_rng_enable(hwrng, 1);
+}
+
+static void msm_rng_cleanup(struct hwrng *hwrng)
+{
+ msm_rng_enable(hwrng, 0);
+}
+
+static int msm_rng_probe(struct platform_device *pdev)
+{
+ struct resource *res;
+ struct msm_rng *rng;
+ int ret;
+
+ rng = devm_kzalloc(&pdev->dev, sizeof(*rng), GFP_KERNEL);
+ if (!rng)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, rng);
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ rng->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(rng->base))
+ return PTR_ERR(rng->base);
+
+ rng->clk = devm_clk_get(&pdev->dev, "core");
+ if (IS_ERR(rng->clk))
+ return PTR_ERR(rng->clk);
+
+ rng->hwrng.name = KBUILD_MODNAME,
+ rng->hwrng.init = msm_rng_init,
+ rng->hwrng.cleanup = msm_rng_cleanup,
+ rng->hwrng.read = msm_rng_read,
+
+ ret = hwrng_register(&rng->hwrng);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to register hwrng\n");
+ return ret;
+ }
+
+ return 0;
+}
+
+static int msm_rng_remove(struct platform_device *pdev)
+{
+ struct msm_rng *rng = platform_get_drvdata(pdev);
+
+ hwrng_unregister(&rng->hwrng);
+ return 0;
+}
+
+static const struct of_device_id msm_rng_of_match[] = {
+ { .compatible = "qcom,prng", },
+ {}
+};
+MODULE_DEVICE_TABLE(of, msm_rng_of_match);
+
+static struct platform_driver msm_rng_driver = {
+ .probe = msm_rng_probe,
+ .remove = msm_rng_remove,
+ .driver = {
+ .name = KBUILD_MODNAME,
+ .owner = THIS_MODULE,
+ .of_match_table = of_match_ptr(msm_rng_of_match),
+ }
+};
+module_platform_driver(msm_rng_driver);
+
+MODULE_ALIAS("platform:" KBUILD_MODNAME);
+MODULE_AUTHOR("The Linux Foundation");
+MODULE_DESCRIPTION("Qualcomm MSM random number generator driver");
+MODULE_LICENSE("GPL v2");