Re: MMC_CAP_SDIO_IRQ for omap 3430

Madhusudhan Chikkature
2009-10-16T17:43:41Z

Hi Dirk,

I am inlining the patch so that it helps review.

Subject: [PATCH][RFC] OMAP HSMMC: Add SDIO interrupt support
Form: Dirk Behme <dirk.behme@googlemail.com>

At the moment, OMAP HSMMC driver supports only SDIO polling, resulting in poor
performance. Add support for SDIO interrupt handling.

Signed-off-by: Dirk Behme <dirk.behme@googlemail.com>
---

Patch against recent omap-linux head "Linux omap got rebuilt from scratch"
274c94b29ee7c53609a756acca974e4742c59559

Compile tested only. Please comment and help testing.

drivers/mmc/host/omap_hsmmc.c | 48 +++++++++++++++++++++++++++++++++++++-----
1 file changed, 43 insertions(+), 5 deletions(-)

Index: linux-beagle/drivers/mmc/host/omap_hsmmc.c
===================================================================
--- linux-beagle.orig/drivers/mmc/host/omap_hsmmc.c
+++ linux-beagle/drivers/mmc/host/omap_hsmmc.c
@@ -27,6 +27,7 @@
#include <linux/timer.h>
#include <linux/clk.h>
#include <linux/mmc/host.h>
+#include <linux/mmc/card.h>
#include <linux/mmc/core.h>
#include <linux/io.h>
#include <linux/semaphore.h>
@@ -65,6 +66,7 @@
#define SDVSDET 0x00000400
#define AUTOIDLE 0x1
#define SDBP (1 << 8)
+#define IBG (1 << 19)
#define DTO 0xe
#define ICE 0x1
#define ICS 0x2
@@ -76,6 +78,7 @@
#define INT_EN_MASK 0x307F0033
#define BWR_ENABLE (1 << 4)
#define BRR_ENABLE (1 << 5)
+#define CIRQ_ENABLE (1 << 8)
#define INIT_STREAM (1 << 1)
#define DP_SELECT (1 << 21)
#define DDIR (1 << 4)
@@ -87,6 +90,7 @@
#define CC 0x1
#define TC 0x02
#define OD 0x1
+#define CIRQ (1 << 8)
#define ERR (1 << 15)
#define CMD_TIMEOUT (1 << 16)
#define DATA_TIMEOUT (1 << 20)
@@ -653,6 +657,15 @@ static irqreturn_t omap_hsmmc_irq(int ir
status = OMAP_HSMMC_READ(host->base, STAT);
dev_dbg(mmc_dev(host->mmc), "IRQ Status is %x\n", status);

+ if (status & CIRQ) {
+ dev_dbg(mmc_dev(host->mmc), "SDIO interrupt");
+ OMAP_HSMMC_WRITE(host->base, IE, OMAP_HSMMC_READ(host->base, IE)
+ & ~(CIRQ_ENABLE));
+ mmc_signal_sdio_irq(host->mmc);
+ spin_unlock(&host->irq_lock);
+ return IRQ_HANDLED;
+ }
+
if (status & ERR) {
#ifdef CONFIG_MMC_DEBUG
omap_hsmmc_report_irq(host, status);
@@ -1165,8 +1178,15 @@ static void omap_hsmmc_set_ios(struct mm
break;
case MMC_BUS_WIDTH_4:
OMAP_HSMMC_WRITE(host->base, CON, con & ~DW8);
- OMAP_HSMMC_WRITE(host->base, HCTL,
- OMAP_HSMMC_READ(host->base, HCTL) | FOUR_BIT);
+ if (mmc_card_sdio(host->mmc->card)) {

I wish it could be moved to "enable_sdio_irq" so that we can avoid inclusion of
card.h and checking the type of card in the host controller driver. But the
dependancy on 4-bit seems to be a problem here.

On the problems being discussed on testing is the interrupt source geting
cleared at the SDIO card level upon genaration of the CIRQ? If not it remains
asserted.

+ OMAP_HSMMC_WRITE(host->base, HCTL,
+ OMAP_HSMMC_READ(host->base, HCTL)
+ | IBG | FOUR_BIT);
+ } else {
+ OMAP_HSMMC_WRITE(host->base, HCTL,
+ OMAP_HSMMC_READ(host->base, HCTL)
+ | FOUR_BIT);
+ }
break;
case MMC_BUS_WIDTH_1:
OMAP_HSMMC_WRITE(host->base, CON, con & ~DW8);
@@ -1512,6 +1532,24 @@ static int omap_hsmmc_disable_fclk(struc
return 0;
}

+static void omap_hsmmc_enable_sdio_irq(struct mmc_host *mmc, int enable)
+{
+ struct omap_hsmmc_host *host = mmc_priv(mmc);
+ u32 ie, ise;
+
+ ise = OMAP_HSMMC_READ(host->base, ISE);
+ ie = OMAP_HSMMC_READ(host->base, IE);
+
+ if (enable) {
+ OMAP_HSMMC_WRITE(host->base, ISE, ise | CIRQ_ENABLE);
+ OMAP_HSMMC_WRITE(host->base, IE, ie | CIRQ_ENABLE);
+ } else {
+ OMAP_HSMMC_WRITE(host->base, ISE, ise & ~CIRQ_ENABLE);
+ OMAP_HSMMC_WRITE(host->base, IE, ie & ~CIRQ_ENABLE);
+ }
+
+}
+
static const struct mmc_host_ops omap_hsmmc_ops = {
.enable = omap_hsmmc_enable_fclk,
.disable = omap_hsmmc_disable_fclk,
@@ -1519,7 +1557,7 @@ static const struct mmc_host_ops omap_hs
.set_ios = omap_hsmmc_set_ios,
.get_cd = omap_hsmmc_get_cd,
.get_ro = omap_hsmmc_get_ro,
- /* NYET -- enable_sdio_irq */
+ .enable_sdio_irq = omap_hsmmc_enable_sdio_irq,
};

static const struct mmc_host_ops omap_hsmmc_ps_ops = {
@@ -1529,7 +1567,7 @@ static const struct mmc_host_ops omap_hs
.set_ios = omap_hsmmc_set_ios,
.get_cd = omap_hsmmc_get_cd,
.get_ro = omap_hsmmc_get_ro,
- /* NYET -- enable_sdio_irq */
+ .enable_sdio_irq = omap_hsmmc_enable_sdio_irq,
};

#ifdef CONFIG_DEBUG_FS
@@ -1734,7 +1772,7 @@ static int __init omap_hsmmc_probe(struc
mmc->max_seg_size = mmc->max_req_size;

mmc->caps |= MMC_CAP_MMC_HIGHSPEED | MMC_CAP_SD_HIGHSPEED |
- MMC_CAP_WAIT_WHILE_BUSY;
+ MMC_CAP_WAIT_WHILE_BUSY | MMC_CAP_SDIO_IRQ;

if (mmc_slot(host).wires >= 8)
mmc->caps |= MMC_CAP_8_BIT_DATA;

> John Rigby wrote:
>> I have seen several discussions about lack of sdio irq support in the
>> hsmmc driver but no patches. Has anyone on this list implemented this
>> and/or can anyone point me to patches?
>
> What a coincidence ;)
>
> I'm currently working on this. See attachment what I currently have.
> It is compile tested only against recent omap linux head. I don't have
> a board using SDIO at the moment, so no real testing possible :(
>
> Some background, maybe it helps people to step in:
>
> Gumstix OMAP3 based Overo air board connects Marvell 88W8686 wifi by
> MMC port 2 in 4 bit configuration [1]. The wifi performance is quite
> bad (~100kB/s). There is some rumor that this might be SDIO irq
> related [2]. There was an attempt to fix this [3] already, but this
> doesn't work [4]. Having this, I started to look into it.
>
> I used [3], the TI Davinci driver [5] (supporting SDIO irq), the SDIO
> Simplified Specification [6] and the OMAP35x TRM [7] as starting points.
>
> Unfortunately, the Davinci MMC registers and irqs are different
> (Davinci has a dedicated SDIO irq). But combining [3] and [5] helps to
> get an idea what has to be done.
>
> I think the main issues of [3] were that it doesn't enable IBG for 4
> bit mode ([6] chapter 8.1.2) and that mmc_omap_irq() doesn't reset the
> irq bits.
>
> Topics I still open:
>
> - Is it always necessary to deal with IE _and_ ISE register? I'm not
> totally clear what the difference between these two registers are ;)
> And in which order they have to be set.
>
> - Davinci driver [5] in line 1115 checks for data line to call
> mmc_signal_sdio_irq() for irq enable.
>
> - Davinci driver deals with SDIO in xfer_done() (line 873)
>
> - Davinci driver sets block size to 64 if SDIO in line 701
>
> It would be quite nice if anybody likes to comment on attachment and
> help testing.
>
> Many thanks and best regards
>
> Dirk
>
> [1] http://gumstix.net/wiki/index.php?title=Overo_Wifi
>
> [2] http://groups.google.com/group/beagleboard/msg/14e822778c5eeb56
>
> [3] http://groups.google.com/group/beagleboard/msg/d0eb69f4c20673be
>
> [4] http://groups.google.com/group/beagleboard/msg/5cdfe2a319531937
>
> [5]
> http://arago-project.org/git/projects/?p=linux-davinci.git;a=blob;f=drivers/mmc/host/davinci_mmc.c;h=1bf0587250614c6d8abfe02028b96e0e47148ac8;hb=HEAD
>
> [6] http://www.sdcard.org/developers/tech/sdio/sd_bluetooth_spec/
>
> [7] http://focus.ti.com/lit/ug/spruf98c/spruf98c.pdf
>
>