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From: Lars-Peter Clausen on 1 Jul 2010 11:50
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Hi

Andrew Morton wrote:
> On Mon, 28 Jun 2010 03:20:41 +0200
> Lars-Peter Clausen <lars(a)metafoo.de> wrote:
>
>> This patch adds support for the mmc controller on JZ4740 SoCs.
>>
>> Signed-off-by: Lars-Peter Clausen <lars(a)metafoo.de>
>> Cc: Andrew Morton <akpm(a)linux-foundation.org>
>> Cc: Matt Fleming <matt(a)console-pimps.org>
>> Cc: linux-mmc(a)vger.kernel.org
>>
>> ...
>>
>> +#define JZ4740_MMC_MAX_TIMEOUT 10000000
>
> That was a really big timeout. How long do 1e7 readw's take? Oh well.
>

Hm, right. It doesn't hurt though. I'll do some tests and to try to come up with a
more realistic value.

>> ...
>>
>> +static void jz4740_mmc_clock_disable(struct jz4740_mmc_host *host)
>> +{
>> + uint32_t status;
>> +
>> + writew(JZ_MMC_STRPCL_CLOCK_STOP, host->base + JZ_REG_MMC_STRPCL);
>> + do {
>> + status = readl(host->base + JZ_REG_MMC_STATUS);
>> + } while (status & JZ_MMC_STATUS_CLK_EN);
>> +}
>> +
>> +static void jz4740_mmc_reset(struct jz4740_mmc_host *host)
>> +{
>> + uint32_t status;
>> +
>> + writew(JZ_MMC_STRPCL_RESET, host->base + JZ_REG_MMC_STRPCL);
>> + udelay(10);
>> + do {
>> + status = readl(host->base + JZ_REG_MMC_STATUS);
>> + } while (status & JZ_MMC_STATUS_IS_RESETTING);
>> +}
>
> Maybe these should have a timeout too?

Its very unlikely that these will ever timeout. But right, to be on the safe, there
should be a timeout as well.

>
>> ...
>>
>> +static inline unsigned int jz4740_mmc_wait_irq(struct jz4740_mmc_host *host,
>> + unsigned int irq)
>> +{
>> + unsigned int timeout = JZ4740_MMC_MAX_TIMEOUT;
>> + uint16_t status;
>> +
>> + do {
>> + status = readw(host->base + JZ_REG_MMC_IREG);
>> + } while (!(status & irq) && --timeout);
>> +
>> + return timeout;
>> +}
>
> This guy's too big to inline. Recent gcc's know that and they tend to
> uninline such things behind your back anwyay.

Actually, even without the inline attribute and compiling with -Os gcc will inline
this function by itself.

>
>> ...
>>
>> +struct jz4740_mmc_platform_data {
>> + int gpio_power;
>> + int gpio_card_detect;
>> + int gpio_read_only;
>> + unsigned card_detect_active_low:1;
>> + unsigned read_only_active_low:1;
>> + unsigned power_active_low:1;
>> +
>> + unsigned data_1bit:1;
>> +};
>
> The bitfields will all share the same word, so modification of one
> field can race against modification of another field. Hence some form
> of locking which covers *all* the bitfields is needed.
>
> Is that a problem in this driver?
>
They are all read-only in the driver.


Thanks for reviewing the patch
- - Lars

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From: Randy Dunlap on 12 Jul 2010 17:50
Lars-Peter Clausen wrote:
> This patch adds support for the mmc controller on JZ4740 SoCs.
>
> Signed-off-by: Lars-Peter Clausen <lars(a)metafoo.de>
> Acked-by: Matt Fleming <matt(a)console-pimps.org>
> Cc: Andrew Morton <akpm(a)linux-foundation.org>
> Cc: Matt Fleming <matt(a)console-pimps.org>
> Cc: linux-mmc(a)vger.kernel.org
>
> ---
> arch/mips/include/asm/mach-jz4740/jz4740_mmc.h | 15 +
> drivers/mmc/host/Kconfig | 8 +
> drivers/mmc/host/Makefile | 1 +
> drivers/mmc/host/jz4740_mmc.c | 1024 ++++++++++++++++++++++++
> 4 files changed, 1048 insertions(+), 0 deletions(-)
> create mode 100644 arch/mips/include/asm/mach-jz4740/jz4740_mmc.h
> create mode 100644 drivers/mmc/host/jz4740_mmc.c
>
> diff --git a/arch/mips/include/asm/mach-jz4740/jz4740_mmc.h b/arch/mips/include/asm/mach-jz4740/jz4740_mmc.h
> new file mode 100644
> index 0000000..8543f43
> --- /dev/null
> +++ b/arch/mips/include/asm/mach-jz4740/jz4740_mmc.h
> @@ -0,0 +1,15 @@
> +#ifndef __LINUX_MMC_JZ4740_MMC
> +#define __LINUX_MMC_JZ4740_MMC
> +
> +struct jz4740_mmc_platform_data {
> + int gpio_power;
> + int gpio_card_detect;
> + int gpio_read_only;
> + unsigned card_detect_active_low:1;
> + unsigned read_only_active_low:1;
> + unsigned power_active_low:1;
> +
> + unsigned data_1bit:1;
> +};
> +
> +#endif
> diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
> index f06d06e..546fc49 100644
> --- a/drivers/mmc/host/Kconfig
> +++ b/drivers/mmc/host/Kconfig
> @@ -81,6 +81,14 @@ config MMC_RICOH_MMC
>
> If unsure, say Y.
>
> +config MMC_JZ4740
> + tristate "JZ4740 SD/Multimedia Card Interface support"
> + depends on MACH_JZ4740

What tree has the kconfig symbol MACH_JZ4740 in it?
I can't seem to find it...

Should the depends also say anything about GPIO?
I only ask because the header file above mentions gpio.

> + help
> + This selects the Ingenic Z4740 SD/Multimedia card Interface.
> + If you have an ngenic platform with a Multimedia Card slot,

Ingenic ?

> + say Y or M here.
> +
> config MMC_SDHCI_OF
> tristate "SDHCI support on OpenFirmware platforms"
> depends on MMC_SDHCI && PPC_OF

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From: Lars-Peter Clausen on 12 Jul 2010 18:10
Hi

Randy Dunlap wrote:
> Lars-Peter Clausen wrote:
>> This patch adds support for the mmc controller on JZ4740 SoCs.
>>
>> Signed-off-by: Lars-Peter Clausen <lars(a)metafoo.de>
>> Acked-by: Matt Fleming <matt(a)console-pimps.org>
>> Cc: Andrew Morton <akpm(a)linux-foundation.org>
>> Cc: Matt Fleming <matt(a)console-pimps.org>
>> Cc: linux-mmc(a)vger.kernel.org
>>
>> ---
>> arch/mips/include/asm/mach-jz4740/jz4740_mmc.h | 15 +
>> drivers/mmc/host/Kconfig | 8 +
>> drivers/mmc/host/Makefile | 1 +
>> drivers/mmc/host/jz4740_mmc.c | 1024 ++++++++++++++++++++++++
>> 4 files changed, 1048 insertions(+), 0 deletions(-)
>> create mode 100644 arch/mips/include/asm/mach-jz4740/jz4740_mmc.h
>> create mode 100644 drivers/mmc/host/jz4740_mmc.c
>>
>> diff --git a/arch/mips/include/asm/mach-jz4740/jz4740_mmc.h b/arch/mips/include/asm/mach-jz4740/jz4740_mmc.h
>> new file mode 100644
>> index 0000000..8543f43
>> --- /dev/null
>> +++ b/arch/mips/include/asm/mach-jz4740/jz4740_mmc.h
>> @@ -0,0 +1,15 @@
>> +#ifndef __LINUX_MMC_JZ4740_MMC
>> +#define __LINUX_MMC_JZ4740_MMC
>> +
>> +struct jz4740_mmc_platform_data {
>> + int gpio_power;
>> + int gpio_card_detect;
>> + int gpio_read_only;
>> + unsigned card_detect_active_low:1;
>> + unsigned read_only_active_low:1;
>> + unsigned power_active_low:1;
>> +
>> + unsigned data_1bit:1;
>> +};
>> +
>> +#endif
>> diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
>> index f06d06e..546fc49 100644
>> --- a/drivers/mmc/host/Kconfig
>> +++ b/drivers/mmc/host/Kconfig
>> @@ -81,6 +81,14 @@ config MMC_RICOH_MMC
>>
>> If unsure, say Y.
>>
>> +config MMC_JZ4740
>> + tristate "JZ4740 SD/Multimedia Card Interface support"
>> + depends on MACH_JZ4740
>
> What tree has the kconfig symbol MACH_JZ4740 in it?
> I can't seem to find it...
>
> Should the depends also say anything about GPIO?
> I only ask because the header file above mentions gpio.
>

None yet, mips hopefully soon. Version 1 of this patch was part of a series adding
support for the JZ4740.
Since the jz4740 platform code provides the gpio functions I don't think it is
necessary to add an additional depends on GENERIC_GPIO.

>> + help
>> + This selects the Ingenic Z4740 SD/Multimedia card Interface.
>> + If you have an ngenic platform with a Multimedia Card slot,
>
> Ingenic ?
>

Woops, yes.

>> + say Y or M here.
>> +
>> config MMC_SDHCI_OF
>> tristate "SDHCI support on OpenFirmware platforms"
>> depends on MMC_SDHCI && PPC_OF
>
>

Thanks for reviewing
- Lars
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From: Joe Perches on 12 Jul 2010 18:50
On Tue, 2010-07-13 at 00:20 +0200, Lars-Peter Clausen wrote:
> This patch adds support for the mmc controller on JZ4740 SoCs.
> +static bool jz4740_mmc_write_data(struct jz4740_mmc_host *host,
> + struct mmc_data *data)
> +{
> + struct sg_mapping_iter *miter = &host->miter;
> + uint32_t *buf;
> + bool timeout;
> + size_t i, j;
> +
> + while (sg_miter_next(miter)) {
> + buf = miter->addr;
> + i = miter->length / 4;
> + j = i / 8;
> + i = i & 0x7;
> + while (j) {
> + timeout = jz4740_mmc_poll_irq(host, JZ_MMC_IRQ_TXFIFO_WR_REQ);
> + if (unlikely(timeout))
> + goto poll_timeout;
> +
> + writel(buf[0], host->base + JZ_REG_MMC_TXFIFO);

Perhaps it'd be better to use a temporary for
host->base + JZ_REG_MMC_TXFIFO

> + writel(buf[1], host->base + JZ_REG_MMC_TXFIFO);
> + writel(buf[2], host->base + JZ_REG_MMC_TXFIFO);
> + writel(buf[3], host->base + JZ_REG_MMC_TXFIFO);
> + writel(buf[4], host->base + JZ_REG_MMC_TXFIFO);
> + writel(buf[5], host->base + JZ_REG_MMC_TXFIFO);
> + writel(buf[6], host->base + JZ_REG_MMC_TXFIFO);
> + writel(buf[7], host->base + JZ_REG_MMC_TXFIFO);
> + buf += 8;
> + --j;
> + }
> + if (unlikely(i)) {
> + timeout = jz4740_mmc_poll_irq(host, JZ_MMC_IRQ_TXFIFO_WR_REQ);
> + if (unlikely(timeout))
> + goto poll_timeout;
> +
> + while (i) {
> + writel(*buf, host->base + JZ_REG_MMC_TXFIFO);
> + ++buf;
> + --i;
> + }
> + }
> + data->bytes_xfered += miter->length;
> + }


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From: Lars-Peter Clausen on 12 Jul 2010 19:50
Hi

Joe Perches wrote:
> On Tue, 2010-07-13 at 00:20 +0200, Lars-Peter Clausen wrote:
>> This patch adds support for the mmc controller on JZ4740 SoCs.
>> +static bool jz4740_mmc_write_data(struct jz4740_mmc_host *host,
>> + struct mmc_data *data)
>> +{
>> + struct sg_mapping_iter *miter = &host->miter;
>> + uint32_t *buf;
>> + bool timeout;
>> + size_t i, j;
>> +
>> + while (sg_miter_next(miter)) {
>> + buf = miter->addr;
>> + i = miter->length / 4;
>> + j = i / 8;
>> + i = i & 0x7;
>> + while (j) {
>> + timeout = jz4740_mmc_poll_irq(host, JZ_MMC_IRQ_TXFIFO_WR_REQ);
>> + if (unlikely(timeout))
>> + goto poll_timeout;
>> +
>> + writel(buf[0], host->base + JZ_REG_MMC_TXFIFO);
>
> Perhaps it'd be better to use a temporary for
> host->base + JZ_REG_MMC_TXFIFO
Hm, indeed host->addr is reloaded before each write.
>
>> + writel(buf[1], host->base + JZ_REG_MMC_TXFIFO);
>> + writel(buf[2], host->base + JZ_REG_MMC_TXFIFO);
>> + writel(buf[3], host->base + JZ_REG_MMC_TXFIFO);
>> + writel(buf[4], host->base + JZ_REG_MMC_TXFIFO);
>> + writel(buf[5], host->base + JZ_REG_MMC_TXFIFO);
>> + writel(buf[6], host->base + JZ_REG_MMC_TXFIFO);
>> + writel(buf[7], host->base + JZ_REG_MMC_TXFIFO);
>> + buf += 8;
>> + --j;
>> + }
>> + if (unlikely(i)) {
>> + timeout = jz4740_mmc_poll_irq(host, JZ_MMC_IRQ_TXFIFO_WR_REQ);
>> + if (unlikely(timeout))
>> + goto poll_timeout;
>> +
>> + while (i) {
>> + writel(*buf, host->base + JZ_REG_MMC_TXFIFO);
>> + ++buf;
>> + --i;
>> + }
>> + }
>> + data->bytes_xfered += miter->length;
>> + }
>
>

Thanks for reviewing
- Lars

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