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Subject[RFC 1/6] mmc: core: Parse clk scaling dt entries
Date
Add support to parse clk scaling dt entries in mmc
driver.

Signed-off-by: Sujit Reddy Thumma <sthumma@codeaurora.org>
Signed-off-by: Talel Shenhar <tatias@codeaurora.org>
Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
Signed-off-by: Ritesh Harjani <riteshh@codeaurora.org>
Signed-off-by: Veerabhadrarao Badiganti <vbadigan@codeaurora.org>
Signed-off-by: Bao D. Nguyen <nguyenb@codeaurora.org>
Signed-off-by: Can Guo <cang@codeaurora.org>
Signed-off-by: Sayali Lokhande <sayalil@codeaurora.org>
Co-Developed-by: Ram Prakash Gupta <rampraka@codeaurora.org>
Signed-off-by: Ram Prakash Gupta <rampraka@codeaurora.org>
---
drivers/mmc/core/host.c | 63 +++++++++++++++++++++++++++++++++++++++++++++
include/linux/mmc/card.h | 7 +++++
include/linux/mmc/host.h | 66 ++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 136 insertions(+)

diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
index 105b7a7..672f2d6 100644
--- a/drivers/mmc/core/host.c
+++ b/drivers/mmc/core/host.c
@@ -161,6 +161,44 @@ static void mmc_retune_timer(struct timer_list *t)
mmc_retune_needed(host);
}

+static int mmc_dt_get_array(struct device *dev, const char *prop_name,
+ u32 **out, int *len, u32 size)
+{
+ int ret = 0;
+ struct device_node *np = dev->of_node;
+ size_t sz;
+ u32 *arr = NULL;
+
+ if (!of_get_property(np, prop_name, len)) {
+ ret = -EINVAL;
+ goto out;
+ }
+ sz = *len = *len / sizeof(*arr);
+ if (sz <= 0 || (size > 0 && (sz > size))) {
+ dev_err(dev, "%s invalid size\n", prop_name);
+ ret = -EINVAL;
+ goto out;
+ }
+
+ arr = devm_kcalloc(dev, sz, sizeof(*arr), GFP_KERNEL);
+ if (!arr) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ ret = of_property_read_u32_array(np, prop_name, arr, sz);
+ if (ret < 0) {
+ dev_err(dev, "%s failed reading array %d\n", prop_name, ret);
+ goto out;
+ }
+ *out = arr;
+out:
+ if (ret)
+ *len = 0;
+ return ret;
+
+}
+
/**
* mmc_of_parse() - parse host's device-tree node
* @host: host whose node should be parsed.
@@ -173,10 +211,12 @@ static void mmc_retune_timer(struct timer_list *t)
int mmc_of_parse(struct mmc_host *host)
{
struct device *dev = host->parent;
+ struct device_node *np = dev->of_node;
u32 bus_width, drv_type, cd_debounce_delay_ms;
int ret;
bool cd_cap_invert, cd_gpio_invert = false;
bool ro_cap_invert, ro_gpio_invert = false;
+ const char *lower_bus_speed = NULL;

if (!dev || !dev_fwnode(dev))
return 0;
@@ -340,6 +380,29 @@ int mmc_of_parse(struct mmc_host *host)
device_property_read_u32(dev, "post-power-on-delay-ms",
&host->ios.power_delay_ms);

+ if (mmc_dt_get_array(dev, "devfreq,freq-table",
+ &host->clk_scaling.pltfm_freq_table,
+ &host->clk_scaling.pltfm_freq_table_sz, 0))
+ pr_debug("%s: no clock scaling frequencies were supplied\n",
+ dev_name(dev));
+ else if (!host->clk_scaling.pltfm_freq_table ||
+ host->clk_scaling.pltfm_freq_table_sz)
+ dev_info(dev, "bad dts clock scaling frequencies\n");
+
+ /*
+ * Few hosts can support DDR52 mode at the same lower
+ * system voltage corner as high-speed mode. In such
+ * cases, it is always better to put it in DDR
+ * mode which will improve the performance
+ * without any power impact.
+ */
+ if (!of_property_read_string(np, "scaling-lower-bus-speed-mode",
+ &lower_bus_speed)) {
+ if (!strncmp(lower_bus_speed, "DDR52", strlen(lower_bus_speed)))
+ host->clk_scaling.lower_bus_speed_mode |=
+ MMC_SCALING_LOWER_DDR52_MODE;
+ }
+
return mmc_pwrseq_alloc(host);
}

diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index 9b6336a..8b577a1 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -244,6 +244,12 @@ struct mmc_card {
struct mmc_host *host; /* the host this device belongs to */
struct device dev; /* the device */
u32 ocr; /* the current OCR setting */
+ unsigned long clk_scaling_lowest; /* lowest scaleable
+ * frequency
+ */
+ unsigned long clk_scaling_highest; /* highest scaleable
+ * frequency
+ */
unsigned int rca; /* relative card address of device */
unsigned int type; /* card type */
#define MMC_TYPE_MMC 0 /* MMC card */
@@ -306,6 +312,7 @@ struct mmc_card {
struct dentry *debugfs_root;
struct mmc_part part[MMC_NUM_PHY_PARTITION]; /* physical partitions */
unsigned int nr_parts;
+ unsigned int part_curr;

unsigned int bouncesz; /* Bounce buffer size */
struct workqueue_struct *complete_wq; /* Private workqueue */
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index ba70338..bfb47d6 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -9,6 +9,7 @@

#include <linux/sched.h>
#include <linux/device.h>
+#include <linux/devfreq.h>
#include <linux/fault-inject.h>

#include <linux/mmc/core.h>
@@ -268,9 +269,72 @@ struct mmc_ctx {
struct task_struct *task;
};

+enum dev_state {
+ DEV_SUSPENDING = 1,
+ DEV_SUSPENDED,
+ DEV_RESUMED,
+};
+
+enum mmc_load {
+ MMC_LOAD_HIGH,
+ MMC_LOAD_LOW,
+};
+
+/**
+ * struct mmc_devfeq_clk_scaling - main context for MMC clock scaling logic
+ *
+ * @lock: spinlock to protect statistics
+ * @devfreq: struct that represent mmc-host as a client for devfreq
+ * @devfreq_profile: MMC device profile, mostly polling interval and callbacks
+ * @ondemand_gov_data: struct supplied to ondemmand governor (thresholds)
+ * @state: load state, can be HIGH or LOW. used to notify mmc_host_ops callback
+ * @start_busy: timestamped armed once a data request is started
+ * @measure_interval_start: timestamped armed once a measure interval started
+ * @devfreq_abort: flag to sync between different contexts relevant to devfreq
+ * @skip_clk_scale_freq_update: flag that enable/disable frequency change
+ * @freq_table_sz: table size of frequencies supplied to devfreq
+ * @freq_table: frequencies table supplied to devfreq
+ * @curr_freq: current frequency
+ * @polling_delay_ms: polling interval for status collection used by devfreq
+ * @upthreshold: up-threshold supplied to ondemand governor
+ * @downthreshold: down-threshold supplied to ondemand governor
+ * @need_freq_change: flag indicating if a frequency change is required
+ * @is_busy_started: flag indicating if a request is handled by the HW
+ * @enable: flag indicating if the clock scaling logic is enabled for this host
+ * @is_suspended: to make devfreq request queued when mmc is suspened
+ */
+struct mmc_devfeq_clk_scaling {
+ spinlock_t lock;
+ struct devfreq *devfreq;
+ struct devfreq_dev_profile devfreq_profile;
+ struct devfreq_simple_ondemand_data ondemand_gov_data;
+ enum mmc_load state;
+ ktime_t start_busy;
+ ktime_t measure_interval_start;
+ atomic_t devfreq_abort;
+ bool skip_clk_scale_freq_update;
+ int freq_table_sz;
+ int pltfm_freq_table_sz;
+ u32 *freq_table;
+ u32 *pltfm_freq_table;
+ unsigned long total_busy_time_us;
+ unsigned long target_freq;
+ unsigned long curr_freq;
+ unsigned long polling_delay_ms;
+ unsigned int upthreshold;
+ unsigned int downthreshold;
+ unsigned int lower_bus_speed_mode;
+#define MMC_SCALING_LOWER_DDR52_MODE 1
+ bool need_freq_change;
+ bool is_busy_started;
+ bool enable;
+ bool is_suspended;
+};
+
struct mmc_host {
struct device *parent;
struct device class_dev;
+ struct mmc_devfeq_clk_scaling clk_scaling;
int index;
const struct mmc_host_ops *ops;
struct mmc_pwrseq *pwrseq;
@@ -369,6 +433,7 @@ struct mmc_host {
#define MMC_CAP2_CQE_DCMD (1 << 24) /* CQE can issue a direct command */
#define MMC_CAP2_AVOID_3_3V (1 << 25) /* Host must negotiate down from 3.3V */
#define MMC_CAP2_MERGE_CAPABLE (1 << 26) /* Host can merge a segment over the segment size */
+#define MMC_CAP2_CLK_SCALE (1 << 27) /* Allow dynamic clk scaling */

int fixed_drv_type; /* fixed driver type for non-removable media */

@@ -462,6 +527,7 @@ struct mmc_host {
bool cqe_enabled;
bool cqe_on;

+ atomic_t active_reqs;
unsigned long private[0] ____cacheline_aligned;
};

--
1.9.1
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