linux-kernel - [RESEND][PATCH] clk: at91: generated: Truncate divisor to GENERATED_MAX

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Message-ID: <20190625091002.27567-1-codrin.ciubotariu@microchip.com>
Date:   Tue, 25 Jun 2019 12:10:02 +0300
From:   Codrin Ciubotariu <codrin.ciubotariu@...rochip.com>
To:     <sboyd@...nel.org>, <nicolas.ferre@...rochip.com>,
        <alexandre.belloni@...tlin.com>, <ludovic.desroches@...rochip.com>
CC:     <linux-clk@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>,
        Codrin Ciubotariu <codrin.ciubotariu@...rochip.com>
Subject: [RESEND][PATCH] clk: at91: generated: Truncate divisor to GENERATED_MAX_DIV + 1

In clk_generated_determine_rate(), if the divisor is greater than
GENERATED_MAX_DIV + 1, then the wrong best_rate will be returned.
If clk_generated_set_rate() will be called later with this wrong
rate, it will return -EINVAL, so the generated clock won't change
its value. Do no let the divisor be greater than GENERATED_MAX_DIV + 1.

Fixes: 8c7aa6328947 ("clk: at91: clk-generated: remove useless divisor loop")
Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@...rochip.com>
Acked-by: Nicolas Ferre <nicolas.ferre@...rochip.com>
Acked-by: Ludovic Desroches <ludovic.desroches@...rochip.com>
---

- The email-server was converting my patches to base64, so I resend it
  using another server;
- Added acked-bys from Nicolas and Ludovic;

 drivers/clk/at91/clk-generated.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/clk/at91/clk-generated.c b/drivers/clk/at91/clk-generated.c
index 5f18847965c1..290cffe35deb 100644
--- a/drivers/clk/at91/clk-generated.c
+++ b/drivers/clk/at91/clk-generated.c
@@ -146,6 +146,8 @@ static int clk_generated_determine_rate(struct clk_hw *hw,
 			continue;
 
 		div = DIV_ROUND_CLOSEST(parent_rate, req->rate);
+		if (div > GENERATED_MAX_DIV + 1)
+			div = GENERATED_MAX_DIV + 1;
 
 		clk_generated_best_diff(req, parent, parent_rate, div,
 					&best_diff, &best_rate);
-- 
2.20.1