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Commit 89d49a70 authored by Kuninori Morimoto's avatar Kuninori Morimoto Committed by Ulf Hansson
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mmc: sh_mmcif: calculate best clock with parent clock 



MMCIF IP on R-Car series has parent clock which can be set several rate,
and it was not implemented on old SH-Mobile series (= SH-Mobile series
parent clock was fixed rate) R-Car series MMCIF can use more high speed
access if it setups parent clock. This patch adds parent clock setup
method. It will be used if DT has "max-frequency", and then, this driver
assumes it is booted on R-Car Gen2 or later SoC. Because SH-Mobile series
(which doesn't boot from DT) and R-Car series (which boots from DT) have
different divider.

Signed-off-by: default avatarKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Tested-by: default avatarKeita Kobayashi <keita.kobayashi.ym@renesas.com>
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
[Ulf: Silence compiler warning]
parent 1b1a694d

Documentation/devicetree/bindings/mmc/renesas,mmcif.txt

+3 −0
Original line number Diff line number Diff line
@@ -18,6 +18,8 @@ Required properties: 
  dma-names property.

- dma-names: must contain "tx" for the transmit DMA channel and "rx" for the

  receive DMA channel.

- max-frequency: Maximum operating clock frequency, driver uses default clock

  frequency if it is not set.





Example: R8A7790 (R-Car H2) MMCIF0
@@ -29,4 +31,5 @@ Example: R8A7790 (R-Car H2) MMCIF0 
		clocks = <&mstp3_clks R8A7790_CLK_MMCIF0>;

		dmas = <&dmac0 0xd1>, <&dmac0 0xd2>;

		dma-names = "tx", "rx";

		max-frequency = <97500000>;

	};

drivers/mmc/host/sh_mmcif.c

+75 −9
Original line number Diff line number Diff line
@@ -57,6 +57,7 @@ 
#include <linux/mmc/slot-gpio.h>

#include <linux/mod_devicetable.h>

#include <linux/mutex.h>

#include <linux/of_device.h>

#include <linux/pagemap.h>

#include <linux/platform_device.h>

#include <linux/pm_qos.h>
@@ -224,6 +225,9 @@ enum sh_mmcif_wait_for { 
	MMCIF_WAIT_FOR_STOP,

};



/*

 * difference for each SoC

 */

struct sh_mmcif_host {

	struct mmc_host *mmc;

	struct mmc_request *mrq;
@@ -248,6 +252,7 @@ struct sh_mmcif_host { 
	bool ccs_enable;		/* Command Completion Signal support */

	bool clk_ctrl2_enable;

	struct mutex thread_lock;

	u32 clkdiv_map;         /* see CE_CLK_CTRL::CLKDIV */



	/* DMA support */

	struct dma_chan		*chan_rx;
@@ -492,19 +497,55 @@ static void sh_mmcif_clock_control(struct sh_mmcif_host *host, unsigned int clk) 
	struct sh_mmcif_plat_data *p = dev->platform_data;

	bool sup_pclk = p ? p->sup_pclk : false;

	unsigned int current_clk = clk_get_rate(host->clk);

	unsigned int clkdiv;



	sh_mmcif_bitclr(host, MMCIF_CE_CLK_CTRL, CLK_ENABLE);

	sh_mmcif_bitclr(host, MMCIF_CE_CLK_CTRL, CLK_CLEAR);



	if (!clk)

		return;

	if (sup_pclk && clk == current_clk)

		sh_mmcif_bitset(host, MMCIF_CE_CLK_CTRL, CLK_SUP_PCLK);

	else

		sh_mmcif_bitset(host, MMCIF_CE_CLK_CTRL, CLK_CLEAR &

				((fls(DIV_ROUND_UP(current_clk,

						   clk) - 1) - 1) << 16));



	if (host->clkdiv_map) {

		unsigned int freq, best_freq, myclk, div, diff_min, diff;

		int i;



		clkdiv = 0;

		diff_min = ~0;

		best_freq = 0;

		for (i = 31; i >= 0; i--) {

			if (!((1 << i) & host->clkdiv_map))

				continue;



			/*

			 * clk = parent_freq / div

			 * -> parent_freq = clk x div

			 */



			div = 1 << (i + 1);

			freq = clk_round_rate(host->clk, clk * div);

			myclk = freq / div;

			diff = (myclk > clk) ? myclk - clk : clk - myclk;



			if (diff <= diff_min) {

				best_freq = freq;

				clkdiv = i;

				diff_min = diff;

			}

		}



		dev_dbg(dev, "clk %u/%u (%u, 0x%x)\n",

			(best_freq / (1 << (clkdiv + 1))), clk,

			best_freq, clkdiv);



		clk_set_rate(host->clk, best_freq);

		clkdiv = clkdiv << 16;

	} else if (sup_pclk && clk == current_clk) {

		clkdiv = CLK_SUP_PCLK;

	} else {

		clkdiv = (fls(DIV_ROUND_UP(current_clk, clk) - 1) - 1) << 16;

	}



	sh_mmcif_bitset(host, MMCIF_CE_CLK_CTRL, CLK_CLEAR & clkdiv);

	sh_mmcif_bitset(host, MMCIF_CE_CLK_CTRL, CLK_ENABLE);

}
@@ -1000,12 +1041,37 @@ static void sh_mmcif_request(struct mmc_host *mmc, struct mmc_request *mrq) 


static void sh_mmcif_clk_setup(struct sh_mmcif_host *host)

{

	struct device *dev = sh_mmcif_host_to_dev(host);



	if (host->mmc->f_max) {

		unsigned int f_max, f_min = 0, f_min_old;



		f_max = host->mmc->f_max;

		for (f_min_old = f_max; f_min_old > 2;) {

			f_min = clk_round_rate(host->clk, f_min_old / 2);

			if (f_min == f_min_old)

				break;

			f_min_old = f_min;

		}



		/*

		 * This driver assumes this SoC is R-Car Gen2 or later

		 */

		host->clkdiv_map = 0x3ff;



		host->mmc->f_max = f_max / (1 << ffs(host->clkdiv_map));

		host->mmc->f_min = f_min / (1 << fls(host->clkdiv_map));

	} else {

		unsigned int clk = clk_get_rate(host->clk);



		host->mmc->f_max = clk / 2;

		host->mmc->f_min = clk / 512;

	}



	dev_dbg(dev, "clk max/min = %d/%d\n",

		host->mmc->f_max, host->mmc->f_min);

}



static void sh_mmcif_set_power(struct sh_mmcif_host *host, struct mmc_ios *ios)

{

	struct mmc_host *mmc = host->mmc;