@@ -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
@@ -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
new file mode 100644
@@ -0,0 +1,575 @@
+// 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_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_CLKCHANGE_COMPLETE_INT;
+ u32 status;
+
+ status = readl_relaxed(emc->regs + EMC_INTSTATUS) & intmask;
+ if (!status)
+ return IRQ_NONE;
+
+ /* clear interrupts */
+ writel_relaxed(status, emc->regs + EMC_INTSTATUS);
+
+ /* notify about EMC-CAR handshake completion */
+ complete(&emc->clk_handshake_complete);
+
+ 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[0]);
+
+ 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 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;
+ }
+
+ /* allow 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(EMC_CLKCHANGE_COMPLETE_INT, emc->regs + EMC_INTMASK);
+ writel_relaxed(EMC_CLKCHANGE_COMPLETE_INT, emc->regs + EMC_INTSTATUS);
+
+ return 0;
+}
+
+static int emc_init(struct tegra_emc *emc, unsigned long rate)
+{
+ int err, ret;
+
+ 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;
+ }
+
+ ret = clk_set_rate(emc->pll_m, rate);
+ if (ret)
+ dev_err(emc->dev,
+ "failed to change pll_m rate: %d\n", ret);
+
+ 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;
+ }
+
+ return ret;
+}
+
+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);