linux-kernel - [PATCH 4.4 10/43] clk: bcm2835: Protect sections updating shared registers

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Date:   Tue, 27 Mar 2018 18:27:14 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Boris Brezillon <boris.brezillon@...tlin.com>,
        Eric Anholt <eric@...olt.net>, Stephen Boyd <sboyd@...nel.org>
Subject: [PATCH 4.4 10/43] clk: bcm2835: Protect sections updating shared registers

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Boris Brezillon <boris.brezillon@...tlin.com>

commit 7997f3b2df751aab0b8e60149b226a32966c41ac upstream.

CM_PLLx and A2W_XOSC_CTRL registers are accessed by different clock
handlers and must be accessed with ->regs_lock held.
Update the sections where this protection is missing.

Fixes: 41691b8862e2 ("clk: bcm2835: Add support for programming the audio domain clocks")
Cc: <stable@...r.kernel.org>
Signed-off-by: Boris Brezillon <boris.brezillon@...tlin.com>
Reviewed-by: Eric Anholt <eric@...olt.net>
Signed-off-by: Stephen Boyd <sboyd@...nel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/clk/bcm/clk-bcm2835.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/drivers/clk/bcm/clk-bcm2835.c
+++ b/drivers/clk/bcm/clk-bcm2835.c
@@ -912,8 +912,10 @@ static int bcm2835_pll_on(struct clk_hw
 		     ~A2W_PLL_CTRL_PWRDN);
 
 	/* Take the PLL out of reset. */
+	spin_lock(&cprman->regs_lock);
 	cprman_write(cprman, data->cm_ctrl_reg,
 		     cprman_read(cprman, data->cm_ctrl_reg) & ~CM_PLL_ANARST);
+	spin_unlock(&cprman->regs_lock);
 
 	/* Wait for the PLL to lock. */
 	timeout = ktime_add_ns(ktime_get(), LOCK_TIMEOUT_NS);
@@ -997,9 +999,11 @@ static int bcm2835_pll_set_rate(struct c
 	}
 
 	/* Unmask the reference clock from the oscillator. */
+	spin_lock(&cprman->regs_lock);
 	cprman_write(cprman, A2W_XOSC_CTRL,
 		     cprman_read(cprman, A2W_XOSC_CTRL) |
 		     data->reference_enable_mask);
+	spin_unlock(&cprman->regs_lock);
 
 	if (do_ana_setup_first)
 		bcm2835_pll_write_ana(cprman, data->ana_reg_base, ana);