408 lines
11 KiB
C
408 lines
11 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Copyright (c) 2014, Fuzhou Rockchip Electronics Co., Ltd
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*/
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/clk.h>
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#include <linux/mmc/host.h>
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#include <linux/of_address.h>
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#include <linux/mmc/slot-gpio.h>
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#include <linux/pm_runtime.h>
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#include <linux/slab.h>
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#include "dw_mmc.h"
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#include "dw_mmc-pltfm.h"
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#define RK3288_CLKGEN_DIV 2
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static const unsigned int freqs[] = { 100000, 200000, 300000, 400000 };
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struct dw_mci_rockchip_priv_data {
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struct clk *drv_clk;
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struct clk *sample_clk;
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int default_sample_phase;
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int num_phases;
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};
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static void dw_mci_rk3288_set_ios(struct dw_mci *host, struct mmc_ios *ios)
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{
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struct dw_mci_rockchip_priv_data *priv = host->priv;
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int ret;
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unsigned int cclkin;
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u32 bus_hz;
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if (ios->clock == 0)
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return;
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/*
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* cclkin: source clock of mmc controller
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* bus_hz: card interface clock generated by CLKGEN
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* bus_hz = cclkin / RK3288_CLKGEN_DIV
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* ios->clock = (div == 0) ? bus_hz : (bus_hz / (2 * div))
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*
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* Note: div can only be 0 or 1, but div must be set to 1 for eMMC
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* DDR52 8-bit mode.
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*/
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if (ios->bus_width == MMC_BUS_WIDTH_8 &&
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ios->timing == MMC_TIMING_MMC_DDR52)
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cclkin = 2 * ios->clock * RK3288_CLKGEN_DIV;
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else
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cclkin = ios->clock * RK3288_CLKGEN_DIV;
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ret = clk_set_rate(host->ciu_clk, cclkin);
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if (ret)
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dev_warn(host->dev, "failed to set rate %uHz err: %d\n", cclkin, ret);
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bus_hz = clk_get_rate(host->ciu_clk) / RK3288_CLKGEN_DIV;
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if (bus_hz != host->bus_hz) {
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host->bus_hz = bus_hz;
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/* force dw_mci_setup_bus() */
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host->current_speed = 0;
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}
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/* Make sure we use phases which we can enumerate with */
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if (!IS_ERR(priv->sample_clk) && ios->timing <= MMC_TIMING_SD_HS)
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clk_set_phase(priv->sample_clk, priv->default_sample_phase);
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/*
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* Set the drive phase offset based on speed mode to achieve hold times.
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*
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* NOTE: this is _not_ a value that is dynamically tuned and is also
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* _not_ a value that will vary from board to board. It is a value
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* that could vary between different SoC models if they had massively
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* different output clock delays inside their dw_mmc IP block (delay_o),
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* but since it's OK to overshoot a little we don't need to do complex
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* calculations and can pick values that will just work for everyone.
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*
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* When picking values we'll stick with picking 0/90/180/270 since
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* those can be made very accurately on all known Rockchip SoCs.
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*
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* Note that these values match values from the DesignWare Databook
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* tables for the most part except for SDR12 and "ID mode". For those
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* two modes the databook calculations assume a clock in of 50MHz. As
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* seen above, we always use a clock in rate that is exactly the
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* card's input clock (times RK3288_CLKGEN_DIV, but that gets divided
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* back out before the controller sees it).
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*
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* From measurement of a single device, it appears that delay_o is
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* about .5 ns. Since we try to leave a bit of margin, it's expected
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* that numbers here will be fine even with much larger delay_o
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* (the 1.4 ns assumed by the DesignWare Databook would result in the
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* same results, for instance).
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*/
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if (!IS_ERR(priv->drv_clk)) {
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int phase;
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/*
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* In almost all cases a 90 degree phase offset will provide
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* sufficient hold times across all valid input clock rates
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* assuming delay_o is not absurd for a given SoC. We'll use
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* that as a default.
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*/
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phase = 90;
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switch (ios->timing) {
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case MMC_TIMING_MMC_DDR52:
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/*
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* Since clock in rate with MMC_DDR52 is doubled when
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* bus width is 8 we need to double the phase offset
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* to get the same timings.
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*/
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if (ios->bus_width == MMC_BUS_WIDTH_8)
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phase = 180;
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break;
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case MMC_TIMING_UHS_SDR104:
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case MMC_TIMING_MMC_HS200:
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/*
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* In the case of 150 MHz clock (typical max for
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* Rockchip SoCs), 90 degree offset will add a delay
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* of 1.67 ns. That will meet min hold time of .8 ns
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* as long as clock output delay is < .87 ns. On
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* SoCs measured this seems to be OK, but it doesn't
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* hurt to give margin here, so we use 180.
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*/
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phase = 180;
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break;
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}
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clk_set_phase(priv->drv_clk, phase);
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}
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}
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#define TUNING_ITERATION_TO_PHASE(i, num_phases) \
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(DIV_ROUND_UP((i) * 360, num_phases))
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static int dw_mci_rk3288_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
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{
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struct dw_mci *host = slot->host;
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struct dw_mci_rockchip_priv_data *priv = host->priv;
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struct mmc_host *mmc = slot->mmc;
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int ret = 0;
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int i;
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bool v, prev_v = 0, first_v;
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struct range_t {
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int start;
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int end; /* inclusive */
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};
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struct range_t *ranges;
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unsigned int range_count = 0;
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int longest_range_len = -1;
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int longest_range = -1;
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int middle_phase;
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if (IS_ERR(priv->sample_clk)) {
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dev_err(host->dev, "Tuning clock (sample_clk) not defined.\n");
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return -EIO;
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}
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ranges = kmalloc_array(priv->num_phases / 2 + 1,
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sizeof(*ranges), GFP_KERNEL);
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if (!ranges)
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return -ENOMEM;
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/* Try each phase and extract good ranges */
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for (i = 0; i < priv->num_phases; ) {
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clk_set_phase(priv->sample_clk,
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TUNING_ITERATION_TO_PHASE(i, priv->num_phases));
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v = !mmc_send_tuning(mmc, opcode, NULL);
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if (i == 0)
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first_v = v;
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if ((!prev_v) && v) {
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range_count++;
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ranges[range_count-1].start = i;
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}
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if (v) {
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ranges[range_count-1].end = i;
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i++;
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} else if (i == priv->num_phases - 1) {
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/* No extra skipping rules if we're at the end */
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i++;
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} else {
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/*
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* No need to check too close to an invalid
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* one since testing bad phases is slow. Skip
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* 20 degrees.
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*/
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i += DIV_ROUND_UP(20 * priv->num_phases, 360);
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/* Always test the last one */
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if (i >= priv->num_phases)
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i = priv->num_phases - 1;
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}
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prev_v = v;
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}
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if (range_count == 0) {
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dev_warn(host->dev, "All phases bad!");
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ret = -EIO;
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goto free;
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}
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/* wrap around case, merge the end points */
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if ((range_count > 1) && first_v && v) {
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ranges[0].start = ranges[range_count-1].start;
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range_count--;
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}
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if (ranges[0].start == 0 && ranges[0].end == priv->num_phases - 1) {
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clk_set_phase(priv->sample_clk, priv->default_sample_phase);
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dev_info(host->dev, "All phases work, using default phase %d.",
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priv->default_sample_phase);
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goto free;
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}
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/* Find the longest range */
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for (i = 0; i < range_count; i++) {
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int len = (ranges[i].end - ranges[i].start + 1);
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if (len < 0)
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len += priv->num_phases;
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if (longest_range_len < len) {
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longest_range_len = len;
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longest_range = i;
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}
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dev_dbg(host->dev, "Good phase range %d-%d (%d len)\n",
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TUNING_ITERATION_TO_PHASE(ranges[i].start,
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priv->num_phases),
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TUNING_ITERATION_TO_PHASE(ranges[i].end,
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priv->num_phases),
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len
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);
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}
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dev_dbg(host->dev, "Best phase range %d-%d (%d len)\n",
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TUNING_ITERATION_TO_PHASE(ranges[longest_range].start,
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priv->num_phases),
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TUNING_ITERATION_TO_PHASE(ranges[longest_range].end,
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priv->num_phases),
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longest_range_len
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);
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middle_phase = ranges[longest_range].start + longest_range_len / 2;
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middle_phase %= priv->num_phases;
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dev_info(host->dev, "Successfully tuned phase to %d\n",
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TUNING_ITERATION_TO_PHASE(middle_phase, priv->num_phases));
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clk_set_phase(priv->sample_clk,
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TUNING_ITERATION_TO_PHASE(middle_phase,
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priv->num_phases));
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free:
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kfree(ranges);
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return ret;
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}
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static int dw_mci_rk3288_parse_dt(struct dw_mci *host)
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{
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struct device_node *np = host->dev->of_node;
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struct dw_mci_rockchip_priv_data *priv;
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priv = devm_kzalloc(host->dev, sizeof(*priv), GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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if (of_property_read_u32(np, "rockchip,desired-num-phases",
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&priv->num_phases))
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priv->num_phases = 360;
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if (of_property_read_u32(np, "rockchip,default-sample-phase",
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&priv->default_sample_phase))
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priv->default_sample_phase = 0;
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priv->drv_clk = devm_clk_get(host->dev, "ciu-drive");
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if (IS_ERR(priv->drv_clk))
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dev_dbg(host->dev, "ciu-drive not available\n");
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priv->sample_clk = devm_clk_get(host->dev, "ciu-sample");
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if (IS_ERR(priv->sample_clk))
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dev_dbg(host->dev, "ciu-sample not available\n");
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host->priv = priv;
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return 0;
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}
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static int dw_mci_rockchip_init(struct dw_mci *host)
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{
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int ret, i;
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/* It is slot 8 on Rockchip SoCs */
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host->sdio_id0 = 8;
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if (of_device_is_compatible(host->dev->of_node, "rockchip,rk3288-dw-mshc")) {
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host->bus_hz /= RK3288_CLKGEN_DIV;
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/* clock driver will fail if the clock is less than the lowest source clock
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* divided by the internal clock divider. Test for the lowest available
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* clock and set the minimum freq to clock / clock divider.
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*/
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for (i = 0; i < ARRAY_SIZE(freqs); i++) {
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ret = clk_round_rate(host->ciu_clk, freqs[i] * RK3288_CLKGEN_DIV);
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if (ret > 0) {
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host->minimum_speed = ret / RK3288_CLKGEN_DIV;
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break;
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}
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}
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if (ret < 0)
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dev_warn(host->dev, "no valid minimum freq: %d\n", ret);
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}
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return 0;
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}
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static const struct dw_mci_drv_data rk2928_drv_data = {
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.init = dw_mci_rockchip_init,
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};
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static const struct dw_mci_drv_data rk3288_drv_data = {
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.common_caps = MMC_CAP_CMD23,
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.set_ios = dw_mci_rk3288_set_ios,
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.execute_tuning = dw_mci_rk3288_execute_tuning,
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.parse_dt = dw_mci_rk3288_parse_dt,
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.init = dw_mci_rockchip_init,
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};
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static const struct of_device_id dw_mci_rockchip_match[] = {
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{ .compatible = "rockchip,rk2928-dw-mshc",
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.data = &rk2928_drv_data },
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{ .compatible = "rockchip,rk3288-dw-mshc",
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.data = &rk3288_drv_data },
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{},
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};
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MODULE_DEVICE_TABLE(of, dw_mci_rockchip_match);
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static int dw_mci_rockchip_probe(struct platform_device *pdev)
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{
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const struct dw_mci_drv_data *drv_data;
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const struct of_device_id *match;
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int ret;
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if (!pdev->dev.of_node)
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return -ENODEV;
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match = of_match_node(dw_mci_rockchip_match, pdev->dev.of_node);
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drv_data = match->data;
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pm_runtime_get_noresume(&pdev->dev);
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pm_runtime_set_active(&pdev->dev);
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pm_runtime_enable(&pdev->dev);
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pm_runtime_set_autosuspend_delay(&pdev->dev, 50);
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pm_runtime_use_autosuspend(&pdev->dev);
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ret = dw_mci_pltfm_register(pdev, drv_data);
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if (ret) {
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pm_runtime_disable(&pdev->dev);
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pm_runtime_set_suspended(&pdev->dev);
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pm_runtime_put_noidle(&pdev->dev);
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return ret;
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}
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pm_runtime_put_autosuspend(&pdev->dev);
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return 0;
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}
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static int dw_mci_rockchip_remove(struct platform_device *pdev)
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{
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pm_runtime_get_sync(&pdev->dev);
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pm_runtime_disable(&pdev->dev);
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pm_runtime_put_noidle(&pdev->dev);
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return dw_mci_pltfm_remove(pdev);
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}
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static const struct dev_pm_ops dw_mci_rockchip_dev_pm_ops = {
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SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
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pm_runtime_force_resume)
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SET_RUNTIME_PM_OPS(dw_mci_runtime_suspend,
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dw_mci_runtime_resume,
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NULL)
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};
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static struct platform_driver dw_mci_rockchip_pltfm_driver = {
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.probe = dw_mci_rockchip_probe,
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.remove = dw_mci_rockchip_remove,
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.driver = {
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.name = "dwmmc_rockchip",
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.probe_type = PROBE_PREFER_ASYNCHRONOUS,
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.of_match_table = dw_mci_rockchip_match,
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.pm = &dw_mci_rockchip_dev_pm_ops,
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},
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};
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module_platform_driver(dw_mci_rockchip_pltfm_driver);
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MODULE_AUTHOR("Addy Ke <addy.ke@rock-chips.com>");
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MODULE_DESCRIPTION("Rockchip Specific DW-MSHC Driver Extension");
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MODULE_ALIAS("platform:dwmmc_rockchip");
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MODULE_LICENSE("GPL v2");
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