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authorLinus Torvalds <torvalds@linux-foundation.org>2018-12-31 17:32:35 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-12-31 17:32:35 -0800
commitd36377c6eb071e3d0751e9e0e3c19198c58d9a5d (patch)
treebf1d28abd5fac5c826079c4b760ca34263f0fab4 /drivers/memory
parent0922275ef157ba8ac93e7e7857087eb0442d5397 (diff)
parenta6f119a06960ef1dc30570401e43b71f9ebdd2c2 (diff)
downloadlinux-d36377c6eb071e3d0751e9e0e3c19198c58d9a5d.tar.bz2
Merge tag 'armsoc-drivers' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc
Pull ARM SoC driver updates from Olof Johansson: "Misc driver updates for platforms, many of them power related. - Rockchip adds power domain support for rk3066 and rk3188 - Amlogic adds a power measurement driver - Allwinner adds SRAM support for three platforms (F1C100, H5, A64 C1) - Wakeup and ti-sysc (platform bus) fixes for OMAP/DRA7 - Broadcom fixes suspend/resume with Thumb2 kernels, and improves stability of a handful of firmware/platform interfaces - PXA completes their conversion to dmaengine framework - Renesas does a bunch of PM cleanups across many platforms - Tegra adds support for suspend/resume on T186/T194, which includes some driver cleanups and addition of wake events - Tegra also adds a driver for memory controller (EMC) on Tegra2 - i.MX tweaks power domain bindings, and adds support for i.MX8MQ in GPC - Atmel adds identifiers and LPDDR2 support for a new SoC, SAM9X60 and misc cleanups across several platforms" * tag 'armsoc-drivers' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (73 commits) ARM: at91: add support in soc driver for new SAM9X60 ARM: at91: add support in soc driver for LPDDR2 SiP memory: omap-gpmc: Use of_node_name_eq for node name comparisons bus: ti-sysc: Check for no-reset and no-idle flags at the child level ARM: OMAP2+: Check also the first dts child for hwmod flags soc: amlogic: meson-clk-measure: Add missing REGMAP_MMIO dependency soc: imx: gpc: Increase GPC_CLK_MAX to 7 soc: renesas: rcar-sysc: Fix power domain control after system resume soc: renesas: rcar-sysc: Merge PM Domain registration and linking soc: renesas: rcar-sysc: Remove rcar_sysc_power_{down,up}() helpers soc: renesas: r8a77990-sysc: Fix initialization order of 3DG-{A,B} dt-bindings: sram: sunxi: Add compatible for the A64 SRAM C1 dt-bindings: sram: sunxi: Add bindings for the H5 with SRAM C1 dt-bindings: sram: Add Allwinner suniv F1C100s soc: sunxi: sram: Add support for the H5 SoC system control soc: sunxi: sram: Enable EMAC clock access for H3 variant soc: imx: gpcv2: add support for i.MX8MQ SoC soc: imx: gpcv2: move register access table to domain data soc: imx: gpcv2: prefix i.MX7 specific defines dmaengine: pxa: make the filter function internal ...
Diffstat (limited to 'drivers/memory')
-rw-r--r--drivers/memory/omap-gpmc.c8
-rw-r--r--drivers/memory/tegra/Kconfig10
-rw-r--r--drivers/memory/tegra/Makefile1
-rw-r--r--drivers/memory/tegra/tegra20-emc.c591
4 files changed, 606 insertions, 4 deletions
diff --git a/drivers/memory/omap-gpmc.c b/drivers/memory/omap-gpmc.c
index a2188f7c04c6..f6297599433f 100644
--- a/drivers/memory/omap-gpmc.c
+++ b/drivers/memory/omap-gpmc.c
@@ -2061,7 +2061,7 @@ static int gpmc_probe_generic_child(struct platform_device *pdev,
* timings.
*/
name = gpmc_cs_get_name(cs);
- if (name && of_node_cmp(child->name, name) == 0)
+ if (name && of_node_name_eq(child, name))
goto no_timings;
ret = gpmc_cs_request(cs, resource_size(&res), &base);
@@ -2069,7 +2069,7 @@ static int gpmc_probe_generic_child(struct platform_device *pdev,
dev_err(&pdev->dev, "cannot request GPMC CS %d\n", cs);
return ret;
}
- gpmc_cs_set_name(cs, child->name);
+ gpmc_cs_set_name(cs, child->full_name);
gpmc_read_settings_dt(child, &gpmc_s);
gpmc_read_timings_dt(child, &gpmc_t);
@@ -2114,7 +2114,7 @@ static int gpmc_probe_generic_child(struct platform_device *pdev,
goto err;
}
- if (of_node_cmp(child->name, "nand") == 0) {
+ if (of_node_name_eq(child, "nand")) {
/* Warn about older DT blobs with no compatible property */
if (!of_property_read_bool(child, "compatible")) {
dev_warn(&pdev->dev,
@@ -2124,7 +2124,7 @@ static int gpmc_probe_generic_child(struct platform_device *pdev,
}
}
- if (of_node_cmp(child->name, "onenand") == 0) {
+ if (of_node_name_eq(child, "onenand")) {
/* Warn about older DT blobs with no compatible property */
if (!of_property_read_bool(child, "compatible")) {
dev_warn(&pdev->dev,
diff --git a/drivers/memory/tegra/Kconfig b/drivers/memory/tegra/Kconfig
index 6d74e499e18d..34e0b70f5c5f 100644
--- a/drivers/memory/tegra/Kconfig
+++ b/drivers/memory/tegra/Kconfig
@@ -6,6 +6,16 @@ config TEGRA_MC
This driver supports the Memory Controller (MC) hardware found on
NVIDIA Tegra SoCs.
+config TEGRA20_EMC
+ bool "NVIDIA Tegra20 External Memory Controller driver"
+ default y
+ depends on ARCH_TEGRA_2x_SOC
+ help
+ This driver is for the External Memory Controller (EMC) found on
+ Tegra20 chips. The EMC controls the external DRAM on the board.
+ This driver is required to change memory timings / clock rate for
+ external memory.
+
config TEGRA124_EMC
bool "NVIDIA Tegra124 External Memory Controller driver"
default y
diff --git a/drivers/memory/tegra/Makefile b/drivers/memory/tegra/Makefile
index 94ab16ba075b..3971a6b7c487 100644
--- a/drivers/memory/tegra/Makefile
+++ b/drivers/memory/tegra/Makefile
@@ -10,5 +10,6 @@ tegra-mc-$(CONFIG_ARCH_TEGRA_210_SOC) += tegra210.o
obj-$(CONFIG_TEGRA_MC) += tegra-mc.o
+obj-$(CONFIG_TEGRA20_EMC) += tegra20-emc.o
obj-$(CONFIG_TEGRA124_EMC) += tegra124-emc.o
obj-$(CONFIG_ARCH_TEGRA_186_SOC) += tegra186.o
diff --git a/drivers/memory/tegra/tegra20-emc.c b/drivers/memory/tegra/tegra20-emc.c
new file mode 100644
index 000000000000..9ee5bef49e47
--- /dev/null
+++ b/drivers/memory/tegra/tegra20-emc.c
@@ -0,0 +1,591 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Tegra20 External Memory Controller driver
+ *
+ * Author: Dmitry Osipenko <digetx@gmail.com>
+ */
+
+#include <linux/clk.h>
+#include <linux/completion.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/iopoll.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/sort.h>
+#include <linux/types.h>
+
+#include <soc/tegra/fuse.h>
+
+#define EMC_INTSTATUS 0x000
+#define EMC_INTMASK 0x004
+#define EMC_TIMING_CONTROL 0x028
+#define EMC_RC 0x02c
+#define EMC_RFC 0x030
+#define EMC_RAS 0x034
+#define EMC_RP 0x038
+#define EMC_R2W 0x03c
+#define EMC_W2R 0x040
+#define EMC_R2P 0x044
+#define EMC_W2P 0x048
+#define EMC_RD_RCD 0x04c
+#define EMC_WR_RCD 0x050
+#define EMC_RRD 0x054
+#define EMC_REXT 0x058
+#define EMC_WDV 0x05c
+#define EMC_QUSE 0x060
+#define EMC_QRST 0x064
+#define EMC_QSAFE 0x068
+#define EMC_RDV 0x06c
+#define EMC_REFRESH 0x070
+#define EMC_BURST_REFRESH_NUM 0x074
+#define EMC_PDEX2WR 0x078
+#define EMC_PDEX2RD 0x07c
+#define EMC_PCHG2PDEN 0x080
+#define EMC_ACT2PDEN 0x084
+#define EMC_AR2PDEN 0x088
+#define EMC_RW2PDEN 0x08c
+#define EMC_TXSR 0x090
+#define EMC_TCKE 0x094
+#define EMC_TFAW 0x098
+#define EMC_TRPAB 0x09c
+#define EMC_TCLKSTABLE 0x0a0
+#define EMC_TCLKSTOP 0x0a4
+#define EMC_TREFBW 0x0a8
+#define EMC_QUSE_EXTRA 0x0ac
+#define EMC_ODT_WRITE 0x0b0
+#define EMC_ODT_READ 0x0b4
+#define EMC_FBIO_CFG5 0x104
+#define EMC_FBIO_CFG6 0x114
+#define EMC_AUTO_CAL_INTERVAL 0x2a8
+#define EMC_CFG_2 0x2b8
+#define EMC_CFG_DIG_DLL 0x2bc
+#define EMC_DLL_XFORM_DQS 0x2c0
+#define EMC_DLL_XFORM_QUSE 0x2c4
+#define EMC_ZCAL_REF_CNT 0x2e0
+#define EMC_ZCAL_WAIT_CNT 0x2e4
+#define EMC_CFG_CLKTRIM_0 0x2d0
+#define EMC_CFG_CLKTRIM_1 0x2d4
+#define EMC_CFG_CLKTRIM_2 0x2d8
+
+#define EMC_CLKCHANGE_REQ_ENABLE BIT(0)
+#define EMC_CLKCHANGE_PD_ENABLE BIT(1)
+#define EMC_CLKCHANGE_SR_ENABLE BIT(2)
+
+#define EMC_TIMING_UPDATE BIT(0)
+
+#define EMC_REFRESH_OVERFLOW_INT BIT(3)
+#define EMC_CLKCHANGE_COMPLETE_INT BIT(4)
+
+static const u16 emc_timing_registers[] = {
+ EMC_RC,
+ EMC_RFC,
+ EMC_RAS,
+ EMC_RP,
+ EMC_R2W,
+ EMC_W2R,
+ EMC_R2P,
+ EMC_W2P,
+ EMC_RD_RCD,
+ EMC_WR_RCD,
+ EMC_RRD,
+ EMC_REXT,
+ EMC_WDV,
+ EMC_QUSE,
+ EMC_QRST,
+ EMC_QSAFE,
+ EMC_RDV,
+ EMC_REFRESH,
+ EMC_BURST_REFRESH_NUM,
+ EMC_PDEX2WR,
+ EMC_PDEX2RD,
+ EMC_PCHG2PDEN,
+ EMC_ACT2PDEN,
+ EMC_AR2PDEN,
+ EMC_RW2PDEN,
+ EMC_TXSR,
+ EMC_TCKE,
+ EMC_TFAW,
+ EMC_TRPAB,
+ EMC_TCLKSTABLE,
+ EMC_TCLKSTOP,
+ EMC_TREFBW,
+ EMC_QUSE_EXTRA,
+ EMC_FBIO_CFG6,
+ EMC_ODT_WRITE,
+ EMC_ODT_READ,
+ EMC_FBIO_CFG5,
+ EMC_CFG_DIG_DLL,
+ EMC_DLL_XFORM_DQS,
+ EMC_DLL_XFORM_QUSE,
+ EMC_ZCAL_REF_CNT,
+ EMC_ZCAL_WAIT_CNT,
+ EMC_AUTO_CAL_INTERVAL,
+ EMC_CFG_CLKTRIM_0,
+ EMC_CFG_CLKTRIM_1,
+ EMC_CFG_CLKTRIM_2,
+};
+
+struct emc_timing {
+ unsigned long rate;
+ u32 data[ARRAY_SIZE(emc_timing_registers)];
+};
+
+struct tegra_emc {
+ struct device *dev;
+ struct completion clk_handshake_complete;
+ struct notifier_block clk_nb;
+ struct clk *backup_clk;
+ struct clk *emc_mux;
+ struct clk *pll_m;
+ struct clk *clk;
+ void __iomem *regs;
+
+ struct emc_timing *timings;
+ unsigned int num_timings;
+};
+
+static irqreturn_t tegra_emc_isr(int irq, void *data)
+{
+ struct tegra_emc *emc = data;
+ u32 intmask = EMC_REFRESH_OVERFLOW_INT | EMC_CLKCHANGE_COMPLETE_INT;
+ u32 status;
+
+ status = readl_relaxed(emc->regs + EMC_INTSTATUS) & intmask;
+ if (!status)
+ return IRQ_NONE;
+
+ /* notify about EMC-CAR handshake completion */
+ if (status & EMC_CLKCHANGE_COMPLETE_INT)
+ complete(&emc->clk_handshake_complete);
+
+ /* notify about HW problem */
+ if (status & EMC_REFRESH_OVERFLOW_INT)
+ dev_err_ratelimited(emc->dev,
+ "refresh request overflow timeout\n");
+
+ /* clear interrupts */
+ writel_relaxed(status, emc->regs + EMC_INTSTATUS);
+
+ return IRQ_HANDLED;
+}
+
+static struct emc_timing *tegra_emc_find_timing(struct tegra_emc *emc,
+ unsigned long rate)
+{
+ struct emc_timing *timing = NULL;
+ unsigned int i;
+
+ for (i = 0; i < emc->num_timings; i++) {
+ if (emc->timings[i].rate >= rate) {
+ timing = &emc->timings[i];
+ break;
+ }
+ }
+
+ if (!timing) {
+ dev_err(emc->dev, "no timing for rate %lu\n", rate);
+ return NULL;
+ }
+
+ return timing;
+}
+
+static int emc_prepare_timing_change(struct tegra_emc *emc, unsigned long rate)
+{
+ struct emc_timing *timing = tegra_emc_find_timing(emc, rate);
+ unsigned int i;
+
+ if (!timing)
+ return -EINVAL;
+
+ dev_dbg(emc->dev, "%s: using timing rate %lu for requested rate %lu\n",
+ __func__, timing->rate, rate);
+
+ /* program shadow registers */
+ for (i = 0; i < ARRAY_SIZE(timing->data); i++)
+ writel_relaxed(timing->data[i],
+ emc->regs + emc_timing_registers[i]);
+
+ /* wait until programming has settled */
+ readl_relaxed(emc->regs + emc_timing_registers[i - 1]);
+
+ reinit_completion(&emc->clk_handshake_complete);
+
+ return 0;
+}
+
+static int emc_complete_timing_change(struct tegra_emc *emc, bool flush)
+{
+ long timeout;
+
+ dev_dbg(emc->dev, "%s: flush %d\n", __func__, flush);
+
+ if (flush) {
+ /* manually initiate memory timing update */
+ writel_relaxed(EMC_TIMING_UPDATE,
+ emc->regs + EMC_TIMING_CONTROL);
+ return 0;
+ }
+
+ timeout = wait_for_completion_timeout(&emc->clk_handshake_complete,
+ usecs_to_jiffies(100));
+ if (timeout == 0) {
+ dev_err(emc->dev, "EMC-CAR handshake failed\n");
+ return -EIO;
+ } else if (timeout < 0) {
+ dev_err(emc->dev, "failed to wait for EMC-CAR handshake: %ld\n",
+ timeout);
+ return timeout;
+ }
+
+ return 0;
+}
+
+static int tegra_emc_clk_change_notify(struct notifier_block *nb,
+ unsigned long msg, void *data)
+{
+ struct tegra_emc *emc = container_of(nb, struct tegra_emc, clk_nb);
+ struct clk_notifier_data *cnd = data;
+ int err;
+
+ switch (msg) {
+ case PRE_RATE_CHANGE:
+ err = emc_prepare_timing_change(emc, cnd->new_rate);
+ break;
+
+ case ABORT_RATE_CHANGE:
+ err = emc_prepare_timing_change(emc, cnd->old_rate);
+ if (err)
+ break;
+
+ err = emc_complete_timing_change(emc, true);
+ break;
+
+ case POST_RATE_CHANGE:
+ err = emc_complete_timing_change(emc, false);
+ break;
+
+ default:
+ return NOTIFY_DONE;
+ }
+
+ return notifier_from_errno(err);
+}
+
+static int load_one_timing_from_dt(struct tegra_emc *emc,
+ struct emc_timing *timing,
+ struct device_node *node)
+{
+ u32 rate;
+ int err;
+
+ if (!of_device_is_compatible(node, "nvidia,tegra20-emc-table")) {
+ dev_err(emc->dev, "incompatible DT node: %pOF\n", node);
+ return -EINVAL;
+ }
+
+ err = of_property_read_u32(node, "clock-frequency", &rate);
+ if (err) {
+ dev_err(emc->dev, "timing %pOF: failed to read rate: %d\n",
+ node, err);
+ return err;
+ }
+
+ err = of_property_read_u32_array(node, "nvidia,emc-registers",
+ timing->data,
+ ARRAY_SIZE(emc_timing_registers));
+ if (err) {
+ dev_err(emc->dev,
+ "timing %pOF: failed to read emc timing data: %d\n",
+ node, err);
+ return err;
+ }
+
+ /*
+ * The EMC clock rate is twice the bus rate, and the bus rate is
+ * measured in kHz.
+ */
+ timing->rate = rate * 2 * 1000;
+
+ dev_dbg(emc->dev, "%s: %pOF: EMC rate %lu\n",
+ __func__, node, timing->rate);
+
+ return 0;
+}
+
+static int cmp_timings(const void *_a, const void *_b)
+{
+ const struct emc_timing *a = _a;
+ const struct emc_timing *b = _b;
+
+ if (a->rate < b->rate)
+ return -1;
+
+ if (a->rate > b->rate)
+ return 1;
+
+ return 0;
+}
+
+static int tegra_emc_load_timings_from_dt(struct tegra_emc *emc,
+ struct device_node *node)
+{
+ struct device_node *child;
+ struct emc_timing *timing;
+ int child_count;
+ int err;
+
+ child_count = of_get_child_count(node);
+ if (!child_count) {
+ dev_err(emc->dev, "no memory timings in DT node: %pOF\n", node);
+ return -EINVAL;
+ }
+
+ emc->timings = devm_kcalloc(emc->dev, child_count, sizeof(*timing),
+ GFP_KERNEL);
+ if (!emc->timings)
+ return -ENOMEM;
+
+ emc->num_timings = child_count;
+ timing = emc->timings;
+
+ for_each_child_of_node(node, child) {
+ err = load_one_timing_from_dt(emc, timing++, child);
+ if (err) {
+ of_node_put(child);
+ return err;
+ }
+ }
+
+ sort(emc->timings, emc->num_timings, sizeof(*timing), cmp_timings,
+ NULL);
+
+ return 0;
+}
+
+static struct device_node *
+tegra_emc_find_node_by_ram_code(struct device *dev)
+{
+ struct device_node *np;
+ u32 value, ram_code;
+ int err;
+
+ if (!of_property_read_bool(dev->of_node, "nvidia,use-ram-code"))
+ return of_node_get(dev->of_node);
+
+ ram_code = tegra_read_ram_code();
+
+ for (np = of_find_node_by_name(dev->of_node, "emc-tables"); np;
+ np = of_find_node_by_name(np, "emc-tables")) {
+ err = of_property_read_u32(np, "nvidia,ram-code", &value);
+ if (err || value != ram_code) {
+ of_node_put(np);
+ continue;
+ }
+
+ return np;
+ }
+
+ dev_err(dev, "no memory timings for RAM code %u found in device tree\n",
+ ram_code);
+
+ return NULL;
+}
+
+static int emc_setup_hw(struct tegra_emc *emc)
+{
+ u32 intmask = EMC_REFRESH_OVERFLOW_INT | EMC_CLKCHANGE_COMPLETE_INT;
+ u32 emc_cfg;
+
+ emc_cfg = readl_relaxed(emc->regs + EMC_CFG_2);
+
+ /*
+ * Depending on a memory type, DRAM should enter either self-refresh
+ * or power-down state on EMC clock change.
+ */
+ if (!(emc_cfg & EMC_CLKCHANGE_PD_ENABLE) &&
+ !(emc_cfg & EMC_CLKCHANGE_SR_ENABLE)) {
+ dev_err(emc->dev,
+ "bootloader didn't specify DRAM auto-suspend mode\n");
+ return -EINVAL;
+ }
+
+ /* enable EMC and CAR to handshake on PLL divider/source changes */
+ emc_cfg |= EMC_CLKCHANGE_REQ_ENABLE;
+ writel_relaxed(emc_cfg, emc->regs + EMC_CFG_2);
+
+ /* initialize interrupt */
+ writel_relaxed(intmask, emc->regs + EMC_INTMASK);
+ writel_relaxed(intmask, emc->regs + EMC_INTSTATUS);
+
+ return 0;
+}
+
+static int emc_init(struct tegra_emc *emc, unsigned long rate)
+{
+ int err;
+
+ err = clk_set_parent(emc->emc_mux, emc->backup_clk);
+ if (err) {
+ dev_err(emc->dev,
+ "failed to reparent to backup source: %d\n", err);
+ return err;
+ }
+
+ err = clk_set_rate(emc->pll_m, rate);
+ if (err) {
+ dev_err(emc->dev,
+ "failed to change pll_m rate: %d\n", err);
+ return err;
+ }
+
+ err = clk_set_parent(emc->emc_mux, emc->pll_m);
+ if (err) {
+ dev_err(emc->dev,
+ "failed to reparent to pll_m: %d\n", err);
+ return err;
+ }
+
+ err = clk_set_rate(emc->clk, rate);
+ if (err) {
+ dev_err(emc->dev,
+ "failed to change emc rate: %d\n", err);
+ return err;
+ }
+
+ return 0;
+}
+
+static int tegra_emc_probe(struct platform_device *pdev)
+{
+ struct device_node *np;
+ struct tegra_emc *emc;
+ struct resource *res;
+ int irq, err;
+
+ /* driver has nothing to do in a case of memory timing absence */
+ if (of_get_child_count(pdev->dev.of_node) == 0) {
+ dev_info(&pdev->dev,
+ "EMC device tree node doesn't have memory timings\n");
+ return 0;
+ }
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0) {
+ dev_err(&pdev->dev, "interrupt not specified\n");
+ dev_err(&pdev->dev, "please update your device tree\n");
+ return irq;
+ }
+
+ np = tegra_emc_find_node_by_ram_code(&pdev->dev);
+ if (!np)
+ return -EINVAL;
+
+ emc = devm_kzalloc(&pdev->dev, sizeof(*emc), GFP_KERNEL);
+ if (!emc) {
+ of_node_put(np);
+ return -ENOMEM;
+ }
+
+ init_completion(&emc->clk_handshake_complete);
+ emc->clk_nb.notifier_call = tegra_emc_clk_change_notify;
+ emc->dev = &pdev->dev;
+
+ err = tegra_emc_load_timings_from_dt(emc, np);
+ of_node_put(np);
+ if (err)
+ return err;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ emc->regs = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(emc->regs))
+ return PTR_ERR(emc->regs);
+
+ err = emc_setup_hw(emc);
+ if (err)
+ return err;
+
+ err = devm_request_irq(&pdev->dev, irq, tegra_emc_isr, 0,
+ dev_name(&pdev->dev), emc);
+ if (err) {
+ dev_err(&pdev->dev, "failed to request IRQ#%u: %d\n", irq, err);
+ return err;
+ }
+
+ emc->clk = devm_clk_get(&pdev->dev, "emc");
+ if (IS_ERR(emc->clk)) {
+ err = PTR_ERR(emc->clk);
+ dev_err(&pdev->dev, "failed to get emc clock: %d\n", err);
+ return err;
+ }
+
+ emc->pll_m = clk_get_sys(NULL, "pll_m");
+ if (IS_ERR(emc->pll_m)) {
+ err = PTR_ERR(emc->pll_m);
+ dev_err(&pdev->dev, "failed to get pll_m clock: %d\n", err);
+ return err;
+ }
+
+ emc->backup_clk = clk_get_sys(NULL, "pll_p");
+ if (IS_ERR(emc->backup_clk)) {
+ err = PTR_ERR(emc->backup_clk);
+ dev_err(&pdev->dev, "failed to get pll_p clock: %d\n", err);
+ goto put_pll_m;
+ }
+
+ emc->emc_mux = clk_get_parent(emc->clk);
+ if (IS_ERR(emc->emc_mux)) {
+ err = PTR_ERR(emc->emc_mux);
+ dev_err(&pdev->dev, "failed to get emc_mux clock: %d\n", err);
+ goto put_backup;
+ }
+
+ err = clk_notifier_register(emc->clk, &emc->clk_nb);
+ if (err) {
+ dev_err(&pdev->dev, "failed to register clk notifier: %d\n",
+ err);
+ goto put_backup;
+ }
+
+ /* set DRAM clock rate to maximum */
+ err = emc_init(emc, emc->timings[emc->num_timings - 1].rate);
+ if (err) {
+ dev_err(&pdev->dev, "failed to initialize EMC clock rate: %d\n",
+ err);
+ goto unreg_notifier;
+ }
+
+ return 0;
+
+unreg_notifier:
+ clk_notifier_unregister(emc->clk, &emc->clk_nb);
+put_backup:
+ clk_put(emc->backup_clk);
+put_pll_m:
+ clk_put(emc->pll_m);
+
+ return err;
+}
+
+static const struct of_device_id tegra_emc_of_match[] = {
+ { .compatible = "nvidia,tegra20-emc", },
+ {},
+};
+
+static struct platform_driver tegra_emc_driver = {
+ .probe = tegra_emc_probe,
+ .driver = {
+ .name = "tegra20-emc",
+ .of_match_table = tegra_emc_of_match,
+ .suppress_bind_attrs = true,
+ },
+};
+
+static int __init tegra_emc_init(void)
+{
+ return platform_driver_register(&tegra_emc_driver);
+}
+subsys_initcall(tegra_emc_init);