240 lines
7.1 KiB
Diff
Executable file
240 lines
7.1 KiB
Diff
Executable file
From ee83ea40a3a1d1cb6447fdd345384d9cabf21c83 Mon Sep 17 00:00:00 2001
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From: Andy Green <andy@openmoko.com>
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Date: Fri, 25 Jul 2008 23:06:20 +0100
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Subject: [PATCH] fix-force-sdcard-clk-off-when-idle.patch
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Existing Glamo bit for stopping SD Card Clock when there is no
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transfer taking place does not work. This patch adds stuff around
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the transfer code to force the SD clock up when something is going on
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and down when it is idle. This'll save a little power and noise ;-)
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I tested it briefly and was able to SD Boot normally on Sandisk 512M.
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Wider testing is appreciated.
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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 | 126 +++++++++++++++++++++++++++++------------
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1 files changed, 89 insertions(+), 37 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 37e3d3c..b53827e 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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@@ -20,6 +20,7 @@
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#include <linux/pcf50633.h>
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#include <linux/delay.h>
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#include <linux/interrupt.h>
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+#include <linux/spinlock.h>
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#include <asm/dma.h>
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#include <asm/dma-mapping.h>
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@@ -32,6 +33,7 @@
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/* from glamo-core.c */
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extern struct glamo_mci_pdata glamo_mci_def_pdata;
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+static spinlock_t clock_lock;
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#define DRIVER_NAME "glamo-mci"
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#define RESSIZE(ressource) (((ressource)->end - (ressource)->start) + 1)
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@@ -164,6 +166,67 @@ static int do_pio_write(struct glamo_mci_host *host)
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return err;
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}
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+static void __glamo_mci_fix_card_div(struct glamo_mci_host *host, int div)
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+{
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+ unsigned long flags;
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+
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+ spin_lock_irqsave(&clock_lock, flags);
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+
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+ if (div < 0) {
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+ /* stop clock - remove clock from divider input */
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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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+
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+ spin_unlock_irqrestore(&clock_lock, flags);
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+}
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+
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+static int __glamo_mci_set_card_clock(struct glamo_mci_host *host, int freq,
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+ int *division)
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+{
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+ int div = 0;
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+ int real_rate = 0;
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+
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+ if (freq) {
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+ /* Set clock */
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+ for (div = 0; div < 256; div++) {
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+ real_rate = host->clk_rate / (div + 1);
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+ if (real_rate <= freq)
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+ break;
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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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+ if (division)
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+ *division = div;
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+
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+ __glamo_mci_fix_card_div(host, div);
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+
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+ } else {
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+ /* stop clock */
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+ if (division)
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+ *division = 0xff;
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+
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+ __glamo_mci_fix_card_div(host, -1); /* clock off */
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+ }
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+
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+ return real_rate;
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+}
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+
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static void glamo_mci_irq(unsigned int irq, struct irq_desc *desc)
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{
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struct glamo_mci_host *host = (struct glamo_mci_host *)
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@@ -212,6 +275,10 @@ static void glamo_mci_irq(unsigned int irq, struct irq_desc *desc)
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glamo_mci_send_request(host->mmc);
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host->cmd_is_stop = 0;
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}
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+
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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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done:
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host->complete_what = COMPLETION_NONE;
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host->mrq = NULL;
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@@ -441,8 +508,11 @@ static void glamo_mci_send_request(struct mmc_host *mmc)
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cmd->opcode, cmd->arg, cmd->data, cmd->mrq->stop,
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cmd->flags);
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+ /* resume requested clock rate */
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+ __glamo_mci_fix_card_div(host, host->clk_div);
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+
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if (glamo_mci_send_command(host, cmd))
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- return;
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+ goto bail;
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/*
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* we must spin until response is ready or timed out
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* -- we don't get interrupts unless there is a bulk rx
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@@ -464,7 +534,7 @@ static void glamo_mci_send_request(struct mmc_host *mmc)
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cmd->error = -EILSEQ;
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if (host->cmd_is_stop)
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- return;
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+ goto bail;
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if (cmd->error) {
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dev_err(&host->pdev->dev, "Error after cmd: 0x%x\n", status);
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@@ -516,10 +586,12 @@ static void glamo_mci_send_request(struct mmc_host *mmc)
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if (cmd->data->error)
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cmd->data->error = -ETIMEDOUT;
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dev_err(&host->pdev->dev, "Payload timeout\n");
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- return;
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+ goto bail;
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}
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- /* yay we are an interrupt controller! -- call the ISR */
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+ /* yay we are an interrupt controller! -- call the ISR
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+ * it will stop clock to card
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+ */
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glamo_mci_irq(IRQ_GLAMO(GLAMO_IRQIDX_MMC),
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irq_desc + IRQ_GLAMO(GLAMO_IRQIDX_MMC));
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}
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@@ -529,6 +601,12 @@ done:
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host->complete_what = COMPLETION_NONE;
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host->mrq = NULL;
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mmc_request_done(host->mmc, cmd->mrq);
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+ return;
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+
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+bail:
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+ /* stop the clock to card */
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+ __glamo_mci_fix_card_div(host, -1);
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+ return;
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}
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static void glamo_mci_request(struct mmc_host *mmc, struct mmc_request *mrq)
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@@ -556,11 +634,12 @@ static void glamo_mci_reset(struct glamo_mci_host *host)
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glamo_mci_def_pdata.pglamo->base + GLAMO_REG_CLOCK_MMC);
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}
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+
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static void glamo_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
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{
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struct glamo_mci_host *host = mmc_priv(mmc);
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- int mci_psc = 0;
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int n = 0;
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+ int div;
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/* Set power */
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switch(ios->power_mode) {
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@@ -590,43 +669,15 @@ static void glamo_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
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}
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host->power_mode_current = ios->power_mode;
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- /* Set clock */
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-/* if (ios->clock) { */
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- for (mci_psc = 0; mci_psc < 256; mci_psc++) {
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- host->real_rate = host->clk_rate / (mci_psc + 1);
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- if (host->real_rate <= ios->clock)
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- break;
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- }
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- if (mci_psc > 255)
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- mci_psc = 255;
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- host->clk_div = mci_psc;
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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) | host->clk_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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-#if 0
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- } else { /* stop clock */
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- host->real_rate = 0;
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- /* remove clock from divider input */
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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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- }
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-#endif
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+ host->real_rate = __glamo_mci_set_card_clock(host, ios->clock, &div);
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+ host->clk_div = div;
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+
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if ((ios->power_mode == MMC_POWER_ON) ||
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(ios->power_mode == MMC_POWER_UP)) {
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dev_info(&host->pdev->dev,
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"powered (vdd = %d) clk: %lukHz div=%d (req: %ukHz). "
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"Bus width=%d\n",ios->vdd,
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- host->real_rate / 1000, mci_psc,
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+ host->real_rate / 1000, host->real_rate,
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ios->clock / 1000, ios->bus_width);
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} else
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dev_info(&host->pdev->dev, "glamo_mci_set_ios: power down.\n");
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@@ -856,6 +907,7 @@ static struct platform_driver glamo_mci_driver =
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static int __init glamo_mci_init(void)
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{
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+ spin_lock_init(&clock_lock);
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platform_driver_register(&glamo_mci_driver);
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return 0;
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}
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--
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1.5.6.3
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