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authorMirza Krak <mirza.krak@gmail.com>2016-11-07 09:30:05 +0100
committerThierry Reding <treding@nvidia.com>2016-11-15 17:27:53 +0100
commit40eb47767852a9122ef99a48f8d208ec6327e07f (patch)
treea77025b29491d1e6b82f91a3b77079b16f4d73c3 /drivers/bus/tegra-gmi.c
parent1de9aecbb0a41b3d5af0527e683ed9bfd2bdea47 (diff)
bus: Add support for Tegra Generic Memory Interface
The Generic Memory Interface bus can be used to connect high-speed devices such as NOR flash, FPGAs, DSPs... Signed-off-by: Mirza Krak <mirza.krak@gmail.com> Tested-by: Marcel Ziswiler <marcel.ziswiler@toradex.com> Tested-on: Colibri T20/T30 on EvalBoard V3.x and GMI-Memory Board Acked-by: Jon Hunter <jonathanh@nvidia.com> [treding@nvidia.com: symmetry and coding style OCD] Signed-off-by: Thierry Reding <treding@nvidia.com>
Diffstat (limited to 'drivers/bus/tegra-gmi.c')
-rw-r--r--drivers/bus/tegra-gmi.c284
1 files changed, 284 insertions, 0 deletions
diff --git a/drivers/bus/tegra-gmi.c b/drivers/bus/tegra-gmi.c
new file mode 100644
index 000000000000..a6570789f7af
--- /dev/null
+++ b/drivers/bus/tegra-gmi.c
@@ -0,0 +1,284 @@
+/*
+ * Driver for NVIDIA Generic Memory Interface
+ *
+ * Copyright (C) 2016 Host Mobility AB. All rights reserved.
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/reset.h>
+
+#define TEGRA_GMI_CONFIG 0x00
+#define TEGRA_GMI_CONFIG_GO BIT(31)
+#define TEGRA_GMI_BUS_WIDTH_32BIT BIT(30)
+#define TEGRA_GMI_MUX_MODE BIT(28)
+#define TEGRA_GMI_RDY_BEFORE_DATA BIT(24)
+#define TEGRA_GMI_RDY_ACTIVE_HIGH BIT(23)
+#define TEGRA_GMI_ADV_ACTIVE_HIGH BIT(22)
+#define TEGRA_GMI_OE_ACTIVE_HIGH BIT(21)
+#define TEGRA_GMI_CS_ACTIVE_HIGH BIT(20)
+#define TEGRA_GMI_CS_SELECT(x) ((x & 0x7) << 4)
+
+#define TEGRA_GMI_TIMING0 0x10
+#define TEGRA_GMI_MUXED_WIDTH(x) ((x & 0xf) << 12)
+#define TEGRA_GMI_HOLD_WIDTH(x) ((x & 0xf) << 8)
+#define TEGRA_GMI_ADV_WIDTH(x) ((x & 0xf) << 4)
+#define TEGRA_GMI_CE_WIDTH(x) (x & 0xf)
+
+#define TEGRA_GMI_TIMING1 0x14
+#define TEGRA_GMI_WE_WIDTH(x) ((x & 0xff) << 16)
+#define TEGRA_GMI_OE_WIDTH(x) ((x & 0xff) << 8)
+#define TEGRA_GMI_WAIT_WIDTH(x) (x & 0xff)
+
+#define TEGRA_GMI_MAX_CHIP_SELECT 8
+
+struct tegra_gmi {
+ struct device *dev;
+ void __iomem *base;
+ struct clk *clk;
+ struct reset_control *rst;
+
+ u32 snor_config;
+ u32 snor_timing0;
+ u32 snor_timing1;
+};
+
+static int tegra_gmi_enable(struct tegra_gmi *gmi)
+{
+ int err;
+
+ err = clk_prepare_enable(gmi->clk);
+ if (err < 0) {
+ dev_err(gmi->dev, "failed to enable clock: %d\n", err);
+ return err;
+ }
+
+ reset_control_assert(gmi->rst);
+ usleep_range(2000, 4000);
+ reset_control_deassert(gmi->rst);
+
+ writel(gmi->snor_timing0, gmi->base + TEGRA_GMI_TIMING0);
+ writel(gmi->snor_timing1, gmi->base + TEGRA_GMI_TIMING1);
+
+ gmi->snor_config |= TEGRA_GMI_CONFIG_GO;
+ writel(gmi->snor_config, gmi->base + TEGRA_GMI_CONFIG);
+
+ return 0;
+}
+
+static void tegra_gmi_disable(struct tegra_gmi *gmi)
+{
+ u32 config;
+
+ /* stop GMI operation */
+ config = readl(gmi->base + TEGRA_GMI_CONFIG);
+ config &= ~TEGRA_GMI_CONFIG_GO;
+ writel(config, gmi->base + TEGRA_GMI_CONFIG);
+
+ reset_control_assert(gmi->rst);
+ clk_disable_unprepare(gmi->clk);
+}
+
+static int tegra_gmi_parse_dt(struct tegra_gmi *gmi)
+{
+ struct device_node *child;
+ u32 property, ranges[4];
+ int err;
+
+ child = of_get_next_available_child(gmi->dev->of_node, NULL);
+ if (!child) {
+ dev_err(gmi->dev, "no child nodes found\n");
+ return -ENODEV;
+ }
+
+ /*
+ * We currently only support one child device due to lack of
+ * chip-select address decoding. Which means that we only have one
+ * chip-select line from the GMI controller.
+ */
+ if (of_get_child_count(gmi->dev->of_node) > 1)
+ dev_warn(gmi->dev, "only one child device is supported.");
+
+ if (of_property_read_bool(child, "nvidia,snor-data-width-32bit"))
+ gmi->snor_config |= TEGRA_GMI_BUS_WIDTH_32BIT;
+
+ if (of_property_read_bool(child, "nvidia,snor-mux-mode"))
+ gmi->snor_config |= TEGRA_GMI_MUX_MODE;
+
+ if (of_property_read_bool(child, "nvidia,snor-rdy-active-before-data"))
+ gmi->snor_config |= TEGRA_GMI_RDY_BEFORE_DATA;
+
+ if (of_property_read_bool(child, "nvidia,snor-rdy-active-high"))
+ gmi->snor_config |= TEGRA_GMI_RDY_ACTIVE_HIGH;
+
+ if (of_property_read_bool(child, "nvidia,snor-adv-active-high"))
+ gmi->snor_config |= TEGRA_GMI_ADV_ACTIVE_HIGH;
+
+ if (of_property_read_bool(child, "nvidia,snor-oe-active-high"))
+ gmi->snor_config |= TEGRA_GMI_OE_ACTIVE_HIGH;
+
+ if (of_property_read_bool(child, "nvidia,snor-cs-active-high"))
+ gmi->snor_config |= TEGRA_GMI_CS_ACTIVE_HIGH;
+
+ /* Decode the CS# */
+ err = of_property_read_u32_array(child, "ranges", ranges, 4);
+ if (err < 0) {
+ /* Invalid binding */
+ if (err == -EOVERFLOW) {
+ dev_err(gmi->dev,
+ "failed to decode CS: invalid ranges length\n");
+ goto error_cs;
+ }
+
+ /*
+ * If we reach here it means that the child node has an empty
+ * ranges or it does not exist at all. Attempt to decode the
+ * CS# from the reg property instead.
+ */
+ err = of_property_read_u32(child, "reg", &property);
+ if (err < 0) {
+ dev_err(gmi->dev,
+ "failed to decode CS: no reg property found\n");
+ goto error_cs;
+ }
+ } else {
+ property = ranges[1];
+ }
+
+ /* Valid chip selects are CS0-CS7 */
+ if (property >= TEGRA_GMI_MAX_CHIP_SELECT) {
+ dev_err(gmi->dev, "invalid chip select: %d", property);
+ err = -EINVAL;
+ goto error_cs;
+ }
+
+ gmi->snor_config |= TEGRA_GMI_CS_SELECT(property);
+
+ /* The default values that are provided below are reset values */
+ if (!of_property_read_u32(child, "nvidia,snor-muxed-width", &property))
+ gmi->snor_timing0 |= TEGRA_GMI_MUXED_WIDTH(property);
+ else
+ gmi->snor_timing0 |= TEGRA_GMI_MUXED_WIDTH(1);
+
+ if (!of_property_read_u32(child, "nvidia,snor-hold-width", &property))
+ gmi->snor_timing0 |= TEGRA_GMI_HOLD_WIDTH(property);
+ else
+ gmi->snor_timing0 |= TEGRA_GMI_HOLD_WIDTH(1);
+
+ if (!of_property_read_u32(child, "nvidia,snor-adv-width", &property))
+ gmi->snor_timing0 |= TEGRA_GMI_ADV_WIDTH(property);
+ else
+ gmi->snor_timing0 |= TEGRA_GMI_ADV_WIDTH(1);
+
+ if (!of_property_read_u32(child, "nvidia,snor-ce-width", &property))
+ gmi->snor_timing0 |= TEGRA_GMI_CE_WIDTH(property);
+ else
+ gmi->snor_timing0 |= TEGRA_GMI_CE_WIDTH(4);
+
+ if (!of_property_read_u32(child, "nvidia,snor-we-width", &property))
+ gmi->snor_timing1 |= TEGRA_GMI_WE_WIDTH(property);
+ else
+ gmi->snor_timing1 |= TEGRA_GMI_WE_WIDTH(1);
+
+ if (!of_property_read_u32(child, "nvidia,snor-oe-width", &property))
+ gmi->snor_timing1 |= TEGRA_GMI_OE_WIDTH(property);
+ else
+ gmi->snor_timing1 |= TEGRA_GMI_OE_WIDTH(1);
+
+ if (!of_property_read_u32(child, "nvidia,snor-wait-width", &property))
+ gmi->snor_timing1 |= TEGRA_GMI_WAIT_WIDTH(property);
+ else
+ gmi->snor_timing1 |= TEGRA_GMI_WAIT_WIDTH(3);
+
+error_cs:
+ of_node_put(child);
+ return err;
+}
+
+static int tegra_gmi_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct tegra_gmi *gmi;
+ struct resource *res;
+ int err;
+
+ gmi = devm_kzalloc(dev, sizeof(*gmi), GFP_KERNEL);
+ if (!gmi)
+ return -ENOMEM;
+
+ gmi->dev = dev;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ gmi->base = devm_ioremap_resource(dev, res);
+ if (IS_ERR(gmi->base))
+ return PTR_ERR(gmi->base);
+
+ gmi->clk = devm_clk_get(dev, "gmi");
+ if (IS_ERR(gmi->clk)) {
+ dev_err(dev, "can not get clock\n");
+ return PTR_ERR(gmi->clk);
+ }
+
+ gmi->rst = devm_reset_control_get(dev, "gmi");
+ if (IS_ERR(gmi->rst)) {
+ dev_err(dev, "can not get reset\n");
+ return PTR_ERR(gmi->rst);
+ }
+
+ err = tegra_gmi_parse_dt(gmi);
+ if (err)
+ return err;
+
+ err = tegra_gmi_enable(gmi);
+ if (err < 0)
+ return err;
+
+ err = of_platform_default_populate(dev->of_node, NULL, dev);
+ if (err < 0) {
+ dev_err(dev, "fail to create devices.\n");
+ tegra_gmi_disable(gmi);
+ return err;
+ }
+
+ platform_set_drvdata(pdev, gmi);
+
+ return 0;
+}
+
+static int tegra_gmi_remove(struct platform_device *pdev)
+{
+ struct tegra_gmi *gmi = platform_get_drvdata(pdev);
+
+ of_platform_depopulate(gmi->dev);
+ tegra_gmi_disable(gmi);
+
+ return 0;
+}
+
+static const struct of_device_id tegra_gmi_id_table[] = {
+ { .compatible = "nvidia,tegra20-gmi", },
+ { .compatible = "nvidia,tegra30-gmi", },
+ { }
+};
+MODULE_DEVICE_TABLE(of, tegra_gmi_id_table);
+
+static struct platform_driver tegra_gmi_driver = {
+ .probe = tegra_gmi_probe,
+ .remove = tegra_gmi_remove,
+ .driver = {
+ .name = "tegra-gmi",
+ .of_match_table = tegra_gmi_id_table,
+ },
+};
+module_platform_driver(tegra_gmi_driver);
+
+MODULE_AUTHOR("Mirza Krak <mirza.krak@gmail.com");
+MODULE_DESCRIPTION("NVIDIA Tegra GMI Bus Driver");
+MODULE_LICENSE("GPL v2");

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