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fc54b9bf15
(stable-branch of Openmoko) git-svn-id: svn://svn.openwrt.org/openwrt/trunk@13613 3c298f89-4303-0410-b956-a3cf2f4a3e73
262 lines
8.7 KiB
Diff
262 lines
8.7 KiB
Diff
From 9e7ba57b104e9293f746342b7450b10d5fa0c4cd Mon Sep 17 00:00:00 2001
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From: Andy Green <andy@openmoko.com>
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Date: Mon, 22 Sep 2008 22:38:03 +0100
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Subject: [PATCH] fix-glamo-mci-slow-clock-until-first-bulk.patch
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This patch adds another module parameter to glamo-mci which sets the
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SD Card clock rate used inbetween powering the card and the completion of
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the first bulk transfer. You can set it from kernel commandline like this.
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glamo_mci.sd_post_power_clock=1000000
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The period between changing the power state and the first bulk transfer
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completion is critical because larger SDHC cards take longer to initialize
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before they can service the bulk transfer, and the Glamo MMC unit has a
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fixed timeout length of a maximum of 4095 x 16 x SD Card clocks. Large
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cards like 8GB Sandisk SDHC are not ready before this timeout is used up
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at default 16MHz.
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Subsequently, the card can handle 16MHz SD Clock and timeout durations
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okay.
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By default this patch operates the SD Clock at only 1MHz until the first
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bulk transfer is completed after each powerup action from the MCI stack. It
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also keeps the SD Clock running during this time, and disables the SD Clock
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if the card is not present and the MCI stack removes power.
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Signed-off-by: Andy Green <andy@openmoko.com>
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---
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drivers/mfd/glamo/glamo-mci.c | 108 +++++++++++++++++++++++++----------------
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drivers/mfd/glamo/glamo-mci.h | 2 +
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2 files changed, 68 insertions(+), 42 deletions(-)
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diff --git a/drivers/mfd/glamo/glamo-mci.c b/drivers/mfd/glamo/glamo-mci.c
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index 3eece08..cff43db 100644
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--- a/drivers/mfd/glamo/glamo-mci.c
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+++ b/drivers/mfd/glamo/glamo-mci.c
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@@ -74,6 +74,23 @@ static int sd_slow_ratio = 8;
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module_param(sd_slow_ratio, int, 0644);
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/*
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+ * Post-power SD clock rate
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+ *
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+ * you can override this on kernel commandline using
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+ *
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+ * glamo_mci.sd_post_power_clock=1000000
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+ *
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+ * for example
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+ *
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+ * After changing power to card, clock is held at this rate until first bulk
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+ * transfer completes
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+ */
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+
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+static int sd_post_power_clock = 1000000;
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+module_param(sd_post_power_clock, int, 0644);
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+
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+
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+/*
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* SD Signal drive strength
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*
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* you can override this on kernel commandline using
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@@ -240,21 +257,35 @@ static void __glamo_mci_fix_card_div(struct glamo_mci_host *host, int div)
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writew(readw(glamo_mci_def_pdata.pglamo->base +
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GLAMO_REG_CLOCK_GEN5_1) & (~GLAMO_CLOCK_GEN51_EN_DIV_TCLK),
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glamo_mci_def_pdata.pglamo->base + GLAMO_REG_CLOCK_GEN5_1);
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- } else {
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- /* set the nearest prescaler factor
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- *
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- * register shared with SCLK divisor -- no chance of race because
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- * we don't use sensor interface
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- */
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- writew_dly((readw(glamo_mci_def_pdata.pglamo->base +
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- GLAMO_REG_CLOCK_GEN8) & 0xff00) | div,
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- glamo_mci_def_pdata.pglamo->base + GLAMO_REG_CLOCK_GEN8);
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- /* enable clock to divider input */
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- writew_dly(readw(glamo_mci_def_pdata.pglamo->base +
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- GLAMO_REG_CLOCK_GEN5_1) | GLAMO_CLOCK_GEN51_EN_DIV_TCLK,
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- glamo_mci_def_pdata.pglamo->base + GLAMO_REG_CLOCK_GEN5_1);
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+
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+ goto done;
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}
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+ if (host->force_slow_during_powerup)
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+ div = host->clk_rate / sd_post_power_clock;
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+ else
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+ if (host->pdata->glamo_mci_use_slow)
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+ if ((host->pdata->glamo_mci_use_slow)())
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+ div = div * sd_slow_ratio;
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+
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+ if (div > 255)
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+ div = 255;
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+
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+ /*
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+ * set the nearest prescaler factor
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+ *
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+ * register shared with SCLK divisor -- no chance of race because
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+ * we don't use sensor interface
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+ */
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+ writew_dly((readw(glamo_mci_def_pdata.pglamo->base +
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+ GLAMO_REG_CLOCK_GEN8) & 0xff00) | div,
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+ glamo_mci_def_pdata.pglamo->base + GLAMO_REG_CLOCK_GEN8);
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+ /* enable clock to divider input */
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+ writew_dly(readw(glamo_mci_def_pdata.pglamo->base +
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+ GLAMO_REG_CLOCK_GEN5_1) | GLAMO_CLOCK_GEN51_EN_DIV_TCLK,
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+ glamo_mci_def_pdata.pglamo->base + GLAMO_REG_CLOCK_GEN5_1);
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+
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+done:
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spin_unlock_irqrestore(&clock_lock, flags);
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}
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@@ -284,7 +315,7 @@ static int __glamo_mci_set_card_clock(struct glamo_mci_host *host, int freq,
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if (division)
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*division = 0xff;
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- if (!sd_idleclk)
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+ if (!sd_idleclk && !host->force_slow_during_powerup)
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/* clock off */
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__glamo_mci_fix_card_div(host, -1);
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}
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@@ -327,6 +358,10 @@ static void glamo_mci_irq(unsigned int irq, struct irq_desc *desc)
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goto done;
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}
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+ /* disable the initial slow start after first bulk transfer */
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+ if (host->force_slow_during_powerup)
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+ host->force_slow_during_powerup--;
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+
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if (host->pio_active == XFER_READ)
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do_pio_read(host);
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@@ -341,7 +376,7 @@ static void glamo_mci_irq(unsigned int irq, struct irq_desc *desc)
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host->cmd_is_stop = 0;
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}
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- if (!sd_idleclk)
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+ if (!sd_idleclk && !host->force_slow_during_powerup)
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/* clock off */
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__glamo_mci_fix_card_div(host, -1);
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@@ -357,7 +392,6 @@ static int glamo_mci_send_command(struct glamo_mci_host *host,
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{
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u8 u8a[6];
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u16 fire = 0;
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- u16 timeout = 0xfff; /* max glamo MMC timeout, in units of 16 clocks */
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/* if we can't do it, reject as busy */
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if (!readw_dly(host->base + GLAMO_REG_MMC_RB_STAT1) &
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@@ -467,15 +501,9 @@ static int glamo_mci_send_command(struct glamo_mci_host *host,
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fire |= GLAMO_FIRE_MMC_CC_BASIC; /* "basic command" */
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break;
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}
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- /* enforce timeout, clipping at default 65520 clocks if larger */
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- if (cmd->data)
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- /* so long as there is one... */
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- if (cmd->data->timeout_clks &&
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- /* ... and it is not longer than we can handle */
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- (cmd->data->timeout_clks <= 0xffff))
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- timeout = cmd->data->timeout_clks >> 4; /* / 16 clks */
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- writew(timeout, host->base + GLAMO_REG_MMC_TIMEOUT);
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+ /* always largest timeout */
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+ writew(0xfff, host->base + GLAMO_REG_MMC_TIMEOUT);
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/* Generate interrupt on txfer */
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writew_dly((readw_dly(host->base + GLAMO_REG_MMC_BASIC) & 0x3e) |
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@@ -576,14 +604,7 @@ static void glamo_mci_send_request(struct mmc_host *mmc)
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/* resume requested clock rate
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* scale it down by sd_slow_ratio if platform requests it
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*/
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- if (host->pdata->glamo_mci_use_slow)
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- if ((host->pdata->glamo_mci_use_slow)())
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- __glamo_mci_fix_card_div(host, host->clk_div *
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- sd_slow_ratio);
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- else
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- __glamo_mci_fix_card_div(host, host->clk_div);
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- else
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- __glamo_mci_fix_card_div(host, host->clk_div);
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+ __glamo_mci_fix_card_div(host, host->clk_div);
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if (glamo_mci_send_command(host, cmd))
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goto bail;
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@@ -633,6 +654,7 @@ static void glamo_mci_send_request(struct mmc_host *mmc)
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goto done;
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if (!(cmd->data->flags & (MMC_DATA_READ | MMC_DATA_WRITE)))
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goto done;
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+
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/*
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* Otherwise can can use the interrupt as async completion --
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* if there is read data coming, or we wait for write data to complete,
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@@ -676,7 +698,7 @@ done:
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host->mrq = NULL;
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mmc_request_done(host->mmc, cmd->mrq);
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bail:
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- if (!sd_idleclk)
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+ if (!sd_idleclk && !host->force_slow_during_powerup)
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/* stop the clock to card */
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__glamo_mci_fix_card_div(host, -1);
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}
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@@ -718,6 +740,12 @@ static void glamo_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
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switch(ios->power_mode) {
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case MMC_POWER_ON:
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case MMC_POWER_UP:
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+ /*
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+ * we should use very slow clock until first bulk
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+ * transfer completes OK
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+ */
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+ host->force_slow_during_powerup = 1;
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+
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if (host->vdd_current != ios->vdd) {
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host->pdata->glamo_set_mci_power(ios->power_mode,
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ios->vdd);
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@@ -734,6 +762,9 @@ static void glamo_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
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default:
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if (host->power_mode_current == MMC_POWER_OFF)
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break;
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+ /* never want clocking with dead card */
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+ __glamo_mci_fix_card_div(host, -1);
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+
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glamo_engine_disable(glamo_mci_def_pdata.pglamo,
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GLAMO_ENGINE_MMC);
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host->pdata->glamo_set_mci_power(MMC_POWER_OFF, 0);
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@@ -751,7 +782,7 @@ static void glamo_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
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if (powering)
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msleep(1);
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- if (!sd_idleclk)
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+ if (!sd_idleclk && !host->force_slow_during_powerup)
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/* stop the clock to card, because we are idle until transfer */
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__glamo_mci_fix_card_div(host, -1);
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@@ -954,14 +985,7 @@ static int glamo_mci_suspend(struct platform_device *dev, pm_message_t state)
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* make sure the clock was running during suspend and consequently
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* resume
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*/
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- if (host->pdata->glamo_mci_use_slow)
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- if ((host->pdata->glamo_mci_use_slow)())
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- __glamo_mci_fix_card_div(host, host->clk_div *
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- sd_slow_ratio);
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- else
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- __glamo_mci_fix_card_div(host, host->clk_div);
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- else
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- __glamo_mci_fix_card_div(host, host->clk_div);
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+ __glamo_mci_fix_card_div(host, host->clk_div);
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/* we are going to do more commands to override this in
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* mmc_suspend_host(), so we need to change sd_idleclk for the
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diff --git a/drivers/mfd/glamo/glamo-mci.h b/drivers/mfd/glamo/glamo-mci.h
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index f3f170e..38f6376 100644
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--- a/drivers/mfd/glamo/glamo-mci.h
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+++ b/drivers/mfd/glamo/glamo-mci.h
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@@ -44,6 +44,8 @@ struct glamo_mci_host {
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unsigned long real_rate;
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u8 prescaler;
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+ int force_slow_during_powerup;
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+
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unsigned sdiimsk;
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int dodma;
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--
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1.5.6.5
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