Re: [PATCH V3] mmc: sdhci-msm: Reset GCC_SDCC_BCR register for SDHC
From: Sajida Bhanu (Temp)
Date: Wed Apr 06 2022 - 10:08:37 EST
On 4/1/2022 12:12 AM, Bjorn Andersson wrote:
On Thu 31 Mar 00:03 PDT 2022, Shaik Sajida Bhanu wrote:
Reset GCC_SDCC_BCR register before every fresh initilazation. This will
reset whole SDHC-msm controller, clears the previous power control
states and avoids, software reset timeout issues as below.
[ 5.458061][ T262] mmc1: Reset 0x1 never completed.
[ 5.462454][ T262] mmc1: sdhci: ============ SDHCI REGISTER DUMP ===========
[ 5.469065][ T262] mmc1: sdhci: Sys addr: 0x00000000 | Version: 0x00007202
[ 5.475688][ T262] mmc1: sdhci: Blk size: 0x00000000 | Blk cnt: 0x00000000
[ 5.482315][ T262] mmc1: sdhci: Argument: 0x00000000 | Trn mode: 0x00000000
[ 5.488927][ T262] mmc1: sdhci: Present: 0x01f800f0 | Host ctl: 0x00000000
[ 5.495539][ T262] mmc1: sdhci: Power: 0x00000000 | Blk gap: 0x00000000
[ 5.502162][ T262] mmc1: sdhci: Wake-up: 0x00000000 | Clock: 0x00000003
[ 5.508768][ T262] mmc1: sdhci: Timeout: 0x00000000 | Int stat: 0x00000000
[ 5.515381][ T262] mmc1: sdhci: Int enab: 0x00000000 | Sig enab: 0x00000000
[ 5.521996][ T262] mmc1: sdhci: ACmd stat: 0x00000000 | Slot int: 0x00000000
[ 5.528607][ T262] mmc1: sdhci: Caps: 0x362dc8b2 | Caps_1: 0x0000808f
[ 5.535227][ T262] mmc1: sdhci: Cmd: 0x00000000 | Max curr: 0x00000000
[ 5.541841][ T262] mmc1: sdhci: Resp[0]: 0x00000000 | Resp[1]: 0x00000000
[ 5.548454][ T262] mmc1: sdhci: Resp[2]: 0x00000000 | Resp[3]: 0x00000000
[ 5.555079][ T262] mmc1: sdhci: Host ctl2: 0x00000000
[ 5.559651][ T262] mmc1: sdhci_msm: ----------- VENDOR REGISTER DUMP-----------
[ 5.566621][ T262] mmc1: sdhci_msm: DLL sts: 0x00000000 | DLL cfg: 0x6000642c | DLL cfg2: 0x0020a000
[ 5.575465][ T262] mmc1: sdhci_msm: DLL cfg3: 0x00000000 | DLL usr ctl: 0x00010800 | DDR cfg: 0x80040873
[ 5.584658][ T262] mmc1: sdhci_msm: Vndr func: 0x00018a9c | Vndr func2 : 0xf88218a8 Vndr func3: 0x02626040
Fixes: 0eb0d9f4de34 ("mmc: sdhci-msm: Initial support for Qualcomm chipsets")
Signed-off-by: Shaik Sajida Bhanu <quic_c_sbhanu@xxxxxxxxxxx>
---
Changes since V2:
- Dropped new line after fixes tag as suggested by Bjorn
Andersson.
- Passed device structure instead of passing platform_device
structure as a argument for sdhci_msm_gcc_reset() as suggested
by Bjorn Andersson.
- Replaced dev_err() with dev_err_probe() as suggested by Bjorn
Andersson.
Thanks, looks much better. Still some things I would like to see
improved below.
Sure
Changes since V1:
- Added fixes tag as suggested by Ulf Hansson.
- Replaced devm_reset_control_get() with
devm_reset_control_get_optional_exclusive() as suggested by
Ulf Hansson.
---
drivers/mmc/host/sdhci-msm.c | 39 +++++++++++++++++++++++++++++++++++++++
1 file changed, 39 insertions(+)
diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
index 50c71e0..e15e789 100644
--- a/drivers/mmc/host/sdhci-msm.c
+++ b/drivers/mmc/host/sdhci-msm.c
@@ -17,6 +17,7 @@
#include <linux/regulator/consumer.h>
#include <linux/interconnect.h>
#include <linux/pinctrl/consumer.h>
+#include <linux/reset.h>
#include "sdhci-pltfm.h"
#include "cqhci.h"
@@ -284,6 +285,7 @@ struct sdhci_msm_host {
bool uses_tassadar_dll;
u32 dll_config;
u32 ddr_config;
+ struct reset_control *core_reset;
bool vqmmc_enabled;
};
@@ -2482,6 +2484,39 @@ static inline void sdhci_msm_get_of_property(struct platform_device *pdev,
of_property_read_u32(node, "qcom,dll-config", &msm_host->dll_config);
}
+static int sdhci_msm_gcc_reset(struct device *dev, struct sdhci_host *host)
+{
+ struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+ struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host);
+ int ret = 0;
First use of this variable is an assignment, so no need to initialize it
here.
Sure
+
+ msm_host->core_reset = devm_reset_control_get_optional_exclusive(dev, "core_reset");
reset-names will only be used to identify resets and hence there's no
reason to include "_reset" in the identifier.
If this is the only reset for the controller, there's actually no reason
for identifying it, you can omit reset-names from the binding and just
pass NULL here (to get the first resets = <>).
ok Sure
+ if (IS_ERR(msm_host->core_reset))
+ return dev_err_probe(dev, PTR_ERR(msm_host->core_reset),
+ "unable to acquire core_reset\n");
+
+ if (!msm_host->core_reset)
+ return 0;
+
+ ret = reset_control_assert(msm_host->core_reset);
+ if (ret)
+ return dev_err_probe(dev, ret, "core_reset assert failed\n");
+
+ /*
+ * The hardware requirement for delay between assert/deassert
+ * is at least 3-4 sleep clock (32.7KHz) cycles, which comes to
+ * ~125us (4/32768). To be on the safe side add 200us delay.
+ */
+ usleep_range(200, 210);
+
+ ret = reset_control_deassert(msm_host->core_reset);
+ if (ret)
+ return dev_err_probe(dev, ret, "core_reset deassert failed\n");
+
+ usleep_range(200, 210);
+
sdhci_msm_gcc_reset() is only called once during probe(), so there's no
reason to carry the reset_control pointer in struct sdhci_msm_host. Make
it a local variable and use reset_control_get_optional_exclusive() and
reset_control_put() the reset here before returning.
Regards,
Bjorn
Sure Thanks for the review.
+ return 0;
+}
static int sdhci_msm_probe(struct platform_device *pdev)
{
@@ -2529,6 +2564,10 @@ static int sdhci_msm_probe(struct platform_device *pdev)
msm_host->saved_tuning_phase = INVALID_TUNING_PHASE;
+ ret = sdhci_msm_gcc_reset(&pdev->dev, host);
+ if (ret)
+ goto pltfm_free;
+
/* Setup SDCC bus voter clock. */
msm_host->bus_clk = devm_clk_get(&pdev->dev, "bus");
if (!IS_ERR(msm_host->bus_clk)) {
--
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