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Commit 8bb7d5a6 authored by Lina Iyer's avatar Lina Iyer
Browse files

drivers: mailbox: qti_tcs: Use udelay instead of cpu_relax 



On newer SoCs cpu_relax may be mapped to just pause or mapped to noop.
Use udelay(1) instead to allow CPU to relinquish control really.

Change-Id: Iaf10a82e83974b69052cc4bbf4fa3e069ad556c4
Signed-off-by: default avatarLina Iyer <ilina@codeaurora.org>
parent 16496105

drivers/mailbox/qti-tcs.c

+6 −5
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ 


#include <linux/atomic.h>

#include <linux/bitmap.h>

#include <linux/delay.h>

#include <linux/interrupt.h>

#include <linux/jiffies.h>

#include <linux/kernel.h>
@@ -226,7 +227,7 @@ static inline void write_tcs_reg_sync(void __iomem *base, int reg, int m, int n, 
		write_tcs_reg(base, reg, m, n, data);

		if (data == read_tcs_reg(base, reg, m, n))

			break;

		cpu_relax();

		udelay(1);

	} while (1);

}
@@ -590,7 +591,7 @@ static void wait_for_req_inflight(struct tcs_drv *drv, struct tcs_mbox *tcs, 
		}

retry:

		if (!is_free)

			cpu_relax();

			udelay(1);

	} while (!is_free);

}
@@ -606,7 +607,7 @@ static int find_free_tcs(struct tcs_mbox *tcs) 
		}

		if (++m >= tcs->num_tcs)

			m = 0;

		cpu_relax();

		udelay(1);

	} while (1);



	return slot;
@@ -733,7 +734,7 @@ static int tcs_mbox_write(struct mbox_chan *chan, struct tcs_mbox_msg *msg, 
		wait_for_req_inflight(drv, tcs, msg);

		/* If the TCS is busy there is nothing to do but spin wait */

		while (!tcs_is_free(drv, m))

			cpu_relax();

			udelay(1);

	}



	/* Write to the TCS or AMC */
@@ -771,7 +772,7 @@ static int tcs_mbox_invalidate(struct mbox_chan *chan) 
			m = i + tcs->tcs_offset;

			spin_lock(&tcs->tcs_m_lock[i]);

			while (!tcs_is_free(drv, m))

				cpu_relax();

				udelay(1);

			__tcs_buffer_invalidate(drv->reg_base, m);

			spin_unlock(&tcs->tcs_m_lock[i]);

		}