mmc: sdhci-msm: Vote for MSM bus clocks before enabling iface_clk
The current driver just enables "iface_clk" before accessing its
registers but MSM bus clocks are also required for register access
without which any register access would result in chip reset.
The MSM bus clocks can be enabled by setting vote to MSM bus bandwidth
driver. Currently, voting is being done in sdhci_enable/disable but these
functions will not be invoked by MMC core layer for some cases such
as mmc_power_up/mmc_power_off, which require peripheral register
access.
To resolve the above mentioned problem, bus voting and de-voting will
now be done as part of clock management within the sdhci MSM driver
i.e., before enabling SDHC clocks and after disabling SDHC clocks.
Change-Id: Iff608fba4c58bf37a6f4ce8eb36876c79969feaf
Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
index d850782..3c0576e 100644
--- a/drivers/mmc/host/sdhci-msm.c
+++ b/drivers/mmc/host/sdhci-msm.c
@@ -1418,10 +1418,20 @@
return;
bw = sdhci_get_bw_required(host, ios);
- if (enable)
+ if (enable) {
sdhci_msm_bus_cancel_work_and_set_vote(host, bw);
- else
- sdhci_msm_bus_queue_work(host);
+ } else {
+ /*
+ * If clock gating is enabled, then remove the vote
+ * immediately because clocks will be disabled only
+ * after SDHCI_MSM_MMC_CLK_GATE_DELAY and thus no
+ * additional delay is required to remove the bus vote.
+ */
+ if (host->mmc->clkgate_delay)
+ sdhci_msm_bus_cancel_work_and_set_vote(host, 0);
+ else
+ sdhci_msm_bus_queue_work(host);
+ }
}
/* Regulator utility functions */
@@ -1942,12 +1952,15 @@
if (enable && !atomic_read(&msm_host->clks_on)) {
pr_debug("%s: request to enable clocks\n",
mmc_hostname(host->mmc));
+
+ sdhci_msm_bus_voting(host, 1);
+
if (!IS_ERR_OR_NULL(msm_host->bus_clk)) {
rc = clk_prepare_enable(msm_host->bus_clk);
if (rc) {
pr_err("%s: %s: failed to enable the bus-clock with error %d\n",
mmc_hostname(host->mmc), __func__, rc);
- goto out;
+ goto remove_vote;
}
}
if (!IS_ERR(msm_host->pclk)) {
@@ -1976,6 +1989,8 @@
clk_disable_unprepare(msm_host->pclk);
if (!IS_ERR_OR_NULL(msm_host->bus_clk))
clk_disable_unprepare(msm_host->bus_clk);
+
+ sdhci_msm_bus_voting(host, 0);
}
atomic_set(&msm_host->clks_on, enable);
goto out;
@@ -1985,6 +2000,9 @@
disable_bus_clk:
if (!IS_ERR_OR_NULL(msm_host->bus_clk))
clk_disable_unprepare(msm_host->bus_clk);
+remove_vote:
+ if (msm_host->msm_bus_vote.client_handle)
+ sdhci_msm_bus_cancel_work_and_set_vote(host, 0);
out:
return rc;
}
@@ -2031,6 +2049,11 @@
}
msm_host->clk_rate = sup_clock;
host->clock = clock;
+ /*
+ * Update the bus vote in case of frequency change due to
+ * clock scaling.
+ */
+ sdhci_msm_bus_voting(host, 1);
}
}
@@ -2122,7 +2145,6 @@
.toggle_cdr = sdhci_msm_toggle_cdr,
.get_max_segments = sdhci_msm_max_segs,
.set_clock = sdhci_msm_set_clock,
- .platform_bus_voting = sdhci_msm_bus_voting,
.get_min_clock = sdhci_msm_get_min_clock,
.get_max_clock = sdhci_msm_get_max_clock,
.disable_data_xfer = sdhci_msm_disable_data_xfer,
@@ -2226,11 +2248,20 @@
msm_host->clk_rate = sdhci_msm_get_min_clock(host);
atomic_set(&msm_host->clks_on, 1);
+ ret = sdhci_msm_bus_register(msm_host, pdev);
+ if (ret)
+ goto clk_disable;
+
+ if (msm_host->msm_bus_vote.client_handle)
+ INIT_DELAYED_WORK(&msm_host->msm_bus_vote.vote_work,
+ sdhci_msm_bus_work);
+ sdhci_msm_bus_voting(host, 1);
+
/* Setup regulators */
ret = sdhci_msm_vreg_init(&pdev->dev, msm_host->pdata, true);
if (ret) {
dev_err(&pdev->dev, "Regulator setup failed (%d)\n", ret);
- goto clk_disable;
+ goto bus_unregister;
}
/* Reset the core and Enable SDHC mode */
@@ -2377,14 +2408,6 @@
host->cpu_dma_latency_us = msm_host->pdata->cpu_dma_latency_us;
- ret = sdhci_msm_bus_register(msm_host, pdev);
- if (ret)
- goto vreg_deinit;
-
- if (msm_host->msm_bus_vote.client_handle)
- INIT_DELAYED_WORK(&msm_host->msm_bus_vote.vote_work,
- sdhci_msm_bus_work);
-
init_completion(&msm_host->pwr_irq_completion);
if (gpio_is_valid(msm_host->pdata->status_gpio)) {
@@ -2393,7 +2416,7 @@
if (ret) {
dev_err(&pdev->dev, "%s: Failed to request card detection IRQ %d\n",
__func__, ret);
- goto bus_unregister;
+ goto vreg_deinit;
}
}
@@ -2436,10 +2459,12 @@
free_cd_gpio:
if (gpio_is_valid(msm_host->pdata->status_gpio))
mmc_cd_gpio_free(msm_host->mmc);
-bus_unregister:
- sdhci_msm_bus_unregister(msm_host);
vreg_deinit:
sdhci_msm_vreg_init(&pdev->dev, msm_host->pdata, false);
+bus_unregister:
+ if (msm_host->msm_bus_vote.client_handle)
+ sdhci_msm_bus_cancel_work_and_set_vote(host, 0);
+ sdhci_msm_bus_unregister(msm_host);
clk_disable:
if (!IS_ERR(msm_host->clk))
clk_disable_unprepare(msm_host->clk);
@@ -2495,6 +2520,16 @@
disable_irq(host->irq);
disable_irq(msm_host->pwr_irq);
+ /*
+ * Remove the vote immediately only if clocks are off in which
+ * case we might have queued work to remove vote but it may not
+ * be completed before runtime suspend or system suspend.
+ */
+ if (!atomic_read(&msm_host->clks_on)) {
+ if (msm_host->msm_bus_vote.client_handle)
+ sdhci_msm_bus_cancel_work_and_set_vote(host, 0);
+ }
+
return 0;
}
@@ -2528,9 +2563,6 @@
goto out;
}
- if (msm_host->msm_bus_vote.client_handle)
- sdhci_msm_bus_cancel_work_and_set_vote(host, 0);
-
return sdhci_msm_runtime_suspend(dev);
out:
return ret;